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2005-9285 G ,JDATE GEOTECHNICAL EVALUATION AND BLUFF STL PROPOSED ADDITION, 330 NEPTUNE AVENUE CITY OF ENCINITAS, SAN DIEGO COUNTY, CALIFORNIA FOR -- MR. JUSTIN GOODING AND MR. KARL WEINGARTEN c/o MR. STEVEN LOMBARDI, ARCHITECT 1889 BACON STREET, #8 SAN DIEGO, CALIFORNIA 92107 s, Geotechnical • Geologic • Environmental UPDATE GEOTECHNICAL EVALUATION AND BLUFF STUDY PROPOSED ADDITION, 330 NEPTUNE AVENUE CITY OF ENCINITAS, SAN DIEGO COUNTY, CALIFORNIA FOR _. MR. JUSTIN GOODING AND MR. KARL WEINGARTEN c/o MR. STEVEN LOMBARDI, ARCHITECT 1889 BACON STREET, #8 -- SAN DIEGO, CALIFORNIA 92107 W.O. 4362-A-SC JUNE 28, 2004 S9 Geotechnical * Geologic - Environmental 5741 Palmer Way Carlsbad, California 92008 - (760) 438-3155 - FAX (760) 931-0915 June 28, 2004 W.O. 4362-A-SC Mr. Justin Gooding and Mr. Karl Weingarten c/o Mr. Steven Lombardi, Architect 1889 Bacon Street, #8 San Diego, California 92107 Attention: Mr. Steve Lombardi Subject: Update Geotechnical Evaluation and Bluff Study, Proposed Addition, 330 Neptune Avenue, City of Encinitas, San Diego County, California Dear Mr. Lombardi: In accordance with your request, GeoSoils, Inc. (GSI) is pleased to present the results of our update geotechnical evaluation of the subject site. The purpose of our investigation was to evaluate the geologic and geotechnical conditions of the upper bluff,including bluff stability, so that recommendations for foundation design and earthwork parameters could be provided for the proposed addition. EXECUTIVE SUMMARY Based on our review of existing, published documents (see Appendix A),field exploration, geologic and geotechnical engineering analysis, the proposed development appears feasible from a soils engineering and geologic viewpoint, provided that the recommendations presented in the text of this report are properly incorporated into the design and construction of the project. The most significant elements of our study are summarized below: • Terrace deposits overlying the Torrey Sandstone were encountered during our previous investigation (GSI, 2000). These earth materials are typically porous, loose,and subject to consolidation,at least in the near-surface. In the near-surface, they are considered potentially compressible in their existing state, and have a moderate potential for hydrocompaction; thus, terrace deposits onsite may settle appreciably under additional fill, foundation, or improvement loadings. Recommendations for the treatment of surficial terrace deposits are presented in the earthwork section of this report. • Based on published and accepted erosion rates by the City, the existing slope is surficially unstable. Gross stability analyses, however, indicate generally gross stable conditions for this slope in its existing state, provided the bluff doesn't retreat (an unrealistic assumption). Based on the proposed loading conditions,the results from our slope stability analysis indicate that proposed additional structures should be located at least 50 feet (landward)from the edge of the existing bluff and behind the daylight line. The actual location of the top of bluff should be determined by the design civil engineer. • It should be noted that future long-term bluff retreat (up to 67.5 feet in 75 years) may jeopardize the stability of any existing or proposed improvements located 67.5 feet landward of the top of the coastal bluff, based on the available data. Failures within this zone and distress to any improvements should be anticipated, and disclosed to all interested parties. Further, a failure within this zone will render all slope stability analyses performed to date invalid, and will necessitate a re-evaluation. Laboratory testing performed in the preparation of GSI (2000) indicates that site soils are very low expansive. Conventional foundations for the proposed addition may be utilized for this type of soil condition. Any new foundations should be constructed independently from any existing foundations. An expansion/construction joint,designed bythe project structural engineer should be provided between the existing and proposed improvements to permit relative movement. • Subsurface and surface water,as discussed previously,are not anticipated to affect - site development, provided that the recommendations contained in this report are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along fill/bedrock contacts and along zones of contrasting permeabilities should not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. The groundwater conditions observed and opinions generated were those at the time of our investigation. Conditions may change with the introduction of irrigation, rainfall, or other factors that were not obvious at the time of our investigation. • It should be noted that any structures placed within the 50-foot setback zone from the top of the bluff, may also be subject to instability and distress and/or may jeopardize the stability of the coastal bluff. If requested, this office could provide mitigation recommendations(i.e.structural tiebacks),concerning bluff stability if any future improvements are proposed within the recommended 50-foot structural setback zone from the top of bluff. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC Fi1e:e:lwp7\4300\4362a.uge Page Two GeoSoils, Inc. • The geotechnical design parameters provided herein should be considered during construction by the project structural engineer and/or architect. We appreciate the opportunity to be of service. If you have any questions pertaining to this report, please contact us at (760) 438-3155. Respectfully submitted, Geosoils, Inc. _ an Boehmer Staff Geologist ,e FR,q�,�`D��N 1340 . ohn Franklin a�j +.og'st p�` David W. Skelly Engineering Geolo �# Civil Engineer, RCE 47857 RB/JPF/DWS/jh Distribution: (4) Addressee Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc Fi1e:e:\wp7\4300\4362a.uge Page Three GeoSoils, Inc. TABLE OF CONTENTS SCOPEOF SERVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SITE DESCRIPTION AND PROPOSED DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . 1 FIELDSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 REGIONAL GEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 COASTAL BLUFF GEOMORPHOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 SITE GEOLOGIC UNITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Artificial Fill - Undocumented (Not mapped) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Beach Deposits (Map Symbol - Qb) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • • • • 4 - Terrace Deposits (Map Symbol - Qt) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Torrey Sandstone (Map Symbol -Tt) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 GEOLOGIC STRUCTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 FAULTING AND REGIONAL SEISMICITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 RegionalFaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Seismic Shaking Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SECONDARY SEISMIC HAZARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 GROUNDWATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 _- LONG-TERM SEA LEVEL CHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 COASTAL-BLUFF RETREAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MarineErosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Mechanical and Biological Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Water Depth, Wave Height, and Platform Slope . . . . . . . . . . . . . . . . . . . 10 Marine Erosion at the Cliff-Platform Junction . . . . . . . . . . . . . . . . . . . . . . 10 Subaerial Erosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 SlopeDecline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 LABORATORY TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Moisture-Density Relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 _. Laboratory Standard-Maximum Dry Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Expansion Index Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Direct Shear Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 GeoSoils, Inc. Consolidation Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Corrosivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SLOPE STABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SLOPE STABILITY ANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Gross Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Surficial Slope Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 SlopeSetbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 DISCUSSION AND PRELIMINARY CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Artificial Fill and Terrace Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Slope Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Subsurface and Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Corrosivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 RECOMMENDATIONS-EARTHWORK CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . 17 Grading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Removals (Unsuitable Materials) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Overexcavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Fill Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Erosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Subdrain Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 PRELIMINARY RECOMMENDATIONS - FOUNDATIONS . . . . . . . . . . . . . . . . . . . . . . . 19 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I - . 19 Foundation Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Foundation Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Footing Setbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Very Low Expansion Potential (E.I. 0 to 20) . . . . . . . . . . . . . . . . . . . . . . . 21 WALL DESIGN PARAMETERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Conventional Retaining Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Restrained Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Cantilevered Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Retaining Wall Backfill and Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Wall/Retaining Wall Footing Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Mr.Justin Gooding and Mr. Karl Weingarten Table of Contents F11e:eAwp7\4300\4362a.uge Page ii GeoSoils, Inc. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 27 SlopeCreep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Top of Slope Walls/Fences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS . . . . . . . . . . . . . . . . . . . . . . . 29 DEVELOPMENT CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Slope Deformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Slope Maintenance and Planting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Drainage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Toe of Slope Drains/Toe Drains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Erosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Landscape Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Gutters and Downspouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Subsurface and Surface Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Site Improvements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 - Tile Flooring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Additional Grading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Footing Trench Excavation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Trenching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Utility Trench Backfill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Y SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 OTHER DESIGN PROFESSIONALS/CONSULTANTS . . . . . . . . . . . . . . . . . . . . . . . . . . 3 PLANREVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Mr.Justin Gooding and Mr. Karl Weingarten Table of Contents Fi1e:e:\wp7\4300\4362a.uge Page iii GeoSoils, Inc. FIGURES: Figure 1 - Site Location Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 -. Figure 2 - California Fault Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Detail - Typical Retaining Wall Backfill and Drainage Detail . . . . . . . . . . . . . . . 24 Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain . . . . . . . 25 Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill . . . . . . . . . . . 26 Detail 4 - Schematic Toe Drain Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Detail 5 - Subdrain Along Retaining Wall Detail . . . . . . . . . . . . . . . . . . . . . . . . . 35 ATTACHMENTS: Appendix A - References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text Appendix B - Boring Logs (GSI, 2000) . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text Appendix C - Seismicity Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text w Appendix D - Laboratory Test Results (GSI, 2000) . . . . . . . . . . . . . . . Rear of Text Appendix E - Slope Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text Appendix F - General Earthwork and Grading Guidelines . . . . . . . . . Rear of Text Appendix G - Guidelines for the Homeowner . . . . . . . . . . . . . . . . . . . Rear of Text Plate 1 - Geotechnical Map . . . . . . . . . . . . . . . . . . . . . . . . . Rear of Text in Folder Plate 2 - Geologic Cross Section A-A. . . . . . . . . . . . . . . . . . Rear of Text in Folder Mr. Justin Gooding and Mr. Karl Weingarten Table of Contents _g File:e:\wp7\4300\4362a.uge Page iv GeoSoils, Inc. UPDATE GEOTECHNICAL EVALUATION AND BLUFF STUDY PROPOSED ADDITION, 330 NEPTUNE AVENUE CITY OF ENCINITAS, SAN DIEGO COUNTY, CALIFORNIA SCOPE OF SERVICES The scope of our services has included the following: 1. Review of readily available published literature and maps of the vicinity, including review of stereoscopic aerial photographs and our prior report for the site (Appendix A). 2. Site geologic reconnaissance. 3. Boring Logs from GSI (2000) are included as Appendix B. 4. Seismicity analyses (Appendix C) 5. Laboratory data from GSI (2000) is included as Appendix D. 6. Slope stability analyses (Appendix E). 7. Appropriate engineering and geologic analyses of data collected, and preparation of this report and accompaniments SITE DESCRIPTION AND PROPOSED DEVELOPMENT The study area is a coastal bluff located above the beach in Encinitas, California (see Site Location Map, Figure 1). A single-family; wood-frame residence exists on a rectangular-shaped parcel that fronts on the beach. Access to the beach below the bluff on the site is via public stairs west of El Portal Street, adjoining and north of the site. Slope gradients of the approximately 75-foot high bluff range up to 50 to 60 degrees in the upper portions of the bluff, and near vertical in the lower portion of the bluff (Torrey Sandstone). Minor seepage was observed in the bluff along the contact between overlying terrace deposits and the Torrey Sandstone. Based on conversations with Mr. Steven Lombardi, Architect, proposed development on the site will consist of the construction of a three-story, 230 square foot addition to be constructed in the general location of the existing, eastern patio. It is anticipated that the proposed addition will utilize continuous footings and slab-on-grade, with wood-frame and/or masonry block construction. Building loads are assumed to be typical for this type of relatively light construction. GeoSoils, Inc. ,, � • :,.,�` iii% <: �/, - Off AWRF ra i i�,�k x W.O. JL N • • . . . � . . FIELD STUDIES Site specific field studies were previously conducted by GSI on April 19, 2000 and consisted of geologic mapping of the existing geologic conditions in the bluff, and the drilling of two exploratory borings for evaluation of near-surface soil and geologic - conditions. The boring was logged by a geologist from our firm who collected representative bulk and undisturbed samples from the boring for appropriate laboratory testing. The Boring Logs are presented in Appendix B. The location of the borings are presented on Plates 1 and 2. REGIONAL GEOLOGY The site is located in Peninsular Ranges geomorphic province of California. The Peninsular Ranges are characterized by northwest-trending, steep, elongated ranges and valleys. The Peninsular Ranges extend north to the base of the San Gabriel Mountains and south into Mexico to Baja California. The province is bounded by the east-west trending Transverse Ranges geomorphic province to the north and northeast, by the Colorado Desert geomorphic province to the southeast, and by the Continental Borderlands geomorphic province to the west. In the Peninsular Ranges, sedimentary and volcanic units discontinuously mantle the crystalline bedrock, alluvial deposits have filled in the lower valley areas, and young marine sediments are currently being deposited/eroded in the coastal and beach areas. COASTAL BLUFF GEOMORPHOLOGY The typical coastal-bluff profile may be divided into three zones;the shore platform,a lower near-vertical cliff surface termed the sea cliff, and an upper bluff slope generally ranging in inclination between about 50 and 65 degrees. The bluff top is the boundary between the upper bluff and coastal terrace. Offshore from the sea cliff is an area of indefinite extent termed the near-shore zone. The bedrock surface in the near-shore zone,which extends out to sea from the base of the sea cliff, is the shore platform. As pointed out by Trenhaile (1987), worldwide, the shore platform may vary in inclination from near horizontal to as steep as 3:1 (horizontal to - vertical [h:v]). The boundary between the sea cliff (the lower vertical and near-vertical section of the bluff) and the shore platform is called the cliff-platform junction, or sometimes the shoreline angle. Within the near-shore zone is a subdivision called the inshore zone, beginning where the waves begin to break. This boundary varies with time because the point at which waves begin to break changes dramatically with changes in wave size and tidal level. During low tides, large waves will begin to break further away from shore. During high tides, waves Mr.Justin Gooding and Mr. Karl Weingarten W.O.4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 3 GeoSoils, Inc. may not break at all or they may break directly on the lower cliff. Closer to shore is the foreshore zone, that portion of the shore lying between the upper limit of wave wash at high tide and the ordinary low water mark. Both of these boundaries often lie on a sand or cobble beach. In this case of a shoreline with a bluff, the foreshore zone extends from low water to the lower face of the bluff. Emery and Kuhn (1982)developed a global system of classification of coastal bluff profiles, and applied that system to the San Diego County coastline from San Onofre State Park to the southerly tip of Point Loma. Emery and Kuhn (1982), designated this portion of the coast as "active" and "Type C (c)," as the surficial deposits are relatively thick with respect to the underlying bedrock. The letter "C" designates coastal bluffs having a resistant geologic formation at the bottom of the bluff and less resistant cap on the remaining height of the bluff. The relative effectiveness of marine erosion compared to subaerial erosion of the bluff produces a characteristic profile. Extremely rapid marine erosion produces a less gently-sloping and steeper upper bluff. The letter"(c)" indicates that the long-term rate of subaerial erosion is about equal to that of marine erosion. SITE GEOLOGIC UNITS Three earth materials units were observed and/or encountered in the vicinity of the subject site. Mappable units are shown on Plate 1. A general description of each material type is presented as follows, from youngest to oldest. Artificial Fill - Undocumented (Not mapped) Undocumented artificial fill was encountered to a depth of at least 4 feet. These soils consist of brown, moist to wet, loose, silty sand. The fill is typically porous and loose and is considered potentially compressible and unsuitable for support of additional fill, settlement-sensitive improvements, or structures in its existing state. Beach Deposits (Map Symbol - Qb) A transient shingle beach composed of rounded cobbles and sand exists at the base of the bluff. The beach deposits will not be encountered in the vicinity of the proposed