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Home My WebLink AboutCDP 16-06; BAPTIE RESIDENCE; LIMITED GEOTECHNICAL INVESTIGATION; 2016-01-29,.,. ' I 0 0 EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 (619) 258-7901 Fax 258-7902 Ken & Sandra Baptie P. 0. Box 1221 Woodinville, Washington 98072 Subject: Limited Geotechnical Investigation Proposed Single-Family Residence 5070 Carlsbad Bou]evard Carlsbad, California 92008 Dear Mr. & Mrs. Baptie: January 29, 2016 Project No. 16-l 126F2 In accordance with your request, we have perfonned a limited geotechnical investigation at the subject site to discuss the geotechnical aspects of the project and provide recommendations for the proposed development. Our investigation has found that the proposed building pad is underlain by topsoil and slopewash to a maximum depth of approximately 2.5 feet below existing grade. These soils were underlain by dense terrace deposits to the explored depth of IO feet. It is our opinion that the development of the proposed residence is geotechnicaUy feasible provided the recommendations herein are implemented in the design and construction. Should you have any questions with regard to the contents of this report, please do not hesitate to contact our office. Respectfully submitted, ItECORD COPY _ _:i(.G lP { =,-/ rr _ L----------------------·--· RECEIVED JUL 2 6 2016 LAND DEVELOPMENT ENGINEERING P'ft a 1 7 I 177 , ')W, 0 0 KEN & SANDRA BAPT/EI CARLSBAD BOULEVARD PROJECT NO. /6-1 /26F2 TABLE OF CONTENTS INTRODUCTION .............•.........••........••.••..••••.•••••.........•.•..•.•••••.••.•.••.•..••.••.•..•.•.•......••.....••...••••••.•••••..•..••........ 3 SCOPE OF SERVICES ......................................................................................................................................... 3 SITE DESCRIPTION AND PROPOSED CONSTRUCTION ........................................................................ 3 FIELD INVESTIGATION AND LABORATORY TBSTING ....................................................................... .4 GEOLOGY ............................................................................................................................................................ 4 Geologic Setti~g ......................................................................................... , ....•.....•....•.....•..•••.••...•..•....... 4 Site Stratigraphy ............................................................................................................................ , ..... , ............. 4 SEJSMICJTY ................................................ , ........................................... , .................................................................... 5 Regional Seis1nicity ......................................................................................................................................... 5 Seismic Analysis ................................................................................................................................................. 5 2013 CBC Seismic Design Criteria ........................................................................................................... 6 Geologic Hazard Assesstnent .......................................................................................... , ....................... 6 OEOTECJ--INJCAL EVALUATION ..................................................................................................................... 7 Compressible Soils .......................•..•...................••................................... , ............................................... 7 Expansive Soils ................................................................................................................ , .......•....•.......... 7 Groundwater ....................................................... , ...................................................................................... 8 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................ 8 CLBARING AND GRUBBJNG, .......................................................................................................................... 8 FOUNDATIONS AND SLABS ................................. , ........................................................................................ 8 SBITLEMENT ., ................................................................................................................................................... 