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HomeMy WebLinkAboutSDP 98-23; Carlsbad Pacific Center Phase II and III; Soils Report Preliminary; 1987-09-15- - - - - - - - - - - - - - P&5 2.87. 43 PRELIMINARY GEOTECHNICAL INVESTIGATION, CARLSBAO PACIFIC CENTER, PHASES II AND III, CARLSBAD, CALIFORNIA September 15, 1987 Project No. 8841485-04 ENGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive CarlsbaQ CA 920094859 ENGfNEERlNG DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive Carlsbad CA92009-4859 Prepared for: CALIBER DEVELOPMENT, INC. 701 Palomar Airport Road, Suite 250 Carlsbad. California 92009 Attention: Mr. Jim Bosler, President LEIGHTON and ASSOCIATES - September 15, 1987 Project No. 8841485-04 - - -. - .- - - - - - TO: Caliber Development, Inc. 701 Palomar Airport Road, Suite 250 Carlsbad, California 92009 ATTENTION: Jim Bosler, President SUBJECT: Preliminary Geotechnical Investigation, Carlsbad Pacific Center, Phases II and III, Carlsbad, California In accordance with your authorization, we conducted a preliminary geotechnical investigation of the subject site. The accompanying report presents a summary of our investigation and provides conclusions and recommendations relative to the proposed site development. If you have any questions regarding our report, please do not hesitate to contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Stan Helenschmidt, RCE 36570 Chief Engineer RLW/SRH/RW/lj Distribution: (3) Addressee (2) The Falick/Klein Partnership Attention: Mr. Wayne Marchand (3) Lusardi Construction Attention: Mr. Chris Tallon 542) AVENlDA ENCINAS, SUITE C. CARLSBAD, CAL,FORN,A 92008 (619) 931.9953 lR”lNE . WESTLA.KE,“ENTVRA . DlAMOND BA”,WA,.N”T . S&N BERNARDIN”!RIYERSIDF . SAN Dir PALMDESERT . S~NT~CLn”,T~/“nllNCln . CA”,~TBA~ . TEMf?C,1IL*~s~.&N’H” C,%L,FORNI& 8841485-04 - - -~ - - - - - - - - - - 1.0 2.0 3.0 4.0 TABLE OF CONTENTS Section INTRODUCTION 1.1 Scope of Services 1.2 Site Description 1.3 Proposed Development 1.4 Subsurface Exploration and Laboratory Testing SOIL AND GEOLOGIC CONDITIONS 2.1 Regional Geology 2.2 Site Geology 2.2.1 Marine Terrace Deposits (Map Symbol - Qt) 2.2.2 Undocumented Artificial Fill (Map Symbol - Afu) 2.3 Geologic Structure 2.4 Ground Water 2.5 Faulting 2.6 Seismicity 2.7 Liquefaction CONCLUSIONS RECOMMENDATIONS 4.1 Earthwork 4.1.1 Site Preparation 4.1.2 Removal of Compressible Soils 4.1.3 Excavations 4.1.4 Fill Placement and Compaction 4.1.5 Trench Excavation and Backfill 4.2 Drainage 4.3 Foundation and Slab Design Considerations 4.3.1 Foundations 4.3.2 Floor Slabs 4.3.3 Moisture Conditioning :: :: 11 4.4 Exterior Concrete Flatwork 12 4.5 Lateral Earth Pressures and Resistance 12 4.6 Type of Cement for Construction 13 4.7 Corrosivity 13 4.8 Pavement Sections 13 4.9 Construction Observation 14 - -. - - - - -~ .- - - - 8841485-04 TABLE OF CONTENTS (continued) LIST OF ILLUSTRATIONS Fiqures Figure 1 - Site Location Map Figure 2 - Fault Location Map Table Table 1 - Seismic Parameters for Active Faults Plate Plate 1 - Geotechnical Map 2 Rear of Text Rear of Text In Pocket APPENDICES Appendix A - References Appendix B - Boring Logs Appendix C - Sampling and Laboratory Testing Procedures and Laboratory Test Results Appendix D - General Earthwork and Grading Specifications - - - - - LEIGHTON and ASSOCIATES ,NCORPORATED ,.- - - - - - - - - 1.0 INTRODUCTION This report presents the results of our geotechnical investigation at the subject site. The purpose of this investigation was to identify and evaluate the geotechnical conditions present on the site and to provide conclusions and geotechnical recommendations pertinent to the proposed development. In addition, this report incorporates the findings, conclusions , and recommendations provided in our reports prepared for the existing Phase I portion of the development (Appendix A, References 16 and 19). 1.1 Scope of Services Our scope of services for this investigation included the following: l Review of available pertinent, published and unpublished geologic literature (Appendix A). o Aerial photographic analysis to assess the general geology and possible faulting (Appendix A). o Field reconnaissance of the existing onsite geotechnical conditions. l Subsurface exploration consisting of the excavation, logging, and sampling of five large-diameter borings in the vicinity of the proposed commercial buildings and adjacent proposed parking areas (see Plate 1, Geotechnical Map). Logs of the borings are presented in Appendix 8. l Laboratory testing of representative undisturbed and bulk soil samples obtained form the subsurface exploration program (Appendix C). e Compilation and analysis of field data and laboratory test results. e Preparation of this report presenting our findings, conclusions, and recommendations with respect to the proposed development. LEIGHTON and ASSOCIATES lNCORPc.RATED - - - - - - - - - - - - - - - - - - .- CALIBER/PAC CEN PHASE II & Ill CARLSBAD, CALIFORNIA Figure 1 0 2000 4000 SITE LOCATION MAP Project No. 884 1485-04 LEIGHTON ,nd ASOClATES scale feet t*c0”Po”ATED - - .- - - - - - - -.