The URL can be used to link to this page

Home My WebLink AboutCT 81-10; Carlsbad Research Center Phase 1; Soils Report; 1981-08-17Woodward-Clyde Consultants ADDITIONAL STUDIES CARLSBAD RESEARCH CENTER PHASE I CARLSBAD, CALIFORNIA CT81-/O for The Koll Company 7330 Engineer Road San Diego, California 92111 t 3467 Kur,z stree. Woodward-Clyde ConsultantsSan Diego. California 92110 * 714-224-2911 RE CEIVE D .-i !;" 1 R 1QO1 The Koll Company " : ~ '^Ol 7330 Engineer Road «.—», ^r- «.r.. «~San Diego, California 92111 CITY OF CARLSBAD Engineering Department Attention: Mr. Bernard Fipp ADDITIONAL STUDIES CARLSBAD RESEARCH CENTER PHASE I CARLSBAD, CALIFORNIA Gentlemen: We are pleased to provide the accompanying report which pre- sents results of our additional studies for the subject project. This study was performed in accordance with our agreement dated August 3, 1981. The report presents our conclusions and recommendations per- taining to the project as well as the results of our field explorations and laboratory tests. If you have any questions or if we can be of further service, please call. Very truly yours, WOODWARD-CLYDE CONSULTANTS James E. Cavallin R.E. 17553 JEC/DS/SAW/eej (3) The Koll Company (1) Rick Engineering Company (2) City of Carlsbad Consulting Engineers, Geologists and Environmental Scientists Offices in Other Principal Cities Project NO. 51113M-AS01 Wood ward-Clyde Consultants TABLE OF CONTENTS Page PURPOSE OF INVESTIGATION 1 BACKGROUND INFORMATION 1 PROJECT DESCRIPTION 2 FIELD AND LABORATORY INVESTIGATIONS 2 SITE, SOIL AND GEOLOGIC CONDITIONS 3 Geologic Setting 3 Topography and Surface Conditions 3 Subsurface Conditions 3 Fill Soils (Qaf) 4 Alluvium (Qal) 4 Pleistocene Terrace Materials (unmapped) 4 Santiago Formation (Ts) 4 Point Loma Formation (Kpl) 4 Ground Water 5 Potential Geologic Hazards 5 DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS 5 Existing Fill Soils 5 Expansive Soils 6 Slope Stability 6 Grading and Earthwork Specifications 8 Foundations 9 RISK AND OTHER CONSIDERATIONS 11 Project No. 51113M-AS01 Woodward-Clyde Consultants TABLE OF CONTENTS (cont'd) FIGURES 1 Site Plan 2 Generalized Geologic Cross Sections A-A1 and B-B1 APPENDIX A Field Investigation A-l FIGURES A-l Key to Logs A-2 through A-6 Logs of Test Borings 1 through 5 A-7 through A-ll Logs of Test Pits 6 through 14 APPENDIX B Laboratory Tests B-l FIGURES B-l Results of Loaded Swell Tests B-2 through B-4 Slow Direct Shear Test APPENDIX C Slope Stability Analyses C-l APPENDIX D Specifications for Controlled Fill D-l APPENDIX E Oversize Rock Placement Areas E-l ll Project No. 51113M-AS01 Woodward-Clyde Consultants ADDITIONAL STUDIES CARLSBAD RESEARCH CENTER PHASE I CARLSBAD, CALIFORNIA This report presents the results of our additional studies for grading of the Phase I area of the Carlsbad Research Center. The site is north of Palomar Airport and west of El Camino Real in Carlsbad, California. PURPOSE OF INVESTIGATION The purpose of our investigation was to assist the Koll Company and their consultants in evaluating the property and in project design. This report presents our conclusions and/or recommendations regarding: 0 General subsurface soil conditions 0 General extent of existing fill soils 0 Presence and effect of expansive soils 0 Stability of proposed cut and fill slopes 0 Grading and earthwork specifications * ° Types and depths of foundations 0 Allowable soil bearing pressures. BACKGROUND INFORMATION * To aid in our study, we have discussed the project with Mr. Bob harding and have been provided with a grading plan entitled "Carlsbad Tract Number 81-10, Carlsbad Research Center" prepared by Rick Engineering Company. Additionally, t we have reviewed the following: Project No. 51113M-AS01 Woodward-Clyde Consultants 0 "Preliminary Soil and Geologic Investigation, Carls- bad Research Center, Carlsbad, California" prepared by Woodward-Clyde Consultants, dated April 27, 1981 0 Stereographic aerial photographs ASN series flown by Cartwright Aerial surveys for USDA (1964) and color Stereographic aerial photographs SDCO series flown in 1979 for the County of San Diego. PROJECT DESCRIPTION We understand it is proposed to grade 24 lots for con- struction of commercial structures. The grading plan indicates that the maximum cuts and fills will be on the order of 21 feet and 30 feet, respectively, and that cut and fill slopes will have maximum heights on the order of 20 feet and 30 feet, respectively, and maximum slope inclinations of 2 to 1 (horizontal to vertical). FIELD AND LABORATORY INVESTIGATIONS Our field investigation included making a visual recon- naissance of existing surface conditions, making five 8-inch diameter continuous flight auger borings, and nine backhoe test pits on August 3 and August 4, 1981, and obtaining repre- sentative soil samples. Samples were returned to our labora- tory for testing. The approximate locations of the test borings and test pits are shown on the Site Plan (Fig. 1). A Key to Logs is presented in Appendix A as Fig. A-l. Simplified logs of the borings and test pits are presented in Appendix A as Figs. A-2 through A-ll. The descriptions on the logs are based on field logs, sample inspection and laboratory test results. Results of the laboratory tests are shown on Appendix B. The field investigation and laboratory testing programs are discussed in Appendixes A and B. Project No. 51113M-AS01 Woodward-Clyde Consultants SITE, SOIL AND GEOLOGIC CONDITIONS Geologic Setting The subject site is in the western San Diego county coastal area which is part of the coastal subprovince within the Peninsular Range Batholith, a well-defined geologic and physiographic province that extends southeastward from southern California to the tip of Baja California. The coastal subprovince consists of gently westward dipping Cre- taceous through Quaternary age sedimentary formations that overlie and abut Jurassic