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HomeMy WebLinkAboutCDP 2019-0032; LOVE RESIDENCE; GEOTECHNICAL INVESTIGATION; 2019-03-11GEOTECHNICAL INVESTIGATION Proposed Single-Family Residence 4615 Telescope Avenue Carlsbad, California HETHERINGTON ENGINEERING, INC. HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING • ENGINEERING GEOLOGY• HYDROGEOLOGY Elite Home Constmction, Inc. 2386 Ivy Road Oceanside, California 92054 Attention: Subject: Mr. Corey Love GEOTECHNICAL INVESTIGATION Proposed Single-Pamily Residence 4615 Telescope A venue Carlsbad, California References: Attached Dear Mr. Love: March 11, 2019 Project No. 8787.1 Log No. 20349 In accordance with your request, we have performed a geotechnical investigation for a proposed single-family residence al the subject site. Our work was performed during February and March 2019. 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 phms and geologic maps/literature pertinent to the site (see References). • Subsurface exploration consisting of two 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. 5'.365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 333 Third Street. Suite 2 • La~)Una Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 9~~1-0545 www.hetheringtonengineering.com GEOTECHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 Page 2 SITE DESCRIPTION The subject property is located at 46 I 5 Telescope Avenue, Carlsbad, California (see Location Map, Figure l). The irregular shaped property is approximately 7000±-square- feet in size. The site currently consists of a relatively level graded pad with a 1 0:l:-feet high slope that descends to Telescope A venue and a 10±-feet high slope that ascends lo a residential prope1ty to the west. The site is bounded by developed residential prope1ties to the north, south and west, and by Telescope A venue to the east. PROPOSED DEVELOPMENT Proposed development consists of a single-family residence. We anticipate a one-story, wood-frame structure founded on conventional continuous/spread footings with slab-on- grade ground floors. The garage will be at Telescope Avenue grade and the residence on the upper pad level. Building loads are expected to be typical for this type of relatively light construction. Proposed grading consists of cut to a maximum depth of approximately 10±-feet to facilitate the street level garage. Retaining walls up to approximately 10±-feet high are proposed to facilitate grade changes. SUBSURFACE EXPLORATION Subsurface conditions were explored by excavating two hollow-stem auger borings to depths of 16 to 20-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 and 5. 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) • Direct Shear (ASTM: D 3080) HETHERINGTON ENGINEERING, INC. ADAPTED FROM: The Thomas Guide, San Diego County, 57th Edition, Page 1106 LOCATION MAP HETHERINGTON ENGINEERING, INC. SCALE: 1" -2000' (1 Grid Equals: 0.5 x 0.5 miles) 4615 Telescope Avenue Carlsbad California GEOTECHNICAL CONSULTANTS PROJECT NO. 8787.1 I FIGURE NO. 1 GEOTECHNICAL INVESTIGATION Project No. 8787 .1 Log No. 20349 March 11, 2019 Page 3 • Maximum Dry Density/Optimum Moisture (ASTM: D 1557) o Expansion Index (ASTM: D 4829) e Soluble Sulfate (Cal Test 417) Results of the dry density and moisture content determinations are presented on the atlached Boring Logs, Figures 4 and 5. The remaining laboratory test results are presented on the attached Laboratory Test Results, Figure 6. GRADING HISTORY Research at the city of Carlsbad resulted in obtaining grading plans and geotechnical rep011s (References 9 through 12). The grading plan has been utilized in the preparation of the attached Plot Plan, Figure 2. The site is reportedly entirely a cut lot exposing Terrace Deposits. 