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2006-116 SG
the Sea Bright OzPm o m p a n y April 19, 2006 f;FR 2 6 20 HYDROLOGY REPORT CHABOT GRADING PLAN EN'11 EERING sERVIC" 348 HORIZON DRIVE CITY Of ENCINITAS 116 - SG APN 259 - 460 - 39 The above referenced project is an existing single family residence with all the basic flatwork improvements already in. The proposed project is to install a 7' retaining wall in the backyard to replace an existing 2' wall. This will increase the useable portion of their backyard. I do not know if additional flatwork will be added. There is an existing 6" drain pipe that exists in the rear yard according to the owners. I saw the outlet of the pipe on the eastern side of their property where it discharges into a 4' wide concrete swale that accommodates the drainage for several of the lots along the eastern boundary of the subdivision. The existing 6" pipe is adequate to handle their drainage needs. As a safety factor, there is secondary surface flow outlet to the previously mentioned drainage swale before the water would get into the house, should the drainage pipe become clogged. chbthyd1 r0. Y ww No.=8302 i s E"P'3 51' CIV 1 Engineering Management General Contracting< Development 4322 Sea Bright Place Carlsbad, CA 92008 Telephone/FAX 760-720-0098 uII AUG 22M ENGINEEFiNG SERVICES CITY OF WIN!TAS Preliminary Geotechnical Investigation Proposed Retaining Wall 348 Horizon Drive Encinitas, California March 29, 2006 Prepared For: CARYL F. CHABOT 348 Horizon Drive Encinitas, California 92024 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #06-161-P VINE 8� MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue Job #06-161-P Escondido,Califomia 92029-1229 Phone'760)743-I2I4 Fax!760)739-0343 March 29, 2006 Caryl F. Chabot 348 Horizon Drive Encinitas, California 92024 PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED RETAINING WALL, j 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA J Pursuant to your request, Vinje and Middleton Engineering, Inc. has completed the j enclosed Preliminary Geotechnical Investigation Report for the proposed retaining wall. 1 The following report summarizes the results of our field investigation, including laboratory j analyses and conclusions, and provides recommendations for the proposed wall 11 construction as understood. From a geotechnical engineering standpoint, it is our opinion that the study area is suitable for the planned new retaining wall provided the recommendations presented in this report are incorporated into the design and construction of the project. The conclusions and recommendations provided in this study are consistent with the indicated site geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of development costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #06-161-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. 1 sRED Gso4O Dennis Middleton `i ��' o o CEG 960 Z CEG #98C is CERTIFIED ENGINEERING DM/jt sX .1�3�/0 ���of CALF°n, TABLE OF CONTENTS PAGE NO. 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. SITE CONDITIONS ! PROPOSED DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . 1 1 Ill. SITE INVESTIGATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 IV. FINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 A. Earth Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. Laboratory Testing / Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 V. SITE CORROSION ASSESSMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 VI. CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 A. Clean-up and Clearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 B. Excavations, Temporary Slope and Wall Back-cuts . . . . . . . . . . . . . . . . . . 6 C. Foundation Trenching and Bearing Soils Preparations. . . . . . . . . . . . . . . . 7 D. Wall Back Drainage 8 E. Backfill Materials and Compaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 F. Soil Design Parameters . • . • • • . . • . • • . . • • . . . . • • • . . • . . • • . • . . . . . . . . • 8 G. Engineering Inspections 10 H. Surface Drainage Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 I. Staking and Grading Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 J. Construction Plans and Geotechnical Plan Review 11 K. Preconstruction Conference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 L. General Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 VII. LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 TABLE NO. Soil Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Grain Size Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Maximum Dry Density and Optimum Moisture Content . . . . . . . . . . . . . . . . . . . . . 3 Moisture-Density Tests (Undisturbed Chunk and Ring Samples) . . . . . . . . . . . . . 4 DirectShear Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . 5 pH and Resistivity Test 6 SulfateTest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 TABLE OF CONTENTS Chloride Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Years to Perforation of Steel Culverts 9 PLATE NO. Regional Index Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PlotPlan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Test Pit Logs (with key) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Geologic Cross Sections . . . . . . . . . 