age metamorphic and Cretaceous age crystalline rocks to the east. Topography and Surface Conditions The project area consists of a series of nearly flat ridges that flank a wide, shallow, westward-draining draw. Elevations at the site range from a high of approximately 325 feet (MSL Datum) near the northeast and southeast corners of the site boundary, to a low of approximately 275 feet where the central draw crosses the west site boundary. An earth dam embankment exists across the central draw. This embankment now forms a shallow pond. A shallow, open pit excavation in the southeast portion of the site was mined for clay. Several small stockpiles of overburden soil remain in this area, and standing water was observed in the open pit. The site is covered by a moderate to dense growth of native grasses. Subsurface Conditions Our review of previous studies and our current geologic reconnaissance and field investigation indicate that the site is separated into distinct areas that are underlain by sedi- mentary formational soils, terrace materials, natural over- burden soils, alluvial soils, and existing fill soils. The approximate areal extent of these units is shown on Fig. 1 in project NO. 5H13M-AS01 Wdodward-ClydeConsultants our April 27, 1981 report. The units are described in the following paragraphs in the order of increasing age. The geologic map symbol for each unit is given after the formal name. (Selective cross sections are presented as Fig. 2.) Fill Soils (Qaf). Several areas of loose fill associated,, with the mine operations and with the earth dam embankment fills are located within the site. These fill soils consist of silty to clayey sands and sandy clays. Alluvium (Qal). Alluvial deposits are present within the wide tributary along the central portion of the project area. The alluvial soils consist of porous, silty to clayey sands and sandy clays. A test boring made through the alluvium upstream from the earthen dam indicates that these deposits are as much as 5 feet deep, and are probably deeper in the immediate ponded area. These alluvial soils are porous and contain a high percentage of organic material and are com- pressible in nature. Pleistocene Terrace Materials (unmapped). These mater- ials were found as 1-foot to 2-foot thick discontinuous remnants of Pleistocene age terrace deposits in two areas in the eastern part of the site. These terrace deposits consist of cemented sandy and clayey gravels. Santiago Formation (Ts). The Eocene age Santiago forma- tion, found in the southeastern part of the site, consists of pale, olive-gray silty claystone that is overlain by a thin section of fine grained sandstone. The section of the Santi- ago Formation present in the project area is equivalent in age and similar in engineering characteristics to the Delmar Formation. The claystone portion of the Santiago Formation is susceptible to landsliding. Point Loma Formation (Kpl). The Cretaceous age Point Loma Formation consists of marine claystone, siltstone, and shale with interbedded cemented fine grained sandstone layers project NO. 51113M-AS01 W6od ward-Clyde Consultants up to 3 feet thick. A thick, deeply weathered residual clay paleosol has been developed locally upon this formation. Ground Water. A regional ground-water table was not encountered in the test borings or test pits excavated during this investigation. A small pond exists behind the low earth dam embankment located in the northeasterly section of the draw which extends from the southwesterly boundary to the central portion of the site. Although not observed during this investigation, some surface water flow was noted in this draw during our recon- naissance for our previous study. Potential Geologic Hazards Based upon our review of the project site, and our current field investigation, there are no potential geologic hazards, such as landslides or faults, within the limits of the current project area. A discussion of potential geologic hazards was presented in our preliminary soil and geologic investigation dated April 27, 1981. DISCUSSIONS, CONCLUSIONS AND RECOMMENDATIONS The discussions, conclusions and recommendations pre- sented in this report are based on the results of our field and laboratory studies, analysis, and professional judgment. Existing Fill Soils Several areas of loose fill soils associated with clay mining operations and with the earth dam embankment fills are located on the site. The approximate locations of these existing fill soils are shown on Fig. 1 of our April 27, 1981 report. Project NO. 51H3M-AS01 Woodward-Clyde Consultants Expansive Soils Our field investigation indicates that the on-site soils are predominantly siltstones and claystones of the Santiago and Point Loma formations which are considered moderate to highly expansive. Laboratory tests performed for this inves- tigation and for our previous study indicate the following approximate range of swell potentials for these soils. Swell, Percent Undisturbed Recompacted Formational Unit Sample Sample Point Loma 4-5 7-11 Santiago 9-10 10-11 In our opinion, the ranges given are reasonable; however, the potential swell of the undisturbed Point Loma Formation may be more than five percent. In our opinion, the expansive soils generated in the proposed cut areas may be used as fill material in the deeper fill areas. In our opinion these soils are not suitable for use at finish grade. Grading recommendations for these soils are presented in the Grading and Earthwork Specifications section of this report. Slope Stability The grading plans indicate that cut and fill slopes will have maximum heights of approximately 20 feet and 30 feet, respectively, and maximum slope inclinations of 2 to 1. We have performed slope stability analyses for the pro- posed cut and fill slopes, utilizing the Janbu method of analysis and the following soil strength parameters: Project No. 