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2001-7233 G ENGINEERING SER VI CES DEPARTMENT City o1 Encinitas Capital Improvement Projects District Support Services Field Operations Sand Replenishment /Stormwater Compliance Subdivision Engineering Traffic Engineering October 3, 2002 Attn: San Diego National Bank 1420 Kettner Boulevard San Diego, California 92101 -4232 RE: Venture Pacific Development SE corner of Lone Jack Road and Dove Hollow Road Grading Permit 7233 -G A.P.N. 264 - 231 -11 Final release of security Permit 7233 -GI authorized earthwork, storm drainage, site retaining wall, and erosion control, all as necessary to build the described project. Therefore, a full release of the security deposited is merited. Letter of Credit 1666, in the amount of $76,710.00, is hereby released in its entirety. The document original is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, Zdha _ Masih Maher y L bach Senior Civil Engineer Finance Manager Field Operations Financial Services CC: Jay Lembach, Finance Manager Venture Pacific Development Debra Geishart File recycled p aper TEL 760- 633 -2600 / FAX 760 - 633 -2627 505 S. Vulcan Avenue, Encinitas, California 9ZU2'� -3633 'LDD 76o-633-2700 Y P P 1 k WESTERN SOIL AND FOUNDATION ENGINEERING, INC. 423 HALE AVENUE PHONE: (760) 746 -3553 ESCONDIDO, CALIFORNIA 92029 FAX: (760) 746 -4912 July 13, 2001 Mr. Bob Booker Venture Pacific Development P.O. Box 231639 Encinitas, CA 92023 -1639 Project: Job. No, 01 -35 Dove Hollow Custom Home Dove Hollow Road Encinitas, California APN 264 - 231 -11 Subject: Report of Geotechnical Investigation Dear Mr. Booker: In accordance with your request, we have completed a geotechnical investigation for the proposed project. We are presenting to you, herewith, our findings and recommendations for the development of this site. The findings of this study indicate that the site is suitable for development if the recommendations provided in the attached report are incorporated into the design and construction of this project. Dove Hollow Custom Home Our Job No. 01 35 July 13, 2001 Page 2 If you have any questions after reviewing the findings and recommendations contained in the attached report, please do not hesitate to contact this office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, WESTERN SOIL AND FOUNDATION ENGINTERNG, INC.' WU CX Vincent W. Gaby, CEG 1755, Expires 7/31/03 Engineering Geologist tis ESS1p Ne. 921 i ;l Dennis E. Zimmerman, C 26676, GE 928, Expires 3/31/04 Geotechnical Engineer Distribution: (4) Addressee VWG:DEZ /kmg WESTERN SOIL AND FOUNDATION ENGINEERING, INC. i GEOTECHNICAL NVESTIGATION DOVE HOLLOW CUSTONT HOME DOVE HOLLOW ROAD ENCINITAS, CALIFORNIA Prepared For: Mr. Bob Booker Venture Pacific Development P.O. Box 23 163 9 Encinitas, CA 92023 -1639 JOB NO. 01-35 July 13, 2001 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. x TABLE OF CONTENTS Page Introduction and Project Description .... ............................... .................... 1 ..... ............................... Project Scope ... ............................... ............1 ................................................. ............................... Findings ..................... ............................... ..................2 ................................. ............................... SiteDescription ................................................................................. ..............................2 Subsurface Conditions ......................... 3 . . ........................................ ............................... Santiago Peak Volcanics ......... ............................... ..•...........' ............ ............................... C .............................. Riabilit .................. .................................... ..............................4 Groundwater........ ................................................... ......................... ............................... 5 GeologicHazards ..... ............................................................ . ........................ ..............................6 Faults and Seismic Hazards ............................................................... .............................. Seismicityof Major Faults .......................... ............................... ........ ..............................7 Liquefaction ................................. ............................... ..................... .......... .. ................... 7 Landslides and Slope Stability .................... ............................." Recommendations and Conclusions ............................................................. ............................... 8 SitePreparation ................................................................................. .............................. General ............................. ................ 8 .................................... ............................... ExpansiveSoil ...................................................................... ..............................9 ImportedFill . ........................................................................ ............................. Earthwork........................................................................... ............................... 10 CutSlopes ............................................................................ .............................10 FillSlopes ........................................................................... ............................... 11 SurfaceDrainage ................................................................ ............................... 12 Subdrains........ ............................... ........................................ WESTERN SOIL AND FOUNDATION ENGINEERING, INC. s � TABLE OF CONTENTS (cont' d.) Page Foundation Recommendations .............. ............14 .............................. ............................... Seismic Site Categorization ............................. ... ....... ... 14 F ............................. Concrete -On -Grade ......................... ............................... .. .......................15 Post Tensioned Foundations .................................................. ............................. TransitionAreas ................................................................... .............................17 Lateral Resistance ................... .........-- .--- - -..18 ......................... ............................... Lateral Resistance Values ............................... ............................. .. ...................18 FootingObservations ............................................................ .............................18 RetainingWalls ................................................................................ .............................19 Lateral Pressures ............... ............................... ..........19 Drainage and Waterproofing ................................................. ............................. Backfill .................... ................... 20 ........................................ ............................... FieldExplorations ........................................................................................ .............................20 Laboratory Testing .......................21 ....... ............................... Plan Review ................................................................................................. .............................21 Limitations .............. ............................... 