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Home My WebLink AboutCT 81-10; Carlsbad Research Center Phase II and III; Foundation Investigation; 1985-07-31July 31, 1985 - The ~011 Company - 7330 Engineer Road San Diego, California 92111 - Attention: Mike Dunnigan Job No. SD1425-00 Log No. 3529 SUBJECT : FOUNDATION INVESTIGATION Carlsbad Research Center Lots 33-37 Carlsbad, California ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Cartsbad, CA92009-4859 - References: 1. As-Graded Geotechnical Report Carlsbad Research Center, Phase II and III Carlsbad Tract No. 81-10 - - Carlsbad, California (Job No. 1162-10) 2. Supplemental Preliminary Geotechnical Investigation Carlsbad Research Center, Phase II and III Carlsbad, California (Job No. 1162-001 - Gentlemen: This report presents the results of our Preliminary Soils - Investigation at the subject site. Our investigation was performed in July, 1985, and consisted of field exploration, laboratory testing, engineering analysis of the field and laboratory data, and,the preparation of this report. - SCOPE OF SERVICES The scope of services provided during the preparation of this Preliminary Geotechnical Investigation include: A. Review of previous geologic and soils engineering reports; SUBSIDIARY OF IRVINE CONSULTING GROUP, INC. 6455 NANCY RIDGE DRIVE l SUITE 200 - SAN DIEGO, CA92121 l (619) 567-0250 - - The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 2 -- - - - - B. C. D. E. F. Subsurface exploration, drilling bucket borings to a maximum depth of 26-feet; Logging and sampling of exploratory borings to evaluate the geologic structure and to obtain bulk samples for laboratory testing; Laboratory testing of samples representative of those encoun- tered during the field investigation; Soils analysis of field and laboratory data, which provide the basis for our conclusions and recommendations; Preparation of this report and accompanying maps, and other graphics presenting our findings, conclusions, and recommendations. SITE DESCRIPTION The site consistsof Lots 33 through 37 in the Carlsbad Research Center (see Location Map, Figure 1). These lots are south of Rutherford Road surrounding Farnsworth Court. The total area is approximately 12 acres. The site has been previously rough graded under the observation and testing of this office. The results of our observation and testing were presented in Reference 1. Low slopes to a maximum height of approximately 5-feet exist between them. Lot 37 is a fill lot and Lot 34 a cut lot. Lots 33, 35 and 37 have cut fill transions which may pass beneath the building pads. There is a sparse cover of dry grasses and weeds and a landscaped berm lines the streets on which the lots are facing. - - The Koll Company July 31, 1985 PROPOSED DEVELOPMENT Job No. SD1425-00 Log No. 3529 Page 3 The proposed development consists of 12 buildings of concrete tilt-up construction with adjacent paved areas. Detailed foundation plans were not available at the time of this report. A foundation scheme of a combination of continuous and isolated pad footings with slab-on-grade floors is anticipated. Foundation design loads are estimated to be of the order of - 2 kips per lineal foot for continuous footings and 40 kips for isolated pad footings. - Grading for the site is expected to involve processing dry and loose surficial soils in building and parking areas, to provide - appropriate site drainage , and to mitigate the adverse effects of non-uniform bearing conditions and expansive soil conditions. FIELD EXPLORATION - .,. .Subsurface conditions were explored ,by .drilling bucket auger borings to depths of 3 to 26-feet. ..?Phe approximate locations of .- the borings are shown on the attached Plot Plan, Plate 1. The borings were drilled with a truck-mounted 30-inch diameter bucket - auger. Drilling of the test borings was supervised by our field engineer who logged the soils and obtained bulk and relatively undisturbed samples for laboratory testing. - - - - - - - - - - - -- .- -- -- - - - - - 0 2000 4000 I - ADAPTED FROM U.S.Q.S. 7.5 ENCINITAS (197S) AND SAN LUIS REY (1975) QUADRANQLE MAPS SCALE IN FEET - LOCATION MAP JOB NO.: DATE: JULY 1986 FIQURE: - 1425-00 1 SAN DIEQO SOILS ENQINEERINQ. INC. - - - - - - - - - .- - -. - .~ The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 4 LABORATORY TESTING A. Classification Soils were classified visually according to the Unified Soil Classification System. Classification was supplemented by index tests, such as Particle Size Analysis and Atterberg Limits. Moisture content and dry density determinations were made for representative undisturbed samples. Results of moisture-density determinations, together with classifications, are shown on the Logs of Borings, Figures 4 through 15. B. Particle Size Analysis. Particle size analyses were performed on representative samples of the site subgrade soils in accordance with ASTM: D 422-63. Test results are shown on Figure 16 through 19. C. Atterberg Limits Atterberg limits tests consisting of liquid limit in accordance with ASTM: D 423-66 and plastic limit in accordance with ASTM: D 424-59 were performed on representative samples of the on-site soils. The test results are presented on Figure 20. D. Expansion Expansion tests were performed on representative samples of the on-site soils remolded and surcharged under a 144 pound per square foot load in accordance with the Uniform Building Code Standard No. 29-2. The test results are summarized on Figure 21, Table I. - .