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 tenaces of Pleistocene age that have been established above wave-cut platforms of underlying Eocene bedrock and were f01med 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 ten-ace deposits. The tenacc deposits consist of orange brown, light brown, tan and black clayey sand and sand that is damp to moist and dense. Structurally, bedding within the tenace deposits is considered to be essentially massive. The terrace deposits are granular and have a very low expansion potential. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 Page 4 2. Groundwater Groundwater or seepage was not encountered in the exploratory borings. rt should he 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. SEJSMICTTY 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 Rnte /Moment Ma1mitude) /mm/year} Rose Canyon 7.0 5.0 (9 .2-kilometers/ 5. 7-miles southwest) Elsinore (Julian Segment) 6.8 3.0 (35-kilometers/ 21.7-miles northeast) SEISMIC EFFECTS 1. Ground Accelerations The most significant probable earthquake to affect the prope1ty would be a 7.0 magnitude emthquake on the Rose Canyon fault. Based on Section 1803.5.12 of the 2016 California Building Code and Section 11.8.3 of ASCE 7, peak ground accelerations (PGAM) of 0.463g 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 dense nature of the tenace deposits and favorable geologic structure. HETHERINGTON ENGINEERING, INC. GEOTBCHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 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 stmcture 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: 4615 Telescope A venue, Carlsbad, California Latitude: Longitude: 33.1524° -117.3181° HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8787 .1 Log No. 20349 March 11,2019 Page 6 b. ,Spectral Response Accelerations -Using the location of the property and data obtained from the U.S.G.S. Earthquake Hazard Program, shmt period Spectral Response Accelerations Ss (0.2 second period) and Si (1.0 second period) are: Ss= l.llg S1 = 0.426g 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 prope1ty. cl. Site Coefficients F11 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= 1.506 Fv = 1.574 e. Spectral Response Acceleration Parameters Sms 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 = 1.172g Sm1 = 0.671g f. Design Spectral Response Acceleration Parameters Sds and Sd1 -In accordance with Section 1613.3.4 and considering the values of Sms and Sm 1. Design Spectral Response Acceleration Parameters for the Maximum Considered Earthquake are: Sds = 0.781g Sd, = 0.447g 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 -hi 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. 8787.1 Log No. 20349 March 11, 2019 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 buried obstructions 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. The garage level may be cut to grade and is expected to expose competent tenacc deposits. For the upper building pad, within the limits of proposed residence and hardscape and to 5-feet beyond, existing disturbed te1nce deposits should be removed down to approved undisturbed terrace deposits, estimated at 1 to 2-feet, and replaced as compacted fill. Actual removal depths should be determined in the field by the Geoteclmical 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 unifo1m 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. All grading and compaction should be observed and tested as necessary by the Geotechnical Consultant. 