22 .................................................. ............................... WESTERN SOIL AND FOUNDATION ENGINEERING, INC. 2 1 ATTACHMENTS Plate No. 1 Site Plan (In back pocket) Plate No. 2 Unified Soil Classification Chart Plate No. 3 through Plate No. 10 Exploratory Excavation Logs Plate No. 11 and Plate No. 12 Laboratory Test Results Plate No. 13 Table I: Removal Depths Plate No. 14 Fill Slope Key APPENDIX I Specifications for Construction of Controlled Fills APPENDIX II References WESTERN SOIL AND FOUNDATION ENGINEERING, INC. GEOTECHNICAL INVESTIGATION DOVE HOLLOW CUSTOM HOME DOVE HOLLOW ROAD ENCINITAS, CALIFORNIA Introduction and Project Description This report presents the results of our geotechnical investigation performed on the above referenced site. The purpose of this investigation was to evaluate the existing surface and subsurface conditions from a geotechnical perspective and to provide recommendations for grading, foundation design, floor slab support and soil parameters for retaining wall design. The proposed project will be the construction of a single- family residence. Based on verbal information provided by Mr. Bob Booker, the proposed residence will be a wood - framed, one- or two -story building supported on conventional or post- tensioned foundations. According to the site plan prepared by Logan Engineering, grading for the pad will result in a tri -level pad. Maximum cuts and fills will be approximately 18 feet and 12 feet, respectively. Retaining walls up to five feet in height will be constructed along the toe of the proposed slopes. It should be recognized that re- evaluation of our analysis may be necessary as construction documents are produced. We should be provided the opportunity to amend our recommendations if necessary, once the grading and improvement plans are finished. The site configuration and the approximate locations of our subsurface explorations are shown on the enclosed Site Plan, Plate No 1. Project Scope This investigation consisted of a surface reconnaissance coupled with a subsurface exploration. Representative samples of soil material were obtained from the site and returned to our laboratory for observation and testing. The results of the field and laboratory data collected are presented in this report. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. r � Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 2 Specifically, the intent of this investigation was to: a) Explore the subsurface conditions to the depths that could be influenced by the proposed construction; b) Evaluate, by laboratory tests, the pertinent static physical properties of the various soil and rock stratigraphic units which could influence the development of this project; c) Describe the site geology, including potential geologic hazards and their effect upon the proposed development; d) Provide recommendations for site preparation and grading; e) Present recommendations for foundation design, including bearing capacity, estimated settlements, lateral pressures, and expansion potential of the on -site soils; and f) Furnish soil parameters for the design and construction of retaining walls. This report has been prepared for Venture Pacific Development to be used in the evaluation of the referenced site. This report has not been prepared for use by other parties, and may not contain sufficient information for purposes of other parties or other uses. The information in this report represents professional opinions that have been developed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the professional advice included in this report. Findings Site Description: The project site is located on the south side of Dove Hollow Road and the east side of Lone Jack Road, in the community of Olivenhain, in the city of Encinitas, California. The site vicinity can be found in the northwest quarter of grid C -4, Page 1148 of the Thomas Brothers Guide for San Diego County, 1999 edition. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page' The subject property is irregular in configuration and encompasses approximately three acres. It is bounded to the east and south by residential property. Approximately 682 feet front Dove Hollow Road along the north property line, while about 110 feet front Lone Jack Road along the west border. A private drive runs along the south boundary. The majority of the site is situated on the northwest facing hillside of a tributary alluvial basin of the Escondido Creek. The terrain varies from very steep to gently inclined. Elevations range from on the order of 321 feet above mean sea level (m. s.l.) at the southeast property corner to approximately 200 feet m.s.l. at the northwest property corner. No improvements were observed on the site at the time of our investigation. Vegetation consisted primarily of recently disced wild grasses. Subsurface Conditions: The subject site is underlain by Jurassic age metamorphic rocks that have been mapped by Tan and Kennedy (1996) as the Santiago Peak Volcanics. The formational materials are mantled with a moderately thin layer of colluvium. Each unit is described below beginning with the oldest. Santiago Peak Volcanics: The Santiago Peak Volcanics are comprised of metamorphosed volcanic and volcaniclastic rocks which extend from the southern Los Angeles Basin to Mexico (Kennedy, 1975). They are represented at the higher elevations of the site by very hard, moderately fractured metamorphosed volcanic rocks. They are dark green in color on fresh surfaces and orangish -brown when weathered. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. 1 Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 4 At the lower elevations (approximately 270 msl and lower) the Santiago Peak Volcanics is characterized by yellowish -brown to orangish -green volcaniclastic rocks (ash and sandstone). Bedding is difficult to discern, although it is estimated that this unit is dipping approximately 55° to the east. Although hard and relatively resistant to erosion, the metamorphic rocks are jointed and moderately fractured. Near the contact with overlying soil materials, the Santiago Peak Volcanics is deeply weathered. This weathered bedrock material is identified in the trench logs as residuum. It varies in consistency from clayey, sandy silt to gravelly, sandy and clayey silt. It contains fragmented bedrock ranging in size from cobble to boulders. Colluvium: At the locations explored, poorly consolidated colluvium ranging from 1' /z to 4 feet in thickness was observed mantling the bedrock materials. It generally consisted of brown, slightly sandy, gravelly silt that graded with depth to reddish - brown, clayey silt. At the time of our investigation, it varied from moist to very moist, was moderately fractured and contained minor amounts of thin roots. The results of laboratory testing performed on samples of the clayey colluvium indicated that it had a high expansion potential. In its present condition, the colluvium is not considered suitable for the support of foundations or fill. Rippability: The exploratory trenches were excavated with moderate to extreme difficulty by a rubber -tired backhoe. The trenches ranged from 5 to 13 feet in depth. Refusal was experienced in trenches T -1 and T -2 at depths of 5' /z feet and 5 feet, respectively. Near refusal occurred in exploratory trench T -3 at 11 feet and exploratory trench T -4 at 9 feet. Refusal is defined as the inability of the backhoe to excavate the bedrock materials. Near refusal is a subjective determination and describes the difficulty of the backhoe to deepen the exploratory excavation more then six inches in a 15 to 20 minute period. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 5 It appears that the hard crystalline bedrock occurs at the higher elevations in the southeast portion of the property. The more weathered residuum and volcaniclastic materials are present at the remaining areas explored. It is our opinion that heavy -duty equipment similar to a D -9 with a single tooth ripper could excavate the weathered and fractured bedrock materials at least a few feet deeper. However, it is likely that hard, unfractured, resistant bedrock and/or boulders may be encountered at locations not explored. Groundwater: Free groundwater was not observed in any of our exploratory excavations. However, mottling and caliche precipitate indicate that these soils have experienced at least episodic seepage. It should be noted that for the last three years precipitation levels have been below average. Fluctuations of subsurface water will be affected by variations in annual precipitation and local irrigation. Moreover, it has been our experience that periodic events of seepage will occur in areas of significant "cut" or any "below- grade" structures. Therefore, consideration must be given to appropriate surface and subsurface drainage systems such as underdrains and swales as recommended further in this report WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 6 Geologic Hazards Faults and Seismic Hazards: The numerous fault zones in southern California include active, potentially active, and inactive faults. Active faults are those which display evidence of movement within Holocene time (from the present to approximately 11 thousand years). Faults that have ruptured geologic units of Pleistocene age (11 thousand to 2 million years) but not Holocene age materials are considered potentially active. Inactive faults are those which exhibit movement that is older than 2 million years. According to available published information, there are no known active or potentially active faults which intercept the project site. The site is not located within an Alquist - Priolo Special Studies Zone. Therefore, the potential for ground rupture at this site is considered low. There are, however, several faults located in close proximity that movement associated with them could cause significant ground motion at the site. The table below presents the maximum credible earthquake magnitudes and estimated peak accelerations anticipated at the site. These accelerations are based on the assumption that the maximum credible earthquake occurs on specific faults at the closest point on that particular fault to the site. The maximum credible earthquake is defined as the maximum earthquake that appears to be reasonably capable of occurring under the conditions of the presently known geologic frame- work. The probability of such an earthquake occurring during the lifetime of this project is considered low. The severity of ground motion is not anticipated to be any greater at this location than in other areas of San Diego County. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. X Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 7 Seismicity of Major Faults Maximum Estimated Credible Bedrock Distance Magnitude Acceleration (1) Fault (Miles) (Richter) (g) Coronado Banks 23 7.6 L (2) 0.25 Elsinore 25 7.5L (3) 0.23 Rose Canyon 8 7.0 L (2) 0.41 San Andreas 74 8.3 L (3) 0.07 San Jacinto 49 7.8 L (3) 0.12 L = Local Magnitude (1) Seed and Idriss, 1982 (2) Slemmons, 1979 (3) Greensfelder, C.D.M. G. Map Sheet 23, 1994 Liquefaction: The potential for seismically induced liquefaction is greatest where shallow ground- water and poorly consolidated, well sorted, fine grained sands and silts are present. Liquefaction potential decreases with increasing density, grain size, clay content and gravel content. Conversely liquefaction potential increases as the ground acceleration and duration of seismic shaking increase. Subsurface water was not observed within our explorations and the site is underlain by shallow bedrock materials. Based on the consistency of the underlying materials and the anticipated recompaction of overburden soils, the potential for generalized liquefaction in the event of a strong to moderate earthquake on nearby faults is considered low. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 8 Landslides and Slope Stability: No evidence indicating the presence of deep - seated landslides was observed on the site or in the immediate site vicinity. The weathered formational materials are fractured and contain discontinuous sheared clay seams. This suggests that these materials may be prone to shallow failure, rock falls and soil creep. Observation of the cut slopes during and after grading will be important to identify potential shallow slope failures. It is anticipated that any incompetent soil materials encountered during the earthwork may be mitigated as recommended further in this report. It is our opinion that the potential for slope failure on this project is low if grading and slope construction is performed in accordance with the recommendations contained in this report. Recommendations and Conclusions Site Preparation General: The poorly consolidated overburden soils (colluvium and weathered residuum) encountered during our subsurface exploration are not considered suitable for the support of foundations, floor slabs or new fill in their present condition. To provide more uniform support for the proposed structures and prior to the placement of any new fill, we recommend that any existing fill, colluvium, weathered residuum or otherwise unsuitable material be completely removed to firm undisturbed natural ground. The horizontal limits of removal and recompaction shall include the entire areas of proposed structures, fill or any proposed fill slopes. All soil removal and replacement should extend at least eight feet beyond the footprint of any structures and shall be accomplished in accordance with the earthwork and foundation recommendations presented in this report. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. 1 Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 9 Based on the results of our field explorations, it appears that the depth of removal will range from 3 to 8 feet. Table I (Plate No. 13) of this report presents anticipated removal depths in the area of our subsurface explorations. Thicker and /or less competent materials may be encountered at locations that were not explored. Unsuitable soils that occur beneath areas to receive retaining walls, asphalt or concrete pavements, driveways, patio slabs, sidewalks or any other improvements shall be treated similarly. The on -site soils minus any debris or organic material may be used as controlled fill. Selective grading and fill placement is recommended further in this report for critical areas such as slope con- struction and building pad capping. All fill shall be compacted to at least 90% of its maximum dry density as determined by ASTM D 1557 -91. The moisture content at the time of compaction should be within 2% of optimum for non - expansive soils and between 2% and 4% over optimum for the clayey materials. All debris organic matter or oversized materials ( geater than 6 inches in maximum dimension) encountered must be removed and legally disposed of at a licensed disposal site. If groundwater is encountered during the removal and recompaction of the soil, or if difficulty is experienced in achieving the minimum of 90% relative compaction (ASTM D1557 -91), then this office shall be consulted for further recommendations. Expansive Soil: Detrimentally expansive soils (Expansion Index of 21 or greater) were encountered during our subsurface exploration. These materials occurred within the colluvium and clayey residuum. We recommend that these soils be placed within the deeper proposed fill areas or legally exported from the site. Potentially expansive soil should not be placed within 4 feet of finish grade for conventional foundations, or 2 feet of finish grade when post- tensioned foundations are used. Expansive soils should not be used as wall backfill, within 4 feet of finish subgrade in paved or hardscaped areas, or within 15 feet (horizontally) of the face of any constructed slope greater than 8 feet in height. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 0 1 -3 5 July 13, 2001 Page 10 Imported Fill: Imported fill, if required at this site, shall be approved by our office prior to importing. We should be given ample time to sample and test potential import soil prior to its delivery to this site. Imported fill material shall have an Expansion Index of 20 or less with not more than 25 percent passing the No. 200 U.S. standard sieve. It shall have an internal angle of friction of not less than 25 degrees, and a cohesion intercept between 200 and 400 psf when compacted to 90 percent of maximum dry density (ASTM D1557 -91). Earthwork: All earthwork performed on -site must be accomplished in accordance with the attached Specifications for Construction of Controlled Fills (Appendix 1). All special site preparation recommendations presented in the sections above will supersede those in the Specifications for Construction of Controlled Fills. All embankments structural fill, and utility trench backfill shall be compacted to no less than 90% of its maximum dry density. The moisture content of the granular fill soils should be within 2% of optimum moisture content at the time of compaction. The moisture content of the clayey soil materials should be maintained between 2% and 4% over optimum moisture content. The maximum dry density of each soil type shall be determined in accordance with ASTM D1557 -91. Prior to commencement of the brushing operation, a pregrading meeting shall be held at the site. The Developer Surveyor, Grading Contractor, and Soil Engineer should attend. Our firm should be given at least 3 days notice of the meeting time and date. Cut Slopes: It is our opinion that cut slopes excavated completely within competent, unfractured, bedrock materials at an inclination of 2' /z:1 (horizontal to vertical) or fatter would be stable to a maximum height of 30 feet. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. y S Dove Hollow Custom Home Our Job No, 01 -35 July 13, 2001 Page 11 Proposed cut slopes that occur in colluvium, severely weathered residuum, landslide debris, adversely fractured formation materials, or any proposed slopes cut into incompetent soil material shall be evaluated by the Soils Engineer or Engineering Geologist. Additional remedial actions may be required to mitigate the effects of detrimental slope conditions. When feasible this would likely include complete removal of all incompetent soil and then reconstruction of the slope as a fill slope in accordance with the recommendations below. Temporary sho-inc may be necessary for the support of adjacent properties. Alternative remedial action may include decreasing the height or inclination of the proposed slope. Fill Slopes: It is our opinion that fill slopes constructed at an inclination of 2:1 (horizontal to vertical) or flatter will be stable to a maximum height of 20 feet. Fill slopes constructed at an inclination of 2'/2.:1 or flatter are expected to be stable to a maximum height of 25 feet. Fill slopes shall be keyed into dense natural ground. The key shall extend through all incompetent soil and be established at least 2 feet into dense competent material. The key shall be a minimum of 2 feet deep at the toe of slope and fall with 5% grade toward the interior of the proposed fill areas. The bottom of the key shall have a width of at least 15 feet (Plate No. 14). All keys must be inspected by the Soil Engineer, Engineering Geologist or their representative in the field. Backdrains shall be installed at the heel of the keyway and on alternating benches. Back- drains will utilize similar dimensions and materials as described in this report under the heading subdrains. Backdrains shall connect to non - perforated down drains at a maximum spacing of 100 feet. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Y Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 12 The soil material placed within the outer 15 feet of any fill slope, as measured inward horizontally from the face of the slope, should consist of on -site or imported granular soil material within an expansion index of 20 or less. Fill slopes constructed with clayey or expansive soils may experience creep and /or surficial failure. We recommend that slopes be compacted by backrolling with a loaded sheepsfoot roller at vertical intervals not to exceed 4 feet and should be track walked at the completion of each slope. The face of the slopes should be compacted to no less than 90 % relative compaction (ASTM D1557- 91). This can best be accomplished by over building the slope at least 4 feet and trimming to design finish slope grade. Surface Drainage: Surface drainage shall be directed away from structures and paved areas. The ponding of water or saturation of soils should not be allowed adjacent to any of the foundations. We recommend that planters be provided with drains and low flow irrigation systems. Gutter, roof drains and other drainage devices shall discharge water away from the structure into surface drains and storm sewers. Surface water must not be allowed to drain in an uncontrolled manner over the top of any slope or excavation. The exterior grades should be sloped to drain away from the structures to minimize ponding of water adjacent to the foundations. Minimum site gradients of at least 2% in the landscaped areas and of 1% in the hardscaped areas are recommended in the areas surrounding buildings. These gradients should extend at least 10 feet from the edge of the structure. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 13 To reduce the potential for erosion, the slopes shall be planted as soon as possible after grading. Slope erosion, including sloughing, rilling, and slumping of surface soils may be anticipated if the slopes are left unplanted for a long period of time, especially during rainy seasons. Swales or earth berms are recommended at the top of all permanent slopes and retaining walls to prevent surface water runoff from overtopping the slopes and /or walls. Animal burrows should be controlled or eliminated since they can serve to collect normal sheet flow on slopes, resulting in rapid and destructive erosion. Erosion control and drainage devices must be installed in compliance with the requirements of the controlling agencies. Subdrains: A subdrain system shall be installed on alternating horizontal benches created within the backcut for walls, fill slopes or stability fills or where fill is proposed over canyons or drainage areas. The final determination for the location of the subdrains shall be made by the Soil Engineer or Engineering Geologist during the site grading. The subdrain shall consist of a trench at least 36 inches deep and 18 inches wide. Mirafi 140N or Amoco 4547 non -woven geotextile fabric, or an approved equivalent shall line the bottom and sides of the trench. Four inches of') /4- inch rock bedding shall be placed on the geotextile at the bottom of the trench. A 4 -inch diameter perforated pipe shall be placed in the trench with the perforations down. The pipe shall be ABS schedule 40 (ASTM -D 1785) or SDR 26 (ASTM- D2241) or approved equal. The drainpipe shall have a minimum 1% gradient and shall be centered within the trench horizontally. The subdrain should be attached to clean -out risers at intervals not to exceed 100 feet. A minimum of 3 cubic feet of 3/4 -inch rock per linear foot of subdrain shall be placed over and around the pipe within the geotextile lined trench. The geotextile shall lap at least 12 inches over the top of the rock. The subdrain shall outlet away from any structures or slopes in an approved legal manner. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. 