4 Retaining Wall Drain Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 REFERENCES 1 PRELIMINARY GEOTECHNICAL INVESTIGATION PLANNED RETAINING WALL 348 HORIZON DRIVE ENCINITAS, CALIFORNIA i I. INTRODUCTION A retaining wall approximately 7-8 feet in height is planned to support the base of a graded slope in order to enlarge the pad area along the north perimeter at 348 Horizon Drive, within the City of Encinitas. A Regional Index Map depicting the property location is enclosed with this report as Plate 1. The purpose of this work was to collect representative soiVrock samples at the proposed wall location and perform necessary laboratory testing for determining pertinent wall design soil parameters. The wall design should be j completed and detailed for construction by the project structural engineer using the soil i design parameters given herein. The scope of this investigation is limited to the planned retaining wall only as delineated in this report. Other areas of the property and existing structures not investigated are beyond the scope of this report. Il. SITE CONDITIONS I PROPOSED DEVELOPMENT The plan is to widen a northerly side yard at the property by cutting out lower portions of a graded slope and utilizing a nearly 65 feet long, 8 feet high maximum transition retaining wall to accommodate elevation changes. A Plot Plan depicting local conditions at the proposed wall areas is included with this report as Plate 2. The new wall will have wing returns on either side as shown. The existing graded slope is a 2:1 (horizontal to vertical) gradient manufactured embankment approximately 10'/z feet in maximum vertical height. A two-foot high block wall currently marks the toe of the graded slope as shown on Plate 2. Documentation pertaining to previous earthworks and construction at the property are not available for review. The existing short wall will be demolished and near vertical back-cuts less than 10 feet in height will be needed to construct the planned new wall. Detailed wall plans are not yet available, however, the use of a conventional masonry wall supported on shallow strip footings is anticipated. III. SITE INVESTIGATION Site conditions at the planned wall areas were chiefly determined by mapping existing exposures and the excavation of two hand-dug test pits. Both test pits were logged by our project geologist, who also retained representative soil and rock samples at selected locations and intervals for subsequent laboratory testing. Test pit locations are shown on Plate 2. Logs of the Test Pits are enclosed with this report as Plate 3. Laboratory test results are summarized in following sections. ViNJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue•Escondido,California 92029-I229 •Phone(760)743-I2I4 r PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 2 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 IV. FINDINGS The proposed wall location is currently occupied by a modest graded fill embankment. i Records of engineering observations and compaction testing 9 9 p g pertinent to the site grading and slope construction are not available for review. Landslides or other forms of slope instability are not in evidence. A Geologic Cross-Section depicting subsurface relationships based on the exposures developed in our exploratory excavations is included with this report as Plate 4. A. Earth Materials i Fill soils, likely placed during original site development, are exposed on the study slope. As encountered, the fill materials range from sandy to clayey sandy soils. t Site existing fills were typically found in moist and loose to soft conditions within the upper 2 to 3 feet grading uniformly compacted below. Formational rock units underlie the upper site fills. As exposed in Test Pit T-1, the formational rocks consist of fine to medium grained sandstone units that locally include clay, and were typically found in weathered friable and weakly to ] moderately cemented conditions overall. Project formational rocks are competent units that will adequately support fills and wall structures. Evidence to benching was noted within Test Pit T-1. B. Laboratory Testing / Results Earth deposits encountered in our exploratory test excavations were closely examined and sampled for laboratory testing. Based upon our test pit and field exposures, site soils have been grouped into the following soil types: TABLE 1 'De§cri f�on 1 brown silty sand with trace of clay (Fill/Formational Rock) 2 tan silty fine to medium sand (Fill) 3 grey to brown sandy clay to clayey sand (Fill) The following tests were conducted in support of this investigation: 1. Grain Size Analysis: Grain size analysis was performed on a representative sample of Soil Type 2. The test result is presented in Table 2. VINJE & MIDDLE;ON ENGINEERING INC. • 2450 Vinevard Avenue•Escondido Cali - , _ California 920..9 I2..9 Phone(i 60)743 I.,I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 3 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 TABLE 2 Sieve Size %" #4 `; #10 #2d '<' #40 #200": Location Soil Type Percent Passing TP-2 1' 2 100 100 100 96 ., = ! 