4. Temporary Slopes Temporary slopes necessary to perfom1 the remedial grading or to facilitate the construction of the various retaining walls may be cut vertically up to 5-feet in tenace deposits where the cuts are not influenced by existing structures or property line constraints. Any portion of temporary slopes higher than 5-feet or located adjacent to existing improvements should be inclined at a slope ratio no steeper than 1: 1 (horizontal to ve11ical) or shored. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 Page 8 Field observations by the Engineering Geologist during grading of temporary slopes is recommended and considered necessary to confirm anticipated conditions and provide additional recommendations as wananted. 5. Foundation and Slab Recommendations The proposed structure may be supported on conventional continuous/spread footings founded at least 18-inches into compacted fill ancl/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. 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 the garage, should be underlain by a 10-mil polyethylene moisture vapor retarder. 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. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Pr~ject No. 8787.l Log No. 20349 March 11, 2019 Page 9 6. Retaining Walls Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 40-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 arc 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. 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 Prqject 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 H2k11 where PA = dynamic lateral force (pounds-per-foot) 'Y unit weight = 120-pounds-per-cubic-foot H -height of wall (feet) k11 seismic coefficient = 0 .154 The dynamic lateral force may also be expressed as 13.9-pounds-per-cubic-foot (equivalent fluid pressure). The dynamic lateral force is in addition to the static force and should be applied as a triangular dish·ibution at 1/311 above the base of the wall. The dynamic lateral force need not be applied to retaining walls 6-feet or less in height. HETHERINGTON ENGINEERING, INC. GEO'T'ECHNICAL INVESTIGATION Project No, 8787 .1 Log No. 20349 March 11, 2019 Page 10 7. Hardscape Concrete t1atwork 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. Conlraction 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. 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 6. 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 conosivity 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 mmnmze the potential adverse effects of water on the structures and appurtenances. 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 away from the structure. b. All site drainage should be directed away from the structure and not allowed to flow over slopes. c. No landscaping should be allowed against the strncture. 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 HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 Pagel 1 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 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 grading. b. Observation of foundation excavations prior to placement of forms and reinforcement. c. Utility trench backfill. d. Retaining wall backdrains and backfill. e. Hardscape/driveway subgrade. 11. Grading and Foundation Plan Review Grading and foundation plans should be reviewed by the Geotechnical Consultant to confirm confonnance with the recommendations presented herein or to modify the recommendations as necessary. LIMITATIONS The analyses, conclusions and recommendations contained in this report are based 011 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. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL INVESTIGATION Project No. 8787.1 Log No. 20349 March 11, 2019 Page 12 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 wananty, 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, HETHERINGT:N,:NGINEERJNG, INC. '/ ,,----> //. ,;:::;,;7<};✓;? / ---_:::::,:><:::::L-~--__ ... /;/, ' ~-.,,,..;/~// .. -----,,,.,.,,, -I,,.."'./,,.,..,.,, ,.,, ,,.,.(' --~-_,,..,,,,.,.,/ tlfe11Ilgt .:--:-c:::-::--..: a-ul-K.J3~gseth Civil Engineer 3048 .IL,JLo.,• Professional Geologist 3772 Geotechnieal Engin 'tJVc.a'Y..J~ Certified Engineering Geologist ( expires 3/31/20) Ce1tified Hydro geologist 591 (expires 3/31/20) Attachn1ents: Location ap Figure l Plot Plan Figure 2 Geologic Cross-Section Figure 3 Boring Logs Figures 4 and 5 Laboratory Test Results Figure 6 Distribution: 5-Addressee 1-via e-mail ( elitehomeconstruction(@,yahoo.com) HETHERINGTON ENGINEERING, INC. REFERENCES Published 1. ASCE 7-10, "Minimmn 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 -· Oceanside Quadrangle/San Luis Rey Quadrangle", California Geological Survey, June 1, 2009. 3. lCBO, California Building Code, 2016 Edition. 4. ICBO, "Maps of Known Active Fault Near-Source Zones in California and Acljacent Portions of Nevada," California Division of Mines and Geology, 1998. 5. Peterson, Mark P., et al, "Documentation for the 2008 Update of the United States National Seismic Hazards Maps," USGS Open File Repo1t 2008-1128, dated 2008. 6. Structural Engineers Association, Earthquake Hazard Program, Seismic Design Maps website. 7. 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 Repo1t 96-02, dated 1996. 8. 2007 Working Group and Califomia Earthquake Probability, "The Unifonn California Earthquake Rupture Forecast, Version 2 (UCERF-2)," USGS Open File Report 2007- 1437 and California Geological Survey Special Report 203, dated 2008. Other (Chronologi_g} 9. Geocon, Inc., "Soil and Geologic Investigation Telescope Point, Carlsbad, California", dated August I, 1983. 10. Action Geotechnical Consultants, "Final Compaction and Grading Report for Lots 1 - 5, 56 -65, 117 -139, for Residential Development; Portion of Tract 86-5; ... ," dated May 18, 1984. 11. Action Engineering Consultants, "Addendum for Grading Inspection and Compaction Repo1t, Dated May 18, 1984", dated June 22, 1984. (Cut Lots 6, 7, 8 should have been included). 12. Cooper and Associates, "Grading Plan -Telescope Point, Carlsbad Tract 82-5", dated As Built July 22, 1996. 13. Design Travis Deal, "Site Plan, 4615 Telescope Ave., Carlsbad, CA", dated January 2019 (Sheets A-1 and A-3). HETHERINGTON ENGINEERING, INC. Project No. 8787.1 Log No. 20349 ____ .,,-~•.r~ . -· _.,..,.--/··< ~--\:.:,.,...-_.,..-___ ,..--· A,.- -~ -------·1 ,_,, , ~- --~ ,.. ----···~·--·.r, .' / '·•/ .. < -•· .--· •.. ·-----"--_I -( I '-· .. _,,.· ,y -I\ 8' ~ ,-, ~-;· .. 1 . ·, "-------;-· . I • ,, '" ., ' ··.,. ·•., I ~ .. f Ji --' • .,_ · I -~ --~-;-POSED RESIDE!'J,CE ~~l-''~~ ~-~~\ , !,'::-.\,,,_,)., l,. . , .. ~ ,. '\, " ' ' N ~!!>zo-___,.:······ ao~ -; · __ -,, }\'.-: f_.;': "·\o : ~ >-,,1',,V .. ~ ' ...... ),, :,,'Ii, ~ --. " • ·=~• l I ~ '••· ~ \ 1, ~ •••~ ,\•~ ff a,:<,• ' .._. i,. -I n. I ' .~ .W?.Q .•C S6 .. 0'!J 1 l\ ~ . \ ,.--\.{\ '.\" , ~,// . I~/ /~; / ~z~ ~ ~ ._(., 3, \··-----.... \ I· .. , . ', Ill-·------,_ ·- . V , .•• =-'-..-$~~, t# I I ► <<I I J t< • ·o,, ---· '1'-l ""T -' _,.--f ,.. -... _ -~ SCALE: 1• = 20' -=====>-z -<==3 0 1 2 L~r==L=F7 0 10 20 30 40 LEGEND 8-2 ~ APPROXIMATE LOCATION OF BORING A A APPROXIMATE LOCATION OF CROSS-SECTION I I PLOT PLAN ---r-uof -.J .. ,...J----.. .-1\ ( --.