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Home My WebLink AboutCT 2018-0008; GRAND JEFFERSON; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2018-06-01GEpTECHNICAL INVESTIGATION The Grand Jefferson Proposed Mixed Use Building 786 Grand Avenue Carlsbarl, California JUL 1 7 2018 HETHERINGTON ENGINEERING, INC. HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING• ENGINEERING GEOLOGY• HYDROGEOLOGY June I, 2018 Project No. 8587.1 Log No. 19860 Rincon Homes/Rincon Real Estate Group 3005 S. El Camino Real . San Clemente, Califomia 92672 Attention: Subject: Mr. Kevin Dunn GEOTECHNICAL INVESTIGATION The Grand Jefferson Proposed Mixed Use Building 786 Grand Avenue Carlsbad, California Refere11ces: Attached Dear Mr. Dunn: In accordance with your request, we have performed a geotechnical investigation for a proposed mixed use building at the subject site. Our work was performed in May 2018. The purpose of our investigation was to evaluate geologic and soil conditions in the area of proposed construction, and to provide grading and foundation recommendations. We were provided a "Conceptual Site Plan ... " (Reference 6) that has been used as the base map for the attached Plot Plan, Figure 2. With the above in mind, our scope of work included the following: • Research and review of available geotechnical reports and geologic literature pertinent to the site (see References). • Subsurface exploration consisting of two hollow-stem auger borings to depths of 20 and 20 1/2-feet for bulk and relatively undisturbed soil and bedrock sampling, and geologic observation. • Laboratory testing of soil samples obtafr1ed from the subsurface exploration. • Engineering and geologic analysis. • Preparation of this report providing the results of our field and laboratory work, analyses, and our conclusions and recommendations. 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) 7155440 • Fax (760) 931-0545 www.hetheringtonengineering.com GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page2 SITEI)ESCRlPTION The subject property is located 786 Grand Avenue in the city of Carlsbad, California (see Location Map, Figure 1 ). The site consists of a relatively level, rectangular shaped property that presently supports a one-story. day care structure with concrete parking areas. The property is bounded by Jefferson Street to the east, Grand Avenue to the south and multi use buildings and parking areas at similar elevations to the west and north. PROPOSED DEVELOPMENT Based on discussions with you and review of the "Architectural Plans ... " (Reference 6), we understand that the proposed development consists of demolishing the existing site improvements and constructing an approximately 7,000-square-foot, four-story, mixed use building with covered parking and driveway areas. The building will include retail/commercial space and residential condominiums. We anticipate that the structure will be of wood or steel frame construction founded on conventional continuous/spread footings with slab-on-grade ground floors. Grading is expected to consist of relatively minor cuts and fills. SUB SURF ACE EXPLORATION Subsurface exploration consisted of drilling two hollow-stem auger borings to depths of 20 and 20 1/2-feet below existing site grades. The approximate locations of the borings are shown on the attached Plot Plan, Figure 2. The subsurface exploration was supervised by an engineer from this office, who visually classified the soil and bedrock materials, and obtained bulk and relatively tmdisturbed samples for laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Soil classifications are shown on the attached Boring Logs, Figures 3 and 4. LABORATORY TESTING Laboratory testing was perfonned on samples obtained during the subsmface exploration. Tests performed consisted of the following: • D1y Density and Moisture Content (ASTM: D 2216) • Soluble Sulfate (Cal. Test 417) • Direct Shear (ASTM: D 3080) HETHERINGTON ENGINEERING, INC. <.-• PAOFIC OCEAN ADAPTED FROM: The Thomas Guide, San Diego County, 57th Edition, Page 1106 SCALE: 1" -2000' (1 Grid Equals: 0.5 x 0.5 miles) LOCATION MAP 786 Grand Avenue HETHERINGTON ENGINEERING, INC. Carlsbad California GEOTECHNICAL CONSULTANTS PROJECT NO. 8587.1 I FIGURE NO. 1 GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 · June 1. 