- - - The Koll Company July 31, 1985 ,- - ,~. .- Job No. SDl425-00 Log No. 3529 Page 5 E. Maximum Density/Optimum Moisture Content The maximum dry density/optimum moisture content relationship was determined for a typical sample of the on-site soils. The laboratory standard used was ASTM: D 1557-18. The test result is summarised on Figure 21, Table II. F. Sulfate A sulfate test was performed on a representative sample of the on-site soils. The laboratory standard used was California 417 A. The test result is presented on Figure 21, Table III. G. R-Value - An R-value test was performed on a representative sample of the on-site surface soils. The laboratory standard used was ASTM: D 2844-75. The test results are summarized on Figureil, iable IV. - H. Direct Shear ._f Direct shear strength tests were performed on representative undisturbed and remolded (to 90 percent compaction) samples of the on-site soils. To simulate possible adverse field conditions, the samples were saturated prior to shearing. A saturating device was used which permitted the samples to absorb moisture while a constant load is applied. The tests results are presented on Figure 22. .- - - .- - - - - - - ,- The Koll Company July 31, 1985 Job No. S~1425-00 Log No. 3529 Page 6 I. Consolidation A consolidation test was performed on representative undisturbed samples of the underlying soils to help determine compressibility characteristics. The samples were saturated mid-way through the tests to simulate possible adverse field conditions. The test results are presented on Figures 23 through 26. SOILS ENGINEERING A. General The logs of borings, Figures 4 through 15, indicate that the predominant material at the site consists of Point Loma Formation bedrock with portions of the site covered with an overlay of compacted fill consisting of predominantly clayey silt. B. Fill Compacted fill was found in Bori‘ngs 1, 2, 7, 10, 11 and 12 to a maximum depth of 20-feet. The upper 12-inches(+) of the fill soils are dry and loose and will require processing. The fill soils are suitable to support additional compacted fill or structural loads, and is also suitable for reuse in compacted fill. The fill materials exhibit a high expansion potential. C. Bedrock (Point Loma Formation) The Point Loma Formation bedrock underlying the site is predominantly a siltstone. Intact bedrock is generally moist and stiff to very stiff. The bedrock materials exhibit a high expansion potential. It is suitable to support compacted fill or structural loads, and is also suitable for use in compacted fills. - - - .- - - The Koll Company July 31, 1985 D. Expansive Soils - Job No. SD1425-00 Log No. 3529 Page 7 The results of expansion tests conducted during the course of this investigation indicate that the on-site soils have a high expansion potential. The final evaluation of the expansion potential will be made after the completion of the grading. Expansion of near-surface soils could damage structures and exterior flatwork. Recommendations to mitigate the effect of expansive soils on proposed improvements are included in our recommendations and should be incorporated in project planning and design. E. Transition Lots A review of the site plan and Reference 1 indicates that future structures may straddle cut/fill transitions created as a result of previous grading. Such transitions are considered generally undesirable because of non-uniform bearing conditions resulting from different materials being exposed at finished grade. To mitigate the potential adverse effects of cut/fill transitions; overexcavation of the cut portion and replacement as compacted fill is recommended. F. Groundwater and Cavinq Groundwater or caving was not encountered in any of the exploratory borings. However, minor seepage was encountered in Boring 1 at a depth of approximately 12-feet below the existing ground. - The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 8 CONCLUSIONS AND RECOMMENDATIONS A. General - The proposed construction is feasible from a soils engi- neering standpoint. The grading and foundation plans should take into account the appropriate soils and engineering features of the site. The major constraints at the site are: (1) expansive soil conditions, and (2) non-uniform bearing conditions. B. Site Gradinq - - .