development. Terrace Deposits (Map Symbol - Qt) Our field and drilling observations and literature review indicate that the upper sloping portion of the sea bluff is composed primarily of Pleistocene-age terrace deposits consisting of relatively sandy sediments, weakly cemented with iron oxide, that rest upon a yet older wave-cut terrace, also Pleistocene in age. The terrace deposits make up the sea bluff primarily between approximately 25 feet Mean Sea Level (MSL) to near the top Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 4 GeoSoiis, Inc. of the bluff. The near surface terrace deposits are generally loose and potentially compressible, and will require some removal and recompaction. Torrey Sandstone (Map Symbol - Tt) The Eocene-age Torrey Sandstone underlies the terrace deposits on the site. These materials were observed in the lower portions of the coastal bluff. Onsite, this formation consists of slightly silty,fine-to coarse-grained sandstone. The materials were moderately cemented and micaceous. This formation is described (Kennedy and Peterson, 1975) as an arkosic sandstone,subangular, and moderately well indurated. The Torrey Sandstone is believed to have been formed along a submerging coast on an arcuate barrier beach. This beach enclosed and later transgressed over lagoonal sediments. Its deposition ceased when submergence slowed and the shoreline retreated. GEOLOGIC STRUCTURE The terrace deposits are generally massively to thickly-bedded, and are relatively flat lying to gently inclined to the southwest. The Torrey Sandstone is generally well bedded and cross bedded,and subhorizontal. Vertical jointing was mapped within this unit, parallel to the bluff. FAULTING AND REGIONAL SEISMICITY Regional Faults Our review indicates that there are no known active faults crossing this site within the area proposed for development, and the site is not within an Earthquake Fault Zone (Hart and Bryant, 1997). However,the site is situated in an area of active as well as potentially active faulting. These include, but are not limited to:the San Andreas fault;the San Jacinto fault; the Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood - Rose Canyon fault zone. The location of these, and other major faults relative to the site, are indicated on Figure 2 (California Fault Map). The possibility of ground acceleration, or shaking at the site, may be considered as approximately similar to the southern California region as a whole. Major active fault zones that may have a significant affect on the site, should they experience activity, are listed in the following table (modified from Blake, 2000a): Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 5 GeoSoiis, Inc. CALIFORNIA FAULT MAP GOODING/WEINGARTEN 1100 1000 900 800 700 600 500 400 300 200 100 •��o o • b SI 0 -100 -400 -300 -200 -100 0 100 200 300 400 500 600 W.O. 4362-A-SC Figure 2 GeoSoils, Inc. APPROXIMATE DISTANCE ABBREVIATED FAULT NAME MILES KM Rose Canyon 3.2 (5.1) Newport-Inglewood (Offshore) 10.4 (16.8) Coronado Bank 17.7 (28.5) Elsinore-Temecula 27.9 (44-9) F-Julian 27.9 (44.9) erdes 40.3 (64.8) -Glen Ivy 40.9 (65.8) ake Valle 42.6 (68.5) Seismicity The acceleration-attenuation relations of Bozorgnia, Campbell, and Niazi (1999) and Campbell and Bozorgnia (1997 Revised) have been incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed by Thomas F. Blake (2000a),which performs deterministic seismic hazard analyses using digitized California faults as earthquake sources. The program estimates the closest distance between each fault and a given site. If a fault is found to be within a user-selected radius,the program estimates peak horizontal ground acceleration that may occur at the site from an upper bound ("maximum credible") earthquake on that fault. Site acceleration (g) is computed by one or more user-selected acceleration-attenuation relations that are contained in EQFAULT. Based on the EQFAULT program, peak horizontal ground accelerations from an upper bound event at the site may be on the order of 0.65g to 0.80g. The computer printouts of portions of the EQFAULT program are included within Appendix C. Historical site seismicity was evaluated with the acceleration-attenuation relations of Campbell and Bozorgnia (1997 Revised) and the computer program EQSEARCH (Blake, 2000b). This program performs a search of the historical earthquake records for magnitude 5.0 to 9.0 seismic events within a 100-mile radius, between the years 1800 to December 31, 2003. Based on the selected acceleration-attenuation relationship, a peak horizontal ground acceleration is estimated, which may have effected the site during the -- specific event listed. Based on the available data and the attenuation relationship used, the estimated maximum (peak) site acceleration during the period 1800 to December 31, 2003, was 0.65g. Site specific probability of exceeding various peak horizontal ground accelerations and a seismic recurrence curve are also estimated/generated from the historical data. Computer printouts of the EQSEARCH program are presented in Appendix C. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 7 GeoSoils, Inc. A probabilistic seismic hazards analyses was performed using FRISKSP (Blake, 2000c), which models earthquake sources as three-dimensional planes and evaluates the site specific probabilities of exceedance for given peak acceleration levels or pseudo-relative velocity levels. Based on a review of this data, and considering the relative seismic activity of the southern California region, a peak horizontal ground acceleration of 0.408 was calculated. This value was chosen as it corresponds to a 10 percent probability of exceedance in 50 years (or a 475-year return period). Computer printouts of the FRISKSP program are included in Appendix C. Seismic Shaking Parameters Based on the site conditions, Chapter 16 of the Uniform Building Code ([UBC], International Conference of Building Officials [ICBO], 1997) seismic parameters are provided in the following table: Seismic zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 -- Soil Profile Type (per Table 16-J*) SC, So Seismic Coefficient C. (per Table 16-Q*) 0.40 NA, 0.44 NA Seismic Coefficient C„(per Table 16-R*) 0.56 N,,, 0.64 Nv Near Source Factor NA (per Table 16-S*) 1.0 Near Source Factor N„ (per Table 16-T*) 1.19 Seismic Source Type (per Table 16-U*) B Distance to Seismic Source 3.2 mi. (5.1 km) Upper Bound Earthquake MW 6.9 * Figure and table references from Chapter 16 of the UBC (ICBO, 1997). ** Dual classifications due to varying earth material types in the upper 100 feet underlying the site. SECONDARY SEISMIC HAZARDS _. Potential secondary seismic related hazards such as ground rupture due to faulting, liquefaction, dynamic settlement,seiche and tsunami, are often associated with a seismic event. Since no active faults are known to cross the site, the potential for ground rupture - is considered low. Based on review of available data,the potential for liquefaction to affect the site appears to be low. The potential for dynamic settlement and associated distress to affect the site appears to be low to moderate. Due to the elevation of the residential structural in regard to the ocean elevation,the potential for seiche or tsunami to affect that area is considered low. However, significant tidal waves generated from a seismic event Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Re:e:\wp7\4300\4362a.uge Page 8 GeoSoils, Inc. could affect the lower portion of the site and affect overall bluff stability, possibly even affecting the existing proposed structures. GROUNDWATER Groundwater was observed seeping from the bluff slope along the contact of the Torrey Sandstone with the overlying terrace deposits and in our hollow-stem auger boring at this contact. Groundwater seepage exiting the bluff face on top of the bedrock tend to cause spring sapping and solution cavities along joints,and bedding planes,locally accelerating marine erosion where these conditions exist. In addition, groundwater may infiltrate bluff-parallel joints, which form naturally behind and parallel to the bluff face as a result of near-surface, stress-relief. Perched groundwater may also occur at pad grade. LONG-TERM SEA LEVEL CHANGE Long-term (geologic) sea level change is likely the major factor determining coastal evolution. Three general sea level conditions are recognized:rising,falling and stationary. -- The rising and falling stages result in massive sediment release and transport, while the stationary stage allows time for adjustment and reorganization towards equilibrium. Major changes in sea level for the Quaternary period were caused by worldwide climate fluctuation resulting in at least 17 glacial and interglacial stages in the last 800,000 years and many before then. Worldwide sea level rise associated with the melting of glaciers is commonly referred to as "glacio-eustatic" or "true" sea level rise. During the past 200,000 years, eustatic sea level has ranged from more than ±350 feet below the present to possibly as high as about ±31 feet above. Sea level changes during the last 18,000 years have resulted in an approximately 400-foot rise in sea level when relatively cold global climates of the Wisconsin ice age started to become warmer, melting a substantial portion of the continental ice caps. Sea level data show a relatively rapid rise of about 1 meter per century from about 18,000 years before present to about 8,000 years ago. About 8,000 years ago,the rate of sea level rise slowed, ultimately to a relatively constant rate of about 10 centimeters per century since about 6,000 years ago (Inman, 1976). More importantly, the world coastline, including that of California and the subject site, has been shaped largely within this 6,000-year period,with the sea at or within about 16 feet of its present level. COASTAL-BLUFF RETREAT Most of San Diego County's coastline has experienced a measurable amount of erosion in the last 20 to 30 years,with more rapid erosion occurring during periods of heavy storm surf (Kuhn and Shepard, 1984). The entire base of the sea cliff portion of the coastal bluff Mr. Justin Gooding and Mr.Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 File:e:\wp7\43W\43Ua.uge Page 9 GeoSoiis, Inc. is exposed to direct wave attack along most of the coast. The waves erode the sea cliff by impact on small joints/fractures and fissures in the otherwise essentially massive bedrock units, and by water-hammer effects. The upper bluffs, which often support little or no vegetation, are subject to wave spray and splash, sometimes causing saturation of the outer layer and subsequent sloughing of over-steepened slopes. Wind,rain,irrigation,and - uncontrolled surface runoff contribute to the erosion of the upper coastal bluff, especially on the more exposed over-steepened portions of the friable sands. Where these processes are active, unraveling of cohesionless sands has resulted along portions of the upper bluffs. Marine Erosion The factors contributing to "Marine Erosion" processes are described below. Mechanical and Biological Processes Mechanical erosion processes at the cliff-platform junction include water abrasion, rock abrasion, cavitation, water hammer, air compression in joints/fractures, breaking-wave shock, and alternation of hydrostatic pressure with the waves and tides. All of these processes are active in backwearing. Downwearing processes include all but breaking- wave shock (Trenhaile, 1987). Backwearing and downwearing by the mechanical processes described above are both augmented by bioerosion,the removal of rock by the direct action of organisms (Trenhaile, 1987). Backwearing at the site is assisted by algae in the intertidal and splash zones and by rock-boring mollusks in the tidal range. Algae and associated small organisms bore into rock up to several millimeters. Mollusks may bore several centimeters into the rock. Chemical and salt weathering also contribute to the erosion process. Water Depth, Wave Height, and Platform Slope The key factors affecting the marine erosion component of bluff-retreat are water depth at the base of the cliff, breaking wave height, and the slope of the shore platform. Along the entire coastline, the sea cliff is subject to periodic attack by breaking and broken waves, which create the dynamic effects of turbulent water and the compression of entrapped air pockets. When acting upon jointed and fractured rock, the "water-hammer" effect tends to cause hydraulic fracturing which exacerbates sea cliff erosion. Erosion associated with breaking waves is most active when water depths at the cliff-platform junction coincide with the respective critical incoming wave height, such that the water depth is approximately equal to 1.3 times the wave-height. Marine Erosion at the Cliff-Platform Junction The cliff-platform junction contribution to retreat of the overall sea cliff is from marine erosion, which includes mechanical, chemical, and biological erosion processes. Marine Mr. Justin Gooding and Mr.Karl Weingarten W.O. 4362-A-SE 330 Neptune Avenue, Encinitas June 28, 2004 File:e:\wp7\4300\4362a.uge Page 10 GeoSoiis, Inc. erosion, which operates horizontally (backwearing) on the cliff as far up as the top of the • splash zone, and vertically (downwearing) on the shore platform (Emery and Kuhn, 1980; Trenhaile, 1987). Backwearing and downwearing typically progress at rates that will maintain the existing gradient of the shore platform. - Subaerial Erosion "Subaerial Erosion" processes are discussed as follows. Groundwater The primary erosive effect of groundwater seepage upon the formation at the site is spring sapping,or the mechanical erosion of sand grains by water exiting the bluff face. Chemical solution,however,is also a significant contributor(especially of carbonate matrix material). As indicated previously, as groundwater approaches the bluff, it infiltrates near-surface, stress=relief, bluff-parallel joints/fractures, which form naturally behind and parallel to the bluff face. Hydrostatic loading of bluff parallel (and sub-parallel) joints/fractures is an important cause of block-toppling on steep-cliffed lower bluffs (Kuhn and Shepard, 1980). Slope Decline The process of slope decline consists of a series of steps, which ultimately cause the bluff to retreat. The base of the bluff is first weakened by wave attack and the development of wave cut niches and/or sea caves, and bluff parallel tension joint/fractures. As the weakened sea cliff fails by blockfall or rockfall, an over-steepened bluff face is left,with the debris at the toe of the sea cliff. Ultimately,the rockfall/blockfall debris is removed by wave action, and the marginal support for the upper bluff is thereby removed. Progressive surFicial slumping and failure of the bluff will occur until a condition approaching the angle of repose is established over time, and the process begins anew. Upper bluffs with slope angles in the 35 to 40 degrees range may indicate ages in the 75- to 100-year range. Steeper slopes indicate a younger age. Slopes at the site vicinity indicate a relatively young age, which are generally typical of active erosion. The estimated rate of blufftop retreat ranges from 0.3 to 0.9 feet per year(U.S.Army Corps. Engineers, 1996). Based on an average rate of 0.6 feet per year, the blufftop has the potential to retreat 45 feet in 75 years. Based on an estimated rate of 0.9 feet per year,the blufftop has the potential to retreat 67.5 feet in 75 years. Based on the designation of type C(C) for the coastal bluff profile, the erosion rate at the base of the bluff equals that at the top of the bluff (Emery and Kuhn, 1982). Based on these estimates, it is considered -- reasonably conservative to deepen footings for the proposed development to at least 67.5 feet east of the top slope. Recommendations are provided in the foundation section. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fle:e:\wp7\4300\4362a.uge Page 11 GeoSoils, Inc. LABORATORY TESTING Laboratory tests were performed on representative samples of representative site earth materials in order to evaluate their physical characteristics. Test procedures used and results obtained are presented below. Classification Soils were classified visually according to the Unified Soils Classification System. The soil classification of onsite soils is provided in the Boring Logs in Appendix B. Moisture-Density Relations The maximum density and optimum moisture content was determined for the major soil type encountered in the boring. The laboratory standard used was ASTM D-1557. Results of this testing are presented on the Boring Logs in Appendix B. Laboratory Standard-Maximum Dry Density To determine the compaction character of a representative sample of onsite soil,laboratory testing was performed in accordance with ASTM test method D-1557. Test results are presented in the following table: LOCATION MAXIMUM OPTIMUM MOISTURE DENSITY c CONTENT % B-1 @ 2-4- 127.5 11.5 Expansion Index Testing Expansion index (E.I.) testing was performed on a representative soil sample, according to UBC Standard 18-2 of the UBC (ICBO, 1997). The test result is presented below: _ LOCATION SOIL TYPE EXPANSION EXPANSION; INDEX, " POTENTIAL B-1 @ 2-4- Sand terrace de osits 2 Very Low Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 12 GeoSoils, Inc. Direct Shear Tests Shear testing was performed on three undisturbed samples in general accordance with ASTM test method D-3080. Test results are presented on the following table. LOCATION COHESION (psfl INTERNAL FRICTION (degrees) B-1 @ 10-11' (Terrace) 320 37 Base of Bluff Bedrock 1,000 37 Consolidation Tests A consolidation test was performed on two samples of site soil in general accordance with ASTM test method D-2435. The results are presented in Appendix C. Corrosivity GSI conducted sampling of representative soils on the subject site for corrosivity. Laboratory test results were completed by M.J. Schiff (consulting corrosion engineers). The results are presented in Appendix C. The testing included determination of soluble sulfates, pH (i.e., 9.2), and saturated resistivity. Results indicate that site soils are very strongly alkaline and are severely corrosive metals(i.e.,830 ohms-cm). Severely corrosive soils are considered to be below 1,000 ohms-cm. In addition,the site is located in an area of high sodium chloride content. Based upon the soluble sulfate results of 0.02 percent by weight in soil, the soils have a negligible corrosion potential to concrete (UBC range for negligible sulfate exposure is 0.00 to 0.10 percentage by weight soluble ISO41 in soil). Alternative methods and additional comments should be obtained from a qualified corrosion engineer regarding foundations, piping, etc.. SLOPE STABILITY The existing bluff slope, as are adjoining slopes to the north and south, although at first -- glance appears generally stable, is currently in the process of eroding and bluff failure. Due to the granular and lightly indurated nature of earth materials exposed at the slope face, they will continue to recede if left exposed to weathering and are in an unconfined condition (slope face). The angle of repose of the upper sediments appears to be approximately 1:1 and is considered susceptible to surficial slumping, subaerial erosion Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 13 GeoSoiils, Inc. and erosion due to urbanization. Portions of the slope appear to be steeper than 1:1 and would likely be relatively more susceptible to these processes than similar materials at flatter gradients. The presence of groundwater seepage along the terrace deposit/Torrey Sandstone contact would also tend to decrease relative slope stability. Hydrostatic loading of bluff-parallel (and sub-parallel)joints within the bedrock may contribute to block-toppling - failures. The Torrey Sandstone did not show considerable signs of wave/cobble induced undercutting at the bluff base at this location; however, localized minor block failures and "pocket" failures were observed within this unit. The site and immediate vicinity is generally characterized by surficial slumps, subaerial erosion and urbanization erosion. No geomorphic evidence for immediate gross slope instability was observed onsite, nor on the adjacent properties. However, this does not preclude the