9 PRBSATURATION OF SLAB SUBGRA.D8 ...................................................................................................... 9 RETAINING WALLS ......................................................................................................................................... 9 TEMPORARY SLOPES .......................................................... ~ ........................................................................ IO TRENCH BACKFILL ................. : ....................................................................... , ............................................... 10 DRAINAGE ............................................................................ , ...................................................................•....... 10 FOUNDATION PLAN REVIEW ......................•.....•..................•..•..•....•..........................•.••••...................•... ,. I I LIMITATIONS OF INVESTIGATION ......................................................................................................... 11 ADDJTJONAL SERVICES .......................•.....................................................................•.•...•...•..•... ,., ............. 12 PLATES Plate I-Location of Exploratory Boreholes Plate 2 -Summary Sheet (Exploration Boreholes and Boring) Plate 3 -USCS Soil Classification Chart PAGE L-1, LABORATORY TEST RESULTS .............................................................................................. 14 REFERENCES .................................................................................................................................. , ......... , ....... 15 2 ., • 0 KEN & SANDRA BAPTIEI CARLSBAD BOULEVARD PROJECT NO. 16-1 /26F2 INTRODUCTION This is to present the findings and conclusions of a limited geotechnical investigation for a proposed two-story, single-family residence over a partial basement to be located at 5070 Carlsbad Boulevard, in the City of Carlsbad, California. The objectives of the investigation were to evaluate the existing soils conditions and provide recommendations for the proposed development. SCOPE OF SERVICES The following services were provided during this investigation: 0 Site reconnaissance and review of published geologic, seismological and geotechnical reports and maps pertinent to the project area 0 Subsurface exploration consisting of three (3} boreholes within the limits of the proposed area of development. The boreholes were logged by our Staff Geologist. 0 Collection of representative soil samples at selected depths. The obtained samples were sealed in moisture-resistant containers and transported to the laboratory for subsequent analysis. 0 Laboratory testing of samples representative of the types of soils encountered during the field investigation 0 Geologic and engineering analysis of the field and laboratory data, which provided the basis for our conclusions and reconµnendations 0 Production of this report, which summarizes the results of the above analysis and presents our findings and recommendations for the proposed development SITE DESCRIPTION AND PROPOSED CONSTRUCTION The subject site is a rectangular-shaped residential lot located on the east side of Carlsbad Boulevard, in the City of Carlsbad, California. The property, which encompass an area of approximately 6,180 square feet (] 03, X 60,) is vacant with an approximately 8-foot high cut slope descending to Carlsbad Boulevard. The building pad slopes gently to the west. Vegetation consisted of grass and a few trees. Site boundaries include Carlsbad Boulevard to the west and similar residential developments to the remaining directions. The preliminary plans prepared by Wright Design of Carlsbad, California indicate the proposed construction will include a single-family residence. The structure wiJI be two-story, wood-framed over a partial basement and founded on continuous footings with slab-on-grade floors. 