51113M-AS01 Woodward-Clyde Consultants Type of Slope <|)' (deg) c* (psf) y(psf) Cut Slopes 10 500 120 Fill Slopes 20 300 120 These parameters are based on laboratory tests performed for the April 27, 1981 report and our experience with the forma- tions in the general site area. Calculations are attached for reference (Appendix C). Our analyses indicate the proposed slopes will have calculated factors of safety in excess of 1.5 against deep- seated slope instability for static conditions. Stability analyses require the use of soil parameters selected from a range of possible values, thus, there is a finite possibility that slopes having calculated factors of safety as indicated above could become unstable. In our opinion, the probability of the slopes becoming unstable is low and it is our profes- sional judgment that the slopes can be constructed as planned. We recommend that the outer zones of fill slopes be composed of properly compacted granular material for a hori- zontal distance equal to at least 10 feet. A key should be cut at the bottom of the slope to accommodate this granular facing material. We recommend that the face of each fill slope be compacted at maximum 4-foot intervals during con- struction and trackwalked on completion. All slopes should be properly drained and maintained to help control erosion. In our opinion, cut slopes in the lower Santiago forma- tional materials in which weak clay seams are exposed will have a potential for deep-seated slope instability. Insta- bility is also indicated by bedding that dips out-of-slope and water seeps. Test pits and borings made for this investiga- tion in the Santiago formational materials in proposed cut areas did not reveal the presence of these adverse conditions. We recommend, however, that all cut slopes be inspected by an Project NO. 51H3M-AS01 Wbodward-ClydeConsultants engineering geologist from our firm during grading to evaluatetactual geologic conditions. If weak clay seams or landslide planes are noted during grading, recommendations will be presented at that time for slope buttressing. i Grading and Earthwork Specifications We recommend that the site be graded in accordance with the attached Specifications for Controlled Fill (Appendix D). We also recommend that the grading be observed by and com- pacted fills be tested by Woodward-Clyde Consultants. We recommend that a pre-construction conference be held at the site with the developer, civil engineer, contractor and geotechnical engineer in attendance. Special soil handlingtand the grading plans can be discussed at that time. Due to the expansive nature of the on-site soils, we recommend that the upper 2-1/2 feet of soil in building areas and the upper 1 foot of soil in areas to be paved be composediof nonexpansive soils. In order to accomplish this, under- cutting of cut areas and replacing materials with nonexpansive import soils, and topping fills with imported select material will be required. If no select soils are imported (i.e., as an alternate to the above recommendation), finish grade soils on the site will probably consist of expansive clayey sands and sandy clays. Swell test results indicate these soils swell on the order of 7 to 11 percent in their recompacted state or natural state. We recommend that these expansive soils placed or existing within the upper 30 inches of grade be properly compacted at moisture contents of 3 to 4 percent above optimum moisture content as determined by ASTM D-1557-70. This moisture content should be maintained up to the time of concrete placement. 8 Project No. 51113M-AS01 Woodward-Clyde Consultants Portions of the terrace materials are non-expansive in nature, but this unit is found in scattered locations and occurs in very thin lenses. In our opinion, it is not prac- tical to stockpile this material for use at finish grade. There are, therefore, no practical sources of select material on the Phase I site. We recommend that in areas to receive new fill or struc- tures all existing fill soils, porous topsoils and alluvium be excavated, watered as required and recompacted prior to con- structing footings or placing any additional fill. The alluvial deposits beneath the small pond behind the earth dam embankment may require drying prior to recompaction. Addi- tionally, should "pumping" occur in the pond area once the alluvium has been excavated, it may be necessary to lay a gravel blanket over the area prior to placing any fill soils. We recommend that the actual depth of fill or alluvial excava- tion and any special handling requirements for alluvial deposits in the pond area be evaluated in the field at the time of grading. We expect that an average of 4 feet of alluvium will have to be excavated from the draw. We recommend that rock fragments, and cemented materials between 2 feet and 4 feet in maximum dimension, be placed in accordance with the attached Oversize Rock Placement Areas (Appendix E). We recommend that no rock fragments larger than 4 feet in size be used in fills. Foundations The following general guideline recommendations for one- and two-story lightweight industrial structures are subject to revision when project plans have been more fully developed. In our opinion, conventional spread or continuous footings placed a minimum of 18 inches below lowest adjacent grade in nonexpansive soil or in properly compacted, nonexpan- Project No. 51113M-AS01 Woodward-Clyde Consultants sive fill soil can be designed for allowable soil bearing pressures of 2,500 psf (dead plus live load). Footings should have a minimum width of 12 inches. In our opinion, these bearing values can be increased by no more than one-third for loads induced by wind or seismic forces. We recommend that footings founded in moderately to highly expansive soil (6 to 12 percent swell) be embedded 24 inches below lowest adjacent grade and be designed for an allowable soil bearing pressure of 3,000 psf. The footings should be reinforced with one No. 4 bar top and bottom. Slab floors should be a minimum of 5 inches thick, and reinforced with No. 3 reinforcing bars placed 18 inches on centers. The slabs should be underlain by 10 mil plastic membrane sheeting and 4 inches of coarse sand. The following sketch clarifies our recommendations. 