~- - - 1. Site. The site should be cleared of existing weeds and grasses. Holes resulting from them removal of any buried obstructions which extend below finished site grades should be backfilled with compacted fill. 2. Preparation of Surface Soils The loose and dry surface soils (12"+) within the building area and to 5-feet beyond, and in areas to to paved with asphaltic concrete should be moisture conditioned and compacted to a minimum relative compaction of 90 percent. Prior to placing fill or asphaltic concrete, the exposed subgrade soils should be scarified to a depth of 8 to 12-inches, brought to near optimum moisture conditions and compacted to at least 90 percent relative compaction. - The Koll Company July 31, 1985 Job No. SDl425-00 Log No. 3529 Page 9 - .- .- - - - - - - .- 3. Compaction and Method of Filling Fill placed at the site should be compacted to a minimum relative compaction of 90 percent, based on ASTM Laboratory Test Designation D 1557-78. Fill should be compacted by mechanical means in uniform lifts of 6 to 8-inches in thickness. Rock fragments greater than 6-inches in maximum dimension should not be placed within the compacted fill. Fills should also be placed and all grading performed in accordance with the City of Carlsbad Grading Ordinance and the requirements of the Uniform Building Code. 4. Import Fill Material Any soils imported to the site for use as fill or subgrade materials should be predominantly granular and approved by the Soils Engineer prior to importing. Laboratory testing required !&:J!: a:-qrcoal of import sources may require 24 to 48 hours. The Soils Engineer should be notified of import locations a minimum of two (2) days prior to its proposed use. 5. Shrinkage, Bulking and Subsidence Shrinkage due to removal and recompaction of existing fill is expected to be negligible. Bulking of bedrock is expected to be 0 to 5 percent. Subsidence is expected to be on the order of O.l-foot overall. These are preliminary estimates which may vary with depth of removal, stripping loss, and field conditions at the time of grading. Shrinkage and subsidence figures are - _- -. - .- - - .- - - .~- - .- .- The Koll Company July 31, 1985 Job No. SD1425-00 Log NO. 3529 Page 10 considered to be rough estimates based on available geotechnical information and should be confirmed in the field during grading. 6. Transition Between Cut and Fill For any non-uniform bearing condition at a given building pad, we recommend that the cut portion be overexcavated to a minimum depth of 3-feet beneath the bottom of the deepest.footing or grade beam. The lateral extent of overexcavation should be 5-feet beyond the building line. 7. Remedial Gradinq The results of our testing indicate that on-site surficial soils exhibit a high potential for expansion. To mitigate the effects of expansion of these materials on at-grade slabs, two alternative methods are presented below: a. Moisture Conditioninq During grading, the upper 24-inches of fill soils within the building pad may be removed and replaced at 5 percent above optimum moisture content. This may eliminate pre-soaking in the slab area if the moisture content of the subgrade soils is maintained prior to placinq visqueen. If pre-soaking of slab subgrade soils is selected (see Section C.4) as the desirable alternative to mitigate the effects of expansive soils, this alternative may be neglected. .,- - .- .- ,- The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 11 b. Selective Gradinq The expansive potential of the on-site soils may be mitigated by selective grading. If this alternative is selected, we recommend that building areas be capped with a minimum of 2.5-feet of non-expansive (U.B.C. Expansion Index less than 201 soils. If pre-soaking of slab subgrade soils is selected (see Section C-4.) as the desirable alternative to mitigate the effects of expansive soils, this alternative may be neglected. C. Foundation and Slab Recommendations 1. General Our investigation indicates that the existing surface soils exhibit a high expansion potential. The following recommendations are provided for the design of footings and slabs based on this expansion potential of the soils presently at the site. These preliminary recommendations should be confirmed by additional expansion testing at the completion of fine grading. Our recommendations are considered generally consistent with the Standards of Practice. The implementation of these recommendations should serve to reduce the risk of distress resulting from expansive soil. The potential for favorable foundation performance can be further enhanced by maintaining uniform moisture conditions. -~ - - - ,- The Koll Company July 31, 1985 Job No. 501425-00 Log No. 3529 Page 12 The footing configurations and reinforcement recommenda- tions herein do not preclude more restrictive criteria by the governing agencies or by structural considerations. A Structural Engineer should evaluate configurations and reinforcement requirements for structural considerations. 