3 0 0 KEN&SANDRABAPTIEICARLSBADBOULEVARDPROJECTNO. /6-l/26F2 FIELD INVESTIGATION AND LADORA TORY TESTING On January 14, 2016, three (3) boreholes were excavated to a maximum depth of approximately JO feet below existing grade with a hand auger. The·approximate locations of the boreholes are shown on the attached Plate No. 1, entitled "Location of Exploratory Boreholes". A continuous Jog of the soils encountered was recorded at the time of excavation and is shown on Plate No. 2 entitled "Summary Sheet". The soils were visually and texturally classified according to the filed identification procedures set forth on Plate No. 3 entitled "USCS Soil Classification". Following the field exploration, laboratory testing was performed to evaluate the pertinent engineering properties of the foundation materials. The laboratory-testing program included moisture and density, particle size analysis and expansion index tests. These tests were performed in general accordance with ASTM standards and other accepted methods. Page L-1 and Plate No. 2 provide a summary of the laboratory test results. GEOLOGY Geologic Setting The subject site is located within the southern portion of what is known as the Peninsular Ranges Geomorphic Province of California. The geologic map pertaining to the area (Reference No. 6) indicates that the site is underlain by Pleistocene marine terrace deposits (Qt). Site Stratigraphy The subsurface descriptions provided are interpreted from con<Jitions exposed during the field investigation and/or inferred from the geologic literature. Detailed descriptions of the subsurface materials encountered during the field investigation are presented on the exploration logs provided on Plate No. 2. The following paragraphs provide general descriptions of the encountered'soil types. Topsoil Topsoil is the surficial soil material that mantles the ground, usually containing roots and other organic materials, which supports vegetation. Topsoil was observed in all boreholes with a thickness of approximately 12 to J 8 inches. It consisted of dark brown, silty sand that was moist, loose and porous in consistency with some organics (roots and rootlets). Slopewash (Osw) Slopewash was encountered under the topsoil with a thickness of approximately 12 inches. It consisted of light brown, silty sand that was dry to moist and loose in consistency. 4 --KEN & SANDRA BAPTIEI CARLSBAD BOULEVARD PRO.JECT NO. /6-l /26F2 Marine Ten·ace Deposits (Qt) Marine terrace deposits were observed below the topsoil layer. They generally consisted of reddish brown, silty sand that was moist and medium dense to dense in consistency. SEISMICITY Regional Seismieitt Generally, Seismicity within California can be attributed to the regional tectonic movement taking place along the San Andreas Fault Zone, which includes the San Andreas Fault and most paralJel and subparallel faults within the state. The portion of southern California where the subject site is located is considered seismicalJy active. Seismic hazards are attributed to groundshaking from earthquake events along nearby or more distant Quaternary faults. The primary factors in evaluating the effect an earthquake has on a site are the magnitude of the event, the distance from the epicenter to the site and the near surface soil profile. According to the Fault-Rupture Hazard Zones Act of 1994 (revised Alquist-Priolo Special Studies Zones Act), quaternary faults have been classified as "active" faults, which show apparent surface rupture during the last 11,000 years (i ,e., Holocene time). "Potentially-active" faults are those faults with evidence of displacing Quaternary sediments between 11,000 to 16,000 years old. Seismic Analysis Based on our evaluation, the closest known "active" fault is the Rose Canyon Fault located approximately 4 miles (6.5 kilometers) to the east. The Rose Canyon Fault is the design fault of the project due to the predicted credible fault magnitude and ground acceleration. The Seismicity of the site was evaluated utilizing the 2008 National Seismic Hazard Maps from the USOS website and Seed and Idriss methods for active Quaternary faults within the regional vicinity. The site may be subjected to a Maximum Probable Earthquake of 6.9 Magnitude along the Rose Canyon fault, with a corresponding Peak Ground Acceleration of 0.45g. The maximum Probable Earthquake is defined as the maximum earthquake that is considered likely to occur within a 100-year time period. The effective ground acceleration at the site is associated with the part of significant ground motion, which contains repetitive strong-energy shaking, and which may produce structural deformation. As such, the effective or "free field" ground acceleration is referred to as the Repeatable High Ground Acceleration (RHGA). It has been determined by Ploessel and Slosson ( 1974) that the RHGA is approximately equal to 65 percent of the Peak Ground