18"I*- .„ -*•! /#3 Dowels, 18" O.Cr Minimum!/ ' iqh or ,ed Grade 12" 4 , 1 1 24" Minimum J , 1 A 1 \1 \ J \ m<+* • _ -. ^fl 5" rnin . concrete slsb X* 1 ^Plastic membrane \ —^#4 bars, top and bottom with #3 bars at ] A • * * * ••• * '.* * ^ both ways .Minimum SCALE: 1" = 20' These recommendations are intended only to reduce the effects of heaving; footings founded in expansive soils should be expected to heave. We recommend that the expansion poten- tial of each lot be determined immediately prior to making footing excavations; adjustments to the foundation design can be made at that time, if appropriate. 10 Project No. 51113M-AS01 Woodward-Clyde Consultants t Due to the nature of the formational soils on the subject site, it is our opinion that some settlement could occur along daylight lines where formational units and fill units are in contact. f We recommend that structures that will not tolerate differential settlements (such as foundations, concrete decks, walls, etc.) not be located within 8 feet of the top of a slope. In those cases where it is necessary to locate j footings in this zone, we recommend that the footings be extended in depth until the outer bottom edge of the footing is at least 8 feet horizontally from the outside face of the slope. * RISK AND OTHER CONSIDERATIONS Our test borings indicate only a small portion of the pertinent soil and ground water conditions. The recommenda- tions made herein are based on the assumption that soil conditions do not deviate appreciably from those found during our field investigation. If the plans for site development are changed, or if variations or undesirable geotechnical conditions are encountered during construction, the geotech- nical consultant should be consulted for further recommenda- tions. We recommend that the geotechnical consultant review the foundation and grading plans to verify that the intent of the recommendations presented herein has been properly interpreted and incorporated into the contract documents. We further recommend that the geotechnical consultant observe the site f grading, subgrade preparation under concrete slabs and paved areas, and foundation excavations. It should also be understood that California, including San Diego, is an area of high seismic risk. It is generally , considered economically unfeasible to build totally earth- 11 project NO. 5H13M-AS01 Woodward-ClydeConsultants quake-resistant structures; therefore, it is possible that a large or nearby earthquake could cause damage at the site. Professional judgments presented herein are based partly on our evaluations of the technical information gathered, partly on our understanding of the proposed construction, and partly on our general experience in the geotechnical field. Our engineering work and judgments rendered meet current professional standards. We do not guarantee the performance of the project in any respect. This firm does not practice or consult in the field of safety engineering. We do not direct the contractor's opera- tions, and we cannot be responsible for the safety of person- nel other than our own on the site; therefore, the safety of others is the responsibility of the contractor. The contrac- tor should notify the owner if he considers any of the recommended actions presented herein to be unsafe. 12 Project NO. 51H3M-AS01 Woodward-ClydeConsultants APPENDIX A FIELD INVESTIGATION Five 8-inch diameter exploratory borings and nine test pits were made at the approximate locations shown on the Site Plan (Fig. 1). Samples of the subsurface materials were obtained from the 8-inch diameter borings using a modified California driven sampler (2-inch inside diameter and 2-1/2-inch outside dia- meter) with thin brass liners. The sampler was generally driven 18 inches into the material at the bottom of the hole by a 140-pound hammer falling 30 inches; thin metal liner tubes containing the sample were removed from the sampler, sealed to preserve the natural moisture content of the sample, and returned to the laboratory for examination and testing. The location of each boring or test pit and the elevation of the ground surface at each location were estimated using the "Tentative Map of Carlsbad Research Center," prepared by Rick Engineering Company. A-l Location Boring Number Elevation DEPTH IN FEET - - ••rf TEST DATA •MC 12 t •DO no J ••c 65 i > •OTHER SAMPLE QOIL DE9CRTESTS NUMBER 1 J>UIL Ut&lK •j p».l Very dense, i r- v ,2 1 - * i WATER LEVEL — ' IPTION damp, brown silty sand (SM) i At time of drilling or as indicated. OVJIL ULAoolrlUA 1 lUrM ' Soil Classifications are based on the Unified Soil Classification System and include color, moisture and consistency. Field descriptions have been modified to reflect results of laboratory analyses where appropriate. ' DISTURBED SAMPLE LOCATION Obtained by collecting the auger cuttings in a plastic or cloth bag. DRIVC "AMPLE LOCATION MODIFIED CALIFORNIA SAMPLER Sample with recorded blows per foot was obtained with a Modified California drive sampler 12" inside diameter, 2.5" outside diameter) lined with sample tubes. The sampler was driven into the soil at the bottom of the hole with a 140 pound hammer falling 30 inches. IfLinif* ATP** ** AfUIPI fINUIt-AI to oAMrLtE TESTED FOR OTHER PROPERTIESGS— Grain Size Distribution CT — Consolidation Test • LC — Laboratory Compaction DCS — Unconf ined Compression Test Test SDS - Slow Direct Shear Test PI — Atterberg Limits Test DS — D irect Shear Test ST - Loaded Swell Test TX - Triaxial Compression Test CC — Confined