2. Foundations The recommended type of foundation is conventional spread footings, either square or continuous. No footings should straddle a cut/fill interface. All footings for a given building should be founded either entirely in bedrock or entirely in compacted fill. a. Columns Columns may be supported on spread footings founded a minimum of 24-inches below lowest adjacent finish subgrade. Reinforcement should be based on structural loadings. b. Walls Exterior footings should be continuous and founded at least 24-inches below lowest adjacent finish grade. Reinforcement in exterior and interior footings should consist of a minimum of two No. 5 reinforcing bars, placed one at the top and one at the bottom of the footing. If the structure is to be supported on isolated spread footings, a moisture cut-off wall should be poured around the perimeter of the building to a depth of 24-inches below lowest adjacent finish subgrade. ..,. .- - The Koll Company July 31, 1985 Job No. SD1425-00 Log NO. 3529 Page 13 3. Slabs _- Slabs should be as designed by the Structural Engineer based on anticipated use and loading and based on a K-value (Subgrade Modulus) of 50 psi-inch and 150 psi-inch for on-site soils and select materials, respectively. Following general recommendations are provided as a guide based on the expansion potential of on-site soils and select materials. .- Slabs should be of 5-inch actual thickness reinforced with welded wire mesh located at mid-height supported on concrete chairs. Slabs should be provided with 4-inches of rounded gravel.or clean sand followed by a 6-mil "visqueen" (or equivalent) moisture barrier, The moisture barrier should be sealed at all splices and overlain by at least l-inch of clean sand. - _- - - - - If the building pad is capped with a minimum of 2.5-feet of non-expansive soils, slabs may be a nominal 4-inches thick, < Slabs shculd he underlain by a 6-mil visqueen moisture barrier. Due to the non-expansive nature of the select materials recommended, no recommendations for reinforcement in the slab areas is made. However, reinforcement may be required and advisable for structural considerations. 4. Pre-Soaking Beneath Slabs Slab subgrade soils should be soaked to at least 5 percent above optimum moisture content to a depth of 24-inches below slab subgrade prior to placement of concrete. The moisture penetration should be verified by the Soils Engineer prior to placing visqueen. .- .- .- .- - .- .- - - The Koll Company July 31, 1985 Job No. SDl425-00 Log No. 3529 Page 14 As an alternate to pre-soaking, remedial grading as recommended earlier (see Section B-7) may be elected. If remedial grading is selected , we recommend that slab suhgrade soils not be allowed to dry out. In order to maintain the desired moisture prior to placing concrete, periodic sprinkling may be necessary. If building pad is capped with a minimum of 2.5-feet of non-expansive select soils , pre-soaking is not required. However, areas to receive concrete should be thoroughly moistened prior to placing concrete. 5. Allowable Bearinq Pressure for Footings Footings may be d&signed for an allowable dead plus live load bearing pressure of 2,000 pounds per square foot with a one-third increase for short-term wind or seismic loads. Footings should have a minimum width of 12-inches.and, where located adjacent to utility trenches, should extend below a one-to-one plane pro,jected upward from the inside bottom corner of the trench. 6. Lateral Load Resistance Lateral loads against buildings may be resisted by friction between the bottom of footings and the supporting soils. An allowable friction coefficient of 0.25 is recommended. Alternatively, an allowable lateral bearing pressure equal to an equivalent fluid weight of 250 pounds per cubic foot acting against the footings may be used, provided the footings are poured tight against undisturbed soils. 7. Retaining Walls Cantilevered retaining walls may be designed in accordance with the following design criteria. The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 15 ..- - .- - .- -- Soil Pressure, Equivalent Fluid Pressure (P.C.F.) Cantilevered Walls Backfill Level 2:l Backfill Soil Type ___ Backfill Ascending On-site soils 60 Import Select Sands (Sand Equivalent greater than 30) 30 65 43 Walls subject to uniform surcharge loads should be designed for an additional uniform lateral pressure equal to one-third the anticipated surcharge pressure in the case of cantilevered walls. Wall design should also consider surcharge from any adjoining structures or traffic located within a zone defined by extension of an imaginary 1:l line-up from the level of the wall footing. To include the effects of additional ;G:ei;.l pressure caused by vehicle traffic, we recommend that retaining walls be designed to resist an additional uniform pressure of 125 pounds per square foot for a distance down the wall equal to the width of the driveway or traffic area behind the wall. Retaining wall footings should be founded at a minimum depth of 18-inches below lowest adjacent grade or at a depth that provides a minimum of 5 feet of horizontal distance between the face of any slope and the front toe - - - - .- .- _- .- - .