81 97 2. Maximum Dry Density and Optimum Moisture Content: The maximum dry density and optimum moisture content of Soil Type 1 was determined in accordance with ASTM D-1557. The test result is presented in Table 3. TABLE 3 r _> Soil; 5 Maximum Dry r! , Optimum Moisture Location T"" "e „> Densi m c Content wopt TP-2 @ 21W 125.0 10.1 3. Moisture-Density Tests (Undisturbed Chunk and Ring Samples): In-place 1 dry density and moisture content of representative soil deposits beneath the site were determined from relatively undisturbed chunk samples using the water i displacement test method, and undisturbed ring samples using the weights and f measurements test method. The test results are presented in Table 4 and tabulated on the enclosed Test Pit Logs (Plate 3). TABLE 4 b#; Field „ Ratio Of In-Place Dry,- Mo�sfu�e y Field Dry Max Dry Density To Max.Dry Sample Soft Content z ens! Density; Density* =location T e d°I° D= c M c D!M x 10Q TP-1 @ 3' 3 14.9 110.0 - - TP-1 @ 31W 1 16.5 108.3 125.0 86.6 TP-2 @ 1' 2 16.2 101.9 - - TP-2 @ 2' 1 10.9 118.4 125.0 94.7 TP-2 @ 3'/z' 1 13.0 113.5 125.0 90.8 FT P__2 @ 4'/Z 1 13.3 1 112.8 1 125.0 1 90.2 * Designated as relative compaction for structural fills. F 7K, um required relative compaction for structural fill is 90% unless otherwise specified. VIN1 E & MIDDLE roN ENGINEERING, INC. • 2 450 t meti ard Avenue Escondido,California 92029-I229 •Phone(760)743-L I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 4 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 4. Direct Shear Test: Three direct shear tests were performed on representative l samples of Soil Types 1 and 3. The prepared specimens were soaked overnight, loaded with normal loads of 1, 2, and 4 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 5. TABLE 5 Wet Angle�of Apparen#„ Sample a k Soil �Int:FDICCohesion Location h T a Condition w- a D-De` . c; s TP-1 @ 3'/2 1 remolded to 100%of m @ % d 125.4 31 136 TP-2 @ 21W 1 remolded to 90%of m @ %wopt 122.4 31 45 TP-1 2'/' 3 remolded to 100% of Y % w 126.1 34 116 5. pH and Resistivity Test: pH and resistivity of a representative sample of Soil Type 3 was determined using "Method for Estimating the Service Life of Steel Culverts," in accordance with the California Test Method (CTM) 643. The test result is presented in Table 6. TABLE 6 SamIeLocation :`SoiIT' a �..�;�.,Minimum Resistivi OHM-CM H TP-1 a@ 2'/z' 3 952 6. Sulfate Test: A sulfate test was performed on a representative sample of Soil Type 3 in accordance with the California Test Method (CTM) 417. The test result is presented in Table 7. TABLE 7 p Amount of Water Soluble Sulfate(soa) Sample Location Soil T e �' YP. In Soil /a-b Weight)==TP-1 @ 2'/2' 3 0.013 7. Chloride Test: A chloride test was erformed p on a representative sample of Soil Type 3 in accordance with the California Test Method (CTM) 422. The test result is presented in Table 8. `� VINJE & MIDDLETON' ENGINEERING, INC. - 2450 Vineyard Avenue-Escondido,California 92029-I229 -Phone(760)743-I2I4 .PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 5 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 TABLE 8 Amount of WatecSolu6le Chloride(CI) 5a'mple LocationSod Type, In Soil %b Wei ht TP-1 @ 21W 3 0.020 V. SITE CORROSION ASSESSMENT A site is considered to be corrosive to foundation elements, walls and drainage structures if one or more of the following conditions exists: Sulfate concentration is greater than or equal to 2000 ppm (0.2% by weight). Chloride concentration is greater than or equal to 500 ppm (0.05 % by weight). pH is less than 5.5. For structural elements, the minimum resistivity of soil (or water) indicates the relative quantity of soluble salts present in the soil (or water). In general, a minimum resistivity value for soil (or water) less than 1000 ohm-cm indicates the presence of high quantities of soluble salts and a higher propensity for corrosion. Appropriate corrosion mitigation measures for corrosive conditions should be selected depending on the service environment, amount of aggressive ion salts (chloride or sulfate), pH levels and the desired service life of the structure. Laboratory test results performed on selected representative site samples indicated that the minimum resistivity is less than 1000 ohm-cm suggesting a potential for presence of high quantities of soluble salts. However, test results further indicated that pH is greater than 5.5, sulfate concentration is less than 2000 ppm, and chloride concentration is less than 500 ppm. Based on the results of the corrosion analyses, the project site is considered non-corrosive. The project site is not located within 1000 feet of salt or brackish water. Based upon the result of the tested soil sample, the amount of water soluble sulfate (SO4) was found to be 0.013 percent by weight which is considered negligible according to the California Building Code Table No. 19-A-4. Portland cement Type II may be used. Table 9 is also appropriate based on the pH-Resistivity test results: TABLE 9 Design soil Type. -� Gage 18:'' 16 14 12 10 $. 