Acceleration for earthquakes occurring within 20 miles of a site. Based on the above, the calculated Credible RHGA at the site is 0.29g. 5 r I ht ' , 1 t t 0 0 KEN & SANDRA BAPTJEI CARLSBAD BOULEVARD PROJECT NO. /6-/ /26F2 2013 CBC Seismic Design Criteria A review of the active fault maps pertaining to the site indicates the location of the Rose Canyon Fault Zone approximately 6.5 km to the east. Ground shaking from this fault or one of the major active fauJts in the region is the most likely happening to affect the site. With respect to this hazard, the site is comparable to others in the general area. The proposed residential structure should be designed in accordance with seismic design requirements of the 2013 California Building Code or the Structural Engineers Association of California using the following seismic design parameters: Site Class D Table 20.3-1/ ASCE 7, Chapter 20 Mapped Spectral Acceleration For Short Periods, 1.J73g Figure 1613.3.1(1) Ss Mapped Spectral Acceleration For a I-Second Period, S1 Site Coefficient, F1 Site Coefficient, F y Adjusted Max. Considered Earthquake Spectral Response Acceleration for Short Periods, SMs Adjusted Max. Considered Earthquake Spectral Response Acceleration for I-Second Period, SM1 5 Percent Damped Design Spectral Response Acceleration for Short Periods, Sos 5 Percent Damped Design Spectral Response Acceleration for I-Second Period, S01 Geologic Hazard Assessment Ground Rupture 0.451g Figure 1613.3.1(2) 1.031 Table 1613.3.3(1} 1.549 Table 1613.3.3(2) 1.209g Equation 16-37 0,699g Equation J 6-38 0.806g Equation 16-39 0.466g Equation 16-40 Ground rupture due to active faulting is not considered likely due to the absence of known fault traces within the vicinity of the project; however, this possibility cannot be completely ruled out. The unlikely hazard of ground rupture should not preclude consideration of "flexible" design for on-site utility lines and connections. Liquefaction Liquefaction involves the substantial loss of shear strength in saturated soils, usually sandy soils with a loose consistency when subjected to earthquake shaking. Based on the consistency of the underlying terrace deposits, it is our opinion that the potential for liquefaction is very low. 6 --. KEN & SANDRA BAPTIEICARLSBAD BOULEVARD PROJECT NO. /6-/ l26F2 Landsliding There is no indication that Jandslides or unstable slope conditions exist on or adjacent to the project site. There are no obvious geologic hazards related to landsliding to the proposed development or adjacent properties. Tsunamis and Seiches The site is not subject to inundation by tsunamis due to its elevation. The site is also not subject to seiches (waves in confined bodies of water). GEOTECHNICAL EVALUATION Based on our investigation and evaluation of the collected infonnation, we conclude that the proposed construction is feasible from a geotechnical standpoint provided the recommendations provided herein will be properly implemented during structural development. In order to provide a unifonn support for the proposed structure, footings should be excavated into the dense terrace deposits. The new foundations may consist of reinforced continuous and/ or spread footings with reinforced slabs. Recommendations and criteria for foundation design are provided in the Foundation and Slab recommendations section of this report. Compressible Soils Our field observations and testing indicate Jow compressibility within the dense terrace deposits, which underJie the site. However, Joose topsoil and slopewash were encountered to a maximum depth of approximately 2.5 feet below surface grades. These soils are compressible. Due to the potential for soil compression upon Joading, remedial grading of these soils, including overexcavation and recompaction will be required unless footings are extended to the dense terrace deposits. Following implementation of the recommendations presented herein, the potential for soil compression resulting from the new development has been estimated to be low. The low-settlement assessment assumes a well-planned and maintained site drainage system. Expansive Soils An expansion index test was perfonned on a representative sample of the terrace deposits to detem1ine volumetric change characteristics with change in moisture content. An expansion index of 5 was obtained which indicate a very low expansion potential for the foundation soils. 