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Home My WebLink AboutCT 16-04; HIGHLAND VIEW HOMES; GEOTECHNICAL INVESTIGATION; 2016-09-30.. .. .. , .. .. .. .. Ill .. 1111 .. .. Ill .. .. .. .. .. .. Ill .. .. .. Ill GEOTECHNICAL INVESTIGATION Proposed Eight-Unit Residential Development 3758 -3794 Highland Drive Carlsbad, California r. ·· EIVED · 01 2016 \ . )f· CARLSBAD ;-, ... \ 1Nil\lG DIVISION RECEIVED OEC 011016 CITY OF CARLSBAD PL.ANNING DlVISlON HETHERINGTON ENGINEERING, INC. .. .. .. Ill .. Ill .. 111111 .. .. -.. -.. ---.. .. .. .. -.. .. .. Ill .. .. -.. .. Ill .. .. .. .. .. .. HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING• ENGINEERING GEOLOGY• HYDROGEOLOGY Carlsbad Coastal Views, LLC 3758 Highland Drive Carlsbad, California 92008 Attention: Mr. Brian Sullivan Subject: GEOTECHNICAL INVESTIGATION Proposed Eight-Unit Residential Development 3758 -3794 Highland Drive Carlsbad, California References: Attached Dear Mr. Sullivan: September 30, 2016 Project No. 8047.1 Log No. 18545 In accordance with your request, we have performed a geotechnical investigation for the proposed construction of an eight-unit residential development at the subject site. Our work was performed during September 2016. The purpose of our investigation was to evaluate the soil and geologic conditions 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) . • Subsurface exploration consisting of four borings for soil sampling and geologic observation . • Laboratory testing of samples obtained from the subsurface exploration. • Engineering and geologic analysis . • Preparation of this report presenting 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) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com -----h .. "•·• -• -1111 .. .. -1111 -1111 -------.. -.. ----.. .. .. .. -.. .. --.. Ill -.. GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page2 SITE DESCRIPTION The subject property is located at 3758 -3794 Highland Drive, Carlsbad, California (see Location Map, Figure 1). The property is approximately 2-acres in size and slopes gently to the east. The site currently supports a single-family residence and several detached outbuildings. The site is bounded by developed residential properties to the north and south, by Highland Drive to the west and by a school to the east. PROPOSED DEVELOPMENT Proposed development consists of an eight-unit residential subdivision. Existing site improvements will be demolished. We anticipate one and/or two story, wood-frame structures founded on conventional continuous/spread footings with slab-on-grade ground floors. Building loads are expected to be typical for this type of relatively light construction. Proposed grading consists of cuts and fills on the order of approximately 5 to 10-feet and less with import required to achieve design finished grades. Retaining walls and slopes, inclined at 2:1 (horizontal to vertical), up to approximately 5 to 10-feet high are proposed to facilitate grade changes. We anticipate that the proposed private drive aisle will consist of asphalt concrete pavement. SUB SURF ACE EXPLORATION Subsurface conditions were explored by excavating four hollow-stem auger borings to depths of 10.5 to 15.5-feet below existing site grades. The approximate locations of the exploratory borings are shown on the attached Plot Plan, Figure 2 and Geologic Cross- Section, Figure 3 . The subsurface exploration was supervised by an engineer 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 4 through 7. LABORATORY TESTING Laboratory testing was performed on samples obtained during the subsurface exploration. Tests performed consisted of the following: • Dry Density/Moisture Content (ASTM: D 2216) HETHERINGTON ENGINEERING, INC . ADAPTED FROM: The Thomas Guide, San Diego County, 57th Edition, Page 1106 ~ N I SCALE: 1" -2000' (1 Grid Equals: 0.5 x 0.5 miles) LOCATION MAP HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS 3758 -3794 Highland Drive Carlsbad California PROJECT NO. 8047.1 I FIGURE NO. 1 -----------•-•n• •·•· • ••• •••••••••-•-••••------~-•------------------•-----•-••---.. .. -.. -.. • .. • .. -.. • .. • • -.. -• -.. -.. -.. .. ... -.. -.. .. .. .. Ill GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 3 • Direct Shear (ASTM: D 3080) • Soluble Sulfate (Cal Test 