The URL can be used to link to this page

Home My WebLink AboutCT 2016-0002; TOWN HOUSE; GEOTECHNICAL INVESTIGATION; 2017-11-03GcOTECHNTCAL lNVESTTGA TJON Proposed Townhouse Building 2677 Slate Strecl Carlsbad, California RECORD COPY oJ<c 2/zt{ i1 Initial Date ECEIVE APR O 2 2018 LAND DEVELOPMENT E:NGI NEERING HETHERINGTON ENGINEERING, INC. I HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGIN EERING • ENGINEERING GEOLOGY • HYDROGEOLOGY Archipelago Development 1>.0. Box 7050 Rancho Santa Fe, California 92067 Attention: Subject: Mr. Mark Benjamin UEOTECHNICJ\.L fNVESTIGATlON Proposed Townhouse .Building 2677 Slale Street Carlsbad, California References: Attached Dear Mr. Benjamin: November 3, 20 17 Project No. 8436. l LogNo.19513 In accordance with your request, we have performed a geotechnical investigation fo r the proposed construction of a four-story, townhouse building at the subject site. Our work was perfonned during October and November 2017. The purpose of our investigation was to evaluale the soil and geologic condi tions at the site in order to provide grading and foundation recommendations for the proposed development. Our scope of work included the following: • Research and review of available plans and geologic maps/literature pertinent to the site (see References). o Subsurface exploration consisting of two borings for soil sampling and geologic observation. • Laboratory testing of samples obtained from the subswface exploration. • Engineering and geologic analysis. • Preparation of thi s report presenting the results of our field and laboratory work, analyses, and om conclusions and reconunendations. 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931 -0545 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931 -0545 www.hetheringtonengineering.com • GEOTECI INTCAl, lNV ESTlUATION Project No. 8436.1 Log No. 19513 November 3, 20 17 Page 2 SITED 12SC1UPT1ON The subject properly is localed at 2677 State Slreel, Ca rlsbad, Cal ifornifl (see Location lVlap, fo'igure I). The rectangular shaped properly is relatively level. The sile currently supports a masonry/wood framed stru cture, an automobi le lifl and asphalt concrete pavement. The site is bounded by residenti al properties to the northwest ancl southeast, State Streel to the northeast and an alley lo the southwest. PROPOSED DEVELOPMENT Proposed development consists of a four-story townhouse building. The first floor will be al ap proxima te existing ground level and will consist of garage and lobby/offi ce space. Existing site improvements wi ll be demolished. We anticipate that fo undations will consist of conventional continuous/spread footings with slab-on-grade ground floors. Building loads are expected to be typical for this type of construction. Design grading is expected to consist of cuts and fills on the order of approximately 1 to 2-feet. No retaining walls or slopes are proposed. SUBSUR17ACE EXPLORATION Subsurface conditions were explored by excavating two ho llow-stem auger borings lo depths of 18.5 and 21-feet below existing site grades. The approximate locations of the exploratory borings are shown on the attached Plot Plan, Figure 2. The subsmface exploration was supervised by a geologist from this office, who visually classified the soil, and obtained relatively undisturbed and bulk soil samples for laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Classifications are shown on the attached Boring Logs, figures 3 and 4. LABORATORY TESTING Laboratory testing was performed on samples obtained during the subsurface exploration. Tests performed consisted of the following: • Dry Density/Moistmc Content (ASTM: D 2216) • Direct SheaJ (ASTM: D 3080) o Soluble Sulfate (Cal Test 417) HETHERINGTON ENGINEERING, INC. ADAPTED FROM: The Thomas Guide, San Diego County, 2006 Edi lion, Page 1106 LOCATION MAP HETHERINGTON ENGINEERING, INC. ~ N I SCALE: 1" -2000' (1 Grid = 0.5 x 0.5 miles) 2677 State Street Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8436.1 FIGURE NO. .. OEOTECIINICAJ, lNVESTlGATlON Project No. 8436.1 Log No. 19513 November J, 2017 Page 3 o Expansion Test (/\STM: f) 4829) o Atterberg Limits (ASTM: D 4318) o Single-Point Consolidation (ASTM: D 2435) Results of the dry density and moisture content determinations are presented on the Boring