7 17'!1 0 0 KEN & SANDRA BAPTIEICARLSBAD BOULEVARD PROJECT NO. 16-1 /26F2 Groundwater Static groundwater was not encountered to the depths of the boreholes. The subject site is located at an elevation of approximately 55 feet above Mean Sea Level. We do not expect groundwater to affect the proposed construction. Recommendations to prevent or mitigate the effects of poor surface drainage are presented in the Drainage section of this report. CONCLUSIONS AND RECOMMENDATIONS The following conclusions and recommendations are based upon the analysis of the data and information obtained from our soil investigation. This includes site reconnaissance; field investigation; laboratory testing and our general knowledge of the soils native to the site. The site is suitable for the proposed residential development provided the recommendations set forth are implemented during construction. CLEARING AND GRUBBING The area of the proposed construction should be cleared of vegetation and deleterious materials. Vegetation and debris from the clearing operation should be properly disposed of off-site. The area should be thoroughly inspected for any possible buried objects, which need to be rerouted or removed prior to construction. All holes, trenches, or pockets left by the removal of these objects should be properly backfilled with compacted fill materials. Our field investigation indicates that dense terrace deposits underlie the site at shallow depths. These soils will be adequate for the support of the proposed structure without detrimental settlement. However, for slab support in the main floor area, we recommend overexcavation and recompaction of the upper 2 feet of subgrade. Foundation excavations should be observed by our representative to verify competent bearing soils. FOUNDATIONS AND SLABS a. Continuous and spread footings are suitable for use and should extend to a minimum depth of 24 inches below the lowest adjacent grade for the proposed two-story structure over basement. Continuous footings should be at least 18 inches in width and reinforced with a minimum of four #4 steel bars; two bars placed near the top of the footings and the other two bars placed near the bottom of the footings. Continuous footings for the main floor may be 18-inch deep and 15-inch wide and reinforced as above. Isolated or spread footings should have a minimum width of 24 inches. Their reinforcement should consist of a minimum of #4 bars spaced 12 inches on center (each way) and placed horizontally near the bottom. The minimum reinforcement recommended is based on soil characteristics and is not intended to supersede the structural engineer requirements. b. Interior concrete floor slabs should be a minimum 4 inches thick. Reinforcement should consist of #3 bars placed at 16 inches on center each way within the middle third of the slabs by supporting the steel on chairs or concrete blocks "dobies". The slabs should be underlain by 2 inches of clean sand over a 10-mil visqueen moisture barrier, The effect of concrete shrinkage will result in cracks in virtually all-concrete slabs. To reduce the extent of shrinkage, the concrete should be placed at a 8 --KEN & SANDRA BAPTIEICARLSBADBOULEJIARDPROJECTNO. /6-l/26F2 maximum of 4-inch slump. The minimum steel recommended is not intended to prevent shrinkage cracks. Actual slab thickness and reinforcement may be designed by the project structural engineer using a coefficient of subgrade reaction of 250 pci. c, Where moisture sensitive floor coverings are anticipated over the slabs, the J 0-mil plastic moisture barrier should be underlain by a capillary break at least 2 inches thick, consisting of coarse sand, gravel or crushed rock not exceeding 3/4 inch in size with no more than 5 percent passing the #200 sieve. d. An allowable soil bearing value of 2,000 pounds per square foot may be used for the design of continuous and spread footings at least 12 inches wide and founded a minimum of 12 inches into the dense terrace deposits as recommended in the 2013 California Building Code, Table 1806.2. This value may be increased by 400 psf for each additional foot of depth or width to a maximum value of 6,000 lb/ft2. e. Lateral resistance to horizontal movement may be provided by the soil passive pressure and the friction of concrete to soil. An allowable passive pressure of 250 pounds per square foot per foot of depth may be used. A coefficient of friction of 0.35 is recommended. The soils passive pressure as