417) • R-Value (Cal Test 301) Results of the dry density and moisture content determinations are presented on the attached Boring Logs, Figures 4 through 7. The remaining laboratory test results are presented on the attached Laboratory Test Results, Figure 8. Previous laboratory test results by Strata-Tech, Inc. are included in Appendix A to this report . SOIL AND GEOLOGIC CONDITIONS 1. Geologic Setting The subject site lies within a relatively level marine terrace 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 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 down to the present day coastline. These marine terraces increase in age eastward. The site area is contained within the central portion of the USGS San Luis Rey 7.5-minute quadrangle . As observed in the borings, the site is underlain by Quaternary terrace deposits. Localized areas of fill are anticipated associated with construction of the existing single-family residence. Structurally, bedding within the terrace deposits is considered to be essentially massive. The terrace deposits are granular and have a very low expansion potential. 2. Geologic Unit Terrace Deposits -Encountered in all of the borings, the terrace deposits are considered massive and consist of red brown silty sand that is damp to moist and dense . HETHERINGTON ENGINEERING, INC. .. 11111 .. .. .. II .. .. .. .. -.. .. .. .. .. .. .. .. .. ... .. -.. .. .. .. .. .. .. .. .. GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page4 3. Groundwater Groundwater or seepage was not encountered in the exploratory borings. It should be noted, however, that fluctuations in the amount and level of groundwater may occur due to variations in rainfall, irrigation and other factors that may not have been evident at the time of our field investigation . SEISMICITY Based on review of the available geologic maps/literature, there are no active or potentially active faults that traverse the subject site, and the property is not located within the currently mapped limits of an Alquist-Priolo Earthquake Fault Zone. 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/year) Rose Canyon 7.0 5.0 (8.9-kilometers/ 5.5-miles southwest) Elsinore (Julian Segment) 6.8 1.5 (37-kilometers/ 23-miles northeast) SEISMIC EFFECTS 1. Ground Accelerations The most significant probable earthquake to affect the property would be a 7.0 magnitude earthquake on the Rose Canyon fault. Based on Section 1803.5.12 of the 2013 California Building Code and Section 11.8.3 of ASCE 7, peak ground accelerations (PGAM) of 0.469g are possible for the design earthquake . 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 seismically induced landsliding affecting the site is considered low due to the gently sloping site topography . HETHERINGTON ENGINEERING, INC. ------"--·-.. .. .. .. .. Ill .. .. .. .. .. .. .. .. -.. .. .. -.. .. .. -.. .. .. .. .. .. .. .. .. .. .. .. .. GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 5 3. Ground Cracks The risk of fault surface rupture due to active faulting is considered low due to the absence of known active faults on site. Ground cracks due to shaking from seismic events in the region are possible, as with all of southern California . 4. Liquefaction The risk of seismically induced liquefaction within the site is considered low due to the dense nature of the terrace deposits and absence of shallow groundwater . 5. Tsunamis The site is not located within a mapped tsunami inundation area (Reference 2). The risk of a tsunamis event adversely impacting the site is considered low due to the elevation of the property above sea level. CONCLUSIONS AND RECOMMENDATIONS 1. General The proposed development is considered feasible from a geotechnical standpoint. Grading and foundation plans should take into account the appropriate geotechnical features 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 properties from a geotechnical standpoint. 