Compression 'R'- R-Value Test NOTE: In this column the results of these tests may be recorded where applicable. Number of blows needed to advance sampler one foot or as indicated. nnvs 1-.I-. ./-..TV/ Pounds per Cubic Foot UniCTI IRE mWTCMT Percent of Dry Weight NOTES ON FIELD INVESTIGATION t. REFUSAL indicate* the inability to extend excavation, practically, with equipment being uted in the investigation. KEY TO LOGS CARLSBAD RESEARCH CENTER DRAWN BY: Ch | CHECKED BY; &&\ PROJECT NO:51113M-ASOl ] DATE: 8-7-81 \ FIGURE NO:A-l WOODWARD-CLYDE CONSULTANTS Boring 1 Approximate El. 324' DEPTH IN FEET . „ m 5- - 10- 15_ 20J - 25- 30- 35- 40- TEST DATA •MC •DO •BC 46 so/ 5" so/ 4" SO/ 5" •OTHER TESTS PI=31 ST SAMPLE NUMBER | SOIL DESCRIPTION i1-1 fc^y 11 1Jl1-2 || 1 I1-3 Illlll « 11 Hard, dry to damp, dark brown, sandy clay (CL) TOPSOIL AND RESIDUAL \ CLAY Very dense, damp, light yellowish brown, clayey siltstone (ML) POINT LOMA FORMATION Very dense, damp, dark olive, silty clay (CL) , shale POINT LOMA FORMATION Bottom of Hole •For description of symbols. IM Figure A-l LOG OF TEST BORING 1 CARLSBAD RESEARCH CENTER DRAWN BY: ch ] CHECKED BY: ff#\ PROJECT NO: 51113M^ASQ1 j DATE; 8-7-81 | FIGURE NO: A-2 WOODWARD-CLYDE CONSULTANTS Boring 2 Approximate E10 320' DEPTH IN FEET • - 5- - - 10 ~" 15- . 20 - 25 - 30 ~ - 35 J 40 - TEST DATA *MC •DO •»c 50/ 5" 50/ 5" 50/ 4" •OTHER TESTS PI=32 ST SAMPLE NUMBER SOIL DESCRIPTION 1 1 III I1:iSSS2-1 •§* , 1 2-2 KSS ! 2-3 11 1 Hard, damp, dark yellowish brown, silty clay (CL-CH) TOPSOIL AND RESIDUAL CLAY Very dense, damp, light yellowish brown, clayey siltstone (ML) POINT LOMA FORMATION Hard, damp, dark olive, silty clay (CL) , shale POINT LOMA FORMATION ~^--Thin, cemented sandstone interbeds ~^~~ Cemented sandstone layer Bottom of Hole •For description of tymbolt, »ee FigureA-l LOG OF TEST BORING 2 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY: #0 \ PROJECT NO. 51113M-AS01 | DATE: 8-7-81 | FIGURE NO: A-3 WOODWARD-CLYDE CONSULTANTS Boring 3 Approximate E10 287' DEPTH IN FEET • • 10- - 15- TEST DATA •MC •DO •K 28 50/ 5" 50/ 4" •OTHER TESTS SAMPLE NUMBER SOIL DESCRIPTION 3-1 1! I3"2 li 3-3 |SS5 Stiff to very stiff, moist to wet, dark brown to black, sandy clay (CH-CL) ALLUVIUM Hard, damp, dark olive, silty clay (CL) , shale POINT LOMA FORMATION Bottom of Hole "For description of symbols, see Figure A-l LOG OF TEST PIT 3 CARLSBAD RESEARCH CENTER DRAWN BY; ch | CHECKED BY: tfff \ PROJECT NO: 5U13M-AS01 | DATE: 8-7-81 | FIGURE NO: A_4 WOODWARD-CLYDE CONSULTANTS Boring 4 Approximate El. 321' DEPTH IN FEET • • 5_ - - 10- . - 15- 20- - 25 _ 30- 35- an - TEST DATA •MC •DO ••C 34 66 94 50/ 5" •OTHER TESTS PI=42 ST £££^=1 SOIL DESCRIPTION i§ 4-1 1 £Sr il4-2 ISx; 1 4-3 ISS^ ^1 4-4 j^l Hard, dry to damp, dark brown, sandy clay <CH) TOPSOIL AND RESIDUAL CLAY Dense, damp, light yellowish brown, clayey fine sand (SC) SANTIAGO FORMATIONv Hard, damp, light greenish gray, silty clay (CL) SANTIAGO FORMATION Bottom of Hole •For description of symbols, «•« Figure LOG OF TEST BORING 4 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY:^^ | PROJECT NO: 51113M-AS01 | DATE: 8-7-81 | FIGURE NO: A_ WOODWARD-CLYDE CONSULTANTS Boring 5 Approximate Elr 326' DEPTH IN FEET 5_ - 10- - - 15- 20- - 25 _ 30- 35 J Art — TEST DATA •MC •DD •BC 47 88/ 11" 94/ 11" •OTHER TESTS SAMPLE NUMBER SOIL DESCRIPTION KSIsP ^Ev:':-:H5-l li11 5-2 ^^1 M| 1 Hard, dry, light brown, gravelly, sandy Clay (CL) TOPSOIL AND RESIDUAL CLAY Dense, damp, light orange brown, clayey fine sand (SC) PLEISTOCENE DEPOSITS Hard, damp, light olive gray, silty clay (CL) SANTIAGO FORMATION Bottom of Hole •For description of symbols, *m Figure A-l LOG OF TEST BORING 5 CARLSBAD RESEARCH CENTER DRAWN BY: cn \ CHECKED BY; J£ \ PHOJECT NO: 51113M-AS01 | DATE; 8-7-81 | FIGURE NO: A- WOODWARD-CLYDE CONSULTANTS Test Pit 6 Approximate Elr 326' DEPTH IN FEET : .. . 5- -• . 15- TEST DATA •MC •DO •BC •OTHERTESTS SAMPLE NUMBER SOIL DESCRIPTION Be-i r~N$s FTP* Loose, dry, light brown, clayey fine sand \ (SC) TOPSOIL i Hard, damp, dark brown, sandy clay (CH) 6~2 1 m\ RESIDUAL CLAY j — R>$J\ Friable, damp, orange brown, gravelly 6"3 KSH\ clayey fine sand (SC) 1 |S\3 \ PT.F.TRTOPFNF DRPORTTS i I I Hard, damp, olive gray, silty claystone \ (CL) SANTIAGO FORMATION Bottom of Hole Test Pit 7 Approximate El. 326' DEPTH IN FEET 5- 10- 15 - TEST DATA •MC •DO •BC •OTHER TESTS SAMPLE NUMBER ~r7-2 p SOIL DESCRIPTION 1 1 1 Stiff, moist, dark brown, sandy clay (CH) , RESIDUAL CLAY Firm to stiff, moist, gray, mottled, silty clay (CL) SANTIAGO FORMATION Very stiff to hard, moist, light gray, silt Claystone (CL) SANTIAGO FORMATION V Bottom of Hole •For description of symbols. *•« Figure A-l LOG OF TEST PITS 6 AND 7 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY: f£ \ PROJECT NO: 51113M-ASO1 j DATE: 8-7-81 | FIGURE NO: A- WOODWARD-CLYDE CONSULTANTS Test Pit 8 Approximate El. 300' DEPTHIN FEET m 5- 10- 15- TEST DATA •MC •DO •BC •OTHER TESTS SAMPLE NUMBER SOIL DESCRIPTION R§ 8-1 8-2 1 1 Hard, dry, dark brown, sandy clay (CL) y TOPSOIL Firm to stiff, moist, dark brown, silty to sandy clay (CH) RESIDUAL CLAY — — Grading to — — — Stiff, moist, dark olive, silty clay (CL) SANTIAGO FORMATION Bottom of Hole Test Pit 9 Approximate El. 324* DEPTH IN FEET 5 _ 10- 15- TEST DATA •MC •DO •BC •OTHER TESTS SAMPLE NUMBER 9-1 1 SOIL DESCRIPTION IF * 1 Loose, dry, light brown, clayey sand (SC) y TOPSOIL Dense, friable, damp, orange brown, gravel] clayey fine sand (SC) r PLEISTOCENE DEPOSITS Hard, damp, olive gray, silty claystone 1 (CL) SANTIAGO FORMATION \ Bottom of Hole •For description of symbols, «•• Figure A-l LOG OF TEST PITS 8 AND 9 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY: ^ \ PROJECT NO: 51113M-AS01 | DATE: 8-7-81 | FIGURE NO: A-8 WOODWARD-CLYDE CONSULTANTS Test Pit 10 Approximate El. 321' DEPTH IN FEET 5- 10- 15- TEST DATA •MC •DD •BC •OTHER TESTS SAMPLE NUMBER 10-1 10-2 