Logs, Figures 3 and 4. The remaining laboratory test results arc presented on the Laboratory Test Results, Figure 5. SOIL AND GEOLOGIC CONDITIONS J . Geologic Setting The subj ect site lies within a relatively level marine terrace that is contained within the coastal plain region of 1101thern San Diego County, California. The coastal plain region is characterized by numerous regressive marine terraces of Pleistocene age that have been established above wave-cut platforms of underlying Eocene bedrock and were formed during glacio-eustatic changes in sea level. The terraces extend from areas of higher elevations east of the site and descend generally west-southwest in a "stairstep" fashion clown to the present day coastline. These marine tenaces increase in age eastward. The site area is contained within the east portion of the USGS Oceanside 7.5-minute quadrangle. As observed in the borings, the site is underlain by fill, Quaternary tenace deposits, and Santiago Formation bedrock. Structurally, bedding within the terrace deposits is considered lo be essentially massive. The terrace deposits are fine to coarse grained and bave a high expansion potential in the upper section. 2. Geologic Units a. Fill -Fill consisting generally of moist, loose to medium dense, red brown silty sand was cncotmt.ered in the borings to a depth of approximately 2-feet. b. Terrace Deposits -Encountered beneath the filJ in both borings, the tenace deposits are considered massive and very highly expansive, and consist of gray sandy clay that is moist and firm to stiff, and transitions to reel brown silty sand with depth that is damp to moist and medium dense to dense. The terrace deposits extend to depths of approximately 11 to 13-feet in the borings. -- HETHERINGTON ENGINEERING, INC. GEOTECIINICAL lNVESTTGAJ'ION Project No. 8436. l Log No. 195 13 November 3, 20 l 7 Page 4 c. Bedrock (Santiago Formation) -Encountered beneath Lhe terrace cleposi.ts at depths of approximately 11 to 13-fect, the bedrock consists of light brown lo li ght gray silty sandstone that is moist a11cl dense lo very dense. 3. Groundwater Seepage was encountered in the exploratory borings perched on lbe bedrock contact at depths of 9 to 11 -fcet. It should be noted, however, that fluctuations in U1e amount and level of groundwater rnay occur due to varia tions in rainfall, irrigation <1nd other factors that may not have been evident at the time of our tield investigation. SEISMlCJTY Based on review of the available geologic maps/literature, there are no active or potentially active faults thal traverse the subject site, and the property is not located within the currently map ped limits of a Stale of California Earthquake Fault Zone. The following tabl e lists the known active fa ults that would have the most significant impact on the site: Maximum Probable Fault Earthquake Slip Rate (Moment Magn itude) (mm/year) Rose Canyon 7.1 5.0 (8.9-kilometers/ 5.5-miles southwest) Elsinore (Julian Segment) 6.8 1.5 (37-kilometers/ 23-miles northeast) SEISMlC EFFECTS I. Ground Accelerations The most significant probable earthquake to affect the properly would be a 7 .1 magnitude earthquake on the Rose Canyon fault. Based on Section 1803.5.12 of the 2016 Califorrua Building Code and Section 11.8.3 of ASCE 7, peak ground accelerations (PGAM) of 0.479g are possible fo r the design eruthquake. 2. Landsliding Review of the referenced geologic maps/literature indicates that the subject property is not included within the limits of any previously mapped landsliding. The risk of HETHERINGTON ENGINEERING, INC. GEOTECHN ICAL rNVTTST(GATlON Project No. 8436. l Log No. l 9513 November 3, 2017 Page 5 seismica lly induced landsliding affecting the site is considered low due to the relatively level site topography. 3. Ground Cracks The risk of fault surface rupture due lo active faulting is considered low dut: lo lbe absence of known active faults on si te. Ground cracks clue lo shaking from seismic evenls in the region are possible, as with al I of southern California. 4. Liquefaclion The risk of seismically induced liquefaction within the site is considered low clue to the firm to dense nature of the terrace deposits and relatively shallow bedrock. 