presence of conditions(structure,soil strength,etc.)contributing to a reduced gross stability. The slope faces, if left untreated, will likely continue to progressively erode and/or slump and may accelerate during strong seismic shaking, severe winter storms or,other similar events. Accordingly, there is some potential that natural slopes may be subject to instability during seismic shaking, heavy precipitation or strong storms, as would other similar existing slopes in the coastal southern California area. Mitigation would likely be necessary for all structures, including patios, spas, flatwork, etc., from being impacted. SLOPE STABILITY ANALYSES Analyses were performed utilizing the two dimensional slope stability computer program "GSTABL7." The program calculates the factor of safety for specified circles or searches for a circular, block, or irregular slip surface having the minimum factor of safety using the Janbu, or general limit equilibrium (Spencer). Additional information regarding the methodology utilized in these programs are included in Appendix D. Computer print-outs of calculations and shear strength parameters used are provided in Appendix D. A representative cross section was prepared for analysis, utilizing data from our investigation and the map that depicts the existing slope. This cross section is provided as Plate 2. The location of the cross-section is shown on Plate 1. - Gross Stability Analysis Based on the available data, the constraints outlined above, and our stability calculations - of the most critical slope indicated on Plate 1,a calculated factor-of-safety less than 1.5 under static loading conditions have been obtained for the existing slope on the subject site. However, a calculated factor-of-safety greater than 1.5 and 1.1 under static and pseudo-static loading conditions(respectively) have been obtained forthe area behind the existing slope on the subject site if a 50-foot structural setback zone is maintained from the Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 File:e:\wp7\4300\4362a.uge Page 14 GeoSoils, Inc. top of the coastal bluff. This assumes that the slope remains in its current condition as depicted on the cross section shown on Plate 2 (i.e.,no erosion, undermining, etc.),which _. is an unrealistic assumption. If future improvements are proposed within the 50-foot structural setback zone, this office could provide mitigation recommendations (i.e. structural tiebacks) concerning bluff stability. Surficial Slope Stability Based on published and accepted erosion rates by the City,the existing slope is surficially unstable. Slope Setbacks The proposed residence should be setback a minimum of 50 feet (landward)from the top of the coastal bluff. The actual location of the top of bluff should be determined by the design civil engineer. DISCUSSION AND PRELIMINARY CONCLUSIONS General Based on our field exploration, laboratory testing and geotechnical engineering analysis, it is our opinion that the subject site appears suitable for the proposed additional development from a geotechnical engineering and geologic viewpoint, provided that the recommendations presented in the following sections are incorporated into the design and construction phases of site development. The primary geotechnical concerns with respect to the proposed development are: • Depth to competent bearing material. • Slope instability and engineering properties of onsite sediments (consolidation, strength, etc.) • Potential for perched water. • Potential for corrosion. Earth Materials Artificial Fill and Terrace Deposits - These earth materials are typically porous, loose, and subject to consolidation, at least in the near-surface. In the near-surface,they are considered potentially compressible in their existing state, and have a moderate potential for hydrocompaction; thus, the fill soils and near-surface terrace deposits onsite may settle appreciably under additional fill,foundation, Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 15 GeoSoils, Inc. or improvement loadings. Recommendations for the treatment of the fill and surficial terrace deposits are presented in the earthwork section of this report. Slope Stability Based on published erosion rates,the existing slope is surficially unstable. Gross stability analyses, however, indicate generally stable conditions for this slope provided that a 50-foot structural setback zone is maintained (or structural stabilization [i.e., structural tiebacks] are provided). Therefore proposed additional structures should be located at least 50 feet from the top of the existing bluff and be demonstrated to be behind the identified daylight line, which is at the 50-foot mark or the bluff should be structurally stabilized. Since the location of the addition is approximately 721/2 feet from the top of the bluff, no recommendations are required to mitigate the effects of slope erosion based on the calculated rates of erosion (67.5 feet in 75 years). Failures within this zone and distress to any improvements should be anticipated, and disclosed to all interested parties. Further, a failure within this zone will render all slope stability analyses performed to date invalid, and will necessitate a re-evaluation. Subsurface.and Surface Water -- Subsurface and surface water, as discussed previously, are not anticipated to affect site development,provided that the recommendations contained in this report are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along fill/bedrock contacts and along zones of contrasting permeabilities should not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. The groundwater conditions observed and opinions generated were those at the time of our investigation. Conditions may change with the introduction of irrigation, rainfall, or other factors that were not obvious at the time of our investigation. - The recommendations presented herein consider these as well as other aspects of the site. In the event that any significant changes are made to proposed site development, the conclusions and recommendations contained in this report shall not be considered valid -- unless the changes are reviewed and the recommendations of. this report verified or modified in writing by this office. Foundation design parameters are considered preliminary until the foundation design, layout, and structural loads are provided to this office for review. Mr. Justin Gooding and Mr. Karl Weingarten W.O.4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\4300\4362a.uge Page 16 GeoSoils, Inc. Corrosivity GSI conducted sampling of representative soils on the subject site for corrosivity Laboratory test results were completed by M.J. Schiff (consulting corrosion engineers). The results are presented in Appendix C. The testing included determination of soluble sulfates, pH (i.e., 9.2), and saturated resistivity. Results indicate that site soils are very strongly alkaline and are severely corrosive of metals (i.e., 830 ohms-cm). Severely corrosive soils are considered to be below 1,000 ohms-cm. In addition,the site is located in an area of high sodium chloride content. Based upon the soluble sulfate results of 0.02 percent by weight in soil, the soils have a negligible corrosion potential to concrete (UBC range for negligible sulfate exposure is 0.00 to 0.10 percentage by weight soluble [SOJ in soil). Alternative methods and additional comments should be obtained from a qualified corrosion engineer regarding foundations, piping, etc. RECOMMENDATIONS-EARTHWORK CONSTRUCTION Grading General All grading should conform to the guidelines presented in Appendix Chapter A33 of the UBC (ICBO, 1997),the requirements of the City, and the Grading Guidelines presented in this report as Appendix E, except where specifically superceded in the text of this report. Prior to grading, a GSI representative should be present at the preconstruction meeting to provide additional grading guidelines, if needed, and review the earthwork schedule. During earthwork construction all site preparation and the general grading procedures of the contractor should be observed and the fill selectively tested by a representatives) of GSI. If unusual or unexpected conditions are exposed in the field,they should be reviewed bythis office and if warranted,modified and/or additional recommendations will be offered. All applicable requirements of local and national construction and general industry safety orders, the Occupational Safety and Health Act, and the Construction Safety Act should be met. Site Preparation Any existing foundations,concrete slabs,debris,vegetation and other deleterious material should be removed from the area of proposed improvements) area prior to the start of construction. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\430014362a.uge Page 17 GeoSoils, Inc. Following removals, areas approved to receive additional fill should first be scarified and moisture conditioned (at or above the soils optimum moisture content) to a depth of - 12 inches and compacted to a minimum 90 percent relative compaction. This excludes the pavement areas, which should be compacted to 95 percent. Removals (Unsuitable Materials) The existing fill soils and upper weathered zone of the terrace deposits should be removed and recompacted or reprocessed in areas proposed for settlement-sensitive improvements. Removal depths are estimated to range from 2 to 6 feet below proposed grade. Materials generated during removal operations may be re-used as compacted fill provided the materials are suitably moisture conditioned prior to placement. Removals should be completed below a 1:1 projection down and away from the edge of any settlement-sensitive structure and/or limit of proposed fill. Once removals are completed, the exposed bottom should be scarified in two perpendicular directions, moisture conditioned to at least optimum moisture content,and recompacted to 90 percent relative -- compaction prior to fill placement. Overexcavation Proposed grading for the addition may create a cut/fill transition in the building pad area where bedrock (i.e., cut areas) is juxtaposed against proposed fill. If this condition becomes apparent during site earthwork, overexcavation of the building pad area to provide for at least 24 inches of compacted fill beneath the proposed footings will be necessary. The overexcavation should be completed to a minimum lateral distance of 5 feet outside the extreme foundation elements, or a 1:1 projection from the bottom of the footing, whichever is greater. Fill Placement Subsequent to ground preparation, onsite soils may be placed in thin (±6-inch) lifts, cleaned of vegetation and debris, brought to a least optimum moisture content, and compacted to achieve a minimum relative compaction of 90 percent of the laboratory standard. If fill materials are imported to the site,the proposed import fill should be submitted to GSI, so laboratory testing can be performed to verify that the intended import material is compatible with onsite material. At least three business days of lead time should be allowed by builders or contractors for proposed import submittals. This lead time will allow for particle size analysis, specific gravity, relative compaction, expansion testing and blended import/native characteristics as deemed necessary. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 18 GeoSoils, Inc. Erosion Control Onsite soils and/or bedrock materials have a moderate to high erosion potential. Use of hay bales,silt fences,and/or sandbags should be considered,as appropriate. Temporary grades should be constructed to drain at 1 to 2 percent to a suitable temporary or permanent outlet. Evaluation of cuts during grading will be necessary in order to identify any areas of loose or non-cohesive materials. Should any significant zones be encountered during earthwork construction remedial grading may be recommended; however no remedial measures are anticipated at this time. Subdrain Systems Based on the nature of the contacts between artificial fill and bedrock, in addition to the possible location(s) of proposed site improvements,there exists a potential for water to be transmitted through the subsurface in irregular quantities. Although not anticipated, subdrain systems may be recommended based on field conditions observed during the grading stage of the project. Typical recommendations for the design/construction of subdrain systems are presented in Appendix E (General Earthwork and Grading Guidelines). Subdrain systems should discharge into an existing drainage pattern or other - appropriate outlet. PRELIMINARY RECOMMENDATIONS - FOUNDATIONS General In the eventthatthe information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed structure are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer or civil engineer specializing in structural design. Upon request,GSI could provide additional input/consultation regarding soil parameters, as related to foundation design. Foundation Design 1. The foundation system for the proposed addition should be constructed independently from the existing foundation system and should be designed and constructed in accordance with guidelines presented in the latest adopted edition of the UBC. All new foundations should be minimally embedded into properly compacted fill. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\430014362a.uge Page 19 GeoSoils, Inc. 2. An allowable bearing value of 1,500 psf may be used for design of footings that maintain a minimum width of 12 inches and a minimum depth of 12 inches, and founded into properly compacted fill. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum value of 2,000 psf. In addition, this value may be increased by one-third when considering short duration seismic or wind loads. Isolated pad footings should have a minimum dimension of at least 24 inches square and a minimum embedment of 24 inches into properly compacted fill 3. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf, with a maximum earth pressure of 2,500 psf. 4. An allowable coefficient of friction between soil and concrete of 0.35 may be used with the dead load forces. 5. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. 6. Soil generated from footing excavations to be used onsite should be moisture conditioned to at least optimum moisture content and compacted to at least 90 percent minimum relative compaction, if it is to be placed in the yard/right-of- away areas. This material must not alter positive drainage patterns that direct drainage away from the structural area and toward the street. 7. Expansion/construction joints for differential movement between proposed and existing improvements should be provided by the structural engineer/architect. Foundation Settlement Foundation systems should be designed to accommodate a differential settlement of at least 1 inch in a 40-foot span. An expansion/construction joint should be placed between any existing and proposed improvements to permit relative movement between the two. Footing Setbacks Footings should maintain a horizontal distance,X, between any adjacent descending slope face and the bottom outer edge of the footing. The horizontal distance, X, may be calculated by using X = h/3,where h is the height of the slope. X should not be less than 7 feet, nor need not be greater than 40 feet. X may be maintained by deepening the footings. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection from the heel of the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances as described in the Retaining Wall Section of this report. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 _. Fi1e:e:\wp7\4300\4362a.uge Page 20 GeoSoils, Inc. Construction The following foundation construction recommendations are presented as a minimum criteria from a soils engineering standpoint. The onsite soil expansion potential is generally very low (E.I. 0 to 20). Recommendations for very low expansive soil conditions are - presented herein. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations,should take precedence over the following minimum requirements. Final foundation design will be provided based on the expansion potential of the near surface soils encountered during grading. Very Low Expansion Potential (E.I. 0 to 20) 1. Exterior and interior footings should be founded at a minimum depth of 12 inches for one-story floor loads, and 18 inches for two-story floor loads, into properly compacted fill. Isolated column and panel pads, or wall footings, should be founded at a minimum depth of 24 inches into properly compacted fill. All footings "should be reinforced with two No. 4 reinforcing bars, once placed near the top and one placed near the bottom of the footing. Footing widths should be as indicated in UBC (ICBO, 1997). 2. A grade beam, reinforced as above, and at least 12 inches square, should be provided across large (e.g., doorways) entrances. The base of the grade beam should be at the same elevation as the bottom of adjoining footings. Isolated, exterior square footings should be tied within the main foundation in at least one direction with a grade beam. 3. Concrete slabs,where moisture condensation is undesirable, should be underlain with a vapor barrier consisting of a minimum of 10 mil polyvinyl chloride, or equivalent membrane,with all laps sealed, per the UBC. This membrane should be covered above with a minimum of 2 inches of sand to aid in uniform curing of the concrete, and to protect the membrane from puncture. 4. Concrete slabs should be a minimum of 5 inches thick and should be reinforced with No. 3 reinforcing bar at 18 inches on center in both directions. All slab reinforcement should be supported to ensure placement near the vertical midpoint of the concrete. "Hooking" of reinforcement is not considered an acceptable method of positioning the reinforcement. 5. Garage slabs should be reinforced as above and poured separately from the structural footings and quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\4300\4362a.uge Page 21 GeoSoils, Inc. 6. An expansion/construction joint should be placed between any existing and proposed improvements to permit relative movement between the two. 7. Presaturation is not required for these soil conditions. The moisture content of the subgrade soils should be equal to,or greaterthan,optimum moisture content in the - slab areas, prior to concrete placement. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided below assume that either non expansive soils (Class 2 permeable filter material or Class 3 aggregate base) or native materials (up to and including an E.I. of 65) are used to backfill any retaining walls. The type of backfill (i.e., select or native), should be specified by the wall designer,and clearly shown on the plans. Building walls, below grade,should be water-proofed or damp-proofed,depending on the degree of moisture protection desired. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections of this report, as appropriate. Footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. There should be no increase in bearing for footing width. Recommendations for specialty walls (i.e.,crib, earthstone, geogrid,etc.) can be provided upon request, and would be based on site specific conditions. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 65 pounds per cubic foot (pcf), plus any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (21-11) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet -- high. Design parameters for walls less than 3 feet in height may be superceded by City and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 22 GeoSoils, Inc. finalized,the appropriate loading conditions for superimposed loads can be provided upon request. SURFACE SLOPE OF EQUIVALENT EQUIVALENT RETAINED MATERIAL FLUID WEIGHT P.C.F. FLUID WEIGHT P.C.F. HORIZONTAL:VERTICAL SELECT BACKFILL NATIVE BACKFILL Level* 35 45-7 2 to 1 50 60 * Level backfill behind a retaining wall is defined as compacted earth materials, properly drained,without a slope for a distance of 2H behind the wall. Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the back drainage options - discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or'/2-inch to 3/4-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to medium expansion potential, continuous Class 2 permeable drain materials should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E.I. potential of greater than 65 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ±100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes in walls higher than 2 feet should not be considered. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.L < 90). Proper surface drainage should also be provided. For additional mitigation,consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Mr. Justin Gooding and Mr. Karl Weingarten W.O.4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 23 GeoSoils, Inc. DETAILS N T . S . _._ 2 Native Backfill 1 Provide Surface Drainage Slope or Level Native Backfill 12" Rock +12" Filter Fabric waterproofing 1 Membrane(optional) 1 or Flatter 0 weep Hole Native Backfill Finished Surface ® Pipe WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. ® ROCK: 3/4 to 1-1/2" (inches) rock. (3) FILTER FABRIC: Mirafi 140N or approved equivalent; place fabric flap behind core. ® PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. ®WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) TYPICAL RETAINING WALL BACKFILL AND DRAINAGE DETAIL . DETAIL 1 Geotechnical • Geologic • Environmental DETAILS N T S . 2 Native Backfill 1 Provide Surface Drainage Slope or Level 6" Native Backfill Waterproofing Membrane(optional) Q Drain 1 1 or Flatter Q Weep Hole Q Filter Fabric Finished Surface ® Pipe O Q WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. Q DRAIN: Miradrain 6000 or]-drain 200 or equivalent for non-waterproofed walls. Miradrain 6200 or]-drain 200 or equivalent for waterproofed walls. (3) FILTER FABRIC: Mirafi 140N or approved equivalent; place fabric flap behind care. ® PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. ® WEEP HOLE: - Minimum 2 (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) RETAINING WALL BACKFILL AND SUBDRAIN DETAIL - §�� • GEOTEXTILE DRAIN !> • DETAIL 2 - Geotechnical • Geologic • Environmental DETAILS N T S . 2 Native Backfill 1 0 Provide Surface Drainage Slope or Level H/2 min. +12" Q Waterproofing 1 Membrane(optional) 1 or Flatter H © Weep Hole Clean Sand Backfill . � Filter Fabric . . Finished Surface ® Roc © Pipe Heel Width F— © WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. ® CLEAN SAND BACKFILL: Must have sand dequivalent value of 30 or greater; can be densified by water jetting. 3) FILTER FABRIC: Mirafi 140N or approved equivalent. ® ROCK: 1 cubic foot per linear feet of pipe or 3/4 to 1-1/2" (inches) rock. ® PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. ©WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) RETAINING WALL AND SUBDRAIN DETAIL CLEAN SAND BACKFILL DETAIL 3 Geotechnical • Geologic • Environmental Wall/Retaining Wall Footing Transitions - Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and - until such transition is between 45 and 90 degrees to the wall alignment. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and therefore, may become desiccated when allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal changes in moisture content. Typically in southern California, during the hot and dry summer period, these soils become desiccated and.shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss in soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials -- experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greater than 10 feet,this creep related soil movement will typically impact all rear yard flatwork and other secondary improvements that are located within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. This influence is normally in the form of detrimental settlement,and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 27 GeoSoiis, Inc. becomes progressively worse. Accordingly,the developer should provide this information to any homeowners and homeowners association. Top of Slope Walls/Fences Due to the potential for slope creep for slopes higher than about 10 feet, some settlement and tilting of the walls/fence with the corresponding distresses, should be expected. To mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on deepened foundations without any consideration for creep forces, where the expansion index of the materials comprising the outer 15 feet of the slope is less than 50, or a combination of grade beam and caisson foundations, for expansion indices greater than 50 comprising the slope, with creep forces taken into account. The grade beam should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom of the grade beam. The strength of the concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design of the grade beam and caissons should be in accordance with the recommendations of the project structural engineer,and include the utilization of the following geotechnical parameters: Creep Zone: 5 400t vertical zone belowthe slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam should be taken as an equivalent fluid approach, having a density of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1.5 times the caisson's diameter, below the creep zone. Passive Resistance: Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter, to a maximum value of 4,500 psf may be - used to determine caisson depth and spacing, provided that they meet or exceed the minimum requirements stated above. To determine the total lateral resistance,the contribution of the creep prone zone above the point of fixity, to passive resistance, should be disregarded. Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 File:eAwp7\4300\4362a.uge Page 28 GeoSoils, Inc. Allowable Axial Capacity: Shaft capacity : 350 psf applied below the point of fixity over the surface area of the shaft. Tip capacity: 4,500 psf. DRIVEWAY FLATWORK, AND OTHER IMPROVEMENTS The soil materials on site may be expansive or compressible. The effects of such soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving/sinking and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To that end,it is recommended that the developer should notify any homeowners or homeowners association of this long-term potential for distress. To reduce the likelihood of distress,the following recommendations are presented for all exterior flatwork: 1. The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction,and then be presoaked to 2 to 3 percentage points above (or 125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. The moisture content of the subgrade should be verified within 72 hours prior to pouring concrete. 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. If very low expansive soils are present,the rock or gravel _ or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete,to minimize loss of concrete moisture to the surrounding earth materials. 3. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, to help impede infiltration of landscape water under the slab. 4. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. Mr.Justin Gooding and Mr. Karl Weingarten W.O.4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\43W\4362a.uge Page 29 GeoSoils, Inc. In order to reduce the potential for unsightly cracks, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, 1/2 to 3/8 inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The - slabs should be separated from the foundations and sidewalks with expansion joint filler material. 5. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6. Driveways, sidewalks, and patio slabs adjacent to the house should be separated from the house with thick expansion joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. 7. Planters and walls should not be tied to the house. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. 10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. 11. Positive site drainage should be maintained at all times. Finish grade on the lots should provide a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post- construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the homeowner or homeowners association. 12. Air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation or constructed on a rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable non-erosive outlet. 13. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 File:e*p7\4300\4362a.uge Page 30 GeoSoils, Inc. curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. DEVELOPMENT CRITERIA Slope Deformation Compacted fill slopes designed using customary factors of safety for gross or surficial stability and constructed in general accordance with the design specifications should be expected to undergo some differential vertical heave or settlement in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep, and lateral fill extension (LIFE). Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., - separations and/or cracking), placed near the top-of-slope, up to a maximum distance of approximately 15 feet from the top-of-slope, depending on the slope height. This movement generally results in rotation and differential settlement of improvements located within the creep zone. LIFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. It is generally not practical to attempt to eliminate the effects of either slope creep or LIFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 1997 UBC and/or California Building Code), positive structural separations (i.e., joints) between improvements, and stiffening and deepening of foundations. All of these measures are recommended for design of structures and improvements. The ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner and/or any homeowners association. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope - stability is significantly reduced by overly wet conditions. Positive surface drainage away from slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements, and cause perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\4300\4362a.uge Page 31 GeoSoiiils, Inc. landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting or other fibrous covers may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc.,to develop. A rodent control program to prevent burrowing should be implemented. - Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. Over-steepening of slopes should be avoided during building construction activities and landscaping. Drainage Adequate lot surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape,and slopes. Surface drainage should be sufficient to prevent ponding of water anywhere on a lot,and especially near structures and tops of slopes. Lot surface drainage should be carefully taken into consideration during fine grading,landscaping,and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas should be provided and maintained - at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 5 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Downspouts,or drainage devices should outlet a minimum of 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Toe of Slope Drains/Toe Drains - Where significant slopes intersect pad areas, surface drainage down the slope allows for some seepage into the subsurface materials, sometimes creating conditions causing or contributing to perched and/or ponded water. Toe of slope/toe drains may be beneficial in the mitigation of this condition due to surface drainage. The general criteria to be utilized by the design engineer for evaluating the need for this type of drain is as follows: • Is there a source of irrigation above or on the slope that could contribute to saturation of soil at the base of the slope? Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 _. Fi1e:eAwp7\4300\4362a.uge Page 32 GeoSoiis, Inc. • Are the slopes hard rock and/or impermeable, or relatively permeable, or; do the slopes already have or are they proposed to have subdrains (i.e., stabilization fills, etc.)? • Was the lot at the base of the slope overexcavated or is it proposed to be overexcavated? Overexcavated lots located at the base of a slope could accumulate subsurface water along the base of the fill cap. • Are the slopes north facing? North facing slopes tend to receive less sunlight (less evaporation) relative to south facing slopes and are more exposed to the currently prevailing seasonal storm tracks. • What is the slope height? It has been our experience that slopes with heights in excess of approximately 10 feet tend to have more problems due to storm runoff and irrigation than slopes of a lesser height. -- 0 Do the slopes"toe out"into a residential lot or a lot where perched or ponded water may adversely impact its proposed use? - Based on these general criteria, the construction of toe drains may be considered by the design engineer along the toe of slopes, or at retaining walls in slopes, descending to the rear of such lots. Following are Detail 4 (Schematic Toe Drain Detail) and Detail 5 (Subdrain Along Retaining Wall Detail). Other drains may be warranted due to unforeseen conditions, homeowner irrigation, or other circumstances. Where drains are constructed during grading, including subdrains, the locations/elevations of such drains should be surveyed, and recorded on the final as-built grading plans by the design engineer. It is recommended thatthe above be disclosed to all interested parties,including homeowners and any homeowners association. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. - Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We would recommend that any proposed open-bottom planters adjacent to proposed structures be eliminated for a minimum distance of 10 feet. As an alternative, closed- bottom type planters could be utilized. An outlet placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. If Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 —• Fi1e:e:\wp7\4300\4362a.uge Page 33 GeoSoiils, Inc. . Y DETAILS N . T . S . SCHEMATIC TOE DRAIN DETAIL Drain May Be Constructed into, INJI or at,the Toe of Slope Pad Grade z = d r NOTES: 1.) Soil Cap Compacted to 90 Percent Relative Compaction.ti `` 12"Minimum 2.) Permeable Material May Be Gravel Wrapped in Filter Fabric(Miraf 140N or Equivalent). 3 4-Inch Diameter Perforated Pipe(SDR 35 or Equivalent)with Perforations Down. 4.) Pipe to Maintain a Minimum 1 Percent Fall. 5.) Concrete Cutoff Wall to be Provided at Transition to Solid Outlet Pipe. Permeable Material 6.) Solid Outlet Pipe to Drain to Approved Area. 7.) Cleanouts are Recomended at Each Property 24" Line. Minimum Drain Pipe 12" SCHEMATIC TOE DRAIN DETAIL DETAIL 4 Geotechnical a Coastal • Geologic • Environmental DETAILS NT . S 1 . 2:1 SLOPE (TYPICAL) TOP OF WALL I —�� BACKFILL WITH COMPATED NOTES: NATIVE SOILS 1.) Soil Cap Compacted to 90 Percent - - - - - - Relative Compaction. 12„ RETAINING WALL _ _ __ _= MIN 2.) Permeable Material May Be Gravel Wrapped in Filter Fabric(Miraf 140N L - - - - - or Equivalent). 3.) 4-Inch Diameter Perforated Pipe r�r (SDR-35 of Equivalent)with LINISHED MIRAFI 140 FILTER FABRIC Perforations Down. GRADE OR EQUAL ,. 4.) Pipe to Maintain a Minimum 1 Percent Fall. 3/4"CRUSHED GRAVEL 5.) Concrete Cutoff Wall to be Provided WALL FOOTING at Transition to Solid Outlet Pipe. g.) Solid Outlet Pipe to Drain to Approved Area. 24" 7.) Cleanouts are Recommended at "+ MI 4"DRAIN Each Property Line. 8.) Compacted Effort Should Be Applied to Drain Rock. 1"TO 2" 12 �e SUBDRAIN ALONG RETAINING WALL DETAIL NOT TO SCALE SUBDRAIN ALONG RETAINING WALL DETAIL L DETAIL 5 Geotechnical • Coastal • Geologic • Environmental planters are constructed adjacent to structures,the sides and bottom of the planter should be provided with a moisture barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e.,some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Gutters and Downspouts _ As previously discussed in the drainage section,the installation of gutters and downspouts should be considered to collect roof water that may otherwise infiltrate the soils adjacent to the structures. If utilized, the downspouts should be drained into PVC collector pipes or non-erosive devices that will carry the water away from the house. Downspouts and gutters are not a requirement; however, from a geotechnical viewpoint, provided that positive drainage is incorporated into project design (as discussed previously). Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided that the recommendations contained in this report are incorporated into final design and construction and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions along zones of contrasting permeabilities may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop,this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Site Improvements Recommendations for exterior concrete flatwork design and construction can be provided upon request. If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site,recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench, and retaining wall backfills. Mr.Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:eAwp7\4300\4362a.uge Page 36 GeoSoils, Inc. Tile Floorinq Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. Therefore, the designer should consider additional steel reinforcement for concrete slabs-on-grade where tile will be placed. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets. Slipsheets or a vinyl crack isolation membrane (approved by the Tile Council of America/Ceramic Tile Institute) are recommended between the and concrete slabs on grade. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street and parking areas and utility trench and retaining wall backfills. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement. The purpose of the observations is to verify that the excavations are made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenchinq Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the trench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to CAL-OSHA and local safety codes. Utility Trench Backfill 1. All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 F11e:e:\wp7\4300\4362a.uge Page 37 GeoSoiis, Inc. 30 or greater may be utilized and jetted or flooded into place. Observation, probing and testing should be provided to verify the desired results. 2. Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Compaction testing and observations, along with probing, should be accomplished to verify the desired results. 3. All trench excavations should conform to CAL-OSHA and local safety codes. 4. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: • During grading/recertification. • During significant excavation (i.e., higher than 4 feet). • During placement of subdrains, toe drains, or other subdrainage devices, prior to placing fill and/or backfill. • After excavation of building footings,retaining wall footings,and free standing walls footings, prior to the placement of reinforcing steel or concrete. • Prior to pouring any slabs or flatwork, after presoaki ng/presatu ration of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor barriers (i.e., visqueen, etc.). • During retaining wall subdrain installation, prior to backfill placement. • During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill. Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-Sc 330 Neptune Avenue, Encinitas June 28, 2004 File:e:\wp7\4300\4362a.uge Page 38 GeoSoils, Inc. • During slope construction/repair. • When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. • When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. • A report of geotechnical observation and testing should be provided at the conclusion of each of the above stages, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer,architect, landscape - architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. In order to mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and design criteria specified herein. PLAN REVIEW Final project plans should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review,supplemental recommendations and/or further geotechnical studies may be warranted. Mr. Justin Gooding and Mr. Karl Weingarten W.O.4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 Fi1e:e:\wp7\4300\4362a.uge Page 39 GeoSoiis, Inc. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory - data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is expressed or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this project. Mr. Justin Gooding and Mr. Karl Weingarten W.O. 4362-A-SC 330 Neptune Avenue, Encinitas June 28, 2004 FHe:e:\wpA4300\4362a.uge Page 40 GeoSoils, Inc. - APPENDIX A REFERENCES APPENDIX A REFERENCES Artim, Ernest R., 1995, Supplement to third party review of geotechnical information prepared by Southern California Soil and Testing Inc., relative to 620 Neptune Avenue, Encinitas, California, Project No. 94-96b, September 1. Artim, E.R., and Elder-Mills, D., 1982,The Rose Canyon fault: a review„in Abbott, P.L.,ed., Geologic Studies in San Diego: San Diego Association of Geologists, April. Artim, E.R., and Streiff, D., 1981, Trenching the Rose Canyon fault zone, San Diego, California,in Woodward-Clyde Consultants Final Technical Report,contract no. 14- 08-0001-19824, September. Bartling, W.A., Keis, R.P., and Abbott, P.L., 1981, Upper Cretaceous sedimentary rocks northwestern San Diego County, in O'Dunn, S and Abbott, P.L. eds, Geologic Investigation of the San Diego County Coastal Plain: San Diego Association of Geologists. Blake, T.F., 2000a, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. 2000b, EQSEARCH, A computer program for the estimation of peak horizontal acceleration from California historical earthquake catalogs; Updated to April,2004, Windows 95/98 version. 2000c, FRISKSP, A computer program for the probabilistic estimation of peak acceleration and uniform hazard spectra using 3-D faults as earthquake sources; Windows 95/98 version. Bowles, J.E., 1988, Foundation analysis and design: McGraw-Hill Book Company, New York. Campbell, K.W., 1993, Empirical prediction of near-source ground motion from large earthquakes, in Johnson, J.A. Campbell, K.W.., and Blake, eds., T.F., AEG Short - Course, Seismic Hazard Analysis, June 18, 1994. 1985. Strong motion attenuation relations, a ten-year perspective, in, Johnson, J.A., Campbell, K.W., and Blake, T.F., eds., AEG Short Course, Seismic Hazard Analysis, June 18, 1994. Civil Engineering Consultants, 1997, Interim Certification of Upper Bluff Stabilizing System, Reference: Dr. Harry Richards, 522 Neptune Ave., Encinitas, CA, October 5. GeoSoils, Inc. Clarke, S.H., Green, H.G., Kennedy, M.P., Vedder, J.G., and Legg, M.R., 1987, Geologic map of the inner-southern California continental margin in Green, H.G., and Kennedy, M.P., eds., California Continental Margin Geologic Map Series: California Department of Conservation, Division of Mines and Geology. Cooper, W.S., 1959, Coastal sand dunes of California: Geological Society of America Memoir. Curran, S.A., and Abbott, P.L., 1994, Fire History of organic fragments Cetaceous Point Loma Foundation at La Jolla Bay, in Rosenberg, P.S., ed., Geology and Natural History, Camp Pendelton, United States Marine Corps Base, San Diego County, California: by the San Diego Association of Geologists. Davis, J.F., 1997 Guidelines for evaluating and mitigating seismic hazards in California: California Division of Mines and Geology, Special Publication 117. Earth System Design Group, 1992, Geotechnical and geologic investigation, Clayton sea bluff, 638 Neptune Avenue, Encinitas, California, October 26. Eisenberg, L.T., 1985, Pleistocene faults and marine terraces, northern San Diego County, in Abbott, P.L., ed., On the Manner of Deposition of the Eocene Strata in Northern San Diego County: San Diego Association of Geologists. Elder-Mills, D., and Artim, E.R., 1982,The Rose Canyon fault; a review,in Abbott, P.L., ed., Geologic Studies in San Diego Association of Geologists. Emery,K.O.,and Kuhn,G.G., 1980, Erosion of rock shores at La Jolla,California,in Marine Geology, v. 37. 1982, Sea cliffs: their processes, profiles, and classification: Geological Society of America Bulletin, v. 93, no 7. Fisher, P.J., and Mills, G.I., 1991, The offshore Newport-Inglewood - Rose Canyon fault zone, California: structure,segmentation, and tectonics,in Abbott, P.L., and Elliott, W.J., eds., Environmental Perils - San Diego Region: San Diego Association of Geologists. Flick, R.E., 1994. Shoreline erosion assessment and atlas of the San Diego region, VI and II, December. Fulton, K., 1981 , A manual for researching historical coastal erosion in Kuhn, G.G., ed., California Sea Grant Report No. T-CSGCP-003. Mr. Justin Gooding and Mr. Karl Weingarten Appendix A File:e:\wp7\4300\4362a.uge Page 2 GeoSoils, Inc. GeoSoils, Inc., 2000, Preliminary geotechnical evaluation and bluff study, 330 Neptune - Avenue, Encinitas, San Diego County California,Work Order No. 2866-A-SC,dated May 12. Group Delta Consultants, Inc., 1993, Shoreline erosion evaluation, Encinitas coastline, - San Diego County, California, project no. 1404-EC01, November 3. Greensfelder, R. W., 1974, Maximum credible rock acceleration from earthquakes in California: California Division of Mines and Geology, Map Sheet 23. Hausman, M.R., 1990, Engineering principles of ground modification: Mcgraw Hill, Inc., New York. Holtz, R.D. and Kovacs, W.D., Undated, An introduction to geotechnical engineering: Prentence-Hall, Englewood Cliffs, New Jersey. Horrer, P.L., 1984, Wave action and related factors for proposed seawall at 6000 Camino de la Costa, dated November 28. Housner, G. W., 1970, Strong ground motion in Earthquake Engineering, Robert Wiegel, ed., Prentice-Hall. Howell, D.G.,Stuart,C.G., Platt,J.P.and Hills, D.J., 1974, Possible strike-slip faulting in the southern California Borderland: Geological Society of America Geology,v.2, no.2. Inman, D.L., 1976, Summary report of man's impact on the California coastal zone; prepared for the Department of Navigation and Ocean Development, State Of California. International Conference of Building Officials, 1997, Uniform building code: Whittier, California. Ishihara, K., 1985 Stability of natural deposits during earthquakes: Proceedings of the Eleventh International Conference on Soil Mechanics and Foundation Engineering: A.A. Balkema Publishers Rotterdam, Netherlands. Jenkins, S. and Skelly, D., 1986, Oceanographic considerations for the proposed seawall at 6040 Camino De La Costa. Jennings, C.W., 1994, Fault activity map of California and adjacent areas: California Division of Mines and Geology, Map Sheet No. 6, scale 1:750,000. Joyner,W.B.and Boore, D.M., 1982a, Estimation of response-spectral values as functions of magnitude, distance and site conditions, in Johnson, J.A., Campbell, K.W., and Blake, T.F., eds., AEG Short Course, Seismic Hazard Analysis, June 18, 1994. Mr.Justin Gooding and Mr. Karl Weingarten Appendix A Fi1e:e:\wp7\4300\4362a.uge Page 3 GeoSoils, Inc. 1982b, Prediction of earthquake response spectra, in Johnson, J.A., Campbell, K.W., and Blake, T.F., eds., AEG Short Course, Seismic Hazard Analysis, June 18, 1994. Kennedy, M.P., 1973, Sea-Cliff erosion at Sunset Cliffs, San Diego: California Geology,26, February. Kern. J.P., 1977, Origin and history of upper Pleistocene marine terraces, San Diego California, Geological Society of American Bulletin 88. Kuhn, G.G., and Shepard, F.P., 1984, Sea Cliffs, beaches and coastal valleys of San Diego County: some amazing histories and some horrifying implications: University of California Press, Berkeley, California, and London, England. 1983, Newly discovered Evidence from the San Diego County area of some principles of coastal retreat: Geological Society of America Bulletin, Shore and Beach, January. 1981,Should Southern California build defenses against violent storms resulting in lowland flooding as in records of past century: Geological Society of America Bulletin , 1980a,Greatly accelerated man-induced coastal erosion and new sources of beach sand, San Onofre State Park and Camp Pendleton, northen San Diego County, California: Geological Society of America Bulletin, Shore and Beach, October. 1980b Coastal erosion in San Diego County, California, in Edge, B.L., ed., Coastal Zone'80, Proceedings of second Symposium on Coastal and Ocean Management held in Hollywood, Florida, on 17-20 November, 1980: American Society of Civil Engineers, V. III. 1979a, Accelerated beach-cliff erosion related to unusual storms in southern California: California Geology, March. 1979,. Coastal erosion in San Diego County, California, in Abbott, P.L. and Elliott, W.J., eds., Earthquakes and other perils San Diego region. Lambe, T.W., 1951, Soil testing for engineers: John Wiley & Sons, New York. Lambe, T.W., and Whitman., R.V., 1969, Soil Mechanics: John Wiley &Sons, New York. Lee, L.J., Schug, D.L. and Raines, G.L. 1990, Seacliff stabilization, Seacliff park (Swami's), beach access stairway, Encinitas, California, in Geotechnical Engineering Case Histories in San Diego County: San Diego Association of Geologists., October 20, Field Trip Guide Book. Mr.Justin Gooding and Mr. Karl Weingarten Appendix A File:e:\wp7\4300\4362a.uge Page 4 GeoSoiis, Inc. Leighton and Associates, Inc., 1983, City of San Diego Seismic Safety Study, June. - Legg, M.R., 1985, Geologic structure and tectonics of the inner continental borderland offshore northen Baja California, Mexico, unpublished doctoral dissertation submitted to the University of California, Santa Barbara. 1989, Faulting and seismotectonics of the inner continental borderland west of San Diego, in Roquemore, G., ed., Proceedings, Workshop on the Seismic Risk in the San Diego Region: Special Focus on the Rose Canyon Fault System. Legg, M.R., and Kennedy, M.P., 1991, Oblique divergence and convergence in the California Continental Borderland, in Abbott, P.L., Elliott,W.J., eds., Environmental Perils - San Diego Region: San Diego Association of Geologist. Lindivall, S.C., Rockwell, T.K.., and Lindivall, E.C., 1989,The seismic hazard of San Diego revised: new evidence for magnitude 6+ Holocene earthquakes on the Rose Canyon fault zone, in Roquemore, G., ed., Proceedings,Workshop on The Seismic Risk in the San Diego Region: Special Focus on the Rose Canyon Fault System. Masters, P.M., 1996, Paleocoastlines, ancient harbors and marine archeology: Geology Society of America Bulletin, Shore and Beach, July. Matti, J.C., and Morton, D.M., 1993, Paleogeographic evolution of the San Andreas fault in Southern California: A reconstruction based a new cross-fault correlation, in Powell, R.E., Weldon, R.J. II, and Matti, J.C., eds., The San Andreas Fault System: Displacement, Palinspastic Reconstruction, and Geologic Evolution: Geological Society of America Memoir 178. Matti,J.C., Morton, D.M.,and Cox, B.F., 1992,The San Andreas fault system in the vicinity of the central Transverse Ranges province, southern California, in Sieh, K.E., and Matti, J.C., eds., Earthquake Geology San Andreas Fault System, Palm Springs to Palmdale. Mitchell, J.K., 1976, Fundamentals of soil behavior: John Wiley & Sons, Inc. New York. Morton, D.M.,and Matti,J.C., 1993,Extension and contraction within an evolving divergent strike-slip fault complex: The San Andreas and San Jacinto fault zones at their convergence in southern California, in Powell, R.E., Weldon, R.J. II, and Matti, J.C., eds., The San Andreas Fault System: Displacement, Palinspatic Reconstruction, and Geologic Evolution: Geological Society of America Memoir 178. Munk, W.H., and Traylor, M.A., 1947, Refraction of ocean waves: a process linking underwater topography to beach erosion: Journal of Geology, v. LV, no. 1. Mr.Justin Gooding and Mr. Karl Weingarten Appendix A Fi1e:e:\wp7\4300\4362a.uge Page 5 GeoSoils, Inc. • Naval Facilities Engineering Command, 1986a, Soil Mechanics, design manual 7.01, Change 1 September: United States Navy. 1986b, Foundations and earth structures, DM 7.02, Change 1 September: United States Navy. 1983, Soil Dynamics, deep stabilization, and special geotechnical construction, design manual 7.3, April: United States Navy. Nordstom, C.E., and Inman, D.L., 1973, Beach and cliff erosion in San Diego County, California,in Ross A.,and Dowlen, R.J.,eds., Studies on the Geology and Geologic Hazards of the Greater San Diego Area, California: the San Diego Association of Geologists, and Association of Engineering Geologists. Petersen, Mark D., Bryant,W.A., and Cramer, C.H., 1996, Interim table of fault parameters used by the California Division of Mines and Geology to compile the probabilistic seismic hazard maps of California. Sadigh, K., Egan, J., and Youngs, R., 1987, Predictive ground motion equations reported in Joyner, W.B., and Boore, D.M., 1988, "Measurement, characterization, and prediction of strong ground motion", in Earthquake Engineering and Soil Dynamics II, Recent Advances in Ground Motion Evaluation, Von Thun, J.L., ed.: American Society of Civil Engineers Geotechnical Special Publication No. 20, pp. 43-102. _. San Diego, City of, 1953, San Diego, San Diego County California metropolitan area, 1 inch = 200 feet,topographic survey compiled by Fairchild Aerial Survey, Inc. Schumm, S.A., and Mosley, P.M., 1973, Slope Morphology: Dowden, Hutchinson & Ross, Inc. Seed, H.B., 1976, Evaluation of soil. liquefaction effects on level ground during earthquakes, state-of-art paper, liquefaction problem: Geotechnical Engineering, American Society of Civil Engineers, Preprint 2753, New York. Seed, H.B. and Idriss, I.M., 1982, Ground motions and soil liquefaction during - earthquakes: Earthquake Engineering Research Institute monograph. 1971, A simplified procedure for evaluating soil liquefaction potential: American Society of Civil Engineers, JSMFD, v. 197. Seed, H.B., Idriss, I.M.,and Arango, 1., 1983, Evaluation of liquefaction potential using feild performance data: American Society of Civil Engineers, Journal of Geotechnical Engineering, v. 109. Mr.Justin Gooding and Mr. Karl Weingarten Appendix A page 6 r R1e:eAwp7\4300\4362a.uge GeoSoils, Inc. Seed, H.B., Tokimatsu, K., Harder, L.F., and Chung, R.M., 1985, Influence of SPT procedures in soil liquefaction resistance evaluations: Journal of the Geotechnical Engineering Division, American Society of Civil Engineers, v. 111, no. GR12, p. 1425-1445. - Shepard, F.P., and Kuhn, G.G., 1983, History of sea arches and remnant stacks of La Jolla California, and their bearing on similar features elsewhere: Marine Geology, v. 51. Shepard, F.P.,and Grant,U.S. IV, 1947,Wave erosion along the southern California coast: Geological Society of America Bulletin, v. 58, Shore and Beach, October. Soil Engineering Construction, 1997, tieback test (field) results, Hallow residence, 492 Neptune Avenue, October 28. Streiff, D., Schmoll, M., and Artim, E.R., 1982, The Rose Canyon fault at Spindrift Drive, La Jolla, California, in Abbott, P.L., ed., Geologic Studies in San Diego: San Diego Association of Geologists. Southern California Soil and Testing Inc., 1994, Stability of erosion control walls on bluff face, 620 Neptune Avenue, Encinitas, California, SCS&T 8921191, October 10. Sowers and Sowers, 1970, Unified soil classification system (After U. S. Waterways Experiment Station and ASTM 02487-667) in Introductory Soil Mechanics, New York. Sunamura,T., 1977,A relationship between wave-induced cliff erosion and erosive forces of waves: Journal of Geology, v. 85. Tan, S.S and Kennedy, M.P., 1996, Geologic maps of the Northwestern part of San Diego County, California, DMG Open-File Report 96-02. Terzaghi, K.,and Peck. Ralph B.,1967,Soil mechanics in engineering practice:John Wiley and Sons, New York, second edition. Teriman, J.A., 1984, The Rose Canyon fault zone, a review and analysis: The California Department of Conservation, Division of Mines and Geology, Cooperative Agreement EMF-83-k0148. Trenhaile, A.S., 1987, The geomorphology of rock coasts: Clarendon Press, Oxford. United States Army Corps of Engineers, 1996, Encinitas Shoreline, San Diego County, California. 1991, State of the coast report San Diego region, CCSTWS 91. Mr.Justin Gooding and Mr. Karl Weingarten Appendix_A 7 LL Fi1e:eAwp7\4300\4362a.uge GeoSoiils, Inc. 1989, Historic wave and sea level data report San Diego region, CCSTWS 88-6. 1988, Coastal cliff segments San Diego region (1887-1947), CCSTWS 88-6. 1984a, Shore protection manual. 1984b, Nearshore bathymetric survey report, no 1, CCSTWS 84-2. Weber, F.H., 1982, Geologic Map of north-central coastal area of San Diego County, California,showing recent slope failures and pre-development landslides:California Department of Conservation, Division of Mines and Geology, OFR 82-12 LA. Wilson, K.L., 1972, Eocene and related geology of a portion of the San Luis Rey and Encinitas quadrangles, San Diego County, California: unpublished masters thesis, university of California, Riverside. Zeevaert, L., 1972, Foundation engineering for difficult subsoil conditions: Van Nostrand Reinhold Company Regional Offices, New York. - Ziony,J.1., 1973, Recency of faulting in the greater San Diego area, California, in Ross,A., and Dowlen, R.J., eds., Studies on the Geology and Geologic Hazards of the Greater San Diego Area, California: San Diego Association of Geologists and Association of Engineering Geologists. Mr.Justin Gooding and Mr. Karl Weingarten Appendix A Page 8 File:e:\wp7\4300\4362a.uge GeoSoiils, Inc. APPENDIX B BORING LOGS (GS1, 2000) i • BORING LOG GeoSoils, Inc. wo. 2866-A-SC BORING B-1 SHEET�OF 3 .-- PROJECT:REFOLD 330 Neptune Avenue DATE EXCAVATED 4-19-00 v SAMPLE METHOD: Sample C Standard Penetration Test .. 3 0 + }^ y _ Water Seepage into hole + - ?4- } 0 Undisturbed, Ring Sample — t N N m 0 0. in 7 a ro Description of Material t X, -jo 3 N.0 v — C n 0 N 31 L m 3 C 7 — � Vl o m D t Co ° ° I EF11 U CE DEPOSITS :s: @ 0' SILTY SAND, orange brown, moist, loose; fine grained sands, well sorted, sub-rounded, roots to rootlets. — 0/6 'SM 107.9 6.4 31.7 @ e SILTY well Dsortedtllsub-rounded�oots. oist, very dense; @ 4', SILTY SAND, light brown to reddish brown, moist, 4.8 47 SM dense; fine grained, well sorted, sub rounded, transition between reddish brown sand to light brown. 90 SM 101 .8 3.3 14.1 @ 6'1 SILTY SAND, light brown, dry, very dense; fine medium grained, well sorted, sub-rounded, biotite, pyrite. 37 SM f : @ 8', SILTY SAND, light browny'dry, dense; fine grained, we ll Y 1'7 :^: sorted, sub-rounded, biotite, py o 10 48 SP 104.5 1.2 5.4 :�: @ 10', SAND, light brown, dry, dense, fine to medium grained, well sorted, sub-angular to rounded. 15 @ @ 15', SILTY SAND, light brown, damp, medium dense; fine 23 SM to medium sand, well sorted, sub-angular. 20 44 SP @ 20', SAND, light brown, dry, dense; fine to medium grained, well sorted, sub-rounded, biotite, quartz. 25 48 SP 1 5 @ 25', SAND, light brown, dry, dense; fine to medium grained, well sorted, sub-angular, feldspar, quartz. GeoSoils, Inc. PLATE B-1 330 Neptune Avenue - BORING LOG GeOSOils, Inc. W.O. 2866-A-SC BORING B-1 SHEET 2 OF 3 PROJECT:REFOLD 330 Neptune Avenue DATE EXCAVATED 4-19-00 SAMPLE METHOD: Sample + x C ® Standard Penetration Test 3 } ai °- Water Seepage into hole + + ,� '�4- 7 ro ® Undisturbed,Ring Sample 1 '0 "1 - u + L t a m m o a N o m Description of Material } �L •-D 3 (A� L O U E v m 1 C7 — N L E N ❑ m :j 4- Co :3 ❑ N / 61 SP 103.3 1.4 6.1 @ 30A SAND,�ight bro ONTIdNY ED Inse; fine to medium grained, well sorted, sub-angular, biotite, quartz. 35 43 SP 3.1 @ 35', SAND, light brown, damp, dense; fine grained, well sorted, sub-rounded. 4o i 25+ SP 101 .9 3.2 13.5 ;; ' @ 40', SAND, light brown, moist, very dense; fine to medium 0/4. grained, well sorted, sub-rounded, orange iron oxide. 45 64 SP 2.0 @ 45', SAND, light.brown, damp to moist, very dense; fine to coarse sand, well sorted, sub-angular, feldspar, quartz. 50 ' SP TORREY SANDSTONE FORMATION very dense; fine to @ 50', SANDSTONE, light brown, moist, 5012 medium grained, well sorted, sub-rounded. 55 50/2, 10.9 @ 55', SANDSTONE, light brown, moist, very dense; fine grained, well sorted sub-rounded. GeoSoils, Inc. PLATE B-2 330 Neptune Avenue i BORING LOG GeoSoils, Inc. W.0. 2866-A-SC BORING B-1 SHEET 3 OF 3 PROJECT:REFOLD 330 Neptune Avenue DATE EXCAVATED 4-19-00 SAMPLE METHOD: Sample \, } C ® Standard Penetration Test ^ 3 U + + } a _ Water Seepage into hole '+ �+ y C m ® Undisturbed, Ring Sample 1 O \ U + L .0 N N N o D a N � a '_` M E o U E v o o Description of Material m 7 C n — N 31 L 0 (a 0 to 7+ m 7 N C1 j 50/2' TORREY SANDSTONE FORMATION (CONTINUED_ @ 60', SANDSTONE, Ilght brown, wet, very dense; fine to medium grained, well sorted, sub-angular, no recovery. @ 60', SEEPAGE. 65 70 5013' 19.0 @ 70', SANDSTONE, olive gray, saturated, very dense; fine to medium grained, well sorted, sub-angular, orange iron oxide staining. 75 80 50/4' 21.8 @ 80', as per 70'. Total Depth = 81.5' Seepage @ 60' Backfilled 04-19-00 85 GeoSoils, Inc. PLATE B-3 330 Neptune Avenue • BORING LOG I GeoSOIIS, Inc. W.0. 