- The Koll Company July 31, 1985 Job No. 501425-00 Log NO. 3529 Page 16 of the footing, whichever is deeper. Footings should be reinforced as recommended by the Structural Engineer. Flooding or jetting of backfill should not be permitted. Backfill placed behind the walls should be compacted to a minimum relative compaction of 90 percent as determined by ASTM Test Method D 1557-78. It should be noted that the use of heavy compaction equipment in close proximity to retaining structures can result in excess wall movement (i.e., strains greater than those normally associated with the development of active conditions), and wall pressures exceeding design values. In this regard, the contractor should take appropriate precautions during the backfill placement. If granular backfill is used, it should be capped with 2-feet of relatively impervious fill to seal the backfill and prevent saturation by run-off due to rainfall or irrigation. Appropriate backdrainage should .b:: designed by the Project Civil Engineer. Typical backdrain and backfill details are provided in the accompanying Figure 2. In addition, any building wall where wall retains earth we recommend that consideration be given to waterproofing the walls prior to placing the backfill. 8. Post-Tensioned Slabs As an alternative to conventional slabs and foundations, post-tensioned slabs may be used. Although typically more expensive, post-tensioned slabs are expected to perform better in expansive soil conditions. .,- .- - - - ,- .- .- - - MINIMUM H/2 hllNlMUM 2’ THICK ,MPE&IoUS SOIL COVER FILTER MATERIALS AROUND PERFORATED PIPE AND WEEPHOLES 4“ PERFORATED PIPE (PERFORATION DOWN) EMBEDDED IN A MINIMUM OF 3 CUBIC FEETOF FILTER MATERIAL (A) GRANULAR BACKFILL FILTER MATERIAL AROUND PERFORATEL PIPE AND WEEPHOLES FILTER MATERIAL PERCENT 4” PERFORATED PIPE SIEVE PASSING (PERFORATION DOWN) EMBEDDED IN A MINIMUM OF 3 CUBIC FEET OF FILTER MATERIAL 1” 100 314” 00-100 318’ 40-100 03) COHESIVE BACKFILL 4 25-40 30 5-15 50 o-7 205 o-3 TYPICAL RETAINING WALL BACKFILL AND DRAIN OETAILS 08 NO.: , 1425-00 DATE: JULY 1965 FIGURE: 2 - - - - - - - - - - - The Koll Company July 31, 1985 Job No. SD1425-00 Log NO. 3529 Page 17 a. Design Criteria Post-tensioned slabs should be designed by a Structural Engineer for a relatively uniform bearing over the slab area. The differential movement recommended for design purposes is a two percent gradient in lo-feet horizontal. b. Subqrade Treatment Post-tensioned siabs in living areas should be underlain by a lo-mil visqueen moisture barrier with 2-inches of clean sand placed between the slab and moisture barrier. The barrier should be sealed at all splices and care should be taken not to puncture the barrier during construction. C. Thickened Ed% Post-tensioned slabs should have a thickened perimeter edge extending at least 18-inches into the slab subgrade soils. 9. Expected Settlement If footings are supported by natural ground or compacted fill and are sized for the recommended bearing pressures, differential settlements are not expected to exceed l/4-inch. - _. _.. - -- -- _~._ - - - .,- - - .- - - The Koll Company July 31, 1985 Job No. SDl425-00 Log No. 3529 Page 18 D. Type of Cement for Construction The results of sulfate testing indicate that either type I or II cement may be utilised for concrete in contact with the subgrade soil. E. Drainage To enhance future site performance, it is recommended that all drainage be collected and directed away from proposed structures to disposal areas. For soil areas, we recommend that a minimum of 2 percent gradient be maintained. Due to the expansive nature of the on-site soils, it is important that drainage be directed away from foundations and that recommended drainage patterns be established at the time of fine-grading and maintained throughout the life of the structures. Property owners should be aware that altering drainage patterns, landscaping, the addition of patios, planters, and other improvements, as well as irrigation and variations in seasonal rainfall, aff affect subsurface moisture conditions, which in turn affect structural performance within expansive soil areas. F. Trench Backfill Utility trench backfill should be placed by mechanical compaction to a minimum of 90 percent of the laboratory maximum density. G. Paved Areas Areas to be paved with asphaltic concrete should be graded in accordance with the site preparation .- - - .- - - .- _- The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 19 recommendations given above. The following preliminary pavement sections are recommended based on an R-value of 6. Light Vehicles (T-1. = 4) 3-inches of asphaltic concrete placed in two lifts over 6-inches of untreated Class II aggregate base or 'I-inches of untreated Class III base (D.G.1 Driveways (T.1. = 5) 3-inches of asphaltic concrete placed in two lifts over 10.5-inches of untreated Class II aggregate base or 13..5-inches of untreated Class III base (D.G.) We recommend that the upper 8 to 12-inches of pavement subgrade soils should be scarified and moistenend to near optimum conditions.and compacted_t?,9F percent of the maximum density. Specifications for aggregate Class II base may be selected from Section 200-2 