3 Years to Perforation of Steel Culverts 24 -31 38 52 F; 81 VINJE & MIDDLETON ENGINEERING, INC. - 2450 Vineyard Avenue-Escondido,California 92029-1229 -Phone(760;,743-I214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 6 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 VI. CONCLUSIONS AND RECOMMENDATIONS Construction of the planned retaining wall is feasible from a geotechnical viewpoint. The existing graded embankment generally exposes compact to well compacted fills within the exception of the upper 2 to 3 feet. The wall backcut is expected to expose fills in upper exposures and formational rock near the bottom and foundation level. Formational rock units will provide suitable bearing soils for the wall support. The proposed wall should be designed and detailed for construction by the project structural engineer. The following geotechnical factors and soil design parameters are jappropriate: A. Clean-up and Clearing Surface vegetation, deleterious materials, and construction debris generated from the demolition of the existing short wall and other unsuitable materials over the l proposed wall construction areas should be removed and properly disposed of. l Trash, vegetation and construction debris shall not be allowed to occur or contaminate new site backfills. Existing underground structures, pipes and utilities should be pot-holed, identified and marked prior to the actual work. All irrigation lines should be properly removed j from the construction areas. Abandoned irrigation lines should be properly capped 1 and sealed off to prevent any future water infiltrations into the foundation bearing and backfill soils. Voids created by the removals of the abandoned underground pipes and structures should be properly backfilled with compacted fills in accordance with the requirements of this report. B. Excavations, Temporary Slopes and Wall Back-cuts Excavations and soil removals along the base of the existing embankment fill slope will be required for completing wall construction as planned. The excavations will create temporary construction backcut slopes which are expected to be on the order of 10 feet high maximum (including foundation trench depths). Temporary backcut slope created by the removal operations and wall foundation trenching may be constructed at near vertical gradient within the lower 5 feet and laid back at Y2:1 gradient maximum within the upper portions. The back-cut slope developed as recommended herein will be grossly stable with respect to deep seated and surficial failures for the indicated maximum vertical heights for temporary conditions. The construction slope should be protected from rain and irrigation water. Stockpiling the removed soils atop the construction slope should also not be allowed. VtNJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue•Escondido,California 92029-I229•Phone(760)743-I2I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 7 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 i The need for shoring of the back cut slope are currently no indicated provided construction and earthworks are completed in a timely manner. Periodic inspections of the temporary back cut should be performed by the project geotechnical consultant. The need for flatter slope gradients, completing wall construction in limited alternating sections or the need for shoring structures should I be determined based on actual field exposures and may be anticipated. The contractor shall also obtain appropriate permits, as necessary, and conform to Cal-OSHA and local governing agencies for a safe construction site and protection of the workmen. C. Foundation Trenching and Bearing Soils Preparations 1 Based on our exploratory excavations, wall foundation trenching is expected to mostly expose competent formational units which can suitably support the new ! wall. However, locally compacted fills may also be exposed at the bottom of foundation trenches. Bearing soils transition from undisturbed formational units to i placed fills should not be permitted underneath the proposed wall foundations. i Wall foundations should be supported entirely on compacted fills or founded entirely on competent bedrock. In the case of bearing soils transitioning, the undisturbed formational rock portions of the foundation trenches should be over- excavated to a minimum of 12 inches below the bottom of the footing and reconstructed to design grades as properly compacted fills. Existing fills exposed l elsewhere at the bottom of the trench should also be prepared, moisture conditioned and recompacted in-place as part of bearing soils preparations as directed in the field. 1 Alternatively, wall foundations may be uniformly founded on competent formational units as approved by the project geotechnical consultant. For this purpose, the wall foundations in the fill exposure areas should be additionally deepened extending through the fills and embedded a minimum of 18 inches into the underlying formational rocks as approved in the field. Wall foundation trenches should be embedded at least 18 inches into the underlying competent undisturbed formational units, or well compacted fills as approved in the field by the project geotechnical consultant or his designated representative. Foundation trenches should expose approved bearing soils throughout. Wall foundation width (and actual size) per structural design is based on the soil design parameters given herein. Foundation bearing fill soils should be manufactured into a uniform mixture, moisture conditioned to near optimum moisture levels, placed in thin horizontal lifts and mechanically compacted to at least 90% of the corresponding laboratory maximum density value per ASTM D-1557, unless otherwise specified. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue•Escondido,California 92029-1229 •Phone(760)743-12I4 f PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 8 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 1 D. Wall Back Drainage A back drainage system consisting of a minimum 4-inch diameter, Schedule 40 (SDR 35) perforated pipe, surrounded in a minimum of 3 cubic feet (minimum 12 inches wide by 36 inches high) per foot of%-inch crushed rocks, wrapped in filter fabric (Mirafi 140 N), or Caltrans Class 2 permeable aggregate will be necessary behind the new retaining wall. Filter fabric can be eliminated if Caltrans Class 2 permeable material is used. The invert of the subdrainage perforated pipe should be established at suitable elevations to ensure positive drainage into an approved drainage facility via a 4-inch diameter solid outlet pipe (SDR 35). The location of ! the proposed back drain should be inspected and approved by the project ! geotechnical consultant in the field. The wall back drain should be constructed in substantial accordance with the enclosed Plate 5. E. Backfill Materials and Compaction On-site soils are generally considered suitable for wall backfills. However, attempt should be made to selectively separate better quality sandy soils from more clayey deposits for reuse as backfill soils as directed in the field. More clayey sand to sandy clay soils generated from the site excavations should be properly removed and disposed of as part of the required export operations. Backfill soils should be adequately processed, manufactured into a uniform mixture, moisture conditioned to near optimum moisture levels, placed in thin horizontal lifts and mechanically compacted to at least 90% of the corresponding laboratory maximum density value per ASTM D-1557, unless otherwise specified. The temporary back-cut behind the wall should be properly benched out and the wall backfills tightly keyed-in into the construction slope as the backfilling progresses. In the event of narrow clearance between the face of the back-cut and back side of the stem, the wall may be backfilled above the back drain with 3%-inch crushed rocks to 18 inches below the top of wall. A layer of Mirafi 50OX soil separation Geotextile should then be placed over the crushed rocks, and the upper 18 inches backfilled with a minimum 90% compacted on-site better quality granular soils. s F. Soil Design Parameters The following preliminary soil design parameters are based upon tested representative samples of on-site earth deposits: Design wet density = 126 pcf. Design angle of internal friction = 31 degrees. '+ VINJE & MIDDLETON ENGINEERING, INC. - 2450 Vineyard Avenue-Escondido,California 92029-I229 0 Phone(760)743-I2I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 9 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 1 Design active soil pressure for retaining structures =40 pcf(EFP), level backfill, cantilever, unrestrained walls. * Design active soil pressure for retaining structures = 66 pcf (EFP), 2:1 sloping backfill, cantilever, unrestrained walls. * Design at-rest soil pressure for retaining structures =61 pcf(EFP), non-yielding, restrained walls. * Design passive soil pressure for retaining structures = 391 pcf (EFP), level surface at the toe. * Design coefficient of friction for concrete on soils = 0.38. * Net allowable foundation pressure for competent undisturbed formational units i (minimum 12 inches wide by 18 inches deep footings) = 2000 psf. l * Net allowable foundation pressure for compacted fills (minimum 12 inches wide by 18 inches deep footings) = 1500 psf. * Allowable lateral bearing pressure (all structures except retaining walls) for undisturbed bedrock = 150 psf/ft. i Notes: i • Additional lateral wall pressures resulted from nearby foundations and load surcharges, if any, should be considered by the project structural engineer. • Use a minimum safety factor of 1.5 for wall overturning and sliding stability. However, because large movements must take place before maximum - passive resistance can be developed, a safety factor of 2 may be considered for sliding stability where sensitive structures and improvements are planned near or on top of retaining walls. • When combining passive pressure and frictional resistance the passive component should be reduced by one-third. * The net allowable foundation pressures provided herein were determined for footings having a minimum width of 12 inches and a minimum depth of 18 inches. These values may be increased by 20% for each additional depth and width to a maximum of 4500 psf, if needed. The allowable foundation pressures provided herein also applies to dead plus live loads and may be - increased by one-third for wind and seismic loading. * The allowable lateral bearing earth pressures may be increased by the amount of the designated value for each additional foot of depth to a maximum 1500 pounds per square foot. VINJE & MIDDLETON ENGINEERING INC. • 2450 Vineyard Avenue•Escondido California y mia 9.,029-I229 Phone(i60)743 I214 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 10 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 1 G. Engineering Inspections All wall foundation trenching and backfilling, including stability of the temporary back-cut slope, back drain installations, suitability of earth deposits used as compacted backfill, and compaction procedures should be continuously inspected and tested by the project geotechnical consultant and presented in the final as- graded wall backfill compaction report. Geotechnical engineering inspections shall include, but not limited to the following: t * Temporary back-cut slope inspection -After clean-up but during removals and j excavations. Local and Cal-OSHA safety requirements for open excavations apply. * Foundation trench inspection - After the foundation