5. Tsunamis The si te is not located within a mapped tsunami immdation area (Reference 3). The risk of a tsunamis event adversely impacting the site is considered low due to the elevation of the property above sea level. CONCLUSIONS J\.ND RECOMMENDATIONS 1. General The proposed development is considered feasible from a geotechnical standpoint. Grading and foundation plans sho uld take into account the appropriate geotechnical fealures of the site. Provided that the recommendations presented in this report and good construction practices are utilized during design and construction, the proposed construction is not anticipated to adversely impact the adjacent propeities from a geotechnical standpoint. 2. Seismic Paramelers for Structural Design Seismic considerations that may be Ltsed for strnctural design at the site include the following: a. Ground Motion -The proposed slructurc should be designed and constructed to resist the effects of seismic ground motions as provided in Section 1613 of the 2016 California Building Code. HETHERINGTON ENGINEERING, INC. .. GEOTECilNICAL INVESTJGATTON Project Nn. 8436.l Log No. 19513 November 3, 2017 Page 6 Sile Address: 2677 Slate Street, Carlsbad, California Latitude: Lo11gi Lucic: 33.16278°N 117.35137°w b. Spectrnl Response Accelerations -Using the location of the property and data obtained from the 1J.S.G.S. Earthquake Hazard Program, shorl period Spectral Response Accelen.1lions Ss (0.2 second period) and S 1 ( 1.0 second period) are: Ss -l.1 59g s, = 0.444g c. Site Class -In accordance with Chapter 20 of J\SCE 7, and Lhe underlying geologic conditions, a Site Class D is considered appropriate for the subject property. cl. Site Coefficients Fa and Fv -ln accordance with Table 1613.3.3 and considering the values of Ss and S 1, Site Coefficients for a Class D site are: FA= 1.037 Fv = 1.556 e. Spectral Response Acceleration Parameters Sms and Sm1 -In accordance with Section 1613.3.3 and considering the values of Ss and S 1, and F11 and Fv, Spectral Response Acceleration Parameters for the Maximum Co nsidered Emthquake are: Sms = 1.201g Sm,= 0.691g f. Design Spectral Response Accelerati on Parameters Sds and Sd1 -ln accordance with Section 1613.3.4 and considering the values of Sms and Sm1, Design Spectral Response Acceleration Parameters for the Maximum Considered Earthquake are: Sds = 0.801g Scl1 -== 0.46 1g g. Long Period Transition Period -A Long Period Transition Period of TL = 8 seconds is provided for use in San Diego County. HETHERINGTON ENGINEERING, INC. Ol·~OTECHNICAL INVl:.<:STlGATfON Project No. 8436. l Log No. 195 13 November 3, 2017 Page 7 h. Seismic Design Category -In accordance with Tables 1604.5, 1613.3.5 and ASCr-: 7, a Risk Ca tegory 11 and a Seismi c Design Category D are co nsidered appropriate for the sub,icct properly. 3. Sile Grading Prior to grad ing, the site should be cleared or existing improvements, surface obstructions, vegetati on and debris. Materi al:; generated during clearing should be disposed of at an approved location off site. Holes resulting from the removal of.' any buried obstruction should be fill ed with compacted fill or Jean concrete. Seepage pi.ts and/o r septi c systems, if encountered during site development, should be abandoned in accordance with local guidelines. Within the limits of proposed improvements and to 3-feet beyo nd where possible, existing loose lill and very highly expansive terrace deposits should be removed down to approved dense sanely terrace deposits. Removal depths are estimated to be 8 Lo I 0-feet below existing site grades. Actual removal depths should be determined in the field by the Geotechnical Consultant based on conditions exposed during grading. The very highly expansive terrace deposits should be expo1ted from the site and replaced with import soils possessing a low expansion potential (EI = 50 or less and ~ = 30° or more). Shoring or slot cutting will likely be necessary to facilitate removals. The exposed subgrade soils should be scarified to a depth of 6 to 8-inches, moisture conditioned to about optimum rnoisllll'C content and compacted by mechanical mem1s to a minimum relative compaction of 90-percenl (ASTM: D 1557). filJ should be moisture conditioned as necessary to about optimum moisture content uncl compacted by mechanical means in uniform horizontal lifts of 6 to 8-inches in thiclmess. All fill should be compacted