2666-A-SC BORING HA-1 SHEET 1 OF PROJECT:REFOLD 330 Neptune Avenue DATE EXCAVATED 4-19-00 SAMPLE METHOD: Hand Auger Sample 3 �• c Standard Penetration Test + + ° Water Seepage into hole \ _ C: y m �� undisturbed, Ring Sample t m m a ° n } u t Y •-D 3 N D CL t _ M � o N � `" ° ro Description of Material m :1 c j _ v► m D N ° ARTIFICIAL FILL SM SILTY SAND, brown, moist to wet, loose; fine . @ 0-4', grained, well sorted, sub-rounded, roots and rootlets present. Total Depth = 4' No groundwater encountered 5 Backfilled 04-19-00 10 15 20 25 GeoSOHS, Inc. PLATE B-4 330 Neptune Avenue APPENDIX C SEISMICITY ANALYSIS MAXIMUM EARTHQUAKES GOODING/WEINGARTEN 1 x x x � x x x C xx m� xx L V Q .01 .001 .. ......... ... L. I-Iff- ... ........ 1 1 10 100 Distance (mi) Plate C-1 W.O. 4362-A-SC EARTHQUAKE RECURRENCE CURVE GOODING WEINGARTEN 100 10 L d Z 1 a c 4) w L .1 E Z > .01 E E U .001 Jill 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 Magnitude (M) Plate C-2 W.O. 4362-A-SC EARTHQUAKE EPICENTER MAP GOODING WEINGARTEN 1100 1000 900 \ 800 i 700 600 1 1 Soo J 400 300 200 LEGEND ivy X M = 4 �. 0 M = S / 100 ❑ M = 6 M = 7 ISI 0 OM = 8 0 0 O -100 600 -400 -300 -200 -100 0 100 200 300 400 500 W.O. 4362-A-SC Plate C-3 PROBABILITY OF EXCEEDANCE CAMP. & BOZ. (1997 Rev.) SR 1 E*:] EK] 25 yrs 50 yrs E:*:] E�:] 75 rs '100 rs 100 90 80 0 70 60 cc m 0 50 CL 40 as 30 as x 20 W 10 0 -_ 0.00 0.25 0.50 0.75 1 .00 1 .25 1 .50 Acceleration (g) Piate C-4 W.O. 4362-A-SC o U) z T O � r W U) J O W > o V %%woo O . LO co N y" N v O m Oa 06 LQ W a a � Z V N O W o � o 0 O 00 . 0 00 0 O 0 0 O O T TM O TM T pO1aad lljnjeH Plate C-5 W.O. 4362-A-SC APPENDIX D LABORATORY TEST RESULTS (GSI, 2000) 0 1 2 3 , 4 z H d' rj N H Z W U 6 Q. W IL e 9 10 2 4 6 1000 2 4 6 10000 2 100 STRESS (PSF) Exploration: B-01 Depth: 2.0' Undisturbed Ring Sample Drw Densitu (Pcf) : 108.0 Sample Innundated 0 1000 Psf Water Content (X) : 6.4 CONSOLIDATION Maw 2000 6eoSolls, Inc, TEST RESULTS W.O. : 2866-SC REFOLD D-1 Plate: M. J. Schiff& Associates,Inc. 1308 iVionte Vista Avenue,Suite 6 Consulting Corrosion Engineers-Since 1959 Upland,CA 91786-8224 Phone: 909/931-1360 Table 1 -Laboratory Tests on Soil Samples GeoSoils,Inc. Your#2866-A-SC,NIJS&A 100-0247LAB 1-Alay-00 Sample ID B-1 ��rx_v✓,��yj um T Resistivity Units ohm-cm 4,300 as-received 830 saturated ohm-cm 9.2 PH Electrical 0.39 Conductivity ms/cm Chemical Analyses Cations 88 calcium CaZ+ mg/kg 7 magnesium Mg+ mg/kg sodium Na+ mg/kg 258 Anions carbonate C032- mg/kg 37 bicarbonate HC031 mgtkg 37 chloride C11- mg/kg 376 sulfate SO42- mg/kg 153 Other Tests ammonium NH41+ mg/kg na nitrate N031' mg/kg na sulfide S2. qual na Redox my na Electrical conductivity in millisiemens/cm and chemical analysis were made on a 1:5 soil-to-water extract. Wig= m milligrams per kilogram(parts per million)of dry soil. Redox=oxidation-reduction potential in millivolts ND=not detected na=not analyzed Page W.O. 2866-A-SC Pa e 1 of 1 Plate D-2 APPENDIX E SLOPE STABILITY ANALYSIS -- APPENDIX E • SLOPE STABILITY ANALYSIS INTRODUCTION OF XSTABL COMPUTER PROGRAM Introduction XSTABL is a fully integrated slope stability analysis program. It permits the engineer to develop the slope geometry interactively and perform slope analysis from within a single program. The slope analysis portion of XSTABL uses a University. version of the popular STABL program, originally developed at Purdue ty XSTABL performs a two dimensional limit equilibrium analysis to compute the factor of can safety for a layered slope using the caldsurfaBe or the factor o methods. be used to search for the most crib afety may be dete mined for specific surfaces. XSTABL, Version 5.005, is programmed to handle: 1. Heterogenous soil systems 2. Anisotropic soil strength properties 3. Reinforced slopes 4. Nonlinear Mohr-Coulomb strength envelope 5. Pore water pressures for effective stress analysis using: a. Phreatic and piezometric surfaces b. Pore pressure grid C. . R factor 4. Constant pore water pressure 6. Pseudo-static earthquake loading 7. Surcharge boundary loads of an unlimited number of circular, noncircular 8. Automatic generation and analysis and block-shaped failure surfaces 9. Analysis of right-facing slopes 10. Both SI and Imperial units General Information If the reviewer wishes to obtain more information concerning slope stability analysis, the following publications may be consulted initially: 1. The Stability of Slopes, by E.N. Bromhead, Surrey University Press, Chapman and Hall, NY, 411 pages, ISBN 0 412 01061 5, 1992. 2. Rock Slope Enaineerina, by E. Hoek and J.W. Bray, Inst. of Mining and Metallurgy, London, England, Third Edition, 358 pages, ISNB 0 900488 573, 1981. GeoSoiils, Inc. 3. Landslides:Analysis and Control,by R.L.Schuster and R.J.Krizek(editors),o Special 176, Transportation Research Board, National Academy 234 pages, ISBN 0 309 02804 3, 1978. XSTABL Features The present version of XSTABL contains the following features: 1. Allows user to calculate factors of safety for static stability and dynamic stability situations. 2. Allows user to analyze stability situations with different failure modes. 3. Allows user to edit input for slope geometry and calculate corresponding factor of safety. 4. Allows user to readily review on-screen the input slope geometry. 5. Allows user to automatically generate and analyze unlimited number of circular, non-circular and block-shaped failure surfaces (i.e., bedding plane, slide plane, etc.). Input Data Input data includes the following items: 1. Unit weight, residual cohesion, residual friction angle, peak cohesion, and peak friction angle of fill material, bedding plane, and bedrock, respectively. Residual cohesion and friction angle is used for static stability analysis, whereas peak cohesion and friction angle is for dynamic stability analysis. 2. Slope geometry and surcharge boundary loads. 3. Apparent dip of bedding plane can be specified in angular range (i.e., from 0 to 90 degrees. - ic earthquake loading (an earthquake loading of 0.12 a was used in the 4. Pseudo-stat analysis. Output Information Output information includes: 1. All input data. Appendix E Mr.Justin Gooding and Mr. Karl Weingarten Page 2 FAe:e:\wp7\4300\4362a.uge GeoSoils, Inc. 2. Factors of safety for the ten most critical surfaces for static and pseudo-static stability situation. 3. High quality plots can be generated. The plots include the slope geometry, the critical surfaces and the factor of safety. 4. Note, that in the analysis,15,000 trial surfaces were analyzed for each section for either static or pseudo-static analysis. _Results of Slope Stability Calculation outpt Table E-1 shows parameters used in slope stability calculations.st bili Detailed analysis is information is presented In Plates E-1 and E-2. Summary of slope tY presented in Table E-2. TABLE E-1 SOIL PARAMETERS USED SOIL UNIT WEIGHT RESIDUAL STRENGTH SOIL MATERIALS TOTAL UNIT, .SATURATED C. WEIGHT :. UNIT WEIGHT (psf) '(degrees) c Quaternary Beach Deposits 115.0 125.0 0.0 30.0 Torrey Sandstone 120.0 130.0 300.0 34.0 Quaternary Terrace Deposits 120.0 125.0 1000.0 37.0 Artificial Fill 120.0 125.0 200.0 30.0 TABLE E-2 SUMMARY OF SLOPE ANALYSIS FACTORS OF SAFETY BEYOND THE RECOMMENDED.50-FOOT SETBACK 20NE�' LOCATION :` . STATIC . t'7777777777, 77:7� SEISMIC , Bluff Section A-A' 1.51 1.21 Appendix E Mr.Justin Gooding and Mr. Karl Weingarten Page 3 R le:e:\wp7\4300\4362a.ug e GeoSoiils, Inc. N • N Ou V --------- ------ N In W ° cc - --- - - ------- . -- ~--- - 11-- - -- - - -- ch M p e r ' N --h--� -'c---- - -;' - ' Q (� NgvN C 1 �m C vr . ; o o p a ; --- - - -- Z ----- ,--------- O m d 1 10:3 f J dL � r � V m a„ 1 2 �W V n / IV � Crrrr ... 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APPENDIX F GENERAL EARTHWORK AND GRADING GUIDELINES GENERAL EARTHWORK AND GRADING GUIDELINES General These guidelines present general procedures and requirements for earthwork and grading as shown on the approved grading plans, including preparation of areas to filled, placement of fill, installation of subdrains and excavations. The recommendations contained in the geotechnical report are part of the earthwork and grading guidelines and would supercede the provisions contained course of grading may hereafter in of conflict.result in Evaluations performed by the consultant during recommendations which could supersede these guidelines or the recommendations contained in the geotechnical report. The contractor is responsible forthe satisfactory completion of all earthwork in accordance with provisions of the project plans and specifications. The project soil engineer and engineering geologist (geotechnical consultant) or their representatives should provide observation and testing services,and geotechnical consultation during the duration of the project. EARTHWORK OBSERVATIONS AND TESTING Geotechnical Consultant Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer and engineering geologist) should be employed for the purpose of observing earthwork procedures and testing the fills for orm plans, with the applicable grading recommendations codes and geotechnical report, the approve grading p ordinances. The geotechnical consultant should provide testing and observation so that determination may be made that the work is being accomplished as specified. It is the responsibility of the contractor to assist the consultants and keep them apprised of anticipated work schedules and changes, so that they may schedule their personnel accordingly. All clean-outs, prepared ground to receive fill, key excavations, and subdrains should be observed and documented by the project engineering geologist and/or soil engineer prior to placing and fill. It is the contractors's responsibility to notify the engineering geologist and soil engineer when such areas are ready for observation. Laboratory and Field Tests Maximum dry density tests to determine the degree of compaction should be performed in accordance with American Standard Testing Materials test method ASTM designation D-1557-78. Random field compaction tests should be performed in accordance with test method ASTM designation D-1556-82, D-2937 or D-2922 and D-3017, at intervals of approximately 2 feet of fill height or every 100 cubic yards of fill placed. These criteria GeoSoi ls, Inc. would vary depending on the soil conditions and the size of the project. The location and frequency of testing would be at the discretion of the geotechnical consultant. Contractor's Responsibility -- All clearing,site preparation,and earthwork performed on the project should be conducted by the contractor, with observation by geotechnical consultants and staged approval by the governing agencies, as applicable. It is the contractor's responsibility to prepare the ground surface to receive the fill, to the satisfaction of the soil engineer, and to place, spread, moisture condition, mix and compact the fill in accordance with the recommendations of the soil engineer. The contractor should also remove all major non- earth material considered unsatisfactory by the soil engineer. It is the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the earthwork in accordance with applicable grading guidelines, codes or agency ordinances, and approved grading plans. Sufficient watering apparatus and _ compaction equipment should be provided by the contractor with due consideration for the fill material, rate of placement, and climatic conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such as questionable weather, - excessive oversized rock, or deleterious material,insufficient support equipment, etc.,are resulting in a quality of work that is not acceptable, the consultant will inform the contractor, and the contractor is expected to rectify the conditions, and if necessary, stop work until conditions are satisfactory. During construction, the contractor shall properly grade all surfaces to maintain good drainage and prevent ponding of water. The contractor shall take remedial measures to control surface water and to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. SITE PREPARATION All major vegetation, including brush, trees, thick grasses, organic debris, and other deleterious material should be removed and disposed of off-site. These removals must be concluded prior to placing fill. Existing fill, soil, alluvium, colluvium, or rock materials determined by the soil engineer or engineering geologist as being unsuitable in-place should be removed prior to fill placement. Depending upon the soil conditions, these materials may be reused as compacted fills. Any materials incorporated as part of the compacted fills should be approved by the soil engineer. Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipelines, or other structures not located prior to grading are to be removed or treated in a manner recommended by the soil engineer. Soft, dry, spongy, highly fractured, or otherwise unsuitable ground extending to such a depth that surface Mr.Justin Gooding and Mr. Karl Weingarten Appendix F Page 2 fi1e:e:\wp7\4300\4362a.uge GeoSoils, Inc. processing cannot adequately improve the condition should be overexcavated down to firm ground and approved by the soil engineer before compaction and filling operations continue. Overexcavated and processed soils which have been properly mixed and moisture conditioned should be re-compacted to the minimum relative compaction as specified in these guidelines. be Existing ground which is determined to be satisfactory for support engineer.fills should he scarified to a minimum depth of 6 inches or as directed by the soi l scarified ground is brought to optimum moisture content or greater and mixed, the materials should be compacted as specified herein. If the scarified zone is grater that 6 inches in depth, it may be necessary to remove the excess and place the material in lifts restricted to about 6 inches in compacted thickness. Existing ground which is not satisfactory to support compacted fill should be overexcavated as required in the geotechnical report or by the on-site soils engineer and/or engineering geologist. Scarification, disc harrowing, or other acceptable form of - mixing should continue until the soils are broken down and free of large lumps or clods, until the working surface is reasonably uniform and free from ruts, hollow, hummocks, or other uneven features which would inhibit compaction as described previously. Where fills are to be placed on ground with slopes t bench, which will al toas aI key, the ground should be stepped or benched. The low s should be a minimum of 15 feet wide and should be at least 2 feet deep into firm material, and approved by the soil engineer and/or engineering geologist. In fill over cut slope conditions, the recommended minimum width of the lowest bench or key is also 15 feet - with the key founded on firm material, as designated by the Geotechnical Consultant. As a general rule, unless specifically recommended otherwise by the Soil Engineer, the minimum width of fill keys should be approximately equal to 1h the height of the slope. Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable material. Benching may be used to remove unsuitable materials,although it is understood that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered for unsuitable materials in excess of 4 feet in thickness. All areas to receive fill, including processed areas, removal areas, and the toe of fill benches should be observed and approved by the soil engineer and/or engineering -- geologist prior to placement of fill. Fills may then be properly placed and compacted until design grades (elevations) are attained. Appendix F Mr.Justin Gooding and Mr. Karl Weingarten Page 3 file:e:\wp7\4300\4362a.uge GeoSoils, Inc. COMPACTED FILLS Any earth materials imported or excavated on the property may be utilized in the fill provided that each material has been determined to be suitable by the soil engineer. These materials should be free of roots, tree branches, other organic matter or other deleterious materials. All unsuitable materials should be removed from the fill as directed by the soil engineer. Soils of poor gradation, undesirable expansion potential, or substandard strength characteristics may be designated by the consultant as unsuitable and may require blending with other soils to serve as a satisfactory fill material. Fill materials derived from benching operations should be dispersed throughout the fill area and blended with other bedrock derived material. Benching operations should not result in the benched material being placed only within a single equipment width away from the fill/bedrock contact. Oversized materials defined as rock or other irreducible materials with a maximum dimension greater than 12 inches should not be buried or placed in fills unless the location of materials and disposal methods are specifically approved by the soil engineer. Oversized material should betaken off-site or placed in accordance with recommendations - of the soil engineer in areas designated as suitable for rock disposal. Oversized material should not be placed within 10 feet vertically of finish grade (elevation) or within 20 feet horizontally of slope faces. To facilitate future trenching, rock should not be placed within the range of foundation excavations, future utilities, or underground construction unless specifically approved by - the soil engineer and/or the developers representative. If import material is required for grading, representative samples of the materials to be utilized as compacted fill should be analyzed in the laboratory by the soil engineer to determine its physical properties. If any material other than that previously tested is encountered during grading,an appropriate analysis of this material should be conducted by the soil engineer as soon as possible. Approved fill material should be placed in areas prepared to receive fill in near horizontal layers that when compacted should not exceed 6 inches in thickness. The soil engineer may approve thick lifts if testing indicates the grading procedures are such that adequate -- compaction is being achieved with lifts of greater thickness. Each layer should be spread evenly and blended to attain uniformity of material and moisture suitable for compaction. Fill layers at a moisture content less than optimum should be watered and mixed,and wet fill layers should be aerated by scarification or should be blended with drier material. Moisture condition, blending, and mixing of the fill layer should continue until the fill materials have a uniform moisture content at or above optimum moisture. � Mr.Justin Gooding and Mr. Karl Weingarten Appendix F Page 4 Flee:\wp7\4300\4362a.uge GeoSoils, Inc. After each layer has been evenly spread, moisture maximum m density as determined by uniformly compacted to a minimum of 90 per cent of ASTM test designation, D-1557-78, or as otherwise recommended by the soil engineer. Compaction equipment should be adequately sized and should be specifically designed for soil compaction or of proven reliability to efficiently achieve the specified degree of compaction. Where tests indicate that the density of any layer of fill, or portion thereof, is below the required relative compaction, or improper moisture is in evidence, the particular layer or portion shall be re-worked until the required density and/or moisture content has been attained. No additional fill shall be placed in an area until the last placed lift of fill has been tested and found to meet the density and moisture requirements, and is approved by the soil engineer. Compaction of slopes should be accomplished by over-building a minimum of 3 feet horizontally, and subsequently trimming back to the design slope configuration. Testing shall be performed as the fill is elevated to evaluate compaction as the fill core is being developed. Special efforts may be necessary to attain the specified compaction in the fill slope zone. Final slope shaping should be performed by trimming and removing loose - materials with appropriate equipment. Afinal determination of fill slope compaction should be based on observation and/or testing of the finished slope face. Where compacted fill slopes are designed steeper than 2:1 (horizontal to vertical), specific material types, a higher minimum relative compaction, and special grading procedures, may be recommended. If an alternative to over-building and cutting back the compacted fill slopes is selected, then special effort should be made to achieve the required compaction in the outer 10 feet of each lift of fill by undertaking the following: 1. An extra piece of equipment consisting of a heavy short shanked sheepsfoot should be used to roll (horizontal) parallel to the slopes continuously as fill is placed. The sheepsfoot roller should also be used to roll perpendicular to the slopes, and extend out over the slope to provide adequate compaction to the face of the slope. 