of the "Standard Specifica- tions for Public Works Construction" and should have an R-value of 78 or more. Specifications for Class III aggregate base may be selected from Section 400 2.3.2. of this reference, and should have a minimum R-value of 73 and a minimum sand equivalent of 30. We recommend that you require the Contractor or supplier to assure conformance with specifications. In addition, we - - The Koll Company July 31, 1985 Job No. SD1425-00 Log No. 3529 Page 20 recommend that verification testing be performed prior to placing base materials. It should be noted that verification testing may require 5 to 7 days. Asphalt concrete type and class should be as required by the project specifications. We recommend that the area within and around the trash enclosure be paved with Portland Cement Concrete. P.C.C. paving should be a minimum 5-inches thick, reinforced with 6x6x10/10 welded wire mesh. Subgrade soils should be prepared as recommended above for asphalt paving. Concrete paving should be provided with appropriate contraction joints at a maximum interval of 20-feet and divided into a nearly square panels as possible. H. Footinq Observations All footing excavations should be observed by the Soils Engineer prior to placing reinforcing steel and concrete. I. Observation of Gradinq Grading should be performed under the testing and observation of the San Diego Soils Engineering, Inc. J. Lifting of Tilt-Up Walls Extreme care and caution should be exercised during construction at the time tilt-up walls are lifted into place. It should be recognized that heavy crane loads, the temporary knife-edge loading of slabs by walls as they are being lifted, etc., can crack slabs. Also, impact loads during wall placement can dislodge and displace pad footings. The Koll Company July 31, 1985 Job No. SD1425-00 Log NO. 3529 Page 21 SUMMARY -.- As foundation and grading plans are completed, they should be forwarded to the Soils Engineer for review for conformance with - the intentions of these recommendations. .- .~- - - .- - - .- - - - - - ,- - - - ,- The Koll Company July 31, 1985 Job No. 591425-00 Log No. 3529 Page 22 LIMITATIONS OF INVESTIGATION Our investigation was performed using the degree of care and skill 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 report. The samples taken and used for.testing and the observations made are believed representative of the entire project; however, soil and geologic conditions can vary significantly between borings. As in most major projects, conditions revealed by excavation may be at variance with preliminary findings. If this occurs, the changed conditions must be evaluated by the Project Soils Engineer and Geologist 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 architect and engineer for the project and incorporated into the plans, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. - The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they be due to natural processes or the works of man on this or adjacent properties. In addition, - -~, _- - - - - Very truly yours, SAN DIEGO SOILS ENGINEERING, INC. Tara S. Sikh, R.C.E 35454 Manager, Engineering Services TSS/tm Enclosures: Location Map,,Fiqure 1; Plot Plan, Plate 1; Retaining Wall Details, Figure 2; Logs of Borings, Figures 3 through 15; - Laboratory Test Data, Figures 16 through 26. The Koll Company July 31, 1985 Job NO. SD1425-00 Log NO. 3529 Page 23 changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. The opportunity to be of continued service is appreciated. If you have any questions, do not hesitate to call. Distribution: (6) Addressee - SUBSURFACE EXPLORATION - - - The subsurface exploration consisted of 10 borings drilled to a maximum depth of 26-feet. Logs of borings are presented herein as Figures 2 through 6. An explanation of Logs of Borings terminology is presented in Figure 3. California sampler resistance blow counts were obtained by driving a 2.625-inch I.D. sampler with a 1,400-pound hammer dropping through a 12-inch free fall. The blows per foot recorded on the boring logs represent the number of blows that were required to drive the sampler 12-inches. Boring log notation for the California sampler is indicated below: I4 California Sampler - - - - - - - .- - - - - - - - - - - -, - CLEAN SANDS SILTS AND CLAYS UOV~DL~(TT~~~~~ANSOS SILTS AND CLAYS LIOLQDLI?~~TSGFIEATERTI~ANJ~% HIGHLY ORGANIC SOILS Pt Peat and other highly organic soils. DEFINITION OF TERMS U.S. STAWARD SERIES SIEVE CLEAR SQUARE SIEVE OPENINGS 200 40 10 4 314’ 3’ 12’ SILTS AND CLAYS SAND I GRAVEL COBBLES EOUL!JERZ FINE MEDIUM COARSE FINE COARSE - -_- GRAIN SIZES .- SAND&GRAVELS AND BLOWS/FOOT’ CLAYS AND NON-PLASTICS SILTS PLASTIC SILTS STRENGTH’ SLOWSlFOOTt VERY LOOSE o-4 VERY SOFT 0 - 114 o-2 LOOSE 4 - 10 SOFT 114 - 112 2-4 MEDIUM DENSE lo- 30 MEDIUM STIFF 112 - , N-6 STIFF l-2 5- 16 DENSE 30 - 50 VERY STIFF 2-4 I6 - 32 VERY DENSE OVER 50 HARD OVER 4 OVER 32 J RELATIVE DENSITY CONSISTENCY t Number at blows of 140 Pound hammer talllng 30 inches to drive a 2 inch 09. (l-3/8 inch Lo3 r&t 6wca (ASTM O-1586). ‘UnCOntkmd compressive strength in tonwsg. 