trench excavations but before steel placement. * Backfill inspection -After the backfill placement is started but before the vertical height of fill/backfill exceeds 2 feet. There should be a minimum of one test for each 2 feet vertical gain within every 25 linear feet of backfill. Finish grade tests shall be required regardless of fill thickness. * Foundation bearing soils inspection - After foundation soils preparations but prior to the placement of concrete for proper moisture and specified compaction levels. In the case of compacted fills bearing soils, there should be a minimum of one test in every 25 linear feet of trench. * Geotechnical foundation steel inspection - After the steel placement is completed but before the scheduled concrete pour. * Wall back drain inspection - during the actual placement. All material shall conform to the project material specifications and approved by the project geotechnical engineer. H. Surface Drainage Control Surface water should be directed away from the top of wall. Final backfill surface should be adequately held below the top of wall to disallow overflow of surface run- off. A drainage ditch should be considered along the top of the wall for proper collection and disposal of surface waters. Area drains should be installed. Water collected in the area/areas should be directed into a suitable outlet via a solid non- perforated pipe. VINJE & MIDDLETON ENGINEERING, INC. • 2450 Vineyard Avenue•Escondido,California 92029-1229•Phone(760)743-I2I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 11 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 1. Staking and Grading Control Adequate staking and construction control are critical factors in properly completing the recommended work. Construction control and staking should be provided by the project grading contractor, or surveyor/civil engineer and is beyond the geotechnical engineering services. Inadequate staking and/or lack of grading control may result in unnecessary additional grading which will increase construction costs. J. Construction Plans and Geotechnical Plan Review A qualified civil engineer may be consulted to prepare accurate plans and construction details for the proposed new wall and associated drainage improvements. Final plans should reflect preliminary recommendations given in this report. Final foundations and wall plans may also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report outlined herein. More specific recommendations may be necessary and should be given when final grading and architectural/structural drawings are available. K. Preconstruction Conference A preconstruction meeting between representatives of the project geotechnical consultant, the property owner or planner, city inspector, project civil engineer and contractor, is recommended in order to discuss grading and construction details associated with the slope repairs. L. General Recommendations 1. Open or backfilled trenches parallel with a footing hall not be below a projected 9 P J plane having a downward slope of 1-unit vertical to 2-units horizontal (50%) from a line 9 inches above the bottom edge of the footing, and not closer than 18 inches form the face of such footing. 2. Where pipes cross under-footings, the footings shall be specially designed. Pipe sleeves shall be provided where pipes cross through footings or footing walls, and sleeve clearances shall provide for possible footing settlement, but not less than 1-inch all around the pipe. 3. Foundations where the surface of the ground slopes more than 1-unit vertical in 10-units horizontal (10% slope) shall be level or shall be stepped so that both top and bottom of such foundations are level. Individual steps in continuous VINJE & MIDDLETON ENGINEERING, INC. • 240 Vineyard Avenue•Escondido,California 92029-1229•Phone(760) - ( )743 L,I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 12 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 footings shall not exceed 18 inches in height, and the slope of a series of such steps shall not exceed 1-unit vertical to 2-units horizontal (50%) unless otherwise specified. The steps shall be detailed on the structural drawings. The local effects due to the discontinuity of the steps shall also be considered in the design of foundations as appropriate and applicable. VII. LIMITATIONS The conclusions and recommendations provided herein have been based on all available data obtained from our field observations, exploratory excavations and laboratory analyses, as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. This report is issued with the understanding that the owner or his representative is responsible to ensure that the information and recommendations are provided to the project architect/structural engineer so that they can be incorporated into the plans. Necessary steps shall be taken to ensure that the project -general contractor and subcontractors carry out such recommendations during construction. VIhJE & MIDDLETON ENGINEERING, INC. - 2450 Vineyard Avenue-Escondido,California 92029-1229 -Phone(760)743-12I4 PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 13 348 HORIZON DRIVE, ENCINITAS, CALIFORNIA MARCH 29, 2006 The project soils engineer should be provided the opportunity for a general review of the project final design plans and specifications in order to ensure that the recommendations provided in this report are property interpreted and implemented. The project soils engineer should also be provided the opportunity to verify the foundations prior the placing of concrete. If the project soils engineer is not provided the opportunity of making these reviews, he can assume no responsibility for misinterpretation of his recommendations. Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the limits prescribed by our client with the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #06-161-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. ED G-;z- �C� �g MIDp� Cis A iddleton a CEG 980 CEG #980 CERTIFIED ENGINEE9ING rcSS/� o� AM q 91 Or C P,0", S. ehdi S. Shariat ,74 �' m ExP. 12-31-06 ~ ) #46174 �9r clvlt �P FOF CAL1Fo 55�p1dAL '�O Steven J. Melzer JAN JAYg�� �o CEG #2362 No.2362 a y CERTIFIED 9 ENGINEERING DM/SMSS/SJM/jt N GEOLOGIST EXP.5-31-07 �Q Distribution: Addressee (5) 9�F�F CA0- c:fjt/myfiles/pre lims.06/06-161-P VINJE & MIDDLETO`v ENGINEERING, INC. • 2450 Vineyard Avenue•Escondido,California 92029-I229 •Phone(760)743-I2I4 unNADACT r \ - NA\'E. OOG �R /�, _,'`.^ \_.ate_' _�1'_• 1 ��a- T i CALLE VALLARTA AVENID� OCIVENHAIN RD O PLATE o REGIONAL t MAP = - 1\ 2 __ SOP% RI y�IO I� 11fOV�N161 P� M -'tea\Dp�� NIDA LAPJA sum EASOW,U4 w N <Oly \• p \�r ���'.� m - ♦CT \ Z rM m 1 •`. oI CfR GIEN•ARBOR.UK `7 Lq m9 N COTTAGE�E CT HUMMOCK LN ""'uy1.r b LEN C7 VANESSA CIA `�� h A W—t SKYK/N"O"CZWA COUNT RV GROVE 'O"LPark Botanical N �k�p 3\ 1 `.3 !y ■ � �,. uRE MFpD r r m I z pI Q - _ti FN`EDGEFt�tfl ll'1 �U 'CEAf.WOOD PL f per f ✓. m i �' O � N\ N •¢4 m ty1\ _ O'aa -,c RED COACH LN w 1BPN DR 70w o / ..4 -w < ) m _SHrELpS GPL R` 41 SC. 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Location of Test Pit I Geologic Cross—Section O9 0 APPROX. SCALE: 1'=10' T-1 A �y T-2 �i CHABOT RESIDENCE POOL VIM Job #06-161—P PRIMARY DIVISIONS GROUP SECONDARY DIVISIONS SYMBOL GRAVELS CLEAN Q GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines. J woo MORE THAN HALF (LESS THAN 1-' N OF COARSE o GP Poorly graded gravels or gravel-sand mixtures, little or no fines. FINES) 2 O FRACTION IS GRAVEL GM Silt p u_ Z W y gravels, gravel-sand-silt mixtures, non-plastic fines. LLJ O Z N LARGER THAN WITH G u_ = 0 NO. 4 SIEVE FINES GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. a: Q F' j SANDS CLEAN C7 = ¢ W SANDS SW Well graded sands, gravelly sands, little or no fines. U) QZ cn MORE THAN HALF (LESS THAN Q H Q OF COARSE 5% FINES) $P Poorly graded sands or gravelly sands, little or no fines. O w FRACTION IS 0 SANDS SM Silty sands, sand-silt mixtures, non-plastic fines. O — SMALLER THAN WITH NO. 4 SIEVE I FINES SC Clayey sands, sand-clay mixtures, plastic fines. u_ w ML Inorganic silts and very fine sands, rock flour, silty or clayey fine N U) O Uj CO SILTS AND CLAYS sands or clayey silts with slight plasticity. UO Qw < w LIQUID LIMIT IS CL Inorganic clays of low to medium plasticity, gravelly clays, sandy 0 2 Cj) CO LESS THAN 50% clays, silty clays, lean clays. uj Zino -Q — O OL Organic silts and organic silty clays of low plasticity. a ~ Q MH Inorganic silts, micaceous or diatomaceous fine sandy or silty W0 EE p CLAYS � w Z SILTS AND soils, elastic silts. Z_ LIQUID LIMIT IS LL = GREATER THAN 50% CH Inorganic clays of high plasticity, fat clays. � OH Organic clays of medium to high plasticity, organic silts. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. GRAIN'SIZES U.S. STANDARD SERIES SIEVE CLEAR SQUARE SIEVE OPENINGS 200 40 10 4 3/4" 3" 12" SILTS AND CLAYS SAND GRAVEL FINE MEDIUM COARSE FINE COARSE COBBLES BOULDERS RELATIVE DENSITY CONSISTENCY ANDS, GRAVELS AND CLAYS AND NON-PLASTIC SILTS BLOWS/FOOT PLASTIC SILTS STRENGTH BLOWS/FOOT VERY LOOSE 0 - 4 VERY SOFT 0 - 1 4 0 - 2 LOOSE 4 - 10 SOFT '/. - '/2 2 . 4 MEDIUM DENSE 10 - 30 FIRM /Y - 1 4 - 8 DENSE 30 - 50 STIFF 1 - 2 8 - 16 VERY DENSE OVER 50 VERY STIFF 2 - 4 16 - 32 HARD OVER 4 OVER 32 1 . Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-1 586) 2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700 • Sand Cone 46 = Standard Penetration Test est e Test ■ Bulk Sample I (SPT) (ASTM D-1586) Chunk Sample O Driven Rings with blow counts per 6 inches ❑ I I 246 = California Sampler with blow counts per 6 inches VINJE & MIDDLETON KEY TO EXPLORATORY BORING LOGS ENGINEERING, INC. Unified Soil Classification System (ASTM D-2487) 2450 Vineyard Ave., #102 Escondido, CA 92029-1229 PROJECT NO. KEY Date: 3-1-2006 LoggeRby DEPTH SAMPLE T-1 (n) FIELD DRY DESCRIPTION USCS MOISTURE DENSITY HSYMBOL (Pct = = FILL: 1 Silty fine sand. A trace of clay. Brown color. Very moist. SC Loose. Roots. oast - 2 %cemented.to medium sand. Tan color. Moist. Firm. ST-2 SM _ 3 - and/sandy clay. Grey to brown color. Moist. 14.9 110.0 I - 4 _ decaying organic layers. Musty odor. Firm to stiff. SC/CL - _ 16.5 108.3 86.6 IONAL ROCK- _ 5 _ e. Fine to medium grained. Locally clayey. Grey SM/SC lor. Weathered. Friable. Weakly to moderately _ 6 _ . Evidence of benching. ST-1 7 End Test Pit at 4'. _ 8 _ No Caving. No Groundwater. KDate3 -2006 Logged by: SJM PLE T-2 FIELD DRY RELATIVE DESCRIPTION USCS MOISTURE DENSITY COMPACTION SYMBOL (%) (Pco (/) FILL: Silty fine to medium sand. Tan color. Moist. Loose to SM firm. A few roots. 16.2 101.9 ST-2 - - Silty fine to medium sand. A trace of clay. Moist. 10.9 118.4 94.7 3 ' ■ Medium dense to dense. _ ST-1 SM/SC _ 4 - 13.0 113.5 90.8 - 5 = = End Test Pit at 5'. 