2018 Page3 • Maximum Dry Density/Optimum Moisture Content (ASTM: D 1557) • Expansion Index (ASTM: D 4829) Results of the dry density and moisture content determinations are presented on the Boring Logs, Figures 3 and 4. The remaining laboratory test results are presented on the Laboratory Test Results, Figure 5. SOIL AND GEOLOGIC CONDITIONS 1. Geologic Setting The subject site is located on a relatively level marine ten-ace that is contained within the coastal plain region of northern 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 sedimentary bedrock and were fo1med during glacio-eustatic changes in sea level. The tetTaces extend from areas of higher elevation east of the site and descend generally west- southwest in a "stafr step" fashion down to the present day coastline. These marine terraces increase in age eastward. The subject property is contained within the southwest portion of the U.S.G.S San Luis Rey 7-1/2 minute quadrangle. Based on the results of our subsurface investigation, the site is underlain by fill, Quaternary marine and non-marine terrace deposits, and Santiago Fonnation bedrock. No known or reported landsliding is lmown. to exist on the site. No lmown or reported active or potentially active faults exist within the site. 2. Geologic Units a. Fill -The fill soils consist of red brown silty sand that is dry and medium dense to dense with a very low expansion potential. The existing fill is not considered suitable to support compacted fill or the proposed improvements. b. Tenace Deposits -Encountered at a depth of approximately 4-feet in boring B-1 and immediately below the ground surface in boring B-2 are terrace deposits consisting of dry to moist, dense, red brown, and light brown silty sand. The terrace deposits are considered suitable for support of compacted fill and proposed improvements, and possess a very low expansion potential. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page4 c. Santiago Fonnation Bedrock -Encountered at a depth of approximately 18 1/2- feet in bo1ing B-1 and 20-feet in boring B-2, the bedrock consists of light grey sandy siltstone and sandstone that is moist and hard to dense. Bedding within the bedrock reportedly dips 10-degrees to the north-northeast. 3. Qr-9undw~ter Groundwater was perched on the bedrock and encountered in both of the borings at approximately 16 to 17-feet below site grades. It should be noted, however, that fluctuations in the amount and level of groundwater may occUJ.· due to variations in rainfall, irrigation, and other factors that may not have been evident at the time of our field investigation. SEISMICITY The site is located witl;un the seismically active southern California region. There are, however, no known active or potentially active faults presently mapped that pass through the site nor is the site located within the presently defined limits of an Alquist-Priolo Earthquake Fault Zone. Active or potentially active fault zones within the site region include the Rose Canyon and Elsinore (Temecula Segment). Strong ground motion could also be expected from earthquakes occurring along the San Jacinto and San Andreas fault zones, which lie northeast of the site at greater distances, as well as numerous other faults which lie offshore. The following table lists the known active faults that would have the most significant impact on the site: Maximum Probable :Fault Earthquake Slip Rate (Moment Magnitude) (mm/vear) Rose Canyon 7.0 1.5 (8 kilometers/5-miles southwest) Elsinore (Temecula Segment) 7.3 3 (39 kilometers/24miles northeast) SEISMIC EFFECTS 1. Ground Accelerations The most significant probable earthquake to effect the site would be a 7.0 magnitude earthquake on the Rose Canyon fault. Based on Section 1803.5.12 of the 2016 HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page 5 California Building Code~ peak ground accelerations (PGAM) of 0.476g are possible for the design earthquake. 2. Landsliding The risk of seismically induced landsliding to effect the site is considered nil due to the level topography of the site. 3. Ground Cracks The risk of surface fault rupture is considered low due to the absence of a known active fault on site. Ground cracks due to shaking from seismic events m the region are possible, as with all of southern California. 