11. as determined by laboratory testing or approximated by the standard wnetration test (ASTM D-1588). pocket penetrometer. twvane, or visual observation. KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM D-2487) xl NO: DATE: FIGURE: 1425-00 July 1985 3 ..a..^-^^ ^^..^ _..^ ..---... - .~~~ -i - - - -- - - - - - - - - - - - IATE OBSERVED: - - METHOD OF DRILLING: Bucket Auqet- 1402-lb. Hammer .OGGED BYI& GROUND ELEVATION: LOCATION: i= E % 2 :,t: Y 0 mw ulz i$ BORING NO. a-!- 5 0 5 % < : $ w- E $6 2: SOIL TEST ii $ g !i$ ; : d 5 gi - ti$ : 0 zg DESCRIPTION 0 6 -r+ C@PKTEC FILL: Brwm olive orange Clayey Expansim Test SILT, waist, stiff 6X 21.4 103.3 5- 3x 19.9 101.1 BM reddish orarp clayey SILT, mist, stiff o- 2x 12.7 115.3 Reddish orange, silty SW, very mist, mxliun dense At i2' minor seepap ‘5- 9x i?EimX 3-q oiive btwn tiY!jTK, 17.6 108.2 waist, stiff 4 1 ! 0. -. m.al &pth 16’ &y=$$ 12’ t@grwr&ater !5- lo- 15- ,o- OS NO.: 1425-W 1 LOG OF BORING FIGURE: 4 .~- - - - - - - - - - - - - - IATE OBSERVED: 07-01-85 METHOD OF DRILLING: Bucket Auger 1402-lb. Mnrer .OGGED BYrmktikm GROUND ELEVATION: LOCATION: BORING NO. 2 DESCRIPTION SOIL TEST -f”fl 2x CCPPACTED FILL: Olive grc?j brcxvn, clayey Etpansim Test slcr, slightly mist, stiff Maximm Density Attertxx~ Limits Sulfate 5- 5x 18.6 105.5 hpansim Test -Mi BEGRXK: Olive bmn grey orange SILTSTCNE, mhard IO- l5- 9x.x 19.5 105.3 Total depth 11’ lb caving Fbgrcuddater r 10- ! / !5- IO- l5- IO- 08 NO.: 1425-00 1 LOG OF BORING FIGURE: 5 - - .- - - - - - - - - - - - - FATE OBSERVED: 07-01-85 METHOD OF DRILLING: Bucket Am I 402-lb. &r .OGGED BY:-&%-GROUND ELEVATION: LOCATION: i: ; ii 2 6 ii !!i b 0 : 2 s UJz gi El+ w- BORING NO.3 F s 3 ma 2 z: ;: 0 Em ?I g 2; SOIL TEST E : 6 iis %I : 0 i$ $! DESCRIPTION 0 -M-d BECRXK: Grey orange olive bm SILTSTOE, drytomist, hard q / 37 7 101.5 Eccmnic refusal Total depth 3' 5- No caving Fbgrnm+waQr IO- IS- 10- !5- IO- l5- 107 OS NO: 1425-m ) LOG OF BORING FIGURE: 6 - - - - - .- - - - - - - - - IATE OQSERVED: - - METHOD OF DRILLING: Eixket Awe 1,4W-lb t!dhr .OGGED By:& GROUND ELEVATION: LOCATION: BORING NO. 4 r 0 1 1 1 DESCRIPTION SOIL TEST -M-l BMXCCK: Grey orange olive brown SILTSTCAE, Consolidation Test %lx>c 18.2 107.5 -hard Direct 3-m Test J- Total depth 4’ i-b caving lb grcmkater o- ‘5- 20- 26- 30- 35- 10- ,nc1 un. I”?C M I I ne -I- nrrn*.,rr ISIP;IIPC. --- .--.. I‘KPW I L”” VC ~“nll”” . .““.,L. 7 SAN DIEGO SOll s FNclUFFnIUl? ahI1 .- - - - - - - - - - - - - - - - IATE OBSERVED: 07-01-85 METHOD OF DRILLING: Bucket Auge 1,4CQ-lb. t&w .OGGED By: MsA GROUND ELEVATION: LOCATION: BORING NO. 5 SOIL TEST DESCRIPTION -Q-l BEDROCK: Grange grey brchn olive CtiYSTO<E, Expansion Test 14x dry to waist, hard FZtfherg Limits 18.5 109.7 Sulfate 5- Total depul 4’ No caving N3gtrundwater io- 25- 30- 35- IO- ,r,m un. , “.-.- “,? I * An A.- .-.A-...e. IsTln,I~C. n #VW I.“.. lW!J-UJ I LUO Vt BUMINQ rlY”nL c) SAN lNFc20 SC,,, S FU~=~UFCC~IUCX IUP : , .- .- - - - - - - .- - - - - - IATE OBSERVED: 07-01-85 METHOD OF DRILLING: Wket Auge 1,4-W-lb. &r .OGGE F i; i 5 t: 0 LL F (0 ii 2 ; o-- -I+ 5- -- o- 5- o- !5- IO- I5- ,o- OS NC ROI - “ij <I- !z ou 5Z 2 - 17.t 3.5 - 3rd - L ii II- ::: JZ L2 $ 12. 2% - IATION: LOCATION: BORING NO. 6 DESCRIPTION BECfXCK: orarpa grey bm olive SILTSTCNE, dry to mist, hard Total depth 6’ No caving lb gtwrx&ater LOG OF BORING SOIL TEST kpansim Test FIGURE: 9 )ATE OBSERVED: 07-01-85 METHOD OF DRILLING: Bucket ,4.&w I -. timer .OGGED q y:ee&4..- GROUND ELEVATION: LOCATION: i= ti BORING NO.7 k E SOIL TEST % DESCRIPTION 0 -tti FILL: Grange grey olive bm clayey SILT, Cmsolidatim Test 4x dryto mist, stiff Direct Shear Test 19.0 104.5 J- 2 20.2 101.7 M-l BEDROCK: Orarq grey olive bm SILTSTONE, rmist,hard IO- * 3, 5 102.0 Total depth 11' Lb caving Fbgrwr&ater 15- !5- IO- 15- .o- OB NO.: 1425~co 1 LOG OF BORING [FIGURE: 10 SAN DIEGO SOILS ENGINEERING. 1,,1( .- .- - - - - - - - - - - - - - - - .- - - - - - - - - - - - IATE OBSERVED: METHOD OF DRILLING: Bucket Homer 1.400-lb. thmw .OGGED 8 1425-w 1 LOti OF BOHING rwunt: SAN DIEM, SO,,~S FNRlNFFPlM~ IF.,,- .- - - .- - - - - - - - - IATE OBSERVED: 07-01-85 METHOD OF DRILLING: Bucket Auqe 1,&X-lb. t&w ,OGGED BY:LGROUND ELEVATION: LOCATION: F :, i 2 g E Y k ; i? 2! % lug Zb on. 5+ w- BORING NO. m?m E z 2 ?$ z !y$ o> g g?;: 5 52 2: i 2 DESCRIPTION 0 6 if 2 ‘Z gz -0 -Mi BEDROCK: Grey bmm olive SILTSTNE, 9x dry,& hard 17.1 109.5 SOIL TEST 5- o- 14 x 17.8 112.3 Total depth 6’ lb caving It3 grwrdwater 5- “4 ’ ‘S- io- ,5- o- AP un. a”-? ^_ I “I ..“.. ~IYLY.KJ 1 I An -I- “em,.In L”” ut CI”nlNU IEI,aI.aC. .n . ,“““L ,L SAN DIFGO SC,,, S i=NOIU~,=~IUR IUC - - - ,- - - - - - - - - - - - IATE OBSERVED: 07-02-a METHOD OF DRILLING: Bu&etAiger , - tmer IED BY: IATION: LOCATION: BORING NO. 10 - DESCRIPTION -1 I LO, - 2 it E i .O- 5- 10. 15. 20. 25, 30. 35. 40. iE = Y % 2 t: 2 - 7 - - ROI - ug :+ $I 52 ‘2 - - 6.C 1 El - g u- :c :g Eg - \ 19.7 FILL: Olive grey brmn clayey SILT, dry mxiiun stiff Expansion Test BEDRXK: Olive grey brown SILTSTOM,dry to naist,rd xl.5 - - !4.t - - Total depth 6' Fb caving Nsgm~rhater B NO.: 1425-W LOG OF BORING SOIL TEST FIGURE: , ,- -- ,- .