2. Seismic Parameters for Structural Design Seismic considerations that may be used for structural design at the site include the following: a. Ground Motion -The proposed structures should be designed and constructed to resist the effects of seismic ground motions as provided in Section 1613 of the 2013 California Building Code . Site Address: 3758 -3794 Highland Drive, Carlsbad, California Latitude: 33.1564° Longitude: -117.3314° HETHERINGTON ENGINEERING, INC. ---·--- .. • .. .. .. .. • • .. • .. • .. • .. --• .. • .. .. .. • .. • .. .. • .. .. • .. .. .. .. .. .. GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 6 b. Spectral Response Accelerations -Using the location of the property and data obtained from the U.S.G.S. Earthquake Hazard Program, short period Spectral Response Accelerations Ss (0.2 second period) and S1 (1.0 second period) are: Ss = 1.130g S1 = 0.434g c. Site Class -In accordance with Chapter 20 of ASCE 7, and the underlying geologic conditions, a Site Class D is considered appropriate for the subject property . d. Site Coefficients Fa and Fv -In accordance with Table 1613.3.3 and considering the values of Ss and S1, Site Coefficients for a Class D site are: Fa= 1.048 Fv = 1.566 e. Spectral Response Acceleration Parameters Sm.s. and Sm1 -In accordance with Section 1613.3.3 and considering the values of Ss and S1, and Fa and Fv, Spectral Response Acceleration Parameters for the Maximum Considered Earthquake are: Sms = (F a)(Ss) = 1.184g Sm1 = (Fv)(S1) = 0.679g f. Design Spectral Response Acceleration Parameters Sds and Sd1 -In accordance with Section 1613.3.4 and considering the values ofSms and Sm1,Design Spectral Response Acceleration Parameters for the Maximum Considered Earthquake are: Sds = 0.789g Sd1 = 0.453g 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(1) and 1613.3.5(2), and ASCE 7, a Risk Category II and a Seismic Design Category D are considered appropriate for the subject property . HETHERINGTON ENGINEERING, INC . .. .. -.. -.. -.. -.. -.. -.. -.. -.. -.. .. .. ... .. ... .. -.. -.. .. .. .. .. -.. .. .. GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 7 3. Site Grading ---------·----·--·------ Prior to grading, the site should be cleared of existing surface obstructions, vegetation and debris. Materials generated during clearing should be disposed of at an approved location off-site. Holes resulting from the removal of any buried obstruction should be filled with compacted fill or lean concrete. Seepage pits and/or septic systems, if encountered during site development, should be abandoned in accordance with local guidelines. Within the limits of proposed improvements and to 3-feet beyond, existing loose fill or disturbed terrace deposits should be removed down to approved undisturbed terrace deposits ( estimated at 2-feet). Due to disturbance as a result of demolition, we anticipate removal depths on the order of 3-feet below existing site grades in the area of the existing residence. Actual removal depths should be determined in the field by the Geotechnical Consultant .based on conditions exposed during grading. The exposed subgrade soils should be scarified 6 to 8-inches, moisture conditioned to about optimum moisture content and compacted by mechanical means to a minimum relative compaction of 90-percent (ASTM: D 1557). Fill should be moisture conditioned as necessary 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 provided all vegetation and debris are removed. Rock fragments over 6-inches in dimension and other perishable or unsuitable materials should be excluded from the fill . Proposed cut and fill slopes should be inclined at a slope ratio of 2: 1 (horizontal to vertical) or flatter. All grading and compaction should be observed and tested as necessary by the Geotechnical Consultant. 4. Foundation and Slab Recommendations The proposed structures may be supported on conventional continuous/spread footings founded at least 18-inches in compacted fill and/or terrace deposits . Continuous footings should be at least 12-inches wide and reinforced with a minimum of four #4 bars, two top and two bottom. Foundations located adjacent to utility trenches should extend below a 1: 1 (horizontal to vertical) plane projected upward from the bottom of the trench . HETHERINGTON ENGINEERING, INC . .. .. -.. .. .. .. .. -• • .. -Ill -.. .. ... .. ... -.. ... ... ... ... -.. -Ill -.. .. .. -• ~,~~•--··•·-.. ,--.. , ________ .,... ________ _ GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 8 Foundations bearing as recommended may be designed for a dead plus live load bearing value of 2000-pounds-per-square-foot. This value may be increased by one- third for