- - - - - - 8841485-04 1.2 Site Description The irregularly-shaped project site encompasses approximately 4 acres of vacant, relatively flat-lying land. The site is situated along the east side of Avenida Encinas, approximately 260 feet south of Palomar Airport Road in Carlsbad, California (see Figure 1). More specifically, the site is bounded by Avenida Encinas to the west, an existing commercial/industrial development to the south, an on-ramp to Interstate 5 to the east, and the existing Phase I portion of the Carlsbad Pacific Center to the north. Existing development on the site apparently consists of various underground utilities near the northern and southern perimeters of the site. Based on the results of our analysis of sequential pairs of aerial photographs (Appendix A) and our subsurface exploration (Appendix 8). the site appears to have been previously used for agricultural purposes. In addition, the majority of the site was used to stockpile soils excavated during the grading of Phase I of the existing Carlsbad Pacific Center development (Appendix A, Reference 14). Prior to the stockpiling operation, surface vegetation was stripped and removed off the site. The stockpile was subsequently utilized as fill material in the widening of the west side of Avenida Encinas adjacent to Palomar Airport Road (Appendix A, Reference 12). A relatively thin veneer of stockpile fill soil mantles much of the subject site (Plate 1. in pocket). A discussion of these soils is provided in Section 2.2.2 of this report. Surface drainage, in general, is toward the west along the present gradient of the site. 1.3 Proposed Development Preliminary project drawings provided by the Falick/Klein Partnership, Inc. (Appendix A, Map Reference 2) indicate that the proposed development will consist of two three-story, commercial/office buildings with associated plaza area, surface parking, and underground utilities (Plate 1). According to the preliminary project drawings, the building on the western portion of the site is designated as Phase II. Likewise, the building on the eastern portion of the site is designated as Phase III. It is our understanding that the proposed buildings will utilize slab-on-grade construction and will be founded on continuous and spread footings. Preliminary structural loads were not provided to this office at the time of the preparation of this report. Therefore, structural loads are assumed to be typical for this type of construction. It is anticipated that only minor grading will be necessary to bring the site to finish grades (see Section 4.1). Because of the intended office use of the proposed structures, large vibratory equipment is not anticipated within the buildings. -3- LE,GHTON and ASSOCIATES lNCc.RPORlTED - .- - - - 8841485-04 1.4 Subsurface Exploration and Laboratory Testing Our subsurface exploration program consisted of drilling five large-diameter borings to depths of 16 to 18 feet in the vicinity of the proposed commer- cial buildings and adjacent parking areas of the proposed site development (Plate 1). The purpose of this program was to evaluate the physical characteristics of the onsite soils pertinent to the proposed development. Borings were down-hole logged and sampled by a geologist from our firm. Sampling consisted of obtaining bulk samples and relatively undisturbed (drive cylinder) samples at frequent intervals. Logs of the borings are presented in Appendix B. Subsequent to logging and sampling, the borings were backfilled. Appropriate laboratory testing was performed on representative samples to evaluate the density, strength, grain size, expansive, and chemical charac- teristics of the subsurface soils. A discussion of the laboratory tests performed and a summary of the laboratory test results are presented in Appendix C. Moisture and density test results are provided on the borings logs (Appendix B). - - - - - - - - -4- LElGHTON and ASSOCIATES ,NCORPORATED 8841485-04 - - - - - - - - - - - 2.0 SOIL AND GEOLOGIC CONDITIONS 2.1 Regional Geology The subject site is situated in the coastal section of the Peninsular Range Province, a California geomorphic province with a long and active geologic history throughout southern California. Through the last 54 million years, the area known as the "San Diego Embayment" has undergone several episodes of marine inundation and subsequent marine regression. This has resulted in a thick sequence of marine and nonmarine sediments deposited on rocks of the southern California batholith with relatively minor tectonic uplift of the area. 2.2 Site Geology Based on our subsurface exploration (Appendix B), aerial photographic analysis, and review of pertinent geotechnical literature (Appendix A), the bedrock unit underlying the site consists of sedimentary, Pleistocene-aged, marine terrace deposits. ~Surficial units noted mantling. These terrace deposits included undocumented fill associated with the former stockpile on the site and agricultural topsoil. The site-specific geology is depicted on the Geotechnical Map, Plate 1. A brief description of the geologic units encountered on the site is presented below. 2.2.1 Marine Terrace Deposits (Map Symbol - Qt) The Quaternary-aged marine terrace deposits, as encountered during our investigation, predominantly consisted of sand with local interbeds of sandy clay to clayey silt. The sands consisted of red-brown and gray-brown, damp to moist, medium dense to dense, slightly silty to silty, fine- to medium-grained sand. The sands were found to be locally very friable. The sandy clay to clayey silt interbeds were observed to be gray-brown, moist to very moist, moderately stiff to stiff, ranging in thickness from 2.5 to 6 feet. A zone of agricultural topsoil and weathered terrace material, ranging in thickness from approximately 3 to 4 feet, was observed mantling the majority of the site. This material generally resembled the marine terrace deposits it was derived from with the exception of a slightly higher clay content . These soils appear to have been disturbed as a result of previous plowing of the site. 2.2.2 Undocumented Artificial Fill (Map Symbol - Afu) Undocumented fill soils blanket portions of the site (Plate 1). The undocumented fill soils represent residual stockpile soils ranging in thickness from 1 to 2 feet. -5- LElOHTON and ASSOCIATES INCc.RCORATEO - - 8841485-04 2.3 Geologic Structure Our subsurface exploration indicates that the marine terrace deposits on the site were generally massive with no apparent structure. Pertinent geotech- nical literature indicates the sedimentary formational soils in the vicinity are generally flat lying. No major folding of the sedimentary units are known or expected to exist at the site. - .