- - - - - - - - - .- .- - - ATE OBSERVED: 07-02-85 METHOD OF DRILLING: Bucket Auger 1,4C&lb. mr OGGED Bk&GROUND ELEVATION: LOCATION: ? z 5 5 : iTI Y 0 mw 0. us Zb 0.2 BORING NO. -!!- 5 0 LL a_r x is gg ;: !5- w- r cc i7l 3 I?4 ;g 2; SOK TEST c 2 0 om ?I : A5 2 :g tig? ?ig DESCRIPTION 0 d -M-l FILL: Grange grey bn%n olive clayey SILT, Consolidatim Test noist, stiff Expansion Test 3x 18.9 103.6 5- 3x 18.5 100.7 Atterix~ Limits -lw ' BEDGCCK: Orarge grey brcwn olive SILTSTONE, noist,hard o- r+' RX Grange bran sandy clayey SILTSTONE, mist, 140 II-EM hani Total depth 11' lb caving N3grwfddater 5- ) !‘I I o- 6- o- 5- o- -- ..- I_____-_ cm No.: 1425-00 1 LOG OF BORING I-l”“Rlz ,IJ s*N DIEGO SCIILA ENCIUFFnIU* lhlf. ,~- - .- - - - - - - - - - - - - MTE OBSERVED: 07-02-85 METHOD OF DRILLING: hcket Auge lb t&w , -. D EJ’ .OGGEl - i: z ti 2 k z E iE ! r: d ,o-- -M- M = !3 ?i ;: 5 5 - 5 x - x - 2 - EL - ii: ‘2 L c u) : - ‘ATION: LOCATION: BORING NO. 12 DESCRIPTION - I t g; Olive brwn grey clayey SILT, moist, %pansim Test S- FILL: Bnwn orange silty CLAY, moist, - tiff -ai Expansion Test Cmsolidatim Test Atterberg Limits IO- 15- 1.1 3.3 - 5.1 7.1 20-- -n 2.2 3.6 13.C 1. 1 1.1 17. 19.2 fg L --I BEDECK: Wy orange brown clayey SILTSTONE slightly noist, hard KU-lb. hamer 25- Total depth 26’ lb caving tb grwctdater 30- 35- 40- JOB N r LOG OF SOIL TEST I FIGURE: ,5 SAN DIEGO SOILS ENGINEERING. INC. I I I I I I I I I I I I I I I / / SAND GRAVEL SILT CLAY COARSE MEDIUM FINE CiEVE SIZES-U.S. STANDARD 3/4" l/2” 114" 4 10 20 i: r, 100 200 100 100 00 so SO SO 70 70 z 80 60 2 :: :: z 58 •I 50 50 •I 2 z : z: f 40 40 z 0 D 30 30 20 20 IO 10 0 0 1010 1:o 0:1 .dl .Obl PARTICLE SIZE-MILLIMETERS BORING NO. DEPTH (FEET) SYMBOL LIQUID LIMIT PLASTICITY INDEX CLASSIFICATION 2 1 56 24 MH I I I I I I I I I I I I I I I I I ORAVEL lxxr SAND MEDIUM I SILT FINE I I CLAY I .c-r.,.YL I I SIEVE SIZES-U.S. STANDARD 3/4" 112" 114" 4 10 20 40 100 200 100 so 70 z 60 E i!! + 50 2 E 2 40 30 20 10 0 CI!II ! ! d.1 PARTICLE SIZE-MILLIMETERS 40 z !a 30 I- 20 10 0 .OOl BORING NO. DEPTH (FEET) SYMBOL LIQUID LFMlTi ?LASTICITY JNDEX CLASSIFICATION 5 3 54 28 CH I I I I I I I I I I I I I I I I I I I I / / I I SAND GRAVEL COARSE 1 MEDIUM FINE I SILT CLAY SIEVE SIZES-U.S. STANDARD 3/4" 112" 114" 4 10 20 40 100 200 100 100 90 90 80 SO 70 70 ii 60 60 zl : : z z •I 50 50 -( 2 :! z.i z z 40 40 0 2 30 30 20 20 10 10 0 0 Id.0 I.‘0 0:1 .dl .Obl PARTICLE SIZE-MILLIMETERS BORING NO. DEPTH (FEET) SYMBOL LIQUID L’WIT PLASTICITY INDEX CLASSIFICATION 11 6 68 29 MH I I I I I I I I I I I I I I I I / SAND GRAVEL SILT CLAY COARSE MEDIUM FINE SIEVE SIZES-U.S. STANDARD 3/4” 112” 114” 4 IO 20 40 100 200 : 60 ii f 50 I 70 I I, IIIItiI 1 I 11 11 1 Ij / I I E z 40 cl 0 I 1 10.0 1.0 0.1 .Ol .Ol PARTICLE SIZE-MILLIMETERS BORING NO. DEPTH (FEET) SYMBOL LIQUID LIMIT PLASTICITY INDEX CLASSIFICATION 12 a 84 42 CH 60 : i! 50 5 2 z 40 z - - .- - - - - - - - - - - - PLASTICITY CHART X i z z G F v) u 2 IO. 0 10 20 30 40 50 60 70 SO SO 100 LIQUID LIMIT (%) SAMPLE NATURAL LIOUID PLAS- SYMBOL ““,“d”” DEPTH WATER LIMIT TICITY ‘N”o”s;~o” LIQUIDITY UNIFIED SOIL (FEET) ‘ONTENT ($1 INDEX &EVE INDEX CLASSI- (%I (%) (%I (%I FICATION SYMBOL A 2 1 65 24 33 MH 0 5 3 64 20 85 CH 0 11 6 58 20 MH 0 12 0 54 42 CH ATTERBERG LIMITS 38 NO.: ~ a.._ A.. [DATE: . . . . __ .-_- IFIGURE: _- ,423-v” I~ ~~~- JULY 1885 I 20 SAN DIEGO SOILS ENGINEERING. INC - .- TABLE I - - - - - ,- - - - - - RESULTS OF EXPANSION TEST(S) (U.B.C. Method 144 psf) I I I Test Expansion Location Index B-l @ 1 91 B-5 @ 3 91 B-6 8 1 B-8 @ 1 1'0: B-10 @ 1 96 B-11 @ 6 112 B-12 @ 1 106 B-12 @ 9 102 Potential Expansion High High High High High High High High TABLE II MAXIMUM DENSITY/OPTIMUM MOISTURE RELATIONSHIP (ASTM: D-1557-70) Maximum Optimum Test Dry Density Moisture Location (pcf) Content (%) B-2 @ 1 110 17.0 TABLE III RESULTS OF SULFATE TESTS Test Location B-2 @ 1 B-5 @ 3 % Soluble Sulfate .0757 .0625 TABLE IV R-VALUE Test Location R-Value B-2 @ 1 6 Job No. SDl425-00 Date: July ,985 Figure: 21 - .~ - - - -.. - - - - - - - - - - - 00 NO.: ,,+~+oo NORMAL LOAD (PSF) SHEARING STRENGTH TEST FIGURE: 22 SAN DIEGO SOILS ENGINEERING, INC I I I I I I I I I I I I I I I ! I ti m CONSOLIDATION (%) I EXPANSION (%) s s .? .? .m .m .? .? .” .” .: 0 .: 0 P P I I ,oDb 0 0 ,oob 0 0 .- .- .P .P 0 0 0 0 0 0 0 0 g 0 g 0 200 200 300 300 400 400 500 500 1000 1000 2000 2000 3000 3000 4000 4000 5000 5000 10000 10000 20000 20000 30000 30000 40000 40000 50000 50000 100000 100000 I I ! I I I I I I I I I I I I / ~ I CONSOLIDATION (96) I EXPANSION (%) I I I I I I I I I I I I I I I I CONSOLIDATION (96) I EXPANSION (%I .-J .PJ .? .P - .- .F .P 0 0 0 0 g b 0 0 0 0 I I I I I I I I I I I I I I I I I I I I I - I I I I I I I I I I I I I CONSOLIDATION (%) I EXPANSION (%) 200 300 400 500 1000 2000 3000 4000 5000 10000 20000 30000 40000 60000 I I I I I I I I I I I I I I I I I 1 I I I I 100000 I I I I I I I I I