well as the bearing value may be increased by 1/3 for wind and seismic loading. SETTLEMENT Since footings for the proposed structure are anticipated to be supported by the dense terrace deposits, total and differential settlement should be within acceptable limits. PRESATURA TION OF SLAB SUBGRADE Because of the granular characteristics of the subgrade soils, presoaking of subg1·ade prior to concrete pour is not required. However, subgrade soils in areas receiving concrete should be watered prior to concrete placement to mitigate any drying shrinkage, which may occur following foundation excavation. RETAINING WALLS Cantilevered retaining walls should be designed for an "active" lateral earth pressure of 35 psf/ft (35 pcf EFP) for approved granular backfill and level backfill conditions. Cantilever waJls subject to unifom1 surcharge loads should be designed for an additional unifonn lateral pressure equal to one- third (1/3) the anticipated surcharge pressure. Restrained walls such as basement walls should be designed utilizing an "at-rest" earth pressure of 60 psf/ft (60 pcf EFP) for approved granulRr and level backfill. Restrained walls subject to W1iform surcharge loads should be designed for an additional uniform lateral pressure equal to one-half ( J /2) the anticipated surcharge. For earthquake motions, additional lateral pressures of 26 and 39 pcf (EFP) may be applied for non restrained and restrained conditions respectively using an inverted triangular distribution if required. 9 0 0 KEN & SANDRA BAPTIEI CARLSBAD BOULEVARD PROJECT NO. /6-/ J26F2 Soil design criteria, such as bearing capacity, passive earth pressure . and sliding resistance as recommended under the Foundation and Slab recommendations section, may be incorporated into the retaining wall design. Footings should be reinforced as recommended by the structural engineer and appropriate back drainage provided to avoid excessive hydrostatic wall pressures. As a minimum we recommend a fabric-wrapped crushed rock and perforated pipe system. At least 2 cubic feet per linear foot of free- drainage crushed rock should be provided. The remaining wall backfill should consist of approved granular material. This fill material should be compacted to a minimum relative compaction of 90 percent as determined by ASTM D-1557 test method. Flooding or jetting of backfill should not be permitted. Granular backfill should be capped with 18 inches (minimum) of relatively impervious fill to seal the backfill and prevent saturation. It should be noted that the use of heavy compaction equipment in close proximity to retaining structures can result in wall pressures exceeding design values and corresponding wall movement greater than that associated with active or at-rest conditions. In this regard, the contractor should take appropriate precautions during the backfill placement. TEMPORARY SLOPES For the excavation of the basement, foundations and utility trenches, temporary vertical cuts to a maximum height of 4 feet may be constructed in natural soils. Any temporary cuts beyond the above height constrah1ts should be shored or further )aid back following a 1 : I (horizontal to vertical) slope ratio. OSHA guidelines for trench excavation safety should be implemented during construction. TRENCH BACKFILL Excavations for utility lines, which extend under structural areas should be properly backfilled and compacted. Utilities should be bedded and backfilled with clean sand or approved granular soil to a depth of at least one foot over the pipe. This backfill should be uniformly watered and compacted to a fim1 condition for pipe support. The remainder of the backfill should be on-site soils or non~expansive imported soils, which should be placed in thin lifts, moisture-conditioned and compacted to at least 90% relative compaction. DRAINAGE Adequate measures should be undertaken after the structure and other improvements are in place, such that the drainage water within the site and adjacent properties is directed away from the foundations, footings, floor slabs and the tops of slopes via rain gutters, downspouts, surface swales and subsurface drains towards the natural drainage for this area. A minimum gradient of 2 percent is recommended in hardscape areas. In earth areas, a minimum gradient of 5 percent away from the structure for a distance of at least 10 feet should be provided. If this requirement cannot be met due to site limitations, drainage