to a minimum relative compaction of 90-percent based upon ASTM: D 1557. The on-site materials, with the exception of the very highly expansive terrace deposits, are suitable for use as compacted fill provided all vegetation and debris are removed. Rock fragments over 6-inches in dimension and other perishable or unsuitable materials should be excluded fro m the fill. All grading and compaction should be observed and tested as necessary by the Geoteclmical Consultant. HETHERINGTON ENGINEERING, INC. GEOTFCHNICAL IN Vl:'.STI.GATION Project No. 8436.1 Log No. 19513 November 3, 2017 Page 8 4. l◄'oundalion and Slab Recommendations The proposed structure may be supported on conventional conlinuous/spread footings founded at least 48-inches in compacted fi 11. Continuous [oot i11gs shmdd be al least 24-inches wide and reinforced with a mirLirnum of four #4 bars, lwo lop and two bollom . Fo11nclations located adjacent to utilily trenches should extend below a I :1 (hori zontal Lo vertical) plane projected upward from the bottom of the trench. Foundations bearing as recommended may be designed for a dead plus Ii ve load bearing value of 4000-pounds-per-square-foot. This value may be increased by one- lhird (or loads including wind and seismic forces. A lateral bearing value of 350- pow1ds-per-square-foot per foot of depth to a maximum value of 4000-pounds-per- square-fool and a coefficient of friction between foundation soil and concrete of 0.35 may be assumed. These values assume that footings will be poured neat against the foundation soils. Footing excavations sho uld be observed by the Geotechnica l Consultant prior to the placement of reinforcing steel in order to verify thal they are founded in suitable bearing materials. Total and differential settlement due to foun dation loads is considered to be less than 3/4 and 3/8-inch, respectively, for foundations founded as recommended. Slab-on-grade floors should have a minimum thickness of 5-inches, and should be reinforced with #4 bars spaced at 18-inches, center to center, in two directions, and supporlecl on chairs so that the reinforcement is at mid-height in the slab. Floor slabs, including the parking garage, should be underlain with a moistlll'e vapor retarder consisting of a rninimum 10-mil polyethylene membrane. At least 2-inches of sand should be placed over the vapor retarder to assist in concrete curing and at least 2- inches of sand should be placed below the vapor retarder. The vapor retarder should be placed in accordance with ASTM: E 1643. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. Vapor retarders are not intended to provide a waterproofing function. Should moistu re vapor sensitive floor coverings be planned, a qualified consultant/contractor sho uld be consulLed to evaluate moisture vapor transmission rates and to provide recommendations to mitigate potential adverse impacts of moisture vapor transmissions on the proposed flooring. HETHERINGTON ENGINEERING, INC. ,. GEOTl1CHNICAL fNVESTlGATTON Project No. 8436. l Log No. 19513 November 3, 2017 Page 9 :S. Temporary Slopes Temporary slopes necessary to facil ilate grading may be cut vertically up to 4-feet where the cuts are not influenced by existing structLu·cs or properly line constrai11ts. Any portion of temporary slopes near existing improvements, property lines, higher Lhan 4-fecl, or exposing potentially unstable soil s should be sloped at a raLio 110 steeper than l: 1 (horizontal to vertical), slot cut, or shored. Field observations by the Engineering Geologist cl ming grading of temporary slopes arc recommended and considered necessary lo con.firm anticipated conditions and provide additional recommendations as warranted. Slot cut/shori ng parameters can be provided upon request. 6. Hard scape Concrete flatwork should be at least 5-inches thick (actual) and reinforced with No. 4 bars spaced at l 8-inches on-center (two ctirections) and placed on chairs so that the reinforcement is in the center of the concrete. Contraction joints should be provided at 8-feet spacing (maximum). Joints should create square panels where possible. for rectangular panels (where necessary) the long dimension should be no more than 1.5 times the short dimension. Joint depth should be at least 0.25 times the flatwork. thickness. Expansion joints should be thoroughly sealed to prevent the infiltration of water into the underlying soils. 