- - - - - .- - - - - - - 2.4 Ground Water NO ground water was encountered during our subsurface exploration. Based on the results of our previous investigation for the existing Phase I portion of the Carlsbad Pacific Center (Appendix A, Reference 19), the ground water table beneath the site is anticipated to be on the order of 20 to 30 feet below existing grades. 2.5 Faulting A review of available geologic literature and aerial photographs pertaining to the subject site indicates that there are no known active faults tran- secting the property. Further, there was no evidence of faulting encountered during our investigation. The nearest active regional faults are the Coronado Banks fault zone, located offshore approximately 21 miles southwest of the site, and the Elsinore fault, located approximately 22 miles northeast of the site. The nearest potentially active fault is the offshore extension of the Rose Canyon fault located approximately 5.5 miles to the west. Figure 3 indicates the location of the site in relationship to known major faults in the San Diego region. 2.6 Seismicity The seismic hazard most likely to impact the subject site is ground shaking following a large earthquake on one of the major active regional faults. Table 1 indicates probable seismic events that could produce ground shaking at the study area. Included in Table 1 are the distances to the faults, maximum credible and probable earthquakes, and the expected peak horizontal bedrock accelerations. The Elsinore fault is the most likely to affect the site with ground shaking should an earthquake occur on the fault. A maximum probable event on the Elsinore fault could produce a peak horizontal bedrock acceleration of about 0.139. The effects of the seismic shaking may be mitigated by adhering to Uniform Building Code or state-of-the-art seismic design parameters of the Structural Engineers Association of California. - -6- LEIGHTON and ASSOCIATES INCORPORATED - 8841485-04 2.7 Liquefaction - - - Liquefaction and dynamic settlement of soils can be caused by strong vibratory motion due to earthquakes. Both research and historical data indicate that loose, saturated, granular soils are susceptible to liquefac- tion and dynamic settlement, while the stability of silty clays and clays is not adversely affected by vibratory motion. Liquefaction is typified by a total loss of shear strength in the affected soil, thereby causing the soil to flow as a liquid. This effect may be manifested by excessive settlements and sand boils at the ground surface. .- - Based on the relatively dense nature of these materials as observed in our subsurface investigation and depth of ground water. it is our professional opinion that the onsite Quaternary terrace deposits do not have a sig- nificant potential for liquefaction. The onsite fill soils are not considered liquefiable due to their generally fine-grained nature and lack of a permanent ground water table within the fill soils. - - - - - - - - -7- LElGHTON and ASSOCIATES ,NCORPORATED ..,.,._I .,... ‘,. ., ..._., “.., .,i,, ,., - 8841485-04 - 3.0 CONCLUSIONS - Based on the results of our preliminary geotechnical investigation of the site, it is our opinion that the proposed development is feasible from a geotechnical .- standpoint, provided the following conclusions and recommendations are incor- porated into the project plans and specifications. The following is a summary of the geotechnical factors which may effect develop- - ment of the site. b - 0 - a - 0 - l - l - l - b - - - - Potentially compressible fill soils and agricultural topsoils mantle the subject site. These soils are not considered suitable for structural loads in their present condition. Remedial grading measures such as removal and recompaction will be necessary to mitigate this condition beneath settlement- sensitive structures (Section 4.1.2). Based on laboratory testing and visual classification, the Pleistocene terrace deposits on the site generally have a relatively high shear strength and possess a low to high expansion potential. Special foundation and slab design considerations will be required should highly expansive soils exist within 4 feet of slab subgrade elevations (Section 4.3). Active faults are not known to exist on or in the vicinity of the site. The maximum anticipated bedrock acceleration on the site is estimated to be approximately 0.139 based on a maximum probable earthquake of Richter Magnitude 6.7 on the active Elsinore fault. No ground water was encountered during our investigation, nor is ground water anticipated to be encountered during site excavation and construction. Laboratory test results indicate potential for sulfate attack is negligible. Laboratory test results indicate onsite soils are mildly corrosive. Estimated design lives for metal culverts are provided in Section 4.7. -8- LEIGHTON and ASSOCIATES INCOFCPORATED - 8841485-04 - 4.0 RECOMMENDATIONS 4.1 Earthwork - We anticipate that earthwork at the site will consist of site preparation, excavation, and backfill. We recommend that earthwork on site be performed - in accordance with the following recommendations and the General Earthwork and Grading Specifications included in Appendix D. In case of conflict, the following recommendations shall supersede the specifications in Appendix D. - 4.1.1 Site Preparation - .