1 Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 14 Foundation Recommendations Seismic Site Categorization: The following seismic site categorization parameters may be used for foundation design. These design parameters are based on the information provided in Chapter 16 of the 1997 Uniform Building Code. Soil Profile Type = SB Near Source Factor N, = 1.0 Near Source Factor N„ = 1.0 Seismic Source Type = B Footings: The on -site overburden soils (colluvium and severely weathered residuum) are not considered suitable for foundation or floor slab support. To provide more uniform support we recommend that proposed structures be entirely supported on compacted fill. Conventional footings should be underlain by at least 2 feet of compacted soil that has an expansion index of 20 or less. Footings shall be designed with the minimum dimensions and allowable dead plus live load soil bearing values given in the following table: Footings Established on Compacted Fill Minimum Minimum Allowable Building Footing Depth Width Soil Bearing Height Type (inches) (inches) Value (p.s.f.) One Story Continuous 12 12 2,000 Two Story Continuous 18 15 2,500 One or Two Story Pad /Square 24 30 3,000 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 15 The minimum depth given shall be below lowest adjacent finish subgrade. If foundations are proposed adjacent to the top of any slope, we recommend that the footings be deepened to provide a horizontal distance of 8 feet between the outer edge of the footing and the adjacent slope face. The soil load bearing values presented above may be increased by one -third for short term loads, including wind or seismic. The soil load bearing values of any imported soil should be determined after its selection but prior to its delivery on -site. All continuous footings shall be reinforced in accordance with recommendations provided by a Structural Engineer. Settlements under building loads are expected to be within tolerable limits for the proposed structure. Concrete Slabs -On- Grade: If the soils are prepared as recommended in this report, concrete slabs- on-grade may be supported entirely on compacted fill. Soil material placed within 4 feet of finish subgrade should have an expansion index of 20 or less. No cut/fill transitions should be allowed to occur beneath the structures. To provide protection against vapor or water transmission through the building and floor slabs, we recommend that the slabs -on -grade be underlain by a 4 -inch layer of Caltrans Class 2 permeable material or gravel. A suggested gradation for the gravel laver is as follows: Sieve Size Percent Passing 3/4" 90 -100 No. 4 0 -10 No. 100 0 -3 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 16 If the slab -on -grade is underlain by at least 4 feet of granular compacted fill, the gravel layer may be replaced by 4 inches of clean sand. An impermeable membrane as described below should be placed at the midpoint of the sand layer. In areas where vinyl or other moisture - sensitive floor coverings are planned or where moisture may be detrimental to the structure's contents, we recommend that the 4- inch -thick gravel layer be overlain by a 10 -mil -thick impermeable plastic membrane to provide additional protection against water vapor transmission through the slab. The vapor barrier should be installed in accordance with the manufacturer's instructions. We recommend that the edges be sealed. To protect the membrane during later concrete work, to facilitate curing of the concrete, and to reduce slab curling, a 2- inch -thick layer of clean sand shall be placed over the membrane. If sand bedding is used, care should be taken during concrete placement to prevent displacement of the sand. A low -slump concrete (4 -inch maximum slump) should be used to further minimize possible curling of the slabs. The concrete slabs should be allowed to cure properly before placing vinyl or other moisture - sensitive floor covering. Slab reinforcing and thickness shall be designed in accordance with the anticipated use and loadings on the slab and as recommended by the Structural Engineer. Construction joint spacing and placement shall be provided by the Structural Engineer. Post Tensioned Foundations: Post tensioned foundations should be designed using the following parameters: WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 17 Thornthwaite Moisture Index: -20 Edge Moisture Variation Distance, e Edge Lift Loading Conditions: 2.6 Center Lift Loading Conditions: 5.3 Percent of Clay: 50 Predominant Clay Mineral: Montmorillonite Depth to Constant Soil Suction: 5 Feet Constant Soil Suction, pF: 3.6 Velocity of Moisture Flow: 0.5 inches /month Differential Swell, y Center Lift: 1.36 inches Edge Lift: 0.32 inches Transition Areas: Any proposed structures should not be allowed to straddle a cut -fill transition line. Footinas and floor slabs should be entirely supported on cut or entirely on fill. The tendency of cut and fill soils to compress differently can frequently result in differential settlement, cracking to portions of the structure and in severe cases structural damage. To reduce the potential for damage due to differential settlement in transition areas, we recommend that on pads where the maximum fill thickness is less than 15 feet, cut areas be over - excavated to a depth of at least 2 feet below the bottom of the deepest footing and replaced with very low expansive soil material compacted to at least 90% of its maximum dry density (ASTM D1557 -91). If the fill thickness exceeds 15 feet (including removal and recompaction of incompetent soil) the cut portion should be over - excavated 4 feet below the bottom of the deepest footing. The compacted fill should extend at least 5 feet beyond the building floor plan. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 0 1 -3 5 July 13, 2001 Page 18 Lateral Resistance: Resistance to lateral loads may be provided by friction at the base of the footings and floor slabs and by the passive resistance of the supporting soils. Allowable values of frictional and passive resistance are presented for the fill soils in the table below. The frictional resistance and the passive resistance of the materials may be combined without reduction in determining the total lateral resistance. Lateral Resistance Values Allowable Coefficient Passive Pressure Soil Type of Friction (psf/ft of depth) Compacted Fill 0.30 300 (Expansion Index 0 -20) Footing Observations: Prior to the placement of reinforcing steel and concrete, all foundation excavations shall be inspected by the Soil Engineer, Engineering Geologist or their representative. Footing excavations shall be cleaned of any loosened soil and debris before placing steel or concrete. Footing excavations should be observed and probed for soft areas. Any soft or disturbed soils shall be over - excavated prior to placement of steel and concrete. Over - excavation of soils should not be performed in locations that were undercut for transition areas. This would compromise the thickness of the soil supporting the footings. In undercut transition areas loose soils should be recompacted. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 0 1-3 5 July 13, 2001 Page 19 Retaining Walls Lateral Pressures: Retaining walls are proposed for development on this site. Specific wall heights and design have not been provided to us. Our analysis anticipated that retaining walls up to 5 feet in height would be constructed. These recommendations should be reviewed and updated if walls greater than 5 feet in height are to be installed. For the design of cantilevered retaining walls where the backfill is well drained, the equivalent fluid pressures for both active and at -rest conditions are presented below. Backfill Active Pressure At -rest Pressure Inclination (p.c.f.) (p.c.f.) 2:1 -Slope 50 67 2%2:1 Slope 43 60 Drainage and Waterproofing: If the backfill is placed and compacted as recommended herein and good surface drainage is provided, the infiltration of water into the wall backfill may be reduced. Adequate drainage of adjacent planters should likewise be provided to reduce water infiltration into wall backfills. To limit the entrapment of water in the backfill behind the proposed walls, backdrains or other drainage measures should be installed. Drainage should consist of vertical gravel drains about 12 inches wide connected to a 4- inch - diameter perforated pipe. The pipe shall be ABS schedule 40 (ASTM- D1527) or SDR 23.5 (_ASTM- D2751) or approved equal. The perforated pipe should be placed with the perforations down and should be surrounded by at least 1 foot of filter gravel or uniformly graded gravel or Caltrans Class 2 permeable material wrapped in geosynthetic filter fabric, such as Mirafi 140N or approved equivalent. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 20 Care should be taken to select a filter fabric compatible with the backfill materials as clogging of the filter material may occur. The drain pipe should be located near the base of the wall and should discharge into a storm drain or onto a surface draining away from the structure. As an alternative to the vertical gravel drains, a drainage geocomposite such as Miradrain, or an approved equivalent, may be used with a 4 inch - diameter perforated pipe collector drain. Backfill: The exterior grades should be sloped to drain away from the structures to minimize ponding of water adjacent to the foundations and retaining walls. Compaction of the backfill as recommended herein will be necessary to reduce settlement of the backfill and associated settle- ment of the overlying walks, paving, and utilities. All backfill should be compacted to at least 90% of the maximum dry density (ASTM D1557-91, reapproved 1998). Some settlement of the backfill should be anticipated, and any utilities supported therein should be designed to accept differential settlement, particularly at the points of entry to buildings. Also, provisions should be made for some settlement of concrete walks on -grade supported on fill. Field Explorations Subsurface conditions were explored by excavating eight backhoe trenches on May 17, 2001. The exploratory trenches were 24- inches in width, approximately 12 feet long and extended to depths ranging from 5 to 13 feet. No caving occurred in anv of the excavation walls. Groundwater was not observed in any of the subsurface explorations. The locations of the exploratory excavations are depicted on the Site Plan, Plate No. 1, in the back pocket of this report. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 21 The surface reconnaissance and subsurface exploration were conducted by our geology and soil engineering personnel. The soils are described in accordance with the Unified Soil Classification System as illustrated on the attached simplified chart (Plate No. 2). In addition, a verbal textural description, the wet color, the apparent moisture and the density or consistency are presented. The density of granular material is given as either very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff or hard. The sampling and logging of our exploratory excavations were performed using standard geotechnical methods. The logs are presented on Plate No. 3 through Plate No. 10. Samples of typical and representative soils were obtained and returned to our laboratory for observation and testing. Laboratory Testing Laboratory tests were performed in accordance with the American Society for Testing and Materials (ASTM) test methods or suggested procedures. Test results are shown on Plate No. 11 and Plate No. 12. Plan Review The recommendations presented in this report are contingent upon our review of final plans and specifications. Western Soil and Foundation Engineering, Inc. should review and verify the compliance of the final plans with this report. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 01 -35 July 13, 2001 Page 22 Limitations It is recommended that Western Soil and Foundation Engineering, Inc. be retained to provide continuous geotechnical engineering services during the earthwork operations. This is to observe compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. Western Soil and Foundation Engineering, Inc. and /or our consultants, will not be held responsible for earthwork of any kind performed without our observation, inspection and testing. The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that are encountered during site development should be brought to the attention of the geotechnical consultant so that they may make modifications, if necessary. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job moo. 01 -35 July 13, 2001 Page 23 This office should be advised of any changes in the project scope so that it may be determined if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they be due to natural processes or the work of man on this or adjacent properties. In addition, changes in the State -of -the -Art and/or Government Codes may occur. Due to such changes, the findings of the report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of one year without a review by us verifying the suitability of the conclusions and recommends lions. We will be responsible for our data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. Dove Hollow Custom Home Our Job No. 0 1-3 5 July 13, 2001 Page 24 It is the responsibility of the Client or the Client's representative to ensure that the information and recommendations contained herein are brought to the attention of the engineer and architect for the project and incorporated into the project's plans and specifications. It is further the responsibility of the Client to take the necessary measures to ensure that the contractor and sub - contractors carry out such recommendations during construction. Respectfully submitted, _ WESTERN SOIL AND FOUNDATION ENGINEERING INC. - I1 t } _ii��'Gr:l��:r ��` Vincent W. Gaby, CEG 1755, Expires 7/ c `' p iip Engineering Geologist EBSi o, No. 928 Dennis E. Zimmerman, C 26676, GE 928, Expires 3/31/04 r' Geotechnical Engineer sa VWG:DEZ /kmg F OF CAL��� WESTERN SOIL AND FOUNDATION ENGINEERING, INC. ATTACIL%ENTS WESTERN SOIL AND FOUNDATION ENGINEERING, INC. � s SITE PLAN (Plate No. 1) In Back Pocket WESTERN SOIL AND FOUNDATION ENGINEERING, INC. SUBSURFACE EXPLORATION LEGEND UNIFIED SOIL CLASSIFICATION CHART Group Soil Description Svmbol Typical Names L COARSE GRALVED: More than half of material is larger than No. 200 sieve size. Gravels: More than half of coarse fraction is larger than No. 4 sieve size but smaller than 3 ". CLEAN GRAVELS GW Well graded gravels, gravel sand mixtures, little or no fines. GP Poorly graded gravels, gravel sand mixtures, little or no fines. GRAVEL W/F rNES GM Silty gravels, poorly graded gravel -sand -silt mixtures. GC Clayey gravels, poorly graded gravel -sand, clay mixtures. Sands: More than half of coarse fraction is smaller than No. 4 sieve size. CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines. SP Poorly graded sands, gravelly sands, little or no fines. SANDS W/FINES SM Silty sands, poorly graded sand and silt mixtures. SC Clayey sands, poorly graded sand and clay mixtures. H. FINE GRAINED: More than half of material is smaller than No. 200 sieve size. Silts & Clays: Liquid limit less than 50 ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey - silt -sand mixtures with slight plasticity. CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. OL Organic silty and organic silty clays of low plasticity. Silts & Clays: Liquid limit greater than 50 MH Inorganic silts, micaceous or diatomaceous line sandy or silty soils, elastic silts. CH Inorganic clays of high plasticity, fat. OH Organic clays of medium to high plasticity. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. Plate No. 2 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. CL p TRENCH NO. T -1 F- Lu F- U w o W Z u j LLI W >_ J U ELEVATION t 297 _ Z LL Z O LU I- f- U a SAMPLING a aa.0 z w ►_ - Q 2 J METHOD BACKHOE Q 2 Q ZO Q g p U Q U DESCRIPTION U °• ML COLLUVIUM - Brown, Sandy Silt with Angular Pebble to Boulder of Meta - Volcanic Damp Soft _ TO .- Rock, Porous = � -1 1- • .GM •_ Grades To — TO 2- B/C -2 Ver Soft 107.3 16.3 - MH Dark Orangish- Brown, Clayey Silt Y with Angular Rock Moist To _ Y ZZ Medium Stiff 3- -3 Very Undulating Contact Q GC RESIDIUM - Mottled Red and Yellow, Gravelly, Very Stiff Clayey Silt with Angular, Meta- Moist 4- Q �; Volcanic Boulders -4 Grades To To / GM . SANTIAGO PEAK VOLCANICS - Orangish -Brown Damp Very 5- (Weathered) to Green (Fresh) Meta - Volcanic Hard -5 Rock, Moderately Fractured REFUSAL @ 5' /z FEET 6- -6 7- -7 8- -8 9_ -9 10- -10 JOB NUMBER DOVE HOLLOW CUSTOM HOME DATE LOGGED LOGGED BY 01 -35 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 3 w p TRENCH NO. T -2 >- -- F a �w Hv H w= wZ w W LU U ELEVATION ± 287 W U Z cn ~ W Q U a 0� SAMPLING CLO aCnn �� pZ wc CL rn METHOD BACKHOE Q Q 0 0 E 0 O 0 Q Q U DESCRIPTION U ML' • COLLUVIUM - Brown, Sandy Silt, Porous, with Damp Soft _ Angular Pebble to Boulder, To To _ - TO Grades Clayey with Depth Moist Medium Stiff _1 1- — G C'- 2 �— Q RESIDIUM - Mottled Red and Yellow, Gravelly, -2 Very Medium Clayey Silt Moist Stiff - PTO: - C_= MH 3- Q L -3 Grades To To 1w � 4- ; ' -4 GM SANTIAGO PEAK VOLCANICS - Orangish -Brown Damp Very (Weathered) to Green, Meta - Volcanic Rock, Hard - t' Fractured t `.. -5 REFUSAL @ 5 FEET 6 - -6 