10-3 10-4 .E SOIL DESCRIPTION •Ll Loose, dry, light brown, gravelly, clayey fine sand (SC) TOPSOIL Hard, damp, dark brown, sandy clay (CL) \ RESIDUAL CLAY Dense, friable, damp, orange brown, clayey . fine sand (SC) PLEISTOCENE DEPOSITS \ Hard, damp, olive gray, silty clay (CL) SANTIAGO FORMATION Bottom of Hole Test Pit 11 Approximate El. 310' DEPTH IN FEET 5- 10J TEST DATA •MC •DD •BC •OTHER TESTS SAMPLE NUMBER "-[ 11-2|- SOIL DESCRIPTION i 11 Hard, dry, light brown, sandy clay (CL) \ TOPSOIL Hard, dry, dark brown, silty clay (CL-CH) RESIDUAL CLAY Hard, damp, light gray, silty clay (CL) SANTIAGO FORMATION Bottom of Hole •For description of lymboli. we Figure A-l LOG OF TEST PITS 10 AND 11 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY:^/j PROJECT NO: 51113M-ASO1 | DATE: 8-7-81 | FIGURE NO: A-9 WOODWARD-CLYDE CONSULTANTS Test Pit 12 Approximate El. 298' DEPTH FEET - ~ - 15- Tl •MC •STDA1 •DD PA •BC •OTHERTESTS SAMPLENUMBER 12-lL 12-2 12-3|- 1KV 1I soil np^pRiPTinw Hard, dry, dark brown, silty to sandy clay (CL-CH) RESIDUAL CLAY Hard, damp, olive yellow, silty clay (CL) POINT LOMA FORMATION trading to Hard, damp, dark olive, silty clay- l Stone (CL) POINT LOMA FORMATION Refusal on sandstone Test Pit 13 Approximate El. 275' DEPTH IN FEET 5~ 10_ 15- TEST DATA •MC •DD •BC •OTHERTESTS SAMPLE NUMBER SOIL DESCRIPTION ill 13-1 11 Loose, dry, light brown, silty sand (SM) \ ALLUVIUM Hard, damp, dark brown, sandy clay (CL) , ALLUVIUM Hard, damp, dark olive, silty claystone (CI <. POINT LOMA FORMATION Bottom of Hole •For description of lymbolf, tee Figure A-l LOG OF TEST PITS 12 AND 13 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY: 0#\ PROJECT NO: 51113M-ASO1 | DATE; 8-7-81 j FIGURE NO: A-10 WOODWARD-CLYDE CONSULTANTS Test Pit 14 Approximate El. 304" DEPTH IN FEET 5- - TEST DATA •MC •DD •BC •OTHER TESTS SAMPLENUMBER SOIL DESCRIPTION 1 I Hard, dry, dark brown, silty to sandy clay (CL-CH) RESIDUAL CLAY Hard, dry to damp, dark brown to olive silty clay (CL) POINT LOMA FORMATIONv Hard, damp, olive, silty claystone (CL) POINT LOMA FORMATION Bottom of Hole •For description of symbols, we Figure A- LOG OF TEST PIT 14 CARLSBAD RESEARCH CENTER DRAWN BY: ch | CHECKED BY: ^ | PROJECT NO: 51113M-ASO1 | PATE: 8-7-81 | FIGURE NO: A-ll WOODWARD-CLYDE CONSULTANTS project NO. 51H3M-AS01 Woodward-Clyde Consultants APPENDIX B LABORATORY TESTS The materials observed in the test borings and test pits were visually classified and evaluated with respect to strength, swelling, and compressibility characteristics, dry density, and moisture content. The classifications were substantiated by evaluating plasticity characteristics of representative samples of the soils. Fill suitability tests, including compaction tests, expansibility tests, and grain size analyses, were performed on samples of the probably fill soils during our previous studies. The strength of the soils was evaluated by considering the density and moisture content of the samples and the pene- tration resistance of the sampler. In addition, we have used the results of slow direct shear tests performed during the previous study. The results of these tests were not available when the April 27, 1981 report was issued. We have included the results of these tests in this report. Swelling charac- teristics were estimated by performing loaded swell tests on undisturbed samples and by reviewing the results of swell tests performed during our previous study. The results of tests on drive samples are shown with the penetration resistance of the sampler at the corresponding sample location on the logs, Figs. A-2 through A-ll. The results of the swell tests are shown on Fig. B-l. The results of the slow direct shear tests are shown on Figs. B-2 through B-4. B-l RESULTS OF LOADED SWELL TESTS Sample Number 1-3 2-1 4-3 Initial Dry Density pcf 94 101 106 Mater Content % 20 21 21 Saturation % 71 85 96 Final Dry Density pcf 90 97 97 Water Content % 31 27 29 Saturation * 97 100 100 Pressure psf 160 160 160 Expansion % of Initial Height 4.4 4.1 9.3 Diameter of Samples:_ii£l_ Height of Samples: -816 LOADED SWELL TESTS CARLSBAD RESEARCH CENTER PHASE I DRAWN BY: Ch | CHECKED iY: &f \ HUMECT MO: 51113M-AS01 | DATE: 8-13-81 | FIGURE NO: B-l WOODWARD-CLYDE CONSULTANTS STRESS-'STRfllN GRRPH 4 OOP 5900 « sea 4000 3503 *•-£ seea in u! 2seo tt: w zeea £^ i seeui leeo see 0 I6d.9 m S a •8 NORMRL STRESS,psf SAMPLE DATA Sample/Classification 20-4 Specimen Number Height, inches Diameter, inches Initial Dry Density, pcf Initial Moisture Content, % Initial Saturation, % Final Dry Density, pcf Final Moisture Content, % Final Saturation, % Normal Stress, psf 1 .816 1.94 94 23 78 95 30 102 2089 2 .816 1.94 97 22 79 99 27 103 4117 TEST DATA Type of Test: Slow Direct Shear Angle of Friction, Effective 0' = 10° Cohesion, Effective C' = 2258 psf Rate of Shear, in/min = .00012800 SLOW DIRECT SHEAR TEST CARLSBAD RESEARCH CENTER - PHASE I DRAWN BY: mrk |CHECKED BY: ££ \ PROJECT NO: 5H13M-SIO1 I PATE: 8-12-81 |p!GURE NO: B-2 WOODWARD-CLYDE CONSULTANTS STRESS/STRRIN GRRPH 4500 «+- J* 336B °» 2500ctcc in 150B 1B00 see a ^_S~~ ( ^^ itie, I ^^ _— -i Kf "^«U«.J p«f .6 1.6 a.4 3.a 4 4.6 5.6 6.4 7.1 STRfllN.X inin 1 5803 4500 4000 3580 3000 2500 3888 1300 1000 see 'a 0' - 25d>g C' - l3S3psf m o e NORhRL STRESS,psf SAMPLE DATA Sample/Classification 20-5 Specimen Number Height, inches Diameter, inches Initial Dry Density, pcf Initial Moisture Content, % Initial Saturation, % Final Dry Density, pcf Final Moisture Content, % Final Saturation, % Normal Stress, psf 1 .816 1.94 1102 16 66 99 26 98 2046 2 .816 1.94 100 16 62 100 26 101 4110 TEST DATA Type of Test: siow Direct Shear Angle of Friction, Effective 0' = 25° Cohesion, Effective C' = 1323 psf | Rate of Shear, in/min = .00009600 SLOW DIRECT SHEAR TEST CARLSBAD RESEARCH CENTER PHASE I DRAWN BY: mrk |CHECKED BY: ff& \ PROJECT NO: 513.13M-SIO1 JPATE; 8^12-81 |FIGURE NO: B"3 WOODWARD-CLYDE CONSULTANTS STRESS/STRRIN GRRPH 3000 27OO 240D «*~£ 210D •inJfl i eoo ct <* 1500 900 600 V3D 0 seea •»sea 4800 3588 sme «" aeeaor1 150° ieoa sea O .6. 