can be done through a swale in accordance with Section 1804.3 of the 2013 California Building Code. Earth swales should have a minimum gradient of 2 percent. Drainage should be directed to approved drainage facilities. Proper surface and subsurface drainage will be required to minimize the potential of water seeking the level of the bearing soiJs to --KEN & SANDRA BAPT/EICARLSBAD BOULEVARD PROJECT NO. /6-l /26F2 under the foundations, footings and floor slabs, which may otherwise result in undermining and differential settlement of the structure and other improvements. FOUNDATION PLAN REVIEW Our firm should review the foundation plans during the design phase to assure conformance with the intent of this report. During construction, foundation excavations should be observed by our representative prior to the placement of forms, reinforcement or concrete for conformance with the plans and specifications. LIMITATIONS OF INVESTIGATION Our investigation was performed using the skill and degree of care ordinarily exercised, under similar circumstances, by reputable soils engineers and geologists practicing in this or similar localities. No other warranty, expressed or implied, is made as to the conclusions and professional advice included in this repo11. This report is prepared for the sole use of our client and may not be assigned to others without the written consent of the client and ECSC&E, Inc. The samples collected and used for testing, and the observations made, are believed representative of site conditions; however, soil and geologic conditions can vary significantly between exploration trenches, boreholes and surface exposures. As in most major projects, conditions revealed by construction excavations may vary with preliminary findings. If this occurs, the changed conditions must be evaluated by a representative of ECSC&E and designs adjusted as required or alternate designs recommended. This report is issued with the understanding that it is the responsibility of the owner, or of his representative to ensure that the information and recommendations contained herein are brought to the attention of the project architect and engineer. Appropriate recommendations should be incorporated into the strnctural plans. The necessary steps should be taken to see that the contractor and subcontractors carry out such recommendations.in the field. The findings of this report are valid as of this present date. However, changes in the conditions of a property can occur with the passage of time, whether they are due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholJy or partially by changes outside of our control. Therefore, this report is subject to review and should be updated after a period of two years. 11 0 0 KEN & SANDRA BAPTIEI CARLSBAD BOULEVARD PROJECT NO. /6-I I 26F2 ADDITIONAL SERVICES The review of plans and specifications, field observations and testing under our direction are integral parts of the recommendations made in this report. If East County Soil Consultation and Engineering, Jnc. is not retained for these services, the client agrees to assume o.ur responsibility for any potential claims that may arise during construction. Observation and testing are additional services, which are provided by our finn, and should be budgeted within the cost of development. Plates No. 1 through 3, Page L-1 and References are parts of this report. 12 ...... ,-..,----,u •c,MU U1'i....,.,.U" ....... , ... , .• -""···"'· ~--·' ..... ,.-.. I .... 11, ........ . ,.,., .. ...,. __ ,1,,, ..... ............... ' ... ,.~, a ••••• EAST COUNTY SOIL CONSULT A TJON & ENGINEERING, INC. 1092S HARTI..EY RD., SUITE I, SANTEE. CA 92071 (619) 258-7901 Pax (619) 258-7902 . 'I I "'-· . .. ,.:::: ..... , .. DEPTH Surface J.O' 1.5 2.01 2.S' 3.0' 3,S' S.O' DEPTI-I Surface I.S 2.5' 3.0' 5.0' DEPTH Surface 1.5 2.5' 3.0' l0.0' 0 0 KEN & SANDRA BAPTJEI CARLSBAD BOULEVARD PROJECT NO. /6-/ J 26F2 PLATENO,2 SUMMARY SHEET BOREHOLE NO. l SOIL DESCRIPTION TOPSOIL dark brown, moist, loose, porous, silty sand with rootlets '' ,, '' " '' ,, SLOPEWASH (Qsw) light brown, dry to moist, loose, silty sand ,, ,, '' '' '' TERRACE DEPOSITS (Qt) reddish brown, moist, medium dense, silty sand becomes dense " " " " " bottom of borehole, no caving, no groundwater borehole backfilled J/14/16 BOREHOLE NO. 2 SOIL DESCRIPTION TOPSOIL " dark brown, moist, loose, porous, silty sand with rootlets SLOPEWASH (Qsw) light