loads including wind and seismic forces. A lateral bearing value of 250- pounds-per-square-foot per foot of depth to a maximum value of 2000-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 the foundation soils. Footing excavations should be observed by the Geotechnical Consultant prior to the placement of reinforcing steel in order to verify that they are founded in suitable bearing materials. Total and differential settlement due to foundation 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 supported on chairs so that the reinforcement is at mid-height in the slab. Floor slabs, including garages, should be underlain with a moisture vapor retarder consisting of a minimum 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. Retaining Walls Retaining walls free to rotate ( cantilevered walls) should be designed for an active pressure of 35-pounds-per-cubic-foot (equivalent fluid pressure). Walls restrained from movement at the top should be designed for an at-rest pressure of 60-pounds- per-cubic-foot (equivalent fluid pressure). These values are based on level backfill consisting of onsite granular soils. Any additional surcharge pressures behind retaining walls should be added to these values. Retaining wall foundations should be designed in accordance with the foundation recommendations provided previously in this report . HETHERINGTON ENGINEERING, INC. ----------------------.. .. .. 11111 .. • -• -• -• -• -• GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 9 Retaining walls should be provided with adequate drainage to prevent buildup of hydrostatic pressure and should be adequately waterproofed. The subdrain system behind retaining walls should consist at a minimum of 4-inch diameter Schedule 40 ( or equivalent) perforated (perforations "down") PVC pipe embedded in at least 1- cubic-foot of 3/4 inch crushed rock per lineal foot of pipe all wrapped in an approved filter fabric. The subdrain system should be connected to a solid outlet pipe with a minimum of I-percent fall that discharges to a suitable drainage device. Recommendations for wall waterproofing should be provided by the Project Architect and/or Structural Engineer. The lateral pressure on retaining walls due to earthquake motions ( dynamic lateral force) should be calculated as PA = 3/8 y H2kh where PA= dynamic lateral force (lbs/ft) 'Y = unit weight= 120 pcf H = height of wall (feet) kh = seismic coefficient= 0.156 The dynamic lateral force may also be expressed as 14-pcf ( equivalent fluid pressure). The dynamic lateral force is in addition to the static force and should be applied as a triangular distribution at 1/3H above the base of the wall. The dynamic lateral force need not be applied to retaining walls 6-feet or less in height. 6. Hardscape Concrete flatwork should be at least 5-inches thick (actual) and reinforced with No. 4 bars spaced at 18-inches on-center (two directions) 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. HETHERINGTON ENGINEERING, INC . 1111 ... 1111 Iii .. 1111 .. .. .. .. .. .. .. II -.. -.. .. .. .. .. .. 1111 1111 .. .. ... GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 10 7. Asphalt Pavement Concrete Based on an R-value of 77 and an assumed traffic index of 5, we recommend that the pavement section for the proposed private drive aisle consist of 3-inches of asphalt concrete pavement over 4-inches of Class 2 aggregate base (Caltrans). Pavement subgrade and aggregate base should be compacted to at least 95-percent relative compaction and tested by the Geotechnical Consultant. 8. Sulfate Content A representative sample of the on-site soils was submitted for sulfate testing. The result of the sulfate test is summarized on the Laboratory Test Results, Figure 7. The sulfate content is consistent with a not applicable sulfate exposure classification per Table 4.2.1 of the American Concrete Institute Publication 318, consequently, no special provisions for sulfate resistant concrete are considered necessary. Other corrosivity testing has not been performed, consequently, on-site soils should be assumed to be severely corrosive to buried metals unless testing is performed to indicate otherwise . 