13 3 6 ' No Caving. No Groundwater. - 7 - - 8 VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 TEST PIT LOGS Escondido, California 92029-1229 348 HORIZON DRIVE, ENCINITAS Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 06-161-P PLATE 3 Groundwater ■ Bulk Sam le 0 Chunk Sam le O Driven Rin s PLATE 4 � Qo I +1° APPROX.LOCATION OF q PROPOSED NEW WALL I +8 I i o o I I +a U11 EXISTING WALL I 7 TO BE REMOVED FILL +2 ° FORMA TIONAL MOCK SCALE: 1"=5' V&M Job #06-161—P RETAINING WALL DRAIN DETAIL -� Typical - no scale draina a Granular, non-expansive backfill. Compacted. Waterproofing :• : ' : : . j. tom• ,' Filter Material. Crushed rock (wrapped i pp n Perforated drain pipe i filter fabric) or Class 2 Permeable Material (see specifications below) fOflt4t4 SP£�IFICAT4pNSFE3i�CAL TRANS 1 GI.�t5SZ:PE€2M04131E MATEFtfAt .,:..., (66 61s 4- Atm Competent, approved 418{►ES# E 'b PASSING soils or bedrock A. tQ>? 90 100 3l8 40-9 Q0 8 4833 No 3E3 fiiit SQ <: Q 7 fJo 2QQ Q 3 Sarui E��ui>fatertt> ?S CONSTRUCTION SPECIFICATIONS: 1. Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact o standard, p backfill to minimum 90/o of laboratory 2. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. 3. Backdrain should consist of 4"diameter PVC pipe(Schedule 40 or equivalent)with perforations down. Drain to suitable outlet at minimum 1%. Provide%'- 1'/" crushed gravel filter wrapped in filter fabric(Mirafi 140N or equivalent). Delete filter fabric wrap if Caltrans Class 2 permeable material is used. Compact Class 2 material to minimum 90%of laboratory standard. 4. Seal back of wall with waterproofing in accordance with architect's specifications. 5. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to minimum 2%flow away from wall is recommended. *Use 1'h cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE 5 REFERENCES - Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.08: Soil And Rock (1); D 420 - D 5611, 2005. Annual Book of ASTM Standards, Section 4 - Construction, Volume 04.09: Soil And Rock - (I1); D 5714 - Latest, 2005. Highway Design Manual, Caltrans. Fifth Edition. - Corrosion Guidelines, Caltrans, Version 1.0, September 2003. - California Building Code, Volumes 1 & 2, International Conference of Building Officials, 2001. - "Green Book" Standard Specifications For Public Works Construction, Public Works Standards, Inc., BNi Building News, 2003 Edition. - California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, DMG Special Publication 117, 71p. - California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1986 (revised), Guidelines for Preparing Engineering Geology Reports: DMG Note 44. - California Department of Conservation, Division of Mines and Geology Geological Survey), 1986 (revised), Guidelines to Geologic and Seismic Reports:DMG Note 42. - EQFAULT, Ver. 3.00, 1997, Deterministic Estimation of Peak Acceleration from Digitized Faults, Computer Program, T. Blake Computer Services And Software. EQSEARCH, Ver 3.00, 1997, Estimation of Peak Acceleration from California Earthquake - Catalogs, Computer Program, T. Blake Computer Services And Software. Tan S.S. and Kennedy, M.P., 1996, Geologic Maps of the Northwestern Part of San Diego County, California, Plate(s) 1 and 2, Open File-Report 96-02, California Division of Mines and Geology, 1:24,000. - UBCSEIS, Ver. 1.03, 1997, Computation of 1997 Uniform Building Code Seismic Design Parameters, Computer Program, T. Blake Computer Services And Software. - "Proceeding of The NCEER Workshop on Evaluation of Liquefaction Resistance Soils," Edited by T. Leslie Youd And Izzat M. Idriss, Technical Report NCEER-97-0022, Dated December 31, 1997. - "Recommended Procedures For Implementation of DMG Special Publication 117 Guidelines For Analyzing And Mitigation Liquefaction In California," Southern California Earthquake center; USC, March 1999. - "Soil Mechanics," Naval Facilities Engineering Command, DM 7.01. "Foundations & Earth Structures," Naval Facilities Engineering Command, DM 7.02. "Introduction to Geotechnical Engineering, Robert D. Holtz, William D. Kovacs. Introductory Soil Mechanics And Foundations: Geotechnical Engineering," George F. Sowers, Fourth Edition. - "Foundation Analysis And Design," Joseph E. Bowels. Caterpillar Performance Handbook, Edition 29, 1998 - Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology Bulletin 200, 56p. a: - Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, California Division of Mines and Geology, 1:24,000. - Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p. Caterpillar Performance Handbook, Edition 29, 1998 - Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas, California Division of Mines and Geology, Geologic Data Map Series, No. 6. Kennedy, M.P., 1977, Recency and Character of Faulting Along the Elsinore Fault Zone in Southern Riverside County, California, Special Report 131, California Division of Mines and Geology, Plate 1 (East/West), 12p. Kennedy, M.P. and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, - California: California Division of Mines and Geology Bulletin 200, 56p. Kennedy, M.P. and Tan, S.S., 1977, Geology of National City, Imperial Beach and Otay Mesa Quadrangles, Southern San Diego Metropolitan Area, California, Map Sheet 24, - California Division of Mines and Geology, 1:24,000. Kennedy, M.P., Tan, S.S., Chapman, R.H., and Chase, G.W., 1975, Character and Recency of Faulting, San Diego Metropolitan Areas, California: Special Report 123, 33p.