- Prior to grading, all areas to receive structural fill or engineered structures should be cleared of surface and subsurface obstructions, including any existing debris, and stripped of vegetation. Removed vegetation and debris should be properly disposed of off site. Holes resulting from removal of buried obstructions which extend below finished site grades should be replaced with suitable compacted fill material. All areas to receive fill and/or other surface improve- ments should be scarified to a minimum depth of 10 inches, brought to near-optimum moisture conditions, and recompacted to at least 90 percent relative compaction (based on ASTM Test Method D1557-78). - - -- .- - - 4.1.2 Removal of Compressible Soils The site is mantled by approximately 4 to 5 feet of potentially compressible soils. These soils are not suitable for the support of proposed fill or structural improvements in their present condition. We recommend that these soils be removed to a minimum of 10 feet outside the proposed building perimeters and settlement-sensitive improvements, including parking areas, and recompacted to at least 90 percent relative compaction (based on ASTM Test Method D1557-78) to provide for a generally uniform pad under the proposed structures and improvements. 4.1.3 Excavations Excavation of the onsite soils may be accomplished with conventional, heavy-duty grading equipment. Due to the generally cohesionless and friable nature of the onsite soils, temporary excavations such as utility trenches with vertical sides may not be stable. Excavations deeper than 5 feet should be shored or should be laid back to 1:l (horizontal to vertical) if workers are to enter such excavations. All trench excavations should be made in accordance with OSHA requirements. - -9- LEIGHTON and ASSOCIATES ,NCORPORATED 8841485-04 4.1.4 Fill Placement and Compaction The onsite soils are generally suitable for use as compacted fill provided they are free of organic material and debris. All fill soils should be brought to near-optimum moisture conditions and compacted in uniform lifts to at least 90,percent relative compaction based on laboratory standard ASTM Test Method D155?-78. The optimum lift thickness required to produce a uniformly compacted fill will depend on the type and size of compaction equipment used. In general, fill should be placed in lifts not exceeding 8 inches in thickness. Materials placed within 3 feet of finish grade should not contain fragments over 6 inches in diameter. - - - 4.1.5 Trench Excavation and Backfill - Excavation of utility trenches and foundations in the onsite soils appears to be generally feasible with light-duty backhoe equipment. The onsite soils may be used as trench backfill provided they are screened of organic matter, debris, and rock fragments greater than 6 inches in diameter. Trench backfill should be brought to near- optimum moisture conditions and compacted in uniform lifts (not exceeding 8 inches in thickness) by mechanical means to at least 90 percent relative compaction (ASTM Test Method D1557-78). 4.2 Drainage - - Surface drainage should be controlled at all times. The subject commercial structure should have appropriate drainage systems to collect roof runoff. Positive surface drainage should be provided to direct surface water away from the structure, toward the street or suitable drainage facilities. Positive drainage may be accomplished by providing a minimum 2 percent gradient from the structure. Ponding of water should be avoided adjacent to the structure. The need for surface drainage devices is within the purview of the design civil engineer. - - Due to the locally expansive nature of the soils at the site, we recommend a subsurface drainage system (i.e., french drains or equivalent) be installed beneath planters adjacent to the proposed building and parking areas to help facilitate drainage. This drainage system should be designed to direct collected water away from the structure and associated improvements. Planter drain design should be checked by the geotechnical engineer prior to construction. In addition, landscape areas may experience difficult drainage due to the presence of low permeability clay interbeds within the formational soils on the site. Relatively higher permeability sand members of the terrace deposits are generally encountered approximately 8 to 9 feet below existing grades. - - 10 - LEIGHTON and ASSOCIATES INCORPORATED - 8841485-04 - 4.3 Foundation and Slab Design Considerations - Foundations and slabs should be designed in accordance with structural considerations and the following recommendations. - - - - - - - - - 4.3.1 Foundations The proposed three-story structures may be supported on conventional, continuous, perimeter footings founded at a minimum depth of 36 inches beneath the lowest adjacent grade. At this depth, footings may be designed for an allowable soil bearing capacity of 4,000 psf if founded into competent terrace deposits or 2,000 psf if founded into properly compacted soils (with an increase of 10 percent per foot of additional depth to a maximum of 5,300 psf). In order to reduce potential uplift due to soil expansion, we recommend that a minimum dead load bearing of 1,500 psf be designed for all footings. Minimum reinforcement for continuous footings should consist of one No. 5 bar top and bottom or equivalent. Isolated spread footings with a