brown, moist, loose, silty sand TERRACE DEPOSITS (Qt) reddish brown, moist, medium dense, silty sand becomes dense bottom of borehole, no caving, no groundwater borehole backfilled 1/14/16 BOREHOLE NO. 3 SOIL DESCRIPTION TOPSOIL dark brown, moist, loose, porous, silty sand with rootlets SLOPEWASH (Qsw) light brown, moist, loose, silty sand TERRACE DEPOSITS (Qt) reddish brown, moist, medium dense, silty sand becomes dense bottom of borehole, no caving, no groundwater borehole backfilled 1/14/16 y y I I I .3 122.2 y Y = DRY DENSITY IN PCF M = MOISTURE CONTENT IN % 13 M 8.4 4.8 4.2 M 7.2 5.3 M . . --MAJOR DIVISIONS SYMBOL DESCRIPTION GW WELL ORADED ORA VELS OR ORA VEL• SAND MIXTURES LITll.E OR NO FINES GRAVELS GP POORLY ORADED ORA VELS OR ORA VEL-SAND (MORETHAN½ OFCOARSE MIXTURES. UTILE OR NO FINES FRACTION GM SILTY ORA VELS, ORA VEL-SANO-SILT MIXTURES >NO.4SIEVE COARSE SIZE) GC GRAINED SOILS CLAVEY ORA VELS, ORA VEL-SANO.CLA Y MIXTURES (MORE THAN ½ OF SOIL SW > NO. 200 SIEVE SIZE) WELL ORADED SANDS OR ORA VELLY SANDS, LITrLE OR NO PINES SANDS SP POORLY GRADED SANDS OR ORA VELLY SANDS, (MORETHAN½ OFCOARSE LmLE OR NO PINES FRACTION SM SILTY SANDS, SILT-SAND MIXTURES <NO.4SIEVE SIZE) SC CLAYEY SANDS, SAND-CLAY MIX11JRES • ML INORGANIC SILTS AND VERY FINE SANDS, ROCK SILTS& FLOUR. SILTY OR CLAVEY PINE SANDS OR CLAVEY SILTS Willi SLIGHT PLASTICITY CLAYS CL INOROANIC CLAYS OF LOW TO MEDIUM LIQUID LIMIT PLASTICITY, ORA VELLY CLAYS, SANDY CLAYS, <SO SILTY Cl.A VS, LEAN CLAYS FINE GRAINED OL SOILS ORGANIC SILTS AND OROANIC SILTY CLAYS OF LOW PLASTICITY (MORE THAN ½ OF SOIL MH < NO. 200 SIBVE SIZE) INORGANIC SILTS, MlCACEOUS OR DlATOMACEOUS SILTS& FINE SANDY OR SILTY son.s ELASTIC SILTS CLAYS CH INORGANIC CLAYS OF HIOH PLASTICITY, FAT LIQUID LIMIT >SO CLAYS OH ORGANIC Cl.A YS OF MEDIUM TO HIOH PLASTICITY, ORGANIC SD.TY CLAYS. ORGANIC SD.TS HIGHLY ORGANIC SOILS Pt PEAT AND OTHER HIOHL Y ORGANIC SOILS CLASSIFICATION CHART (UNIFIED SOIL CLASSIFICATION SYSTEM) CLASSIFICA. TION RANGE OF GRAIN SIZES U.S. STANDARD GRAIN SIZE IN SIEVE SIZE MILLIMETERS BOULDERS Above 12 Inches Above305 COBBLES 12 Inches To 3 Inches 305 To 76.l GRAVEL 3 Inches lo No. 4 76.2 to 4.76 Coarse 3 Inches to ¾ Inch 76.2 to 19.1 Fine ¾ Inch to No. 4 19.l to4,76 SAND No. 4 to No. 200 4. 76 to 0.074 Coarse No. 4 to No. 10 4.76 to 2.00 Medium No. 10 to No. 40 2.00 to 0,420 Fine No. 40 to No. 200 0.420 lo 0.074 SILT AND CLAY Below No. 200 Below0.074 GRAIN SIZE CHART EAST COUNTY SOIL CONSULTATION AND ENGINEERING, INC. 10925 HARTLEY ROAD, SUITE "I" SANTEE, CALIFORNIA 92071 U.S.C.S. SOIL CLASSIFICATION E ,. !! I: i 10 LIGUII Lllllf ILLI ............. PLASTICITY CHART KEN & SANDRA DAPTIEICARLSBAD BOULEVARD PROJECT NO. J6-l/26F2 lNJTlAL MOISTURE CONTENT(%) 8.8 .. PAGE L-1 LABORATORY TEST RESULTS EXPANSION INDEX TEST (ASTM D4829) SATURATED MOISTURE CONTENT(%) 15.9 INITJAL DRY DENSITY EXPANSION (PCF} INDEX 110.1 5 PARTICLE SIZE ANALYSIS (ASTM D422) -·: U,S. Standard ~~ ·. . ·; ~ :Sieve Size I" 1/2" 3/8" #4 100 #8 99 #16 99 100 #30 91 91 #50 44 41 #100 20 20 #200 13 14 uses SM SM 14 ' ' LOCATION BH-1@3.5' 100 93 44 19 13 SM --KEN & SANDRA BAPTIEI CARLSBAD BOULEVARD PRO.JECT NO, 16-1 J 26F2 REFERENCES I. "2013 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2,,, Published by International Code Council. 2. "Geologic Map of the San Diego 30' x 60' Quadrangle, California", by Michael P. Kennedy and Siang S. Tan, 2008. 3. "Geotechnical and Foundation Engineering: Design and Construction'', by Robert W. Day, 1999. 4. "1997 Uniform Building Code, Volume 2, Structural Engineering Design Provisions", Published by International Conference of Building Officials. 5. "Maps of Known Active Faull Near-Source Zones in California and Adjacent Portions of Nevada to be used with 1997 Uniform Building Code", Published by International Conference of Building Officials. 6. "Geologic Maps of the Northwestern Part of San Diego County, California", Department of Conservation, Division of Mines and Geology, by Siang S. Tan and Michael P. Kennedy, 1996. 7. "Bearing Capacity of Soils, Technical Engineering and Design Guides as Adapted from the US Army Corps of Engineers, No. 7", Published by ASCE Press, 1994. 8. ''Foundations and Earth Structures, Design Manual 7.2", by Department of Navy Naval Facilities Engineering Command, May 1982, Revalidated by Change 1 September 1986. 9. "Ground Motions and Soil Liquefaction during Earthquakes", by H.B. Seed and I.M. Idriss, 1982. 15