7. Sulfate Content Representative samples of the on-site soils were submitted for sulfate testing. The results of the sulfate tests are summarized on the Laboratory Test Results, Figure 5. The sulfate contents are consistent with a not applicable sulfate exposure classification per Table 4 .2.1 of the Am erican Concrete Institute Publication 318, consequently, no special provisions for Slllfate resistant concrete are considered necessary. Other conosivity testing has not been performed, consequentl y, on-site soils should be assumed to be severely corrosive lo buried metals unless testing is performed to indicate otherwise. 8. Drainage The following recommendations are intended to minimize the potential adverse effects of water on the structure and apprntenances. HETHERINGTON ENGINEERING, INC. ·' UEOTECI INJC/\1~ INVESTLG/\TION Project No. 8436.1 LogNo.19513 November 3, 2017 Page 10 a. Consideration should be given to providing the structure with roof gutters and dowuspouls tbat discharge to an area drain system and/or lo suitable locations away li·orn the strnclure. b. J\ll site drainage should be directed away l't-0111 lb c structure. c. No landscaping should be al lowed against lhe structure. Moisture c1ccumulalion or watering a~jacent lo foundatio ns can result in deter ioration or building materials and may affect the performance of foundations. cl. Irrigated areas should not be over-watered. irrigation should be limited to that required to mai.ntain the vegetation. Adclitionally, automatic systems must be seasonally adjusted to minimize over-saturation potential particularly in the winter (rainy) season. e. All yard and roof drains should be periodically checked to verify they are not blocked ru1d flow properly, and maintained as necessary. 9. Recommended Observation and Testing During Conslruction The following tests and/or observations by the Geotechnical Consultant are recommended: a. Observation and testing duri ng site grading. b. Observation of foundation excavations prior to placement of forms and reinforcement. c. Utility trench backfill. cl. Hardscape subgrade. 10. Grad ing and Foundation Plan Review Grading and foundalion plans should be reviewed by the Geotechnical Consultant to confirm conformance with the recommendations presented herein or to modify the recommendations as necessary. HETHERINGTON ENGINEERING, INC. GEOTECHNfCA L INVESTLGATION Project No. 8436. l Log No. 19513 November 3, 2017 -Page 11 LIMIT A TTONS The analyses, conclusions and recommendations contained in this report are based on sile cond itions as Lhcy existed at the time of our investiga tion and further assume the excavations to be representative of the sub!:ai rface co ncLitions throughout the site. Tr different subsurface condiLi ons from those enco untered during our exploration arc observed or appea r to be present in excavations during construction, the Geotechnica l Consultant shou ld be promptly notified fo r review and reconsideralion of' recommendations. Om iuvestigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Co nsultants practicing in this or similar localities. No other wanan.ty, express or implied, is made as to the conclusions and profossionaJ advice included in this report. This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, HETHERJNGTON ENGINEERJNG, INC. . ogseth Professional Geo logist 3772 Cc1tified Engineering Geologis'T" '"""'~""' Certified Hydrogeologisl 591 ( expires 3/3 1 /18) Attachments: Loca ti on Map Plot Plan Boring Logs Laboratory Test Results Distribution: 5-Addressee Figure 1 Figure 2 figures 3 and 4 Figure 5 1-via e-mail (mark l benjamin@yahoo.com) HETHERINGTON ENGINEERING, INC. .... REFERl ~N C.:ES I. ASCE 7-l 0, "Mi11i nJ11m Design Loads fo r Buildings and Other Structures", American Society of Civil Engineers/Structural Engineers Institute, claLed May 2010. 2. J\. VRP Stud ios Architecture, "Level l Floor Plan, 2677 State Street, Carlsbad, CA", dated August 7, 2017 (Sheet A2.0l). 3. California Geologica l Survey, "T:rnnami Inundation Map for Emergency Plaruiing -Oceanside Quadrangle", California Geological Survey, dated fanc I, 2009. 4. lCBO, Cal iforn.ia Building Code, 2016 Ed ition. 