minimum width of 24 inches and minimum depth of 36 inches beneath the lowest adjacent grade may be used for interior bearing members. Lateral earth pressure and frictional resistance are discussed in Section 4.5. - - - 4.3.3 Moisture Conditioning 4.3.2 Floor Slabs Floor slabs should be at least 4 inches in thickness and be rein- forced with 6x6-6/6 wire mesh placed midheight in the slab. Slabs should be underlain by a 4-inch layer of clean sand over a 6-mil Visqueen moisture barrier. In addition, the slabs should be saw cut completely across the slab at lo-foot intervals to a minimum depth of 1 inch and not deeper than 2 inches. The potential for slab cracking may be reduced by careful control of water/cement ratios. The contractor should take appropriate curing precautions during the pouring of concrete in hot weather to minimize cracking of slabs. We recommend that a slipsheet (or equivalent) be utilized if grouted tile, marble tile, or other crack-sensitive floor covering is planned directly on concrete slabs. All slabs should be designed in accordance with structural considerations. Prior to the pouring of the floor slabs, the upper 24 inches of subgrade soils should be moistened to at least 5 percent above optimum moisture content as determined by ASTM Test Method D1557-78. In order to help facilitate moisture penetration, the contractor may elect to construct the foundations prior to the pouring of the slabs to help retain water on the slab subgrade soils. - - 11 - LE,G”TON and ASSOCIATES lNCc.RPORATED - 8841485-04 - 4.4 Exterior Concrete Flatwork - - -. In expansive soil areas where cracking of exterior concrete flatwork is not considered tolerable, potential cracking may be reduced by providing reinforcement consisting of 6x6-10/10 wire mesh. Reinforcement should be placed midheight in the concrete. In addition, we recommend control joints be placed at intervals not exceeding 10 feet. Slabs should be designed in accordance with the recommendations of the project structural engineer. Soils should be thoroughly moistened prior to concrete placement. - 4.5 Lateral Earth Pressures and Resistance - - Embedded structural walls should be designed for lateral earth pressures exerted on them. The magnitude of these pressures depends on the amount of deformation that the walls can yield under load. If the wall can yield enough to mobilize the full shear strength of the soil, they can be designed for "active" pressure. If the wall cannot yield under the applied load, the shear strength of the soil cannot be mobilized and the earth pressure will be higher. Such walls should be designed for "at rest" conditions. If a structure moves toward the soils, the resulting resistance developed by the soil is the "passive" resistance. The recommended equivalent fluid pressure for each case for walls founded above the static ground water table is provided below: Equivalent Fluid Pressure Cantilever wall (yielding) 35 pcf Restrained wall (nonyielding) 50 pcf Passive resistance 250 pcf The above pressures assume nonexpansive (imported), level backfill and free- draining conditions. Nonexpansive backfill should extend horizontally at least 0.5H from the back of the wall where H is the wall height. Retaining walls should be provided with appropriate drainage as shown in Appendix 0. Wall footings should be designed in accordance with the previous building foundation recommendations as stated in Section 4.3.1, and reinforced in accordance with structural considerations. - - 12 - LElGHTON and ASSOCIATES ,NCORPORATEO - ..- - - - - - - - - - - - - .- - 8841485-04 4.6 Type of Cement for Construction Concrete in direct contact with soil or water that contains a high con- centration of soluble sulfates can be subject to chemical deterioration commonly known as "sulfate attack." Based on U.S. Bureau of Reclamation criteria, the potential for sulfate attack is negligible for sulfate contents ranging from 0 to 150 p.p.m. Soluble sulfate contents of samples tested at this site were within this range (Appendix C). Foundation members and flatwork should not require the use of sulfate-resistant cement. Therefore, Type II (or equivalent) may be used for construction purposes. 4.7 Corrosivity Minimum resistivity and pH tests were performed on representative samples of the subgrade soils (Appendix C). Based on our results, the site soils are mildly corrosive. Estimated design lives for metal culverts are provided below: 4.8 Gauge 18 16 14 12 Pavement Sections The soil resistance against lateral loading consists of friction or adhesion at the base of foundations and passive resistance against the embedded portion of the structure. Concrete foundations placed directly on terrace deposits may be designed using a coefficient of friction of 0.30 (total frictional resistance equals coefficient of friction times the dead load). In lateral resistance applications , a passive resistance of 250 psf per foot of depth with a maximum value of 3,000 psf can be used for design. The allowable lateral resistance can be taken as the sum of the frictional resistance and the passive resistance provided the passive resistance does not exceed two-thirds of the total allowable lateral resistance. The coefficient of friction and passive resistance values can be increased by one-third when considering loads of short duration such as wind or seismic loading. Estimated Design Life (Years) 54 71 87 120 Design of pavements was not included within the scope of this report. Pavement sections will depend largely on the subgrade soil conditions exposed after grading and should be based on R-value testing. Pavement sections can be