--.J",,._ l-., I T ---., \\ ( f"',. '--I 4615 Telescope Avenue 8 I HETHERINGTON ENGINEERING, INC. Carlsbad, Calfomia GEOTECHNICAL CONSULTANTS PROJECT NO. 8787.1 I FIGURE NO. 2 w ::> z w > ~ ORIGINAL t= PROPOSED j ~ 320 -t : GRA~E-~ ~ RESIDENCE i --_J ---w --I- EXISTING GRADE -~---i-~ ---! 300 "---------,.-~-........_ I - TERRACE 1 DEPOSITS PROPOSED GARAGE B 2 ~-t - B-1 I-320 1-300 L280 A -=:::::::::: I TREND: N80W ======:::i A' SCALE: 1" = 20' t=' w w '=-z 0 f'.= <{ > w _J w 0 1 2 I ~~ GEOLOGIC CROSS SECTION L:==i L___J 0 10 20 30 40 HETHERINGTON ENGINEERING, INC. GEOTECHNICAL CONSULTANTS I 4615 Telescope Avenue _______ c_arl~s_b_a~d, California PROJECT NO, 8787, 1 I FIGURE NO. 3 DRILLING COMPANY: Scott's RIG: Hollow Stem Auger DATE: 02/11/19 BORING DIAMETER: 8" DRIVE WEIGHT: 140lb DROP: 30" ELEVATION: I + -ril E-< ril ...:I >-< -ril ...:I p.. E-< E-< o\O Cf) -ril p.. ::8 0 H -Cf) BORING NO. B-1 ~ -::8 .i: 0 Cf) ril .i: Cf) .i: Cf) ~ z p:; E-< ...:I ::r: Cf) ----- ril :::, z u u E-< ril Cf) 0 -E-< ril p.. :,,:; > 3 ~ Cf) E-< ...:I Ul ril ...:I H 0 >-< 0 H z H 0 :::, p:; ...:I p:; P-, 0 0 0:::, SOIL DESCRIPTION rQ 0 rQ 0 -::8 u Cf) -~ 0.0 TERRACE DEPOSITS: Orange brown slightly clayey sand; moist to wet, medium dense to dense, well graded f-- 182/10" 121 9.3 -f-- -I ,__ 50/6" 102 7.5 @3' -Moist, very dense -- 5.0 -I 50/5.5" 95 7.5 @5' -Moist, very dense, slightly cemented -- -~ -- -- 10.0-185/11" ---111 7.5 @10' -Moist, very dense -~ :Ii)\ f-- ~ -~ ~ 15.0-I 83/11" ---107 4.8 @15' -Tan, black and orange brown sand; moist, dense -- -- -,__ -I ,__ 75 107 4.0 @19' -Orange and tan sand; moist, dense 20.0 Total depth 20-feet -No seepage ,__ No caving -,__ -,__ -,__ 25.0 BORING LOG HETHERINGTON ENGINEERING, INC. 4615 Telescope Avenue Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8787.1 I FIGURE NO. 4 DRILLING COMPANY: Scott's RIG: Hollow Stem Auger DATE: 02/11/19 BORING DIAMETER: 8" DRIVE WEIGHT: 140Ib DROP: 30" ELEVATION: ' + -r,:i E-< r,:i ,-:i >-< -r,:i ,-:i p., E-< E-< o\O C/l -r,:i p., ~ 0 H C/l BORING NO. B-2 i:,.. ~ ::s 0 C/l r,:i .i: C/l .i: C/l i:,.. z r:,:; E-< ,-:i ::i:: C/l '-r,:i :::, z u u r,:i C/l Cl -E-< r,:i E-< :,::; > :,:: 4-l C/l E-< ,-:i C/l p., ,-:i H 0 >-< u H z H r,:i :::, r:,:; ,-:i r:,:; 0.. 0 0 0:::, Cl CQ Cl CQ Cl ~ ::s u C/l ~ SOIL DESCRIPTION ~ 0.0 TERRACE DEPOSITS: Orange brown slightly clayey to silty sand; -Xi moist , dense, well graded '-74 112 9.6 -'- -,_________I '-80/9" 113 6.6 @3' -Moist, medium dense -~ 5.0-I ..... 82 112 6.0 @5' -Dark orange brown sand; moist, dense -- -<---------- :X - - 10.0-<--------- 171/11" --108 4.8 @10' -Tan, black, and orange brown sand; moist, dense '- -'- -'- -'- 15.0-_I -75 107 4.3 @15' -Orange and light brown sand; moist, dense - Total depth 16-feet -No seepage ..__ No caving -..__ -..__ 20.0--- -'- -'- -'- -'- 25.u BORING LOG HETHERINGTON ENGINEERING, INC. 4615 Telesc~e Avenue Carlsbad, alifornia GEOTECHNICAL CONSULTANTS PROJECT NO. 8787.1 I FIGURE NO. 5 LABORATORY TEST RESULTS DIRECT SHEAR (ASTM: D 3080) Sample Location Angle of Internal Cohesion Remarks Friction (0 ) (pst) B-1 (@, 3' 30 100 Undisturbed soaked, consolidated, drained SULFATE TEST RESULTS (Cal Test 417) Sample Location I Soluble Sulfate in Soil(%) B-1 (@, 1 to 5' I 0.0530 EXPANSION INDEX (ASTM: D 4829 Sample Location Initial Compacted Final Expansion Expansion Moisture (%) Dry Moisture Index Potential Density (%) (pct) B-1 (@, 1 to 5' 9.0 113.6 14.8 0 Very low MAXIMUM DRY DENSITY/OPTIMUM MOISTURE CONTENT (ASTM: D 1557 A) Sample Location Description Maximum Dry Optimum Moisture Density (pct) B-1 (@, 1 to 5' Orange brown silty sand 127.5 Content(%) 10.0 Figure 6 Project No. 8787. I Log No. 20349