5. ICBO, "Maps of Known Acti ve Fault Near-Source Zones in Cal i lornia and Adjacent Po1iions of Nevada," California Division of Mi nes and Geology, l 998. 6. Peterson, Mark P., et al, "Documentation for the 2008 Update of the Un ited States Nalional Seismic Hazards Maps," USGS Open File Report 2008-1128, dated 2008. 7. Tan, Siang S. and Ke1rnedy, Michael P., "Geologic Maps of the Northwestern Part of San Diego County, California," Califoniia Division of Mines and Geology, Open-file Report 96-02, dated 1996. 8. USGS, Earthquake Hazard Program, Seismic Design Maps. 9. 2007 Working Group and California Emt hquake Probability, "The Un.ifom1 Cali fornia Earthquake Rupture Forecast, Version 2 (UCERF-2)," USGS Open File Report 2007-1437 and California Geological Survey Special Report 203, dated 2008. HETHERINGTON ENGINEERING, INC. Projccl No. 80il7.I Log No. 18545 ., • 1i r , I . ~ . ',, h ' 1, t 'I t s I ' I,· ---J ~~ ''•~ I C 7r·, L .. JLJ,, f 1 ~ ~ 8 B 0 z ~ w Cl ~ a I 0 ~ al -----.. . '. m I z '.5 a. I-0 -' a. ~ in !f-; ~ ~ i t I ~ i i uJ ~ Z z ~8 ~~ i2 :,: Cl u :;;; 5 ffi ~ i!: uJ :x: ____ _L _.:__ DRIL.~ING COMPANY: Scott's Drilling RIG: Hollow Stem Auger DATE: 10/12/17 BORING DIAMETER: 8" DRIVE WEIGHT: 140 lbs. DROP: 30" ELEVATION: I + -w E-< w ...:l >< -w ...:l 0.. E-< E-< d{) Cf) -w 0.. ~ 0 H -Cf) BORING NO. 8-1 i:,., -~ 0 Cf) w j '1: Cf) i:,., z 0:: E-< :r: Cf) '-w ::> z u u E-< w Cf) 0 -E-< w 0.. :,,:; > :;:: 4-l Cf) E-< ...:l CfJ w ...:l H 0 >< u H z H 0 ::> 0:: ...:l 0:: P. 0 0 0 ::> SOIL DESCRIPTION '° 0 '° 0 ~ u Cf) --0.0 -x -, ASPHALT CONCRETE: 3.5-inches r SM FILL: Red brown silty sand; moist, medium dense - =~1 - 15 104 22.1 TERRACE DEPOSITS : Gray brown sandy clay; moist, firm to - stiff, trace organics -- 5.0-I -15 102 24.1 -- -- ---1 48 114 17.3 @ 8': Brown clayey to silty sand; moist, dense, gravelly - X - 10.0-'SJ_ -@ 10.5': Seepage, water perched on bedrock -- BEDROCK {Santiago Formation}: Light gray to buff clayey :-1 sandstone; moist, dense I- 57 109 19.7 I- -- 15.0--- =X - - ■ 50/6" 117 18.9 @ 18': Very dense - -Total depth 18.5-feet - 20.0- Seepage@ 10.5-feet -No caving -- -.__ -I- -- 25.0---- -I- -- -.__ 30.C BORING LOG 2677 State Street HETHERINGTON ENGINEERING,tNc. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8436.1 I FIGURE NO. 3 D~ILUNG COMPANY: Scott's Drilling RIG: Hollow Stem Auger DATE: 10/12/17 BORING DIAMETER: 8" DRIVE WEIGHT: 140 lbs. DROP: 30" ELEVATION: I 't: E-< w w ,..:i :,-. -w ,..:i °"' E-< E-< ~ Ul -w °"' ;'ii 0 H Ul BORING NO. 8-2 µ., ;'ii 0 <fl w <!; Ul -<fl µ., z 0:: E-< ,..:i ::r: <fl ---- w ::, z u u w <fl 0 -E-< w E-< :,;:; > :s: ""' Ul E-< ,-.'.l Ul °"' w ,..:i H 0 :,-. u H z H 0 ::, 0:: ,..:i 0:: 0.. 0 0 0::, SOIL DESCRIPTION ro 0 ill 0 -::;:: u Ul -,.... 0.0 -I"'\ ASPHALT CONCRETE: 3.5-inches r -FILL: Gray clay and red brown silty sand; moist, soft to loose 1-- =x • 14 99 26.9 TERRACE DEPOSITS: Gray sandy clay, moist, firm to stiff, trace porosity - - 5.0-----I 47 116 17.2 -- -- --@ 9': Olive gray clayey sand; moist, dense 10.0-I -22 95 24.6 @ 10': Sandy -1-- "SJ_ @ 11.5': Seepage, water perched on bedrock -- -BEDROCK {Santiago Formation}: Gray silty sandstone; moist, -very dense, gravelly - 15.0-I ...... 79 124 11 .3 -- -- -- -- 20.0-~I -@ 20': No Recovery -Total depth 21-feet -Seepage@ 11.5-feet I-- No caving -- I--- 25.0-- -- -- -- -- 30.:: BORING LOG 2677 State Street HETHERINGTON ENGINEERING,1Nc. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8436.1 I FIGURE NO. 4 LABORATORY TEST RESULTS DIRECT SHEAR (ASTM: D 3080) Sample Location Angle of Internal Cohesion Remarks Friction (0 ) (psf) B-1 @ 12' Sample Location B-1 (a), l5 to 18' B-2 @J. 2 to 5' Sample Location B-2 (aJ 2 to 5' 36 125 Undisturbed, soaked consolidated, drained SULFATE TEST RESULTS (EPA 9038) Soluble Sulfate in Soil (%) 0.0650 0.0140 EXP ANSI ON INDEX (ASTM: D 4829 Initial Compacted Final Moisture (%) Dry Moisture 12.4 Density (ocf} 99.3 ATTERBERG LIMITS (ASTM: D 4318) (%) 31.0 Expansion Index 164 Expansion Potential Very high Li uid Limit % Plastic Limit % Plastici Index % U.S.C.S. Class 55 23 SINGLE-POINT CONSOLIDATION TEST SUMMARY (ASTM: D 2435) Sample Location Normal Stress at Saturation (pst) B-1@ 3' 383 B-1 (@ 5' 636 B-1 @J 8' 1036 32 CH % Swell(+) or% Consolidation(-) When Water Added +0.82 +0.79 -0.42 Figure 5 Project No. 8436. l LogNo. 195 13