provided upon completion of grading. - - 13 - LE,OHTON and ASSOCIATES ,NCORPORATED - 8841485-04 - 4.9 Construction Observation - - - - - - - - - - - - - The recommendations provided in this report are based on preliminary structural design information for the proposed facilities, and subsurface conditions disclosed by widely spaced borings. The interpolated subsurface conditions should be checked in the field during construction by a repre- sentative of Leighton and Associates, Inc. Final project drawings should be reviewed by Leighton and Associates, Inc. prior to beginning construction. Construction observation of footings and field density of all compacted fill should be performed by a representative of the geotechnical engineer so that construction is in accordance with the recommendations of this report. - 14 - LElGHTON and ASSOCIATES ,NCORPORATEO 8841485-04 - - - - - - - - ,._~ TABLE 1 SEISMIC PARAMETERS FOR ACTIVE FAULTS Caliber/Phases II and III Distance From Fault To Site (Miles) Fault Elsinore Coronado Banks (Offshore) San Andreas San Jacinto San Clemente (Offshore) Newport- Ingl ewood Rose Canyon* La Nation* 24 7.5 6.7 21 6.5 6.0 67 8.5 8.3 0.10 49 7.5 7.2 0.08 54 7.5 7.0 0.06 50 7.0 5.5 6.8 28 6.5 Maximum Credible Earthquake Richter Richter Magnitude Magnitude MAXIMUM PROBABLE EARTHQUAKE (Functional Basis Earthquake) 6.5 Peak Bedrock/ Repeatable Horizontal Ground Acceleration (Gravity)** 0.13 0.11 0.05 --- --- * This fault is considered "potentially active" based on our current knowledge of the geologic conditions of the San Diego County area. l * For design purposes, the repeatable horizontal ground acceleration may be taken as 65% of the peak acceleration for sites within 20+ miles of the epicenter (after Ploessel and Slosson, 1974). LElGHTON and ASSOCIATES ,NCORPORATED 8841485-04 APPENDIX A REFERENCES - - - 1. Albee, A.L., and Smith, J.L, 1966, Earthquake characteristics and fault activity in southern California k Lung, R. and Proctor, R., eds., Engineering Geologist in Southern California, Association of Engineering Geologists, Special Publication, dated October. 2. Allen, C.R., Amand, P., Richter, C.F., and Nordquist, J.M., 1965, Relationship between seismicity and geologic structure in southern California, Seismological Society of America Bulletin, Vol. 55, No. 4. p. 753-797. 3. Bolt, B.A.. 1973, Duration of strong ground motion, Proc. Fifth World Conference on Earthquake Engineering, Rome, Paper No. 292, pp. 1304-1313, dated June. 4. Bonilla, M.J., 1970, Surface faulting and related effects b Wiegel, R. (editor), Earthquake Engineering, Prentice-Hall, Inc., New Jersey, pp. 47-74. 5. California Department of Transportation, 1979, Highway Design Manual, Figure,7-851.3, dated April 2. 6. Eisenberg, L.I., 1985, Pleistocene faults and marine terraces, northern San Diego County in Abbott, P.L., editor, On the manner of deposition of the EoceneTtrata in northern San Diego County, San Diego Association of Geologists, Field Trip Guidebook, pp. 86-91. 7. , 1983, Pleistocene terraces and Eocene geology, Encinitas and Ranch0 Santa Fe quadrangles, San Diego County, California, San Diego State University Master's Thesis (unpublished), p. 386. 8. Greensfelder, R.W., 1974, Maximum credible rock acceleration from earthquakes in California, California Division of Mines and Geology, Map Sheet 23. 9. Hannan, D.L., 1975, Faulting in the Oceanside, Carlsbad, and Vista areas, northern San Diego County, California b Ross, A. and Dowlen, R.J., eds., Studies on the geology of Camp Pendleton and western San Diego County, California, San Diego Association of Geologist Field Trip Guidebook, pp. 56-60. IO. Lamar, D.L., Merifield, P.M., and Proctor, R.J., 1973, Earthquake recurrence intervals on major faults in southern California in Moran, D.E., Slosson, J.E., Stone, R.O., Yelverton, Califorca, eds., 1973, Geology, seismicity. and environmental impact: Association of Engineering Geologists, Special publication. - A-i _- - - - -. - - -. 8841458-04 REFERENCES (continued) 11. Leighton and Associates, Inc., 1986, Observation and testing of storm drain trench backfill, Avenida Encinas, south of Palomar Airport Road, Carlsbad, California, Project No. 4851485-02, dated August 11. 12. , 1986, Grading plan review and general earthwork recommendations for street improvements of Avenida Encinas, Carlsbad, California, Project No. 4851485-02, dated July 17. 13. , 1986, As-graded report, Carlsbad Pacific Center, Palomar Airport Road and Avenida Encinas, Carlsbad, California, Project No. 4851485-02, dated April 18. 14. , 1986, Temporary stockpile, Carlsbad Pacific Center, Palomar Airport Road and Avenida Encinas, Carlsbad, California, Project No. 4841485-02, dated March 2. 15. ) 1985, Pavement design section, Carlsbad Pacific Center, Avenida Encinas, Carlsbad, California, Project No. 8481485-01, dated 16. , 17. , 18. , 19. , September 13. 1 985, Compaction of fill soils, building pad area, Carlsbad Pacific Center, Carlsbad, California Project No. 4841485-02, dated August 22. 1 985, Geotechnical investigation, Carlsbad Pacific Center, Palomar Airport Road and Avenida Encinas, Carlsbad, California, Project No. 4841485-01, dated February 22. 985, Grading plan review, Carlsbad Pacific Center, Phase I, Carlsbad, California, Project No. 4841485-02, dated August 7. 985, Carlsbad Pacific Center, Palomar Airport Road and Avenida Encinas, Carlsbad, California, Project No. 4841485-01, dated March 25. 20. , Unpublished in-house data. 21. Ploessel, M.R., and Slosson, J.E., 1974, Repeatable high ground accelerations from earthquakes-important design criteria, California Geology, Vol. 27, No. 9, dated September. 