9. Drainage The following recommendations are intended to mmmuze the potential adverse effects of water on the structures and appurtenances. a. Consideration should be given to providing the structures with roof gutters and downspouts that discharge to an area drain system and/or to suitable locations away from the structure . b. All site drainage should be directed away from the structures . c. No landscaping should be allowed against the structures. Moisture accumulation or watering adjacent to foundations can result in deterioration of building materials and may affect the performance of foundations. d. Irrigated areas should not be over-watered. Irrigation should be limited to that required to maintain the vegetation. Additionally, automatic systems must be seasonally adjusted to minimize over-saturation potential particularly in the winter (rainy) season . HETHERINGTON ENGINEERING, INC. ... .. ... .. .. .. .. .. .. .. .. .. .. .. --.. .. .. - .. .. .. .. .. .. 11111 .. .. Ill ·---~---·-~----·--------------------- GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 11 e. All yard and roof drains should be periodically checked to verify they are not blocked and flow properly, and maintained as necessary . 10. Recommended Observation and Testing During Construction The following tests and/or observations by the Geotechnical Consultant are recommended: a. Observation and testing during site grading . b. Observation of foundation excavations prior to placement of forms and reinforcement. c. Utility trench backfill. d. Hardscape/driveway subgrade and base . e. Retaining wall backdrains and backfill . 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 during construction, the Geotechnical Consultant should be promptly notified for review and reconsideration of 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 . HETHERINGTON ENGINEERING, INC. ______ ..., .... ,, .. ~ .~,_.., ..... •,•,-•>~•>,..__...Y,_¥~•-••~-~------·------------------·-----.. .. .. .. .. .. .. .. .. .. .. .. ----.. -.. .. ... .. ... ... -.. .. .. .. .. .. .. .. .. .. C GEOTECHNICAL INVESTIGATION Project No. 8047.1 Log No. 18545 September 30, 2016 Page 12 This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office . Sincerely, HETHERINGTON ENGINEERING, INC . &e Attachments: Location Map Plot Plan Geologic Cross-Section Boring Logs Laboratory Test Results Strata-Tech, Inc. Data Distribution: 4-Addressee Professional Geologist 3772 Certified Engineering Geologist Certified Hydrogeologist 591 L..~~~.,.lfi~U'M ( expires 3/31/18) Figure 1 Figure 2 Figure 3 Figures 4 through 7 Figure 8 Appendix A 1-via e-mail (bsu11y59@hotmail.com) 1-via e-mail (sean@coastal-land-solutions.com) HETHERINGTON ENGINEERING, INC. .. .. .. .. .. .. .. .. .. -.. ---.. -.. .. .. .. .. .. .. .. ... tlll Ill .. Ill .. 1111 .. .. ,. .. REFERENCES 1. ASCE 7-10, "Minimum Design Loads for Buildings and Other Structures", American Society of Civil Engineers/Structural Engineers Institute, dated May 2010 . 2. California Geological Survey, "Tsunami Inundation Map for Emergency Planning -Encinitas Quadrangle", California Geologic Survey, June 1, 2009 . 3. Coastal Land Solutions, Inc., Preliminary Grading Plan, 3758 -3794 Highland Drive, Carlsbad, California, dated April 28, 2016. 4. ICBO, California Building Code, 2013 Edition . 5. ICBO, "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada," California Division of Mines and Geology, 1998. 6. 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. 7. Strata-Tech, Inc., "Geotechnical Engineering Investigation of Proposed Multi Family Residential Development, 3758 -3794 Highland Drive, Carlsbad, California," dated May 14, 2016 (no boring logs included) . 8. Tan, Siang S. and Kennedy, Michael P., "Geologic Maps of the Northwestern Part of San Diego County, California," California Division of Mines and Geology, Open-File Report 96-02, dated 1996 . 9. Tan, Siang S. and Giffen, Desmond G., "Landslide Hazards in the Encinitas Quadrangle, San Diego County, California," California Division of Mines and Geology, Open-File Report 96-04, dated 1995 . 10. USGS, Earthquake Hazard Program, Seismic Design Maps . 11. 2007 Working Group and California Earthquake Probability, "The Uniform California 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. Project No. 8047.l Log No. 18545 ! r i l ~·-+-· ---,-~~--~--~,-t;--r- J.