4. Liquefaction The risk of seismically induced liquefaction to effect the site is considered low due to the dense underlying terrace deposits. 5. Tsunamis The "Tsunami Inundation Map ... " (Reference 2) indicates the site is not within a tsunami inundation zone. CONCLUSIONS AND RECOMMENDATIONS 1. General The proposed development is considered feasible from a geotechnical standpoint. Grading and foundation plans should consider the appropriate geotechnical features of the site. Provided that the recommendations presented in this report and good constmction practices are utilized during the design and construction, the proposed grading and construction is not anticipated to adversely impact adjacent properties from a geotechnical standpoint. 2. Seismic Parameters for Structural Design Seismic considerations that may be used for structural design at the site, based on Section 1613 of the 2016 California Building Code and ASCE 7-10, include the following: HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page6 a. Ground Motion -The proposed structure should be designed and constructed to resist the effects of seismic ground motions as provided in Section 1613 of the 2016 California Building Code. Site Address: 786 Grand A venue, Carlsbad, California Latitude: 33.16233°N Longitude: 117.34675° W b. Spectral Response Accelerations --Using the location of the property and data obtained from the U. S. G, S. Earthquake Hazard Program (Reference 10), short period Spectral Response Accelerations Ss (0.2 second period) and S1 (1.0 second period) are: Ss ""'' 1.149g S1 = 0.441g c. Site Class -In accordance with Chapter 20 of ASCE 7-10 and the underlying geologic conditions, a Site Class D is considered appropriate for the subject property. d. Site Coefficienlc; Fa and Fv -In accordance with Table 1613.3.3 and considering the values of Ss and S1, Site Coefficients are: Fa::::: 1.040 Fv "" 1.559 e. Spectral Response Acceleration Parameters Sms and Sm1 In accordance with Section 1613.5.3 and considering the values of Ss and S1, and Fa and Fv, Spectral Response Acceleration Parameters for Maximum Considered Earthquake are: Sms ;;.c: 1.195g Sm1 = 0.687g f. Design Spectral Response Acceleration Parameters Sds and Sd1. -In accordance with Section 1613.3.4 and considering the values of Sms and Sm1, Design Spectral Response Acceleration Paran1eters for Maximum Considered Earthquake are: Sds = 0.797g Sd1 = 0.458g HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page 7 g, Long Period Transition Period -A Long Period Transition Period of TL = 8 seconds is provided for use in San Diego County. h. Seismic Design Category -In accordance with Tables 1604.5, 1613.3.5, and ASCE 7-10, a Risk Category II and a Seismic Design Category Dare considered appropriate for the subject property. 3. Site Grading a. Clearing and Grubbing -Existing site improvements, vegetation and miscellaneous debl'is should be removed to an appropriate offsite disposal area. Holes resulting from the removal of buried obstructions which extend below · finished site grades, should be replaced with compacted fill or lean concrete, In the event that abandoned cesspools, septic tanks or storage tanks are discovered during the excavation of the site, they should be removed and backfilled in accordance with local regulations. Existing utility lines to be abandoned should be removed and capped in accordance with local requirements. b. Removal of Unsuitable Soils -Within the limits of the proposed improvements and to 3-fcet beyond, where possible, existing fill and other unsuitable material should be removed to approved terrace deposits. Removal depths of 1 to 4-feet are anticipated. The actual depths and extent of removals should be determined by the Geotecbnical Consultant during site grading. c. Scarification -All areas to receive fill should be scarified to a minimum depth of 6 to 8-inches, brought to near optimum moisture content, and compacted to at least 90-percent relative compaction based upon ASTM: D 1557. d. Compacted Fill -Fill soils should be moisture conditioned to about optimum moisture content and compacted by mechanical means in uniform horizontal lifts of 6 to 8-inches in thickness. All fill should be compacted to a minimum relative compaction of 90-percent based upon ASTM: D 1557. The on-site materials are suitable for use as compacted fill. Rock fragments over 6-inches in largest dimension and other perishable or unsuitable materials should be excluded from the fill. All grading and compaction should be observed and tested by the Geotechnical Consultant. Any imported soil should have a very low expansion potential and should be approved by the Geotechnical Consultant prior to impo1t. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page 8 4. Foundation and Slab Recommendations The proposed building may be supported on conventional continuous/spread footings founded at least 24-inches below lowest adjacent grade and bearing in compacted fill or terrace deposits. Continuous footings should be at least 18-inche..~ wide and reinforced with a minimum of four #4 bars, two top and two bottom. Foundations bearing as recommended may be designed for a dead plus live load bearing value of 3000-pounds-per-square-foot. This value may be increased by one- third for loads including wind and seismic forces. A lateral bearing value of 300- pounds-per-square-foot per foot of depth to a maxi.mum value to 3000-pounds-per- square-foot 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 compacted fill or tenace deposits. Footing excavations should be observed by the Geotecbnical Consultant prior to the placement of reinforcing steel in order to verify that they are founded in suitable bearing materials. Slab-on-grade floors should have a minimum thickness of 5-inches (actual) and · should be reinforced with #4 bars spaced at 18-inches, center-to-center, in two directions, and supported on chairs so that the reinforcement is at mid-height in the slab. Floor slabs should be underlain with a moisture vapor retarder consisting of a 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 moisture vapor sensitive floor coverings be planned, a qualified consultant/contractor should be consulted to evaluate moisture vapor transmission rates and to provide recommendations to mitigate potential adverse impacts of moisture vapor transmissions on the proposed flooring. 5. Temporary Excavations Temporary excavations may be made up to 5-feet vertically in compacted fill or terrace deposits, and at a 1:1 (horizontal to vertical) above 5-feet. Field observations by the Engineering Geologist during excavation of temporary slopes are recommended and considered necessary to confirm anticipated conditions and provide revised recommendations if warranted. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.l Log No. 19860 June 1, 2018 Page9 6. Soluble Sulfate A representative sample of the on-site soils was submitted for sulfate testing. The result of the test is summarized on the Laboratory Test Results, Figure 5. The sulfate content is consistent with a non-applicable sulfate exposure classification per Table 4.5.3 of the Ame1ican Concrete Institute Publication 318. Consequently, special provisions for sulfate resistant concrete are not considered necessary. Other corrosivity testing has not been performed, consequently, the on-site soils should be assumed to be severely corrosive to buried metals unless testing is performed to indicate otherwise. 7. Concrete Flatwork Concrete flatwork should be at least 5-inches thick (actual) and reinforced with #4 bars spaced at 18-inches on center (two directions) and placed on chairs so that the reinforcement is in the center of the slab. Slab subgrade should be thoroughly moistened prior to placement of 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. 8. Utility Trench Backfill Utility trench backfill soils should be moisture conditioned to about optimum moisture content and compacted by mechanical means in unifonn horizontal lifts. Lift thickness should be dependant on the type of equipment used for compaction, but in no case should exceed 8-inches in thickness. All utility trench backfill should be compacted to a minimum relative compaction of 90-percent based upon ASTM: D 1557. The on-site materials are suitable for use as compacted fill. Rock fragments over 6-inches in dimension and other perishable or unsuitable materials should be excluded from the fill. 9. Site Drainage The following recommendations are intended to minimize the potential adverse effects of water on the structure and appurtenances. Surface drainage should be designed by the project Architect and/or Civil Engineer. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.1 Log No. 19860 June 1, 2018 Page 10 a. Consideration should be given to providing the structure with roof gutters and downspouts that discharge to an area drain system and/or to suitable locations awa.y from the structure. b. All site drainage should be directed away from the structure. The on-site soils are generally sandy in nature and considered erodible if exposed to concentrated drainage. c. Landscaping planned adjacent to the stmcture should be designed so as to minimize the amount of moisture that can penetrate the pad subgrade soils to prevent damage to the structure. Moisture accumulation or watering adjacent to foundations can result in deterioration of wood/stucco. d. Irrigated areas should not be over-watered. Irrigation should be limited to that required to maintain the vegetation. Additionally, automatic systems should 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 clear and flow properly. This may be accomplished either visually or, in the case of subsurface drains, by placing a hose at the inlet and checking the outlet for flow. 10. Recommended Observation and Testing During Construction The following tests and/or observations by the Geotechnical Consultant are recommended: a. Observation and testing of grading. b. Observation of temporary slopes. c. Observation of foundation excavations prior to placement of forms and reinforcing steel. d. Observation of interior and exterior utility trench backfill. e. Observation and testing of concrete flatwork subgrade. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8587.l LogNo. 19860 June 1, 2018 Page 11 11. Grading and Foundation Plan Review Grading and foundation plans should be reviewed by the Geotechnical Consultant to confirm conformance with the recommendations presented herein or to modify the recommendations as necessary. LIMITATIONS The analyses, conclusions and recommendations contained in this report are based on site conditions, as they existed at the time of our investigation and further assume the excavations to be representative of the subsurface conditions throughout the site. If different subsurface conditions from those encountered during our exploration are observed or appear to be present in excavations, the Geotechnical Consultant should be promptly notified for review and reconsideration of the recommendations. Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Consultants practicing in this or similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely, HETHERING ON ENGINEERING, INC. Mark ~'t!:l:';t.'C'n· Civil Engineer 30488 Geotechnical Engineer 3 (expires 3/31/20) Attachments: Location Plot Plan · Boring Logs Laboratory Test Results Distribution: 4-Addressee . Bogseth ional Geologist 3 772 ed Engineering Geologist 11 ed Hydrogeologist 591 es 3/31/20) Figure 1 Figure 2 Figures 3 and 4 Figure 5 I-via email (kdunn@rincongrp.com) HETHERINGTON ENGINEERING, INC. , ' REFERENCES L ASCE 7-10, "Minimum Design Loads for Buildings and Other Structures,'' American Society of Civil Engineers/Structural Engineers Institute, dated May 2010. 2. California Emergency Management Agency, "Tsunami Inundation Map for Planning, Oceanside Quadrangle/San Luis Rey Quadrangle," dated June l, 2009. 3. I CBO, Califomia Building Code, 2016 Edition. 4. ICBO, "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada," California Division of Mines and Geology, 1998. 5. Jennings, Charles W., "Fault Activity Map of California and Adjacent Areas," California Data Map Series, Map No. 6, dated 1994. 6. MAA Architects, "Architectural Plans, Grand Jefferson", dated March 14, 2018 (Sheets A0.1, Al.l, A2J, A2.2 and A3.l). 7. Peterson, Mark P ., et al, "Documentation for the 2008 Update of the United States National Seismic Hazards Maps," USGS Open File Report 2008-1128, dated 2008. 8. Tan, Siang S. and Kennedy, Michael P., "Geologic Maps of the Northwestem Part of San Diego County, California", California Division of Mines and Geology, Open-File Report 96-02, dated 1996. 