22. Schnabel, 8. and Seed, H.G., 1974, Accelerations in rock for earthquakes in the western United States, Bulletin of the Seismological Society of America, Vol. 63, No. 2, pp. 501-516. 23. Seed, H.B., Idriss, I.M., and Kiefer, F.W.. 1969, Characteristics of rock motions during earthquakes, Journal of Soil Mechanics and Foundations Division, ASCE, Vol. 95, No. SM5, Proc. Paper 6783, pp. 1199-1218. September. A - ii - 8841458-04 - REFERENCES (continued) - 24. Seed, H.B., 1979, Soil liquefaction and cyclic mobility evaluation for level ground during earthquakes, ASCE, GT2. p. 201, dated February. 25. Seed, H.B., Idriss, I.M., and Arango, Ignacio, 1983, Evaluation of liquefac- - tion potential using field performance data, ASCE JGE. Vol. 109, No. 3, p. 458, dated March. - 26. Weber, F.H., Jr., 1982, Recent slope failures, ancient landslides, and related geology of the north-central coastal area, San Diego County, California, California Division of Mines and Geology, Open- File Report 82-12LA. 27. Wilson, K.L., 1972, Eocene and related geology of a portion of the San his Rey and Encinitas quadrangles, San Diego, California. - MAPS I Fault map of California, 1. California Division of Mines and Geology, 1975 - Scale 1”=750,000’. 2. The Falick/Klein Partnership, Inc., undated, S Center, Phase II, Scale 1"=50'. - ite plan, Carlsbad Pacific 3. United States Department of the Interior Geological Survey, 1968, Revised 1975, Encinitas Quadrangle, 7.5-minute series, Scale 1"=2,000'. Date 1953 AERIAL PHOTOGRAPHS Source Scale Flight Photo No. USDA 1"=2,000 AXN-8M 99 and 100 - A . . - 111 GEOTECHNICAL BORING LOG DATE Auaust 27, 1987 DRILL HOLE No. B-1 PROJECT CaliberKarlsbad Pacific Center Phases II and III DRILLING Co Gallaoher Drillino HOLE DIAMETER 30" DRIVE WEIGHT 3.887 PQI& to 25 Foot ELEVATION TOP OF HOLE* REF. OR DATUM See1 Nao SHEET-OF& PROJECT No. 8841485-04 TYPE OF RIG- DROP 12 IN, undul- sting undul- ating undul ating undul ating - .2.J - .2.9 4.8 4.8 = - e-2 5; GEOTECHNICAL DESCRIPTION ;5 ;!i :s -0GGED BY RLW II SAMPLED BY RLW = I Medium brown, dry to damp, stiff, wry sandy clay; - SC 3.2 @ 1.2' Medium gray to brown. damp, dense, clayey, fine- to medium-arained sand: locallv stained with red-brown iron oxide; iocal clay interbeds noted - - @ 2' Moderately cemented layer approximately 6 inches SM thick: oossiblv due to miaratino wound water - - - t 3.5 @ 4' Lioht'to medium arau-brown, moist, medium dense, - siity, fine- to medium-grained sand; approxi- :L mate 2-inch clay layer developed atop contact with overlying unit; massive;no apparentbeddin @ 6.5' Medium gray-brown, moist to very moist, firm, very silty clay; slightly sandy; scattered - calcium carbonate blebs; massive '/SM @ 9.1' Mottled medium to light gray and brown-orange, I.3 moist, medium dense to dense, slightly silty, fine-grained sand; locally very friable; finel micaceous !7.E = rotal Depth = 16 Feet ;eologicaTly Logged to I5 Feet Yo Ground Water Encountered YO caving 3ackfiJJed 8/27/87 - I t XIGHTON & ASSOCIATES - - - - - -~ - - -- - - - -. GEOTECHNICAL BORING LOG DATE Auaust 27. 1987 DRILL HOLE No. B-2 SHEET-OF- PROJECT CalCarlsbad Pacific w~hases II and 111 PROJECT No. 884148504 DRILLING Co Gallaqher Orillina TYPE OF RIG- HOLE DIAI IETER 30" ELEVATION 1 [OP OF 2 !I- 2 ra : ii 2:: 2 au ad ;: " It Ii E 1 C \,' -,\ -I -?-- - e-7 '-.I.. s. .- - / G( -..A+ ::N65E/ r-+. 2-4NW 5- .'.A ,y--. _. 5.l --- - - -> i -=- 10 - -= L.:. .- :' -_.,.. - . . .-- . . ^-'. + '-. ._ ', -. -C .- .-. :undul- -.: ating > ._ ._ pj--' .L .L .-. .- Y-J 20 - 25 - 30 DR ZIVE WEIGHT 3.087 Puds to 25 Feet DROP 12 IN. - L6.2 18.4 10.8 DA] - F 5; ;5 j& -s = - 8.6 5.1 3.7 = - - LEIC TIJM L :, ti Jvi g = CL - SC ii3 - - ON GEOTECHNICAL DESCRIPTION GGED BY RKW MPLED BY RKW/RLW Medium red-brown, mottled orange-brown and light brown,. mist, stiff. very sandy clay; scattered roothairs; near-horizontal, sharp contact IEATHEREO TERRACE DEPOSITS/AGRICULTURAL FILL: Medium brown mottled orange-orown, mqTst, slightly sandy clay; broken; highly weathered @ 1.5' Becomes less weathered @ 1.8' Gradational change to light to medium brown, slightly moist. dense, clayey to silty, fine- . grained sand; slightly porous; slightlyfriable; micaceous; massive; contains discontinuous l- . to 4-inch thick, sandy clay layers 'ERRACE OEPOSITS: e 3.7’ Medium tu dark brown, mnist stiff, sandy clay to clayey sand; massive; @ 6’ Becomes silty clay to clayey silt; slightly sandy scattered s&rounded gravel and Calcium carbonate blebs (up tq l/4 inch in diameter); increasing sand content with depth @ 10’ Becomes gray-brown mottled orange-brown, clayey sand @ 12.8' Medium gray-brown mottled oranqe-brown. moist, . dense, silty, fine-grained sand; massive; very micaceous; friable; undulating lower contact @ 13.5' 8ecoiws predominantly orange-brown, silty, fine-grained sand ta1 Depth = 18 Feet ologically Logged to 17 Feet Ground Water Encountered Caving ckfilled 8/27/87 SSOCIATES - GEOTECHNICAL BORING LOG DATE Auoust 27, 1987 DRILL HOLE No. 8-3 PROJECT Caliber/Canlsbad Pacific Center Phases II and III DRILLING Co Gallaoher Orillino HOLE DIAMETER 30" DRIVE WEIGHT 3.087 Pm to 25 FPot SHEET-OF& PROJECT No. 8841485-04 TYPE OF RIG- DROP --.