1.2 1.8 i.4 :• 3.6 « . £ «.8 5.4 6 STRfllH.X C' - I22tp«« G in S in O— — AJ r\i r> NORMRL STRESS,psf e>s SAMPLE DATA Sample/Classification 21-5 Specimen Number Height, inches Diameter, inches Initial Dry Density, pcf Initial Moisture Content, % Initial Saturation, % Final Dry Density, pcf Final Moisture Content, % Final Saturation, % Normal Stress, psf 1 .816 1.94 104 16 66 102 23 95 2046 2 .816 1.94 105 15 67 105 23 99 4110 TEST DATA Type of Test: slow Direct Shear Angle of Friction, Effective 0' = 20° Cohesion, Effective C' = 1221 psf Rate of Shear, in/min .00012800 SLOW DIRECT SHEAR TEST CARLSBAD RESEARCH CENTER PHASE I DRAWN BY: mrk |CHECKED BY: *&g \ PROJECT NO: 51113M-SI01 |PATE: 8-12-81 [FIGURE NO: B-4 WOODWARD-CLYDE CONSULTANTS project NO. 51H3M-AS01 Woodward-Clyde Consultants APPENDIX C Slope Stability Analysis Fill Slopes Assumptions: (1) Maximum height of slopes H = 30 feet (2) Maximum slope inclination 2:1 (3) Unit weight of soil T = 120 pcf (4) Apparent angle of internal friction <|> = 20° (5) Apparent cohesion c = 300 psf (6) No seepage forces References: (1) Janbu, N., "Stability Analysis of Slopes with Dimensionless Parameters," Harvard Soil Mechanics Series No. 46, 1954. (2) Janbu, N., "Dimensionless Parameters for Homogeneous Earth Slopes," JSMFD, NO. SM6, November, 1967. Analyses Where N f is the stability Safety Factor, F.S. = Ncfw- number for slopes with both c and <|>. X f= TH tan + = 4.4cf c From Fig. 10 of Reference (2) Ncf =18.5 F.S. = 1.5 C-l Project No. 51113M-AS01 Woodward-Clyde Consultants Slope Stability Analysis Cut Slopes Assumptions: (1) Maximum height of slopes (2) Maximum slope inclination (3) Unit weight of soil (4) Apparent angle of internal friction (5) Apparent cohesion (6) No seepage forces References: H = 20 feet 2:1 T = 120 pcf 4 = 10° c = 500 psf (1) Janbu, N., "Stability Analysis of Slopes with Dimensionless Parameters," Harvard Soil Mechanics Series No. 46, 1954. (2) Janbu, N., "Dimensionless Parameters for Homogeneous Earth Slopes," JSMFD, NO. SM6, November, 1967. Analyses Safety Factor, F.S. = TH tan _ 0 ftt- - 0.85 Where N f is the stability number for slopes with both c and <|>. From Fig. 10 of Reference (2) N f = 9 F.S. = 1.9 C-2 Project No. 51113M-AS01 APPENDIX D SPECIFICATIONS FOR CONTROLLED FILL I. GENERAL These specifications cover preparation of existing surfaces to receive fills, the type of soil suitable for use in fills, the control of compaction, and the methods of testing compacted fills. It shall be the contractor's responsibility to place, spread, water and compact the fill in strict accordance with these specifications. A soil engineer shall be the owner's representative to inspect the construction of fills. Exca- vation and the placing of fill shall be under the direct in- spection of the soil engineer, and he shall give written notice of conformance with the specifications upon completion of grad- ing. Deviations from these specifications will be permitted only upon written authorization from the soil engineer. A soil investigation has been made for this project; any recommenda- tions made in the report of the soil investigation or subse- quent reports shall become an addendum to these specifications. II. SCOPE The placement of controlled fill by the contractor shall in- clude all clearing and grubbing, removal of existing unsatis- factory material, preparation of the areas to be filled, spreading and compaction of fill in the areas to be filled, and all other work necessary to complete the grading of the filled areas. III. MATERIALS 1. Materials for compacted fill shall consist of any material imported or excavated from the cut areas that, in the opinion of the soil engineer, is suitable for use in constructing fills. The material shall contain no rocks or hard lumps greater than 48 inches in size and shall contain at least 40% of material smaller than %-inch in size. (Materials greater than 6 inches in size and less than 24 inches in size shall be placed by the contractor so that they are surrounded by com- pacted fines; no nesting of rocks shall be permitted. Mater- ials greater than 2 feet and less than 4 feet in size shall be placed in accordance with "Oversize Rock Placement Areas" - Appendix E.) No material of a perishable, spongy, or otherwise improper nature shall be used in filling. 2. Material placed within 30 inches of rough grade shall be select material that contains no rocks or hard lumps greater than 6 inches in size and that swells less than 3% when compac- ted as hereinafter specified for compacted fill and soaked under an axial pressure of 160 psf. An alternate to placement of sheet material on building lots is given within the text of this report. D-l Project No. 51113M-AS01 3. Representative samples of material to be used for fill shall be tested in the laboratory by the soil engineer in order to determine the maximum density, optimum moisture content, and classification of the soil. In addition, the soil engineer shall determine the approximate bearing value of a recompacted, saturated sample by direct shear tests or other tests applic- able to the particular soil. 4. During grading operations, soil types other than those analyzed in the report of the soil investigation may be en- countered by the contractor. The soil engineer shall be con- sulted to determine the suitability of these soils. IV. COMPACTED FILLS 1. General (a) Unless otherwise specified, fill material shall be com- pacted by the contractor while at a moisture content near the optimum moisture content and to a density that is not less than 90% of the maximum dry density determined in accordance with ASTM Test No. D1557-70, or other density test methods that will obtain equivalent results. (b) Potentially expansive soils may be used in fills below a depth of 30 inches and shall be compacted at a moisture content greater than the optimum moisture content for the material. 