9. United States Geological Survey, "San Luis Rey 7.5-Minute Quadrangle," dated 1997. 10. USGS, Earthquake Hazard Program, Seismic Design Maps. 11. Weber, F. Harold, "Recent Slope Failures, Ancient Landslides, And Related Geology of the North-Central Coastal Area, San Diego County, California," California Division of Mines and Geology, Open-File Report 82-12, dated 1982. 12. 2007 Working C.rroup and California Earthquake Probability, "The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF-2),11 USGS Open File Report 2007-1437 and California Geological Survey Special Report 203, dated 2008 HETHERINGTON ENGINEERING, INC. Project No. 8587.l Log No. 19860 •► rht!(:';'/::;.;;;;::/:m .. :\:: ff:'i:/:=r:-i\f~\;;;'o/,t~%:~:W't.<sr:¥?:::t,~%';:m•;:;~:iit'JS'.:fj,:i:':':ci} .. /)• ..... . .,,, ~-~~,-~ -· . I l•j ~ ;;-,;· , ... -.: ,.-,, _,__ C :; C ; ::11 II,, d COMMERCIAi. 25:fo SF t,",>\ n~i :;rNr~ ·-··") :\,'.'\:'<:(l,',:Z< <,.",J,_f ;V;;f. : ~ ~;;.,-',~f.j B-2~ ---~":::·l ' -~;;:;;;i -v ., __ . _ I k.t f,( ::,,,;:-s-~<>r: ~:-i':.'::':":'<>~ v.-.:,i-;::.,..;--s ~~ z.-~'f»~.::,( .)..':1::E~J.i=~ -·... ~~~--:, ____ _,,/ --------'"---------------------....... ·--,,.-,:-,,------ GRAND AVENUE , - l i , l ! I j / tE ~ -"" ~ Q ~ t:E ~ LEGEND B-1 ~ APPROXIMATE LOCATION OF BORING I cf // ~ // . / ...... 'L_j ¼ I ~--1,, c,c.; /"-' I I / / I I •·-/ 0 1 2 I I . f I 0 10 20 30 40 PLOT PLAN HETHERINGTON ENGINEERING, INC. 786 Grand Avenue Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8587.1 I FIGURE NO. 2 DRILLING COMPANY: Scott's Drilling RIG: Deere 319E DATE: 05/05/18 BORING DIAMETER: 8" DRIVE WEIGHT: 140Ibs DROP: 30" ELEVATION: ' + ~ ril E-< ril ...cl >-< ~ ril ...cl Os E-< E-< 0\0 U) ~ ril Os ~ 0 H -U) BORING NO. B-1 µ., ~ 0 U) ril ,:C U) -U) µ., z er: E-< ...:I ::r: U) ----ril ::, z u u ril U) a ~ E-< ril E-< ~ > 3: 4-< U) E-< ...:I UJ Os ril ...:I H 0 >-< u H z H a ::, er: ...:I er: 0. 0 0 0::, SOIL DESCRIPTION il1 a il1 a -:E u U) -~ 0.0 SM FILL: Red brown silty sand; damp to moist, medium dense to -SP dense f-- :~ f-- @ 2': Angular gravel f-- - I TERRACE DEPOSITS: Red brown silty sand; moist, dense 5.0-43 121 6.9 - -- --- :X I 50 108 6.6 - - 10.0--- -I 88 112 9.5 - -- -- -- 15.0-- -I 95 115 16.9 -@ 16': Sand; very moist to wet; groundwater -- - 1 85/10" 95 29.5 BEDROCK {Santiago Formation}: Grey sandy siltstone; moist, -hard - 20.0 Total depth 20.0' -Groundwater @ 16' - No caving -- -- -- 25.0---- f--- -- -- 30.0 BORING LOG 786 Grand Avenue HETHERINGTON ENGINEERING, INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8587.1 I FIGURE NO. 3 DRILLING COMPANY: Scott's Drilling RIG: Deere 319E DATE: 05/05/18 BORING DIAMETER: 8" DRIVE WEIGHT: 140Ibs DROP: 30" ELEVATION: • + -w E--< w >-< :,-, -w >-< 0.. E--< E--< 0\0 Cf) -w 0.. ~ 0 H -Cf) BORING NO. B-2 µ., ~ 0 Cf) w st: Cf) -Cf) µ., z n: E--< >-< :r:: Cf) '-w t) z u u E--< w Cf) Cl -E--< w 0.. ~ > :s: 4-< Cf) E--< >-< C/J w >-< H 0 :,-, u H z H Cl t) n: >-< n: 0.. 0 0 0 t) SOIL DESCRIPTION CQ Cl CQ Cl -~ u Cf) -~ 0.0 SM TERRACE DEPOSITS: Red brown silty sand; damp to moist, -SP dense, trace roots in upper 18 inches - -- -I -83 130 6.5 -- 5.0-,..... -- -I 69 116 6.6 - -- -I -79 116 7.4 @9': Sand 10.0-- -- -- -I -50/6" 103 7.3 -~ - 15.0-- - -- @ 17': Groundwater -I 50/4" @ 17.5': Sand; very dense - 117 14.4 -- 20.0-[I! i:;.r,u:::.n -11 ~ ~7 A ----Total depth 20.5' - Groundwater @ 17' --Caving @ 18' to 20' -- -- 25.0-- -- -- -- -- 30.0 BORING LOG 786 Grand Avenue HETHERINGTON ENGINEERING, INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8587.1 I FIGURE NO. 4 I I B-1 @ 7 to 10' LABORATORY TEST RESULTS SULFATE TEST RESULTS A~gle of Intern,iJ ·•·•·•~·Friction. 0 .. . 30 (Cal Test 417) 0.030 DIRECT SHEAR (ASTM: D 3080) Cohesion. (pn5.,\··· 75 Remolded to 90% relative compaction at optimum moisture content, soaked, consolidated, drained MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT Sample Location B-1 (a), 7 to 10' Sample Location B-1 (a), 7 to 10' (ASTM: D 1557 A) Description Maximum Dry Optimum Moisture Density ( ocf) Content(%) Red brown si lty sand 131.0 9.0 EXP ANSI ON INDEX (ASTM: D 4829) Initial Compacted Final Expansion .Expansion Moisture (%) Dry Moisture Index Potential Density (%) (pcf) 8.1 118 .1 12 .1 0 Very low Figure 5 Project No. 8587 .. 1 Log No 19860