2. Loose fill should not be spilled over a over the face of the d slope face should be compacted. Any loose fill spilled previously - trimmed off or be subject to re-rolling. 3. Field compaction tests will be made in the outer (horizontal) 2 to 8 feet of the slope at appropriate vertical intervals, subsequent to compaction operations. 4. After completion of the slope,the slope face should be shaped with a small tractor and then re-rolled with a sheepsfoot to achieve compaction to near the slope face. Subsequent to testing to verify compaction, the slopes should be grid-rolled to Mr.Justin Gooding and Mr. Karl Weingarten Appendix F page 5 Fie:e:\wp7\4300\4362a.uge GeoSoiils, I»e. achieve compaction to the slope face. Final testing should be used to confirm compaction after grid rolling. 5. Where testing indicates less than adequate compaction, the contractor will be responsible to rip, water, mix and re-compact the slope material as necessary to achieve compaction. Additional testing should be performed to verify compaction. 6. Erosion control and drainage devices should be designed by the project civil engineer in compliance with ordinances of the controlling governmental agencies, and/or in accordance with the recommendation of the soil engineer or engineering geologist. SUBDRAIN INSTALLATION Subdrains should be installed in approved ground in accordance with the approximate alignment and details indicated by the geotechnical consultant. Subdrain locations or materials should not be changed or modified without approval of the geotechnical - consultant. The soil engineer and/or engineering geologist may recommend and direct changes in subdrain line, grade and field, pending expos c d conditions. The location of constructed subdrains should beecoded by the project engineer. EXCAVATIONS Excavations and cut slopes should be examined during grading by the engineering geologist. If directed by the engineering geologist,further excavations or overexcavation of cut slopes and re-filling of cut areas should beperformed e narerto remedial be graded�luness otherwise should be performed: When fill over p approved, the cut portion of the slope of the fill portion of theslope engineering geologist prior to placement of materials for construction The engineering geologist should observe all cut slopes and should be notified by the contractor when cut slopes are started. If, during the course of grading, unforeseen adverse or potential adverse geologic conditions are encountered, the engineering geologist and soil engineer should investigate, evaluate and make recommendations to treat these problems. The need for cut slope buttressing or stabilizing should be based on in-grading evaluation by the engineering geologist, whether anticipated or not. Unless otherwise specified in soil and geological reports, no cut slopes should be excavated higher or steeper than that stability of temporary cut slopes sllthe governmental agencies. Additionally, short-term contractors responsibility. Mr.Justin Gooding and Mr. Karl Weingarten Appendix F page 6 Fi1e:eAwp7\4300\4362a.uge GeoSoils, Inc. Erosion control and drainage devices should be designed by the project civil engineer and should be constructed in compliance with the ordinances of the controlling governmental agencies, and/or in accordance with the recommendations of the soil engineer or engineering geologist. COMPLETION Observation,testing and consultation by the geotechnical consultant should be conducted during the grading operations in order to state an opinion that all cut and filled areas are graded in accordance with the approved project specifications. After completion of grading and after the soil engineer and engineering geologist have finished their observations of the work,final reports should be submitted subject to review by the controlling governmental agencies. No further excavation or filling should be undertaken without prior notification of the soil engineer and/or engineering geologist. All finished cut and fill slopes should be protected from erosion and/or be planted in accordance with the project specifications and/or as recommended by a landscape architect. Such protection and/or planning should be undertaken as soon as practical after completion of grading. JOB SAFETY General At GeoSoils, Inc. (GSI) getting the job done safely is of primary concern. The following is the company's safety considerations for use by all employees on multi-employer construction sites. On ground personnel are at highest risk of injury and possible fatality on grading and construction projects. GSI recognizes that construction activities will vary on each site and that site safety is the rp ime responsibility of the contractor; however, everyone must be safety conscious and responsible at all times. To achieve our goal of avoiding accidents,cooperation between the client,the contractor and GSI personnel must be maintained. -- In an effort to minimize risks associated with geotechnical testing and observation, the following precautions are to be implemented for the safety of field personnel on grading and construction projects: Safety Meetings: GSI field personnel are directed to attend contractors regularly scheduled and documented safety meetings. Safety Vests: Safety vests are provided for and are to be worn by GSI personnel at all times when they are working in the field. Appendix F Mr. Justin Gooding and Mr. Karl Weingarten App Page F Fi1e:e:\wp7\4300\4W2a.uge GeoSoils, Inc. Safety Flags: Two safety flags are provided to GSI field technicians; one is to be • affixed to the vehicle when on site,the other is to be placed atop the spoil pile on all test pits. Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashing amber beacon, or strobe lights, on the vehicle during all field testing. While operating a vehicle in the grading area, the emergency flasher on the vehicle shall be activated. In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office. Test Pits Location Orientation and Clearance The technician is responsible for selecting test pit locations. A primary concern should be the technicians's safety. Efforts will be made to coordinate locations with the grading -- contractors authorized representative, and to select locations following or behind the established traffic pattern, preferably outside of current traffic. The contractors authorized representative (dump man, operator, supervisor, grade checker, etc.) should direct - excavation of the pit and safety during the test period. Of paramount concern should be the soil technicians safety and obtaining enough tests to represent the fill. Test pits should be excavated so that the spoil pile is placed away form oncoming traffic, whenever possible. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates the fill be maintained in a driveable condition. Alternatively, the contractor may wish to park a piece of equipment in front of the test holes, particularly in small fill areas or those with limited access. A zone of non-encroachment should be established for all test pits. No grading equipment should enter this zone during the testing procedure. The zone should extend approximately 50 feet outward from the center of the test pit. This zone is established for safety and to avoid excessive ground vibration which typically decreased test results. When taking slope tests the technician should park the vehicle directly above or below the of the test location. If this is not possible, should effectively ively keep all equipment at a s slope. The contractor's representative operation distance (e.g., 50 feet) away from the slope during this testing. The technician is directed to withdraw from the active portion of the fill as soon as possible following testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location, well away from the equipment traffic pattern. The contractor should inform our personnel of all changes to haul roads,cut and fill areas or other factors that may affect site access and site safety. Mr. Justin Gooding and Mr. Karl Weingarten Appendix F Page 8 File:e:\wp7\4300\4362a.uge GeoSoils, Inc. In the event that the technicians safety is jeopardized or compromised as a result of the contractors failure to comply with any of the above,the technician is required, by company policy, to immediately withdraw and notify his/her supervisor. The grading contractors representative will eventually be contacted in an effort to effect a solution. However, in the interim, no further testing will be performed until the situation is rectified. Any fill place can be considered unacceptable and subject to reprocessing, recompaction or removal. In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor brings this to his/her attention and notify this office. Effective communication and coordination between the contractors representative and the soils technician is strongly encouraged in order to implement the above safety plan. Trench and Vertical Excavation It is the contractor's responsibility to provide safe access into trenches where compaction __. testing is needed. Our personnel are directed not to enter any excavation or vertical cut which: 1) is 5 feet or -- deeper unless shored or laid back; 2) displays any evidence of instability, has any loose rock or other debris which could fall into the trench; or 3) displays any other evidence of any unsafe conditions regardless of depth. All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters, should be shored or laid back. Trench access should be provided in accordance with CAL-OSHA and/or state and local standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment. If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraw and notify his/her supervisor. The contractors representative will eventually be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other reasons could be subject to reprocessing and/or removal. If GSI personnel become aware of anyone working beneath an unsafe trench wall or vertical excavation, we have a legal obligation to put the contractor and owner/developer - on notice to immediately correct the situation. If corrective steps are not taken, GSI then has an obligation to notify CAL-OSHA and/or the proper authorities. Appendix F Mr.Justin Gooding and Mr. Karl Weingarten Page 9 File:eAwp7\4300\4362a.uge GeoSoils, Inc. TRANSITION LOT DETAIL CUT LOT (MATERIAL TYPE TRANSITION) NATU RAL GRAD �� / 5' MINIM M PAD GRAD E / OVEREXCAVATE AND RECOMPACT COMPACTED FILL 3' MINIMUM* o \ UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING CUT--FILL LOT (DAYLIGHT TRANSITION) 4 NATURAL GRADE MN.�tiR�P 5'MI MUM - PAD GRADE �NSV��P OYEREXCAVATE ' OR AND RECOMPACT COMPACTED FILL w.oz \ /�\ �//\��// T MINIMUM* UNWEATHERED BEDROCK OR APPROVED MATERIAL TYPICAL BENCHING NOTE: * DEEPER OVEREXCAVATION MAY BE RECOMMENDED BY THE SOILS AREAS.ENGINEER AND/OR ENGINEERING GEOLOGIST IN STEEP CUT-FILL TRANSITION PLATE EG-11 GeoSoiis, Inc. TEST PIT SAFETY DIAGRAM SLOE VIEVN v�I1cL.E SPOIL PILE TEST PIT ( NOT TO SCALE 1 TOP VIEW 100 FEET °n 50 FEET 50 FEET FLAG SPOIL TEST PIT A. :LE PIS F- FLAG APPROXIMATE CEPITER LL OF 'TEST PIT tn ( NOT TO SCALE GeoSoils, Inc. P LATE EG—"16 APPENDIX G GUIDELINES FOR THE HOMEOWNER u. GUIDELINES FOR THE HOMEOWNER Tips for the Homeowner Homesites, in general, and hillside lots, in particular, need maintenance to continue to function and retain their value. Many homeowners are unaware of this and allow deterioration of their property. In addition to one's own property,the homeowner may be subject to liability for damage occurring to neighboring properties as a result of his negligence. It is,therefore, important to th l aware of the importance of maintenance. maintenance of their properties and m ake em Nature slowly wears away land, but human activities such as construction increase the rate of erosion 200, even 2,000 times that amount. When vegetation or other objects are removed that hold soil in place, the soil is exposed to the action of wind and water and increase its chances of eroding. The following maintenance guidelines are provided for the protection of the homeowner's investment, and should be employed throughout the year. 1. Care should be taken that slopes,terraces, berms (ridges at crown of slopes), and proper lot drainage are not disturbed. Surface drainage should be conducted from the rear yard to the street by a graded swale through the side yard, or alternative approved devices. 2. In general, roof and yard runoff should be conducted to either the street or storm drain by nonerosive devices such as sidewalks,drainage pipes,ground gutters,and driveways. Drainage systems should not be altered without expert consultation. 3. All drains should be kept cleaned and unclogged, including gutters and downspouts. Terrace drains or gunite ditches should be kept free of debris to allow proper drainage. During heavy rain periods, performance of the drainage system should be inspected. Problems, such as gullying and ponding, if observed,should be corrected as soon as possible. 4. Any leakage from pools,water lines, etc. or bypassing of drains should be repaired as soon as possible. 5. Animal burrows should be filled inasmuch as they may cause diversion of surface runoff, promote accelerated erosion, and even trigger shallow soil failures. 6. Slopes should not be altered without expert consultation. Whenever a homeowner plans a significant topographic modification of the slope, a qualified geotechnical consultant should be contacted. GeoSOUS9 Inc. 7. If plans for modification of cut,fill or natural slopes within a property are considered, an engineering geologist should be consulted. Any oversteepening may result in - a need for expensive retaining devices. Undercutting of the bottom of a slope might possibly lead to slope instability or failure and should not be undertaken without expert consultation. 8. If unusual cracking, settling, or earth slippage occurs on the property, the homeowner should consult a qualified soil engineer or an engineering geologist immediately. g. The most common causes of slope erosion and shallow slope failures are as follows: • Gross neglect of the care and maintenance of the slopes and drainage devices. • Inadequate and/or improper planting. (Barren areas should be replanted as soon as possible). • Excessive or insufficient irrigation or diversion of runoff over the slope. • Foot traffic on slopes destroying vegetation and exposing soil to erosion potential. 10. Homeowners should not let conditions on their property create a problem for their neighbors. Cooperation with neighbors could prevent problems,and also increase the aesthetic attractiveness of the properties. Winter Alert it is especially important to "winterize" your property by mid-September. Don't wait until spring to put in landscaping. You need winter protection. Final landscaping can be done later. Inexpensive measures installed by mid-September will give you protection quickly that will last all during the wet season. • Check before storms to see that drains, gutters, downspouts, and ditches are not clogged by leaves and rubble. • Check after major storms to be sure drains are clear and vegetation is holding on slopes. Repair as necessary. • Spot seed any bare areas. Broadcast seeds or use a mechanical seeder. Atypical slope or bare area can be done in less than an hour. Mr.Justin Gooding and Mr. Karl Weingarten Appendix G Page 2 Fi1e:e:\wp7\4300\4362a.uge GeoSoiils, Inc. • Give seeds a boost with fertilizer. • Mulch if you can, with grass clippings and leaves, bark chips or straw. • Use netting to hold soil and seeds on steep slopes. • Check with your landscape architect or local nursery for advice. • Prepare berms and ditched to drain surface runoff water away from problem areas such as steep, bare slopes. • Prepare bare areas on slopes for seeding by raking the surface to loosen and roughen soil so it will hold seeds. CONSTRUCTION 1. Plan construction activities during spring and summer, so that erosion control measures can be in place when rain comes. 2. Examine your site carefully before building. Be aware of the slope,o dexpensive dr iag patterns and soil types. Proper site design will hel p yp stabilization work. 3. Preserve existing vegetation as much as possible. Vegetation will naturally curb erosion, improve the appearance value of your property, and reduce the cost of landscaping later. 4. Use fencing to protect plan from h It or material paving blocks.0 have to pave near trees, do so with permeable p porous 5. Minimize the length and steepness of slopes by benching,terracing,or constructing diversion structures. Landscape benched areas to stabilize the slope and improve its appearance. 6. As soon as possible after grading a site, plant vegetation on all areas that are not paved or otherwise covered. TEMPORARY MEASURES TO STABILIZE SOIL Grass provides the cheapest and most effective short-term erosion control. It grows quickly and covers the ground completely. To find the best seed mixtures and plants for your area,check with your local landscape architect,local nursery,orthe U.S.Department of Agriculture Soil Conservation Service. A ppendix G Mr.Justin Gooding and Mr. Karl Weingarten Page 3 Fi1e:e:\wp7\4300\4362a.uge GeoSoils, Inc. es hold soil moisture and provide ground protection from rain damage. mulches Mulch plants. Easy to ob provide a favorable environment for starting and growing are grass clippings, leaves, sawdust, bark chips, and straw. Straw Mulch is nearly 100 percent effective when held in place by shovel or ith an r oa is glue or wood fiber (tackifliers), by punching it into s tacking a netting over it. Commercial applications of wood fibers combinew yeas.various Hydrauli seeds mul hing with ra (hydraulic mulching) are effective in stabilizing sloped tackifier should be done in two separate applications: remaining ns:tthefirr t p s ch of seed fertilizer er. and half the mulch, the second composed o Commercial hydraulic mulch applicators-who also provide other erosion control services-are listed under "landscaping" in the phone book. Mats of excelsior, jute netting, and plastic sheets can effective o twork effectively.covers, but they must be in contact with the soil and fastened Roof drainage can be collected in barrels or storage ed water o you don't collect mosquitos. planter boxes,and gardens. Be sure to cover stored Excessive runoff should be directed away from your house. Too much water can damage trees and make foundations unstable. STRUCTURAL RUNOFF CONTROLS Even with propertiming and planting,you may need toprotect disturbed t ways to until the plants have time to establish themselves. O r y ou Y need permanent transport water across your property so that it doesn't cause erosion. lots, streets, To keep water from carrying soil from your site tsvolumedumping ispeedySome examples streams and channels, you need ways to reduce of what you might use are: 1. Rip-rap (rock lining) -to protect channel banks from erosive water flow. 2. Sediment trap -to stop runoff carrying sediment and trap the sediment. 3. Storm drain outlet protection-to reduce the speed of water flowing from a pipe onto open ground or into a natural channel. 4. Diversion dike or perimeter dike -to divert excess water to places where it can be disposed of properly. Appendix G Mr.Justin Gooding and Mr. Karl Weingarten Page 4 File:e:\wp7\4300\4362a.uge GeoSoiils, Inc. 5. Straw bale dike - to stop and detain sediment from small unprotected areas (a short term measure). g. Perimeter swale -to divert runoff from a disturbed area or contain runoff within a disturbed area. 7. Grade stabilization structure -to carry concentrated runoff down a slope. Appendix G Mr.Justin Gooding and Mr. Karl Weingarten Page 5 File:e:\wp7\4300\4362a.uge GeoSoiis, Inc. Mar 16 05 06: 15p Steven Lombardi 619-523-4785 p. 2 Mar 16 05 06: 11p John Finbhony Micita 619-463-4964 p. l ��F(�SSiOiJA(E�, O Ole Pi 2 SA*-A P 6NI aTz- G tit l l_ c sQU�P Oqc—�—, zq GAP D e:IP5 T . 