7— —7 8— —8 9 —9 10— —10 JOB NUMBER DOVE HOLLOW CUSTOM HOME DATE LOGGED LOGGED BY 01 -35 05-17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 4 w p TRENCH NO. T -3 a a Uj a H � w F U F w o w z w � N J a ELEVATION ± 285 W w w z � H > O LU U uJ U F- w Q U d 0 � SAMPLING iL- na.Z Da pZ w a w (n METHOD B A C KHOE a a a. O 2 O LU 0 (n J U U O p U DESCRIPTION ML = COLLUVIUM - Brown, Sandy Silt, Porous Damp Soft TO - Grades To To To _ GC _ Very Medium 1 — Dark Brown, Clayey Silt Moist Stiff -1 2- - M`_ RESIDIUM - Orangish- Yellow, Slightly Clayey, Moist Soft _ TO = Sandy Silt To To � Very Medium - Moist Stiff 3- -3 Grades To 4- B -4 -5 (; GM -" Reddish - Orange with Yellow Mottling, Moist Hard Very Fractured Rock, Remolds to _ r Gravelly, Sandy Silt 6- -6 7- Joint N75 °E /38 °SE -7 Joints Tight with Cemented Infilling 8- 9- t Grades To -9 z 10— GM SANTIAGO PEAK VOLCANICS — Olive Green, Damp Very —10 _ Moderately Fractured, Meta - Volcanic Rock Hard _ 11— I / —11 NEAR REFUSAL @ 11 FEET 12— —12 13— —13 14— —14 JOB NUMBER DOVE HOLLOW CUSTOM HOME DATE LOGGED LOGGED BY 0 1 - 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 5 e L p TRENCH NO. T-4 >- L a 0 1 I H Lo LZ lLU � ELEVATION F} J Q ± 280 Z Z Z z ^ = > O t w L L U �H �� LU i - w QU T CL CO (n SAMPLING dO d� Qom- 0Z L ja F- CL rn METHOD BACKHOE Q g Q ZO E O W Lu Q O Q U Q U U Q U DESCRIPTION ML - COLLUVIUM - Brown, Sandy Silt Damp Soft _'TO _ To To MH - Very Medium _1 1_ Grades To Moist Stiff Dark Reddish - Brown, Clayey Silt - 2- -2 ML: 4- RESIDIUM - Oran gish- Yellow, Slightly Clayey, Very . Medium - - Very Sandy Silt Moist Stiff 3 -3 - :74 Grades To - ¢ 7o ` -4 GM ,, Mottled Reddish- Orange and Yellow - ��' Fractured Rock, Remolds to Orange, Moist Hard 5- Gravelly, Fine Grained Sand -5 '.L 6- ' i Grades To -6 7- Hard -7 GM SANTIA Moist GO PEAK VOLCANICS - Olive Green, To - Meta- Voicanic Rock, Fractured with Lenses Very 8- { }', of Lavender, Clayey Silt (Weathered Ash ?) Hard -$ NEAR REFUSAL @ 9 FEET 9- -9 10- -10 11- -11 12- -12 13- -13 14- -14 JOB NUMBER DOVE HOLLOW CUSTOM HOME DATE LOGGED LOGGED BY 01 -35 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 6 a p TRENCH NO. T -5 w v w = W Z w w Q ELEVATION ± 270 w= w� z = Z O uj JV Q� Qfn WU NW QU = = nJ. U) N SAMPLING n- p n- n p Z w d CL V) METHOD BACKHOE Q Q ZO n O w CL U U O V DESCRIPTION ML COLLUVIUM - Brown, Sandy Silt, Porous, Damp Soft - Contains Minor Angular Gravel -1 Grades To 2_ B!C T MH _ Dark, Very Clayey Silt Very Medium 101.3 18.7 -2 Moist Stiff 3- " RESIDIUM - Yellowish - Green, Clayey, Very Sandy Very Medium -3 _ Silt Moist Stiff - ML -4 4- Grades To �?� -5 Olive Green (Fresh), Red (Weathered), Moist Hard - SM Very Fractured, Silty Sandstone ✓: Remolds to Very Silty Fine Grained ,. Sand _g 6- -7 7- - Grades To 8- `fG t., SANTIAGO PEAK VOLCANICS - Yellowish- Brown, Dam y Ver -8 Metamorphosed, Volcaniclastic Rock M Hard - (Ash Sandstones) Very Weathered 9- �� �� -9 -10 BOTTOM OF TRENCH @ 10 FEET -11 11- -12 12- -13 13- -14 14- JOB NUMBER DATE LOGGED LOGGED BY DOVE HOLLOW CUSTOM HOME 01 -35 05 -17 -01 v.G• SURFACE EXPLORATORY LOGS Plate? w TRENCH NO. T -& F- Lu F V u1 o W z w w a z� z �^ �" > O w Q ELEVATION ± 247 N �_ z Z F- U W U Qri QT WU (n W Q aa.. Cn SAMPLING a ~ Q a Q av� O wa a 2 U) METHOD BACKHOE ¢ g a Q 20 2 w O U 0 U U Q N U DESCRIPTION -ML _ COLLUVIUM - Brown, Sandy Silt Moist Soft —_ TO To To MH = Very Medium _1 1 _ Grades To Moist Stiff Dark Brown, Clayey Silt - -2 2- RESIDIUM - Brownish - Orange, Gravelly, Very - Silty, Fine Grained Sand, Fractured Moist Stiff 3- o with Colluvium Infilling, Minor Roots -3 GM O _: 4- Grades To 5- 1 :� -5 k -6 6- GM SANTIAGO PEAK VOLCANICS - Orangish- Green, Fine Grained, Metamorphosed Hard - Volcaniclastic Rock Damp To _ (Sandstone and Ash) Very -7 7 j Moderately Fractured Hard g_ I Some Fractures Steeply Dipping -$ to East with Thin, Pale Lavender, _ Clayey Silt Infilling 9- -9 ' -10 10 -� BOTTOM OF TRENCH @ 10' /z FEET -11 11- 1 -12 2- -13 13- 14- -14 JOB NUMBER DATE LOGGED LOGGED BY DOVE HOLLOW CUSTOM HOME 01 -35 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 8 a LU ZO TRENCH NO. T -7 F- U H w a w Z LLj zLu Z U5 �" >2 w � �. U ELEVATION ±247 � Z U Z Q U � Ou. Qcn QL o0- �I Uj �Q CL to CL v METHOD BACKHOE Q Q ZO v O O wQ U U U U DESCRIPTION COLLUVIUM - Dark Brown, Sandy Silt Damp Soft . ML: -1 1- Grades To To - TO -2 2- Very Medium Dark Yellowish - Brown, Very Clayey ry MH T Silt, Desiccation Cracking Moist Stiff - -3 3- - -- A - 4 '}- - ML = RESIDIUM - Orangish- Brown, Clayey, Sandy Silt Very Medium - Moist Stiff - 5- TO— -5 _ - M_H - _ -6 6- _ — �-- Random Lenses of Clayey Silt - Wet Soft -7 7- SANTIAGO PEAK VOLCANICS - Dark Gray, Sandy Moist Stiff _ - -ML _ Silt To To _8 8- Contains White, Very Very - Relict Phenocrysts Moist Hard - -9 9- 10- C GM ; Very Weathered 124.6 11.7 -10 Meta- volcanic Rock 11- Weathered, Oxidized Fracture Zone, -11 Yellowish- Orange, Poorly _ Cemented Precipitate 12- C 94.7 25.8 -12 BOTTOM OF TRENCH @ 13 FEET -14 14- JOB NUMBER DATE LOGGED LOGGED BY DOVE HOLLOW CUSTOM HOME 01 -35 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 9 a LU d 0 TRENCH NO. T -8 w V W o W Z W Z Z Z> O W J U ELEVATION ±257 LU Uj LJJ w U Z W Qln Q� C]G. �� JQ CL SAMPLING a p n- � O Z W� n~. w Q Q METHOD BACKHOE Q a Z 0 Ix 2 O o w D to U V n U U DESCRIPTION ML COLLUVIUM - Brown, Sandy Silt Damp Soft _ To To Very Medium _ Grades To Moist Stiff MH = Dark Brown, Clayey Silt -2 2- RESIDIUM - Orangish- Brown, Gravelly, Moist Dense -3 3- ' ° Silty, Fine Grained Sand �GM� 4- -5 5- :� -6 6- BOTTOM OF TRENCH @ 6 FEET -7 7- -8 8- -9 9- -10 10- -11 11- -12 12- -13 13- -14 14- JOB NUMBER DATELOGGED LOGGED BY 01 -35 DOVE HOLLOW CUSTOM HOME 05 -17 -01 V.G. SURFACE EXPLORATORY LOGS Plate 10 LABORATORY TEST RESULTS — Cont'd. Expansion Index Sample Initial Final Expansion Expansion p Moisture Moisture Location o % Index Potential Content { / o) Content ( ) T -1 @ 2' 13.7 29.0 91 High T -3 @ 4' 13.0 27.3 52 Medium In -Place Densitv and Moisture Sample Dry Density Moisture Location (pc fl (percent) T -1 @ 2' 107.3 16.3 T -5 @ 2' 101.3 18.7 T -7 @ 10' 124.6 11.7 T -7 @ IT 94.7 25.8 Plate No. 12 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. LABORATORY TEST RESULTS Maximum Density /Optimum Moisture Maximum Optimum Dry Moisture Sample Density Content Location Description (pcf) (percent) T -1 @ 2' Orangish- Brown, Clayey Silt 120.5 14.5 T -3 @ 4' Orangish- Yellow, Clayey, Gravelly Silt 129.0 12.0 Direct Shear Angle of Apparent Internal Sample Cohesion Friction Location (psf) (de *T -3 @ 4' 360 36 * Sample remolded to 90 percent of maximum dry density and 3 percent over optimum moisture content. Plate No. 11 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. r TABLE 1 Depth of Soil Removal Below Trench Existing Grade Number (ft.) T -1 4 T -2 3 T -3 4 T -4 4 T -5 4'/2 T -6 4 T -7 8 T -8 ' NOTE: It should be recognized that variations in soil conditions might occur between exploratory excavations that will require additional removal. In areas where fill slope toe keys are proposed, add a minimum of 2 feet to removal depths presented above. Exploratory trenches encountered in the removal process should be recompacted an additional 2 feet below the depths shown in the above table. Plate No. 13 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. FILL SLOPE KEY PROJECTED PLANE 1 TO 1 MAXIMUM FROM TOE OF NATURAL GROUND SLOPE TO APPROVED GROUND FILL ' TOE OF SLOPE ' �ER0P -' - M p, - 8' MINIMUM BENCH x - '0 .' COMPETENT EARTH MATERIAL - - - 2 5% MINIMUM - TYPICAL BENCH — MINIMUM BASE KEY WIDTH (HEIGHT VARIES) 15' MINIMUM DOWNSLOPE KEY DEPTH BACKDRAINS MAY BE REQUIRED PER RECOMMENDATIONS OF SOILS ENGINEER DOVE HOLLOW CUSTOM HOME JOB NO.: 01 -35 DATE 07 -13 -01 Plate No. 14 WESTERN SOIL AND FOUNDATION ENGINEERING, INC. APPENDIX I WESTERN SOIL AND FOUNDATION ENGINEERING, INC. SPECIFICATIONS FOR CONSTRUCTION OF CONTROLLED FILLS General Description: The construction of controlled fills shall consist of adequate geotechnical investigations, and clearing, removal of existing structures and foundations, preparation of land to be