-1 1: A 8-4~ A' • J'/ 11/ 0 1 2 0 20 40 60 80 LEGEND APPROXIMATE LOCATION OF BORING APPROXIMATE LOCATION OF GEOLOGIC CROSS-SECTION PLOT PLAN HETHERINGTON ENGINEERING, INC. 3758 -3794 Highland Drive Carlsbad, California PROJECT NO. 8047.1 I FIGURE NO. GEOTECHNICAL CONSULTANTS 2 ~ 8-1 I EXISTING GRADE I (PROJECTED) I -PROPOSED GRADE 200· I I I 8-2 -200 I I " (PROJECTED) ' I I I ' I I I ' I LOTS • ' LOT7 I ' I . I I I -I 180· I I .. LOT6 ~ 180 I I ', I I I I I I PRIVATE I I I 11 I .. DRIVE -1 I I --------------LOT4 I ' I ........ r I I I I ...., __________ -----------------.. I I I I 160 I, - I -160 ------, I I I I I _j __________ l ... I I ---... 1, _____________ ..-I ',, I --I ~----------------------, I I -TERRACE DEPOSITS I 140 -140 -120 120 -A TREND: N25E A' SCALE: 1" = 20' 0 1 2 I I I I I GEOLOGIC CROSS-SECTION I I I I I 0 10 20 30 40 3758 -3794 Highland Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 I FIGURE NO. 3 __ ,._ -------------------------------------------------------------------------------------- DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER: 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION: I 'I: -w E-< w H :>-< -w H p... E-< E-< dP U) -w i:,_. p... ~ 0 H -U) BORING NO. 8-1 -~ 0 U) w ,=x: U) -.: U) i:,_. z 0:: E-< H ::r:: U) ----w :::, z u u w C/l Cl -E-< w E-< ~ > ~ 4--l U) E-< H U'J p... w H H 0 :>-< (.) H z H Cl :::, 0:: H 0:: 0.. 0 0 0:::, SOIL DESCRIPTION co Cl co Cl -~ u U) - -0.0 TERRACE DEPOSITS Red brown silty fine to medium sand, damp, dense ..._ - ..._ -; 50/6" 106 5.6 -- -- 5.0-~ -~ 50/6" 113 6.2 -- ..._ - ..._ - -- 10.0 5/2" - ~ @ 10': No sample returned in Cal., drove an SPT 25/6" -26/6" - 30/6" -Total depth: 11.5 feet - No groundwater No caving -- ..._ - 15.0--- ~ - -- -- -- 20.0 BORING LO G HETHERINGTON ENGINEERING, INC. 3758 -3794 Highland Drive Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 I FIGURE NO. 4 DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER: 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION: I + -r,.i E:-< r,.i ..:I >-t -r,.i ..:I °' E:-< E:-< dP U) -r,.i °' ::;:: 0 H -U) BORING NO. B-2 i:,.. ::;:: ,:i:: 0 U) r,.i ,:i:: U) -,:i:: U) µ; :z rx: E:-< ..:I ::r: U) '-r,.i p :z u u E:-< r,.i U) Cl -E--< r,.i °' ~ > ~ 'H U) E:-< ..:I Ul r,.i ..:I H 0 >-t u H :z H p rx: ..:I rx: 0.. 0 0 0 p Cl '1l Cl '1l Cl -::;:: u Ul -SOIL DESCRIPTION -0.0 TERRACE DEPOSITS: Red brown silty fine to medium sand, damp, dense -- --.... •< 50/6" 106 5.5 = -- I--- 5.0---• 50/6" 116 4.4 ~ -- -- -- -- 10.0 --x· 50/6" 88 7.4 - -I @ 11': Difficulty drilling, chalk like fragment in tailings r Total depth: 15.5 feet --No groundwater - No cavina -- 1--- 15.0-I 5016" - 98 6.9 -- -- -- 1--- 20.0 BORING LOG HETHERINGTON ENGINEERING, INC. 3758 -3794 Highland Drive Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 I FIGURE NO. 5 DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER: -i:,:i E-< i:,:i i:,:i ,-.:i w ,-.:i 0.. E-< i:,, 0.. ::;:: 0 -~ ,:i:: 0 Cf) i:,, ::c Cf) -----w Cf) E-< ~ > :s: 0.. ,-.:i H 0 w 0 :::i o:; ,-.:i IX! 0 IX! -0.0 - - ; 47/6" - - 5.0-"::.': 50/6" b:: - - - - 10.0 ··-50/6" •·-· - - - - 15.0- - - - 20.u- 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION: :>-< -E-< <JP H -Cf) w z o:; E-< w :::i z 0 -E-< w 'H Cf) E-< :>-< 0 H z o:; 0. 0 0 0 -::;:: u 104 3.3 103 4 .5 109 7.5 Cf) -Cf) ,:i:: Cf) ,-.:i u u ,-.:i Cf) H 0 :::i Cf) - BORING NO. 8-3 SOIL DESCRIPTION TERRACE DEPOSITS: Red brown silty fine to medium sand, damp, dense BORING LOG Total depth: 10.5 feet No groundwater No caving HETHERINGTON ENGINEERING, INC. 3758 -3794 Highland Drive Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 804 7 .1 I FIGURE NO. 6 - - - - t-- - DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER: 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION: I + -w E-< w >-< >-< -w >-< p.. E-< E-< dP U) -w p.. ~ 0 H -U) BORING NO. B-4 l:x, ~ 0 U) w ,;; U) -U) l:x, z 0:: E-< >-< ::r! U) ----w :::, z u u w U) 0 -E-< w E-< :,,:; > :s: 4-l U) E-< e-=I U) p.. >-< H 0 >-< u H z H w :::, 0:: >-< 0:: 0. 