4 Re.,,%4H C izU W lDe K'2h„ �E�� k=,gODOrm 1 1 cD�c. M 66*4r- =[400o PSk, if n"c �--` Gay LSSo 1,4 V\I�C¢) - v Ear ` 2 7-t�es cs—;, f 2°tDlc l2'-0" PAt1rL -� ��;50e�.5 'tro �e-- L�DGA -ie7lp � G�c• coCZN� �- ��o� M4 ce-p w� ��r aJ 15;7---3 4-Z 9 S _ — City of Encinitas r 505 South Vulcan Avenue Fire Encinitas,California 92024-3633 Building Tel 760-633-2600•Fax 760-943-2226 TDD 760-633-2700 wN%iv.ci.encinitas.ca.us Planning Engineering Field Clearance to Allow Occupancy. TO: Subdivision Engineering Public Service Counter FROM: Field Operations Private Contract Inspection RE: Building Permit No. -- Name of Project .i ���.r t Name of Developer I have inspected the site at 0 ,nom address sffeet name suffix and have determined that finish (precise) grading (lot no.) (bldg.no.) and any other.related site improvements are substantially complete and that occupancy is merited. Signature of Engineering Inspector Date Signature of Senior.Civil Engineer,only if appropriate Date Reference: Engineering Permit No.929.5-111 Special Note: Please do not sign the"blue card"that is issued by Building Inspection Division and given to the developer.Your are only being asked to verify field conditions. Office staff still has the responsibility to verify that compliance with administrative requirements is achieved,typically payment of impact fees or execution of documents. Return-this form,if completed,to counter staff by dropping it in the slot labeled "Final Inspection". Also,.please remember to do final inspections on the related engineering permits and return that paperwork,ifcompleted. Thank you. SENT BY: GEOSOILS, INC. ; 7609310915; MAR-17-05 10:39AM; PAGE 2 is Geotechnical • Geologic Envieonmental 5741 Palmer Way Carlsbad, California 9200a • (760)4383155 • FM(7W)931-0915 MEM0RANUUM DATE: March 17, 2005 W.O. 4362- �SrpNAC OF TO: Mr. Justin Gooding and Mr. Carl Weingarten �OfEasio p� zi6 FRq'`' c/o Mr. Steven Lombardi, Architect No. 1340 certified FROM: John P. Franklin and Andrew T. Guatelll NO. GE-2320 En4lnearinq 7r (#so1091st 1 EXP. 12-31-06 a :A E- SUBJECT: Amended Recommendations, Proposed a wne Ave F0 CA%.% ° Encinitas, San Diego, California F a►Oc�� Due to deeper removals than were anticipated based on the then-available daila,within the footprint of the proposed addition, 11 is our understanding that the clients'and/or their representative(s)electto support the proposed addition with deepened foundations in lieu of remedial earthwork to remove unsuitable bearing soils. In light: of this development decision (by others), remedial grading of the undocumented fill onsite appears to be unnecessary given the deep foundation as currently planned. GeoSoils,: Inc.'s (GSI) recommendations for a pier and grade beam foundation system have been provided in the referenced documents provided below. References: 1. "Geotechnical Review of Foundation Detail, 330 Neptune Avenue, City of Encinitas, San Diego County, California," W.O. 4362-C1-SC, dated March 17, 2005, by GeoSoils, Inc. 2. "Geotechnical Review of Typical Grade Beam/Caisson Foundations, 330 Neptune Avenue, City of Encinitas, San Diego County, California," W.O. 4362-Cl-SC, dated March 17, 2005. 3. "Amended Foundation Recommendations,330 Neptune Avenue, City of Encinitas, San Diego County, California", W.O. 4362-C-SC, dated March 10, 2005, by GeoSoils, Inc. RB/JPF/ATG/jk MAR-17-05 10: 40AM; 7609310915; . °E°sdlLS� INC. ; SEN"� onment I al L: . • ologic Env, ical • G e .3 Geotec n 760)931-0915 FAX (760)438-$1 92008 � . ..: California 7,1 Palmer Way Ga ,bad, 17,2005 W.O. 43602'C'-S C 5 Mar rl W ein9a�en Gooding and IMr. af, Mr. JS even even Lombardi, Arc clo,�Bacon Street, #0 gan Diego. California 92107 Foundation Detail, Mr. Steven Lombardi eam�Caisso Caldornia Attention: of Typical Grade B o County, ub Subject: Geotechni el Review venue, City of Encinitas, San ple9 a None,facsimile S I 330 Neptun venue':'Scat Caisson pdn-,"330 Neptune A 1. 330 Neptune,TYp•Gr.Bm-1 on Nielta. References: " arch 16,2005,by john Anth Y ven�-1e,City of Fnanitas.San dated M Neptune A GeoSoils,Inc. endations�a3� March 10,2005,by 2 Amended Foundation R O 4362-CIgG, D1ego County,Calforrna Dear Mr. Lombardi: has review ed the typical grade GeoSoils, Inc. (CSI) nthony Nicita, Pf Oject our request by Mr. John A Ian revisal In accordance with y sled this 9eotechnical.p eamlc�sson foundation u No�)f and has prepared No 1 for general cQ%rv, es has b meal(see Reference Structural Eng Was to review Referent our of servlc ur ose of our study 2- prole structural letter. Thep P Unless No, the recommendations 1 and 2, discussions Wi cal rev ew letter. with mendations outlined in Reference 'NI of Reference eotec resented in included a review and the preparation of this 9 recommendations P. o riately analysis of data, the recornm consultant, applicable, and should be apPrth t the specific ceded in the to gal d andeapp l please note s�eC are considered design, and construction. eclude the implemented No.during Planning, do not entirely Pr ede the implemented m reference No. 2 recommendations provided here 1n and a slab. Recommendations o"equest. fe° or and/or water through th Slab could be provided up transmission of vapor and/or water through the transmission of vap T� GEOTECHNICAL REVIEW 0� FOU antra with th structural detail appears to be in general conform from e reviewed this office and presented in Reference N�provided: Th provided by the following comments are recommendations 9 eotethnical viewpoint• Rased on our review, S9 Geotechnical • Geologic . Environmental 5741 Palmer Way • Carlsbad, California 92008 • (760) 438-3155 - FAX (760) 931-0915 April 20, 2005 W.O. 4362-B-SC Mr. Justin Gooding and Mr. Karl Weingarten c/o Mr. Steven Lombardi, Architect 1889 Bacon Street, #8 San Diego, California 92107 Attention: Mr. Steven Lombardi Subject: Alternative Earthwork Recommendations, 330 Neptune Avenue, City of Encinitas, San Diego County, California References: 1_ "Preliminary Shoring Recommendations, 330 Neptune Avenue, City of Encinitas, San Diego County, California," W.O. 4362-C-SC, dated March 30, 2005, by GeoSoils, Inc. 2_ "Amended Foundation Recommendation, 330 Neptune Avenue, City of Encinitas, San Diego County, California," W.O. 4362-C-SC, dated March 10, 2005, by GeoSoils, Inc_ 3_ "Update Geotechnical Evaluation and Bluff Study, Proposed Addition, 330 Neptune Avenue, City of Encinitas, San Diego County, California," W.O. 4362-A-SC, dated June 28, 2004, by GeoSoils, Inc. Dear Mr. Lombardi: Per your request, GeoSoils, Inc. (GSI) is providing the following earthwork recommendations as an alternative to the drilled pier and shoring recommendations that you had previously requested from our office. It is our understanding that the drilled pier recommendations, provided in Reference No. 2, will require plan revision and approval by the City and the requested shoring recommendations,provided in Reference No. 1,will not likely be cost effective, based on your analysis. Therefore, GSI is providing the following alternative recommendations to complete the necessary remedial earthwork at the site. ALTERNATIVE EARTHWORK RECOMMENDATIONS The following alternative earthwork recommendations should be reviewed and approved by the project structural engineer in order to assure that the existing residence will not be subjected to structural deformations during the removal of unsuitable bearing soils, and the materials proposed for foundation support will not compromise the stability of the proposed addition. In order to perform the necessary remedial earthwork, GSI recommends the following: T 'd SSG -EZS-6T9 3PJegwol uanags 492 : 10 S D 12 u d d 1. The upper portions of unsuitable bearing soils may be removed to the top of the existing residential and retaining wall footings for a section of no more than 15 lateral feet along the strip footing. 2. The removal of unsuitable bearing soils should be accommodated by the excavation of vertical slots. The width of the slot excavations should not exceed 36 inches and should be approved by the structural engineer prior to implementation. Multiple slots should be spaced at 36 inches. However, two consecutive "side by side" slots should be avoided. Additionally, the number of slots and the slot widths should not cause the allowable bearing capacity of the existing, adjacent residential or wall footing to increase by more than 2.0 times the allowable bearing. This will require proper sequencing during construction. Slot removals should be completed to encounter suitable bearing terrace deposits. The depths of removals are anticipated to be on the order of ±6 to +7 feet below the existing grade. A representative from this office should be present during all remedial earthwork to observe the completion of removals into suitable bearing terrace deposits. Any loose materials remaining in slot excavations should be removed or dynamically compacted in place. Trench shoring may be necessary if the contractor or other parties have to enter any of the slot excavations to remove loose materials, or observe removal bottoms. The contractor should ensure the safety and stability of excavations. 3. Once removals have been completed, the bottoms of the excavations should be throughly wetted and subsequently backfilled with a controlled density fill (i.e., 3 sack slurry) that has been vibrated in place. Care should be taken to not utilize a slurry mix that could impede future excavations for utilities and footings. GSI recommends performing density tests on the controlled density fill once it has achieved its 7-day strength. Footing embedments for the proposed addition should be in accordance with the recommendations provided in Reference No. 3. Footing excavations should be observed by this office for proper embedment below the lowest adjacent grade, prior to the placement of reinforcing steel. Slurry may be in-filled to within 6 to 12 inches of surface grade, planned for this area. The balance of the grade (upper 6 to 12 inches) should be completed with properly compacted fill soil. It should be noted that the existing retaining wall, along the southern property boundary, appears to be in an active mode of failure. Remedial earthwork in this area could result in complete wall failure. Therefore, GSI recommends that this wall be removed prior to performing slot excavations. Once the wall has been removed, the backcut should be trimmed to a gradient of 1:1 (ho rizo ntal:vertical [h:vj). Remedial earthwork for the wall should consist of the removal of all unsuitable bearing soils to encounter suitable bearing terrace deposits. The resultant removal excavation should then be backfilled with a controlled density fill, as specified previously, to the top of the proposed wall footing and allowed to cure to its design strength. Density testing on the controlled density fill (slurry) Mr.Justin Gooding and Mr. Karl Weingarten 330 Neptune Avenue, Encinitas W_O. 4362-B-SC File:e:\WP%4300\4362\4362a.aer April 20, 2005 GeeSeiits, Inc_ Page 2 Zd SBL-IF-cas-619 110-1egwol uanags d µ'�"- 9Z = 1 0 SD la add should be performed after seven days. The retaining wall should be constructed in accordance with the recommendations provided in Reference No. 3. The adjacent, southerly property owner should be notified of the removal of this wall prior to the start of earthwork, as the excavation of the wall may require offsite grading and grade restoration in this area. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors_ Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented_ Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the client, in writing. The opportunity to be of service is sincerely appreciated. questions, please do not hesitate to contact our oce If you should have any Respectfully submitted, �sXoNAL GF GeoSoils, Inc. O��r�9. FR, °�o QAOFESSlO No. 1340 Z Q�OQ`�w T. GUq�9�F CerIttled Engfnoering q Geologist No. GE2320 �^ Fnngineering P. Franklin 9�F ��`� /// Exp. 12-31-05 a Geologist, ° �F° Andrew T. uatelli # v # Principal Engineer, G ��'P .r RB/JPF/ATG/jk/jh OF CAl1F Distribution: (4) Addressee (1) Mr. John Nicita (via email) Mr. Justin Gooding and Mr. Karl Weingarten 330 Neptune Avenue, Encinitas W.O. 4362-B-SC File:e:lwp914 3 0 014 3 6 214 3 62a_aer April 20, 2005 GeoSoils, Inc. Page 3 E d SBGb-EZ5-6i9 tpuegwol uanaqs 49a : 10 So 12 udd May 17 05 12: 23p John Rnthony Nicita 619-463-4964 P- 1 JOHN NICITA ENGINEERING& CODE CONSUL 9757 Wym� Way, Spring Valley TING, CA 91977-3447 (619)463-7719, FAX: (619)463-4964 May 17, 2005 SUBJECT: Report on review and approval of the "Alternate Earthwork Recommendations contained in the report W.O. 4362-B-SC dated April 20, 2005 by Geosoils, Inc.. This is to certify that I have reviewed and hereby approve the subject recommendations and that I have determined that implementation of the subject recommendations will not cause the bearing pressure at the existing adjacent residential wail footing to increase by more than 2.0 times the allowable bearing pressure. Respectfully submitted, John Nicita C-21617 FIELD TESTING REPORT w.O. DATE _ NAME HOURS CLIENT `�.�-�; ria�,` �' a�:• ENGI A1�Tv4'S TRACT ";/.: #fir?-?" A LOCATION. SUPT. CONTRACTOR �' J EQUIPMENT TEST NO. ELEV. MOISTURE DRY LOCATION OR CONTENT DENSITY °° TEST SOIL DEPTH P RELATIVE TYPE TYPE P.C.F. COMPACTION 4 ''r n _ - f r f re COMMENTS: ' Geosous, Inc. E:/wp/forms/fieldtst.wpd PAGE OF_, FIELD TESTING REPORT w.O. DATE NAME HOURS CLIENT /°.. ,', 1. ' r:�,. �NG(1�1 rr�✓4"S SUPT. CONTRACTOR 4.,YI �.F r R EQUIPMENT (` ,:1 9 f' ` A TEST NO. ELEV. MOISTURE DRY LOCATION OR CONTENT DENSITY RELATIVE TYPE TYPE P.C.F. COMPACTION E �.. 77" � . V s �^ . __ COMMENTS: Geosous, Ive. BY: ---- PAGE OF E:1wp/forms/fieldtst.wpd FIELD TESTING REPORT DATE:, NAME HOURS CLIENT ,le -IA1170 LOCATION SUPT. CONTRACTOR EQUIPMENT TEST No. LOCATION ELEV. MOISTURE DRY % TEST SOIL DEPTH OR CONTENT DENSITY RELATIVE TYPE TYPE % P.C.F. COMPACTION Ati f (If COMMENTS: Geosoms, Inc, BY: E:/wp/forms/f i eldtst.wpd PAGE OF FIELD TESTING REPORT W.O. 1/3& Z -� DATE - / NAME E E HOURS C) CLIENT � ! TRACT &IVC.N 17-AS LOCATION ,`.: SUPT. CONTRACTOR �,�^' EQUIPMENT � r TEST NO. LOCATION ELEV. MOISTURE DRY OR CONTENT DENSITY ��� TEST SOIL DEPTH RELATIVE TYPE TYPE P.C.F. COMPACTION i, A e d -, i ,r i 1 .. v f COMMENTS: Geosoils, Iue. BY: E:/wp/forms/fieldtst,wpd PAGE OF _ FIELD TESTING REPORT W.O. DATE NAME HOURS ' CLIENT E/��I nJ 17' TRACT LOCATION- SUPT. CONTRACTOR EQUIPMENT TEST ELEV. MOISTURE DRY NO. LOCATION % TEST SOIL OR CONTENT DENSITY RELATIVE DEPTH % P.C.F. COMPACTION TYPE TYPE r COMMENTS: Geosons, Inc. BY: PAGE OF E:/wp/forms/fieldtst.wpd FIELD -TESTING REPORT w.O.' DATE NAME HOURS CLIENT i s t 71 -/1l ice'` TRACT r 'i - SUPT. i r LOCATION CONTRACTOR '. _ _�"��'� <-, ,� J EQUIPMENT ATr TEST ' NO. ELEV. MOISTURE DRY LOCATION OR CONTENT DENSITY RELATIVE TYPE TYPE P.C.F. COMPACTION On f r, k COMMENTS: GeOSoils, Inc, BY: PAGE I E'.lwpltormslfiel dtst.wpd OF C I T Y O ,F "E N C .I N' I T A. S ENG I NEERI At ' SERVICES DEPARTMENT , 505^"S. VULCAN AVE. :t EVCIN'I,TA;,S, 'ACA 92024 I GRADING PERMIT PERMIT NO'. 928��I' PARCEL NO. G-35t-0130' +- JOB SITE ADDRESS : ;330 PLAN Nfl. ; a_G APP-LATE NAME NEPTUNE AVE. C-A E Nei 4 JUSTIN G.00DING 044.0 CLAP . MAILING ADDRESS: 330 NEPTUNE AVE. CITY: ENCIN'ITAS PHONE NO. e58-354-.5 S .S TATL: CA ZIP. 9?°02�- CONTRACTOR : OWNER/BUILDER ` LICENSE NO: : PHONE NO. " 8 8-.3 . -e_r, I CENSE T�= ENGINEER STEVEN .LflMBARD I PERMIT ISSS]FJ TE:- 5 PHONE ,NQ, : 619-523 4 1'22 PERMIT 25 PFRAIIT r • INSPE" OR:" RONALD QUIGG SS,VED .BY..-"" / --------------- IT1,jfits & DEPOSITS -t '�-°�_ 3 INPECTSON FEE PLRN CHECK;'�IF� SS .fi': 00 5 . , *LAN rEY 500 ,00 4 IN PPECTION'. 3RUIT: K FEE:. 200ti . Ofd + 7..'"FLOOD CONTROL FEE" � S"ECUR i T DE IT :7O = . 00 '. TRAFFIC �F E �- -------- - O"F F � K 3ESCR I PT I O - iP ;IFIEII A PERMIT t IF,.' _ - - SSUED " SIR ' t�ERE CAVAT s� Mt3ET2, T€ OL4SRVE RECOMPACTIQ _ R" EIZL�ING: fl£ TP INT`A t 1 PRFfl ` AE OF, tRAtNO: AND IRr RECOdENDATIfjNS OWNER Tt7A . TA PROVED 1VI� S3ILS S: '1�Ni?ARDS flR-CTYPiPPRC3�/ED ;TRA � N' ROL. ':LA1 ; A. T Y. : . 4 � SRECT I ON - - INSPECTOR' , TNSTlht INSPECTION LMPA FtEPQRT itI RECJ�.IUED RQtI � RT REC E I V,ED , 4 -"-- I ItSPON a •g.- +�= � �. — I HEREBY ACKNOWLEDGE THAT I HAVE READ THE APPLICATION AND } INFORMATION IB CORRECT° AND ' GI EE ;TC3 .-COMPLY WITH ALL C TY t3RDTP EN A' T iE LAWS REt7LATNG EKC £VATING AND GR "DING, CEO AND STATE ISSUED PUFC66i TC) TIi S ,APT?LIOATIflNE PROVI�IOIYS AND C 'H tITIOVS OF N .-n Ar PF rK✓ - cS' } k T N� �.3 . : cr, 'QE TLLEFiONE � � SENT- BY: GEOSOILS, INC. ; 7609310915; MAR-17-05 10:40AM; PAGE 7/9 frk. Geotechnical • Geologic Environmental 5741 Palmer Way Carlsbad, California 92008 (760)439-3-155 • FAX (760) 931-0915 March 17, 2005 W.O. 4362-C1-SC Mr. Justin Gooding and Mr. Karl Weingarten c/o Mr. Steven Lombardi, Architect 1989 Bacon Street, #8 San Diego, California 92107 Attention: Mr. Steven Lombardi Subject: Geotechnical Review of Typical Grade Beam/Caisson Foundation Detail, 330 Neptune Avenue, City of Encinitas, San Diego County, California References: 1."330 Neptune,Typ.Gr.Bm./Caisson Fdn.,"330 Neptune Avenue:,"Scale:None,facsimile dated March 16, 2005, by John Anthony Nicita. 2. 'Amended Foundation Recommendations, 330 Neptune Avenue, City of Encinitas, San Diego County, California% W.O. 4362-C-SC, dated March 10, 2005, by GeoSoils, Inc. Dear Mr. Lombardi: In accordance with your request, GeoSoils, Inc. (GSI) has reviewed the typical grade beam/caisson foundation structural detail prepared by Mr. John Anthony Nicita, Project Structural Engineer(see Reference No. 1),and has prepared this geotechnicalplan review letter. The purpose of our study was to review Reference No. 1 for general conformance with the recommendations outlined in Reference No. 2- Our scope of services has included a review of Reference Nos. 1 and 2, discussions with the project structural consultant,analysis of data,and the preparation of this geotechnical review fetter. Unless specifically superceded in the text of this report, the recommendations presented in Reference No. 2 are considered valid and applicable, and should be appropriately implemented during planning, design, and construction. Please note that the recommendations provided herein and in reference No. 2 do not entirely preclude the transmission of vapor and/or water through the slab. Recommendations to:impede the transmission of vapor and/or water through the slab could be provided upon request. GEOTECHNICAL REVIEW OF FOUNDATION DETA11. The reviewed structural detail appears to be in general conformance with the recommendations provided by this office and presented in Reference No. 2, from a geotechnical viewpoint. Based on our review, the following comments are provided: SEN1 BY: GEOSOILS, INC. ; 7609310915; MAR-17-05 10:40AM; PAGE 8/9 1. The concrete water to cement ratio for the caissons,grade beam,and slabs should be 0.50 with a concrete compressive strength of 4,000 pounds per square inch (as noted for caissons)- 2. The thickness of the vapor barrier should be increased to 1()-mil- 3. The boring should be relatively clean of all loose materials prior to placing reinforcement. Mr. Justin Gooding and Mr. Karl Weingarten 330 Neptune Avenue, Encinitas W-0.4362-C1-SC Fi1e:e:\wp5%43(XjWjWct-gra March 16,2005 QeoBoils, IAC. Page 2 ��w1L5� INC. ; 7609310915; MAR-17-05 10:41AM; . PAGE 9/9 The Opportunity to be of Service sincerely questions, please do not hesitate ofcont ct our o lPPfeciated, It you shout have any fice. Respectfully submitted, G oSoils. Inc. cXONAL NF���< 4QPFEs9i 0 W. No. 1340 Z 4 R Ca 'iri go, CE 479'57 1 �e9tnen"er�rt{� I John P. Franklin l aO°'Ofl�:r `� Engineering Geolo °F uf o�� c1v�L �t gist, David W. Skelly of k pQA T� �� Civil Engineer, RCi= 857 �A�1F� rew T. No.G z 0 Il Exp. /_ - T Principal Engineer, G �T r�CHN�C���Q RB/JPF/ATG/DWS/jk F°F CAufe�` Distribution: (4) Addressee Mr.Justin Cyooding and 1VIr. Weingarten 330 Neptune Avenue. Encinitas'rl Fle:e:lyP,g14300%4362c 1.gre W.Q.4362-C1-SC Geoasa ls, Zfte. Mgrch 16, 2005 Page 3