2. Clearing and Preparing Areas to be Filled (a) All trees, brush, grass and other objectionable material shall be collected, piled, and burned or otherwise dis- posed of by the contractor so as to leave the areas that have been cleared with a neat and finished appearance free from unsightly debris. (b) All vegetable matter and objectionable material shall be removed by the contractor from the surface upon which the fill is to be placed, and any loose or porous soils shall be removed or compacted to the depth shown on the plans. The surface shall then be plowed or scarified to a minimum depth of 6 inches until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. (c) Where fills are constructed on hillsides or slopes, the slope of the original ground on which the fill is to be placed shall be stepped or keyed by the contractor as shown on the figure on Page 4 of these specifications. The steps shall extend completely through the soil mantle and into the underlying formational materials. D-2 Project No. 51113M-AS01 (d) After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed by the contrac- tor until it is uniform and free from large clods, brought to the proper moisture content, and compacted as specified for fill. 3. Placing, Spreading, and Compaction of Fill Material (a) The fill material shall be placed by the contractor in layers that, when compacted, shall not exceed 6 inches. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to obtain uniformity of mater- ial in each layer. (b) When the moisture content of the fill material is below that specified by the soil engineer, water shall be added by the contractor until the moisture content is as specified. (c) When the moisture content of the fill material is above that specified by the soil engineer, the fill material shall be aerated by the contractor by blading, mixing, or other satisfactory methods until the moisture content is as specified. (d) After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted by the contractor to the specified density. Compaction shall be accomplished by sheepsfoot rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compacting equipment. Equipment shall be of such design that it will be able to compact the fill to the specified density. Compaction shall be continuous over the entire area, and the equipment shall make sufficient trips to in- sure that the desired density has been obtained throughout the entire fill. (e) The surface of fill slopes shall be compacted and there shall be no excess loose soil on the slopes. V. INSPECTION 1. Observation and compaction tests shall be made by the soil engineer during the filling and compacting operations so that he can state his opinion that the fill was constructed in ac- cordance with the specifications. 2. The soil engineer shall make field density tests in ac- cordance with ASTM Test No. D155664. Density tests shall be made in the compacted materials below the surface where the D-3 Project No. 51113M-AS01 surface is disturbed. When these tests indicate that the den- sity of any layer of fill or portion thereof is below the specified density, the particular layer or portion shall be re- worked until the specified density has been obtained. VI. PROTECTION OF WORK 1. During construction the contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. He shall control surface water to avoid damage to adjoining properties or to finished work on the site. The contractor shall take remedial measures to prevent erosion of freshly graded areas and until such time as permanent drain- age and erosion control features have been installed. 2. After completion of grading and when the soil engineer has finished his observation of the work, no further excavation or filling shall be done except under the observation of the soil engineer. Strip as specified •Original ground Slope ratio = N M Slope to be f\ such that —* sloughing or sliding does not occur Remove all topsoil See Note NOTES:'See Note ' The minimum width "B" of key shall be 2 feet wider than the com- paction equipment, and not less than 10 feet. The outside edge of bottom key shall be below topsoil or loose surface material. Keys are required where the natural slope is steeper than 6 horizontal to 1 vertical, or where specified by the soil engineer. D-4 Cn I Project No. 51113M-AS01 APPENDIX E OVERSIZE ROCK PLACEMENT AREAS (No Scale) Varies Vari Fill placed in accordance with Specifications For Controlled Fill Original ground surface -I In LEGEND Place no oversize rocks in this area. Oversize rock can be placed in this area. NOTES (1) Oversize rocks are those rock fragments between 2 feet and 4 feet in maximum dimension. (2) Rocks between 2 feet and 4 feet in size should be pro- perly isolated and completely surrounded by properly compacted soil. (3) No rocks greater than 4 feet in maximum dimension can be used in fills. (4) The oversize rock should be surrounded by sufficient fines to obtain proper compaction. (5) No oversize rock can be placed within 4 feet of finish lot grade or within expected depth of utilities, which- ever is deeper. E-l . 350- a,0)u. 2300- H LLI_iuu 250-1 "1CD a •o §*.V- </» oo CQ a •a0)4-tu J^£ Q. I ffl a>*•« 12 D. PLEISTOCENE DEPOSITS SILTY CLAY - SHALE lion VJI\/MJC —v,^ H PLEISTOCENE DEPOSITS POINT LOMA FORMATION POINT LOMA FORMATION SANTIAGO (DELMAR) FORMATION A1 r350 - 300 - 250 B r350 2a. 5 3il00, D. a B1 350- SILTY CLAY - SHALE 300- POINT LOMA FORMATION SANTIAGO (DELMAR) FORMATION L250 250J VERTICAL SCALE: 1" = 50' HORIZONTAL SCALE: 1" = 200' VERTICAL EXAGGERATION IX GENERALIZED GEOLOGIC CROSS SECTIONS A-A1 AND B-B1 CARLSBAD RESEARCH CENTER DRAWN BY: mrk | CHECKED BY: DATE:8-11-81 \ | FIGURE HO: 2 PROJECT NO: WOODWARD-CLYDE CONSULTANTS