filled, excavation of earth and rock from cut area, compaction and control of the fill, and all other work necessary to complete the grading of the filled area to conform with the lines, grades, and slopes as shown on the accepted plans. Clearing And Preparation Of Areas To Be Filled: (1) All fill control projects shall have an investigation or a visual examination, depending upon the nature of the job, performed by a qualified soil engineer prior to grading. (2) All timber, trees, brush, vegetation, and other rubbish shall be removed, piled and burned, or otherwise disposed of to leave the prepared area with a finished appearance free from unsightly debris. (3) Any soft, swampy or otherwise unsuitable areas shall be corrected by drainage or removal of compressible material, or both, to the depths indicated on the plans or as directed by the soil engineer. (4) The natural ground which is determined to be satisfactory for the support of the filled ground shall then be plowed or scarified to a depth of at least six inches (6 ") or deeper as specified by the soil engineer, and until the surface is free from ruts, hummocks, or other uneven features which would tend to prevent uniform compaction by the equipment to be used. (5) No fill shall be placed until the prepared native ground has been approved by the soil engineer. (6) Where fills are made on the hillsides with slopes greater than 5 (horizontal) to 1 (vertical), horizontal benches shall be cut into firm undisturbed natural ground to provide lateral and vertical stability. The initial bench at the toe of the fill shall be a least 10 feet in width on firm undisturbed natural ground at the elevation of the toe stake. The soil engineer shall determine the width and frequency of all succeeding benches which will vary with the soil conditions and the steepness of slope. (7) (After the natural ground has been prepared, it shall be brought to the proper moisture content and compacted to not less than 90% of maximum density, A.S.T.M. D1557 -91. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. (8) Expansive soils may require special compaction specifications as directed in the report of geotechnical investigation by the soil engineer. (9) The cut portions of building pads may require excavation and recompaction for density compatibility with the fill as directed by the soil engineer. Materials: The fill soils shall consist of select materials graded so that at least 40 percent of the material passes the No. 4 sieve. The material may be obtained from the excavation, a borrow pit or by mixing soils from one or more sources. The material used shall be free from vegetable matter, and other deleterious substances, and shall not contain rocks or lumps greater than 6 inches in diameter. If excessive vegetation, rocks, or soils with unacceptable physical characteristics are encountered, these materials shall be disposed of in waste areas designated on the plans or as directed by the soil engineer. If soils are encountered during the grading operation which were not reported in the report of geotechnical investigation, further testing will be required to ascertain their engineering properties. Any special treatment recommended in the preliminary or subsequent soil reports not covered herein shall become an addendum to these specifications. No material of perishable, spongy, or otherwise unstable nature shall be used in the fills. Placing, Spreading And Compacting Fill Material: (1) The selected fill material shall be placed in layers which shall not exceed six inches (6 ") when compacted. Each layer shall be spread evenly and shall be thoroughly blade -mixed during the spreading to insure uniformity of material and moisture in each layer. (2) When the moisture content of the fill material is below that specified by the soil engineer, water shall be added until the moisture content is near optimum as determined by the soil engineer to assure thorough bonding during the compacting process. (3) When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by blading and scarifying, or other satisfactory methods until the moisture content is near optimum as determined by the soils engineer. (4) After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to not less than the specified maximum density in accordance with A. S.T.M. D1557 -91. Compaction shall be by means of tamping or sheepsfoot rollers, multiple -wheel pneumatic - tired rollers, or other types of rollers. Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling of each layer shall be continuous over its entire area and the roller shall make sufficient passes to obtain the desired density. The entire area to be filled shall be compacted to the specified density. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. (5) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting operations shall be continued until the slopes are stable and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrolling the slopes in increments of 3 to 5 feet in elevation gain or by other methods producing satisfactory results. (6) Field density tests shall be made by the soil engineer for approximately each foot in elevation gain after compaction, but not to exceed two feet in vertical height between tests. The location of the tests in plan shall be spaced to give the best possible coverage and shall be taken no farther than 100 feet apart. Tests shall be taken on corner and terrace lots for each two feet in elevation again. The soil engineer may take additional tests as considered necessary to check on the uniformity of compaction. Where sheepsfoot rollers are used, the tests shall be taken in the compacted material below the disturbed surface. No additional layers of fill shall be spread until the field density tests indicate that the specified density has been obtained. (7) The fill operation shall be continued in six inch (6 ") compacted layers, as specified above, until the fill has been brought to the finished slopes and grades as shown on the accepted plans. Supervision: Supervision by the soil engineer shall be made during the filling and compacting operations so that he /she can certify that the fill was made in accordance with accepted specifications. The specifications and soil testing of subgrade, subbase, and base materials for roads, or other public property shall be done in accordance with specifications of the governing agency. Seasonal Limits: No fill material shall be placed, spread, or rolled during unfavorable weather conditions. When the work is interrupted by heavy rain, grading shall not be resumed until field tests by the soil engineer indicate that the moisture content and density of the fill are as previously specified. In the event that, in the opinion of the engineer, soils unsatisfactory as foundation material are encountered, they shall not be incorporated in the grading, and disposition will be made at the engineer's discretion. WESTERN SOIL AND FOUNDATION ENGINEERING, INC. i I APPENDIX II WESTERN SOIL AND FOUNDATION ENGINEERING, INC. � r REFERENCES CITED Greensfelder, R.W., 1974, Maximum Credible Rock Accelerations from Earthquakes in California: CDMG Map Sheet 23. Kennedy, M. P., 1975, Geology of The San Diego Metropolitan Area, California: California Division of Mines and Geology, Bulletin 200. Seed, H.B. and Idriss, I.M., 1982, Ground Motions and Soil Liquefaction During Earthquakes, EERI Monograph Series. Slemmons, D.B., 1979, "Evaluation of Geomorphic Features of Active Faults for Engineering Design and Siting Studies ", Association of Engineering Geologists Short Course. Tan, S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San Diego County, California: CDMG Open -File Report 96 -02. Weber, Harold F. Jr., 1982, Recent Slope Failures, Ancient Landslides, and Related Geology of The North - Central Coastal Area, San Diego County, California: CDMG Report 82 -12. Wilson, Kenneth L., 1972 Eocene and Related Geology of a Portion of the San Luis Rey and Encinitas Quadrangles San Diego County, California: Masters Thesis, U.C. Riverside. 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