0 0 0:::, 0 Ill 0 Ill 0 -::;:: u U) -SOIL DESCRIPTION ,_ 0.0 TERRACE DEPOSITS: Red brown fine to medium sand, damp, dense -- -I;;_ -~ 50/6" 114 7.8 -1-- -- 5.0-r,,, 1-- ._!L 50/6" 11 3 7.7 -1-- -- -1-- -- 10.0-E 50t5.5" 120 - 11.1 -Total depth: 10.5 feet - No groundwater No caving -- -1-- -- 15.0-,__ -1-- -- -- -- 20.0 BORIN G LOG HETHERINGTON ENGINEERING, 3758 -3794 Highland Drive INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 I FIGURE NO. 7 Sample Location LABORATORY TEST RESULTS Angle of Internal Friction ° DIRECT SHEAR (ASTM: D 3080) Cohesion (psf) Remarks B-1 a 2' 34 0 Undisturbed, soaked consolidated, drained Sample Location Pavement Subgrade SULFATE TEST RESULTS (EPA 9038) Soluble Sulfate in Soil % 0.0210 0.0100 R-Value (Cal Test 301) R-Value 77 Figure 8 Project No. 8047.1 Log No. 18545 APPENDIX A (Strata-Tech, Inc. Laboratory Test Results) STRATA-TECH,INC. GEOCONSULTANTS APPENDIX A This appendix contains a description of the field investigation, laboratory testing procedures and results, site plan. and exploratory logs. FIELD INVESTIGATION As excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing Sample Retrieval-Backhoe Undisturbed samples of earth materials were obtained at frequent intervals by driving a thin- walled steel sampler by the hydraulic action of the backhoe bucket. The material was retained in brass rings of 2.41 inches inside diameter and 1.00 inch height. The central portion of the sample was in close-fitting, watertight containers for transportation to the labordtory. Descriptions of the soils encountered are presented on the attached boring Logs. The data presented on these logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated . It is not warranted to be representative of subsurface conditions at other locations and times. Laboratory Testing Field samples were examined in the laboratory and a testing program was then established to develop data for preliminary evaluation of geotechnical conditions. Moisture Density Field moisture content and dry density were determined for each or the undisturbed soil samples. The dry density was determined in pounds per cubic foot. The moisture content was determined as a percentage of the dry soil weight. The results of the tests are shown in the test results section of this appendix. Compaction Character Compaction tests were performed on bulk sample of the existing soil in accordance with ASTM 01557-07. The results of the tests are shown in the test results section of this appendix. Shear Strength The ultimate shear strengths of the soil, remolded soil. highly weathered bedrock and bedrock was detennined by performing direct shear tests. The tests were performed in a strain-controlled machine manufactured by GeoMatic. The rate of deformation was 0.005 inches per minute. Samples were sheared under varying confining pressure, as shown on the "Shear Test Diagrams''. ST RA T A -T E CH ,I NC. GEOC:ONSULTANTS The samples indicated as saturated were artificially saturated in the laboratory and were shear under submerged conditions. The results of tests are based on 80 percent peak strength or ultimate strength, wh ichever is lower, and are attached. In addition, a shear was performed on an upper layer sample remolded to 90-percent of the laboratory standard with low confining pressure. TEST RESULTS Maximum Density/Optimum Moisture (ASTM:D-1557-07) Boring Depth in Feet Maximum Density Optimum Moisture (ocf) (%) 3 1-3 124 12.0 In-Situ Dry Density/ Moisture Boring Depth in Feet Dry Density Moisture (ocf) (%) I 3.5 114.0 6.1 3 4 114.1 6.0 3 9 11 3.7 5.8 Direct Shear Cohesion Angle of Internal Boring Depth in Feet (psf) Friction (degrees) 3 4 100 31 APPENDIXB ~ ¢:; ci-en --en .9-.:.:: ---en en ~ u5 SHEAR TEST RESULT ( Boring No. 1 @4 Feet (Remoldec;j to 90 %) J 4 ,----------,...; ---------, 3 1-------'-I ---~. -. --~ - 2 ,_ ______ --··-·-·---. .-.-</ . -- // 1 o/ /. 1-----' ---~.,./ _ _J ___ ·-·-- ♦.,;/.,,,. . / v ·; 0 ...__ ___ ,_, ------------' 0 1 2 3 Confining Pressure (kips/sq. ft.) Stress -Displacement Diagram 4 ~-----..... ,-------.. 3 ---A•····••A•AAAAA,~ 2 ~llfll"T-■ ■'■■■■■Bl 11 ■-DU 1 1-ft-+--.-.--........... 1-+-+-•-.-· .. -· .... ♦' 0 0 2 Horizontal Displacement (X 1/10 inch) 4 :;-:;-·KIP 7 I I ! 1112 KIP A3 KIP Natural soil samples were submerged for at least 24 hours. The sample had a density of 11 3 lbs./cu.ft. and a moisture content of 17 %. Cohesion= 100 psf Friction Angle:: 31 degrees Based on 80% peak strength or ultimate strength, whichever is lower Geotechnical Engineering Investigation 3758 Highland Dr. Carlsbad , California STRATA -TECH, INC. Work Order 277515 Plate No. 5