&-- IN -0P OF z z F s C undul ating hori- zontal undul ating N67W/ 18NE undul ating DATUP - se z;, ;$ -s = 8.4 3.3 18.9 GEOTECHNICAL DESCRIPTION II LOGGED BY RKW II t See1 Mao L +. II 4ui 2; w; 2s I , SAMPLED BY RKW = M TER RACE DEPOSITS/AGRICULTURAL FILL: - C Light brown, mottled orange-brown, dry to slightly ii-- damp, medium dense, very silty, fine- to medium-grained sand; friable; very micaceous; scattered roothairs E @ 0.9' Medium red-brown, moist, medium stiff to stiff, sandy clay; undulating lower contact SM @ 1.6' Light brown mottled orange-brown, moist, medium dense, silty, fine- to medium-grained sand; slightly micaceous; massive @ 2.8' Dark arav-brown to dark brown, moist to very moist: stiff, silty clay; slightly sandy; calcium carbonate blebs; near-vertical sand fractures (uo to I inch wide) :RRACE DEPOSITS: - @ 3.4' Medium brown, rcoist, dense, clayey sand; mica- CL coous; massive; slightly friable 8 7.5' Oark brown to dark brown-grry, moist, medium stiff, silty clay; slightly sandy; massive; calcium carbonate blebs (up to l/8 inch in diameter); contains pockets of medium brown, friable, silty sand - ;M/SI > @ 14' Medium gray mottled orange-brown, moist, dense, silty, fine- to medium-grained sand; massive; very micaceous; friable; contains pockets of dark brown clay Tot :a1 Depth = 18 Feet GM Ilogically Logged to 17 Feet NO Ground Water Encountered NO Caving 8% :kfilled 8/27/87 LEIGHTON & ASSOCIATES - - - - - - - - - - -. - - - - - - - 20 25 E 30 505A(11/77) undul ating - : ;i > = ri i.9 19.0 21.; = u" - z? L1:. 4v) GEOTECHNICAL DESCRIPTION ZG j; "P - ng mg LOGGED BY RKW SAMPLED BY RKW ) 2! 2 GEOTECHNICAL BORING LOG DATE Ausust 27. 1987 DRILL HOLE No. B-4 PROJECT- CaliberKarlsbad Pacific Center Phases 11 and III DRILLING Co Gallwher Drilling HOLE DIAMETER 30" DRIVE WEIGHT 3.087~ to zF@pt ELEVATION TOP OF HOLE= REF. OR DATUM %&w&xwl Man SHEET-OF- PROJECT No. 8841485-04 TYPE OF RIG- DROP 12 IN. FIL L: SM/SC Medium 6'3 %/ML clayey @ 0.4’ brown. slightly Mist, medium dense, silty to fine-grained sand; scattered roothairs l-l ' Orange-brown, damp, medium dense, '.' story, fine- - to medium-arained sand: micaceous @ 1.1’ @ 1.4’ Light brow?, slightly damp, medium dense to loose, very silty sand to sandy silt; roothairs Becomes damp to slishtly molsr, 1, _ -'4-inch open - UCE DEPOSITS: 5.6 x- X ixP fracture fl Light brown, damp to slightly moist, medium dense to dense, silty. fine- to medium-grained sand; massive; - micaceous; contains layers of medium to dark brown, silty clay (up to 4 inches thick) @ 5.3' Gray-medium brown, moist, medium dense. clayey sand; interbedded silty to clayey sand and sandy clay (up to 2 to 3 inches in thickness); undulating lower contact @ 7.6' Gray-dark brown, moist, medium stiff, silty clay: slightly sandy; calcium carbonate bleb - (up to l/4 inch in diameter); massive @ 10’ Becomes moist to very moist @ 12.3' Gray-brown, moist, medium dense, clayey, fine- grained sand; micaceous; contains pockets of silty sand @ 13.2' Gradational changes to gray mottled orange- brown, moist, dense, silty, fine-grained sand; slightly clayey; massive; very micaceous; friable otal Depth = 16 Feet eologically Logged to 15 Feet o Ground Water Encountered 0 Caving ackfilled B/27/87 LEIGHTON & ASSOCIATES GEOTECHNICAL BORING LOG DATE Auwst 27, 1987 DRILL HOLE No. B-5 PROJECT Caliber/Carlsbad Pacific Center Phases II and III DRILLING Co Gallaqher Orillins HOLE DIAMETER 30" DRIVE WEIGHT m to 25 Feet SHEET-I-• PROJECT No. 8841485-04 TYPE OF RIG- DROP & IN. ELEVATIOI FL 2 kliu 20" =u. 4-l Is W E 0 \ \- \'\ - \;\ - '1 .-'I. T7J-T -;'+ :-. ., 5-Y" -' -. 7 i _ : '.< _- T ,A A-z=Y - ..i -. 10 -AZ d - . . :-.. . 7 . . .., -. ‘,L Is---: TOP OF undul ating undul ating lLEt59’ ,F, - : z ,"i s = - 11.5 20.4 04.3 DA - M E. 'r; g -s = 11.1 4.0 2.3 TUM GEOTECHNICAL DESCRIPTION II I See’ Mao n- I1 :v; id w; g L OGGED BY RKW S AMPLED BY RKW = FIL I/SC &: .I Orange-medium brown, moist, medium dense, clayey to silty, fine- to medium-grained, sand; scattered root- lets and small, less than l/2 inch, wood pieces; micaceous; sharp, irregular contact iM IW\CE DEPOSITS: rl/sc 4 Light brown mottled orange-brown, slightly moist to moist, dense, silty, fine- to medium-grained sand; slightly clayey; massive; micaceous; slightly friable @ 3' On east side of boring, Is-inch long, 4-inch wide concretion @ 4' Grades to silty to clayey sand; becomes moist to Very moist rr @ 8.5' Very gradational change to medium to dark gray- brown, very moist, stiff, sandy clay; massive; very occasional calcium carbonate blebs (approx irately l/4 inch); sharp undulating lower CO"t.Ct _ _ _ _ _ _ @ 10.9’Gray amttled orange-brown, moist. medium dense, silty, fine- to medium-grained sand; massive; very micaceous; friable VSP rota1 Depth = 16 Feet I ieologically Logged to 15 Feet lo Ground Water Encountered I lo Caving I lackfilled B/27/87 884148504 - - - - - - - - - - - - APPENDIX C SAMPLING AND LABORATORY TESTING PROCEDURES AND LABORATORY TEST RESULTS SAMPLING PROCEDURES Undisturbed Samples: Samples of the subsurface materials were obtained from the exploratory boring in relatively undisturbed conditions. The depth at which each undisturbed sample was obtained is shown on the boring log. The sampler used to obtain undisturbed samples is a split-core barrel drive sampler with an external diameter of 3.0 inches which is lined with thin brass rings with an inside diameter of 2.41 inches. Each ring is 1 inch long. The sample barrel is driven into the ground with an effective weight of the kelly bar of the boring machine. The kelly bar is permitted to free fall. The approximate length of the fall, the approximate weight of the bar, and the number of blows per foot of driving are noted and recorded on the boring logs. Blow counts have been noted in the log of borings as an index to the relative resis- tance of the sampled material. The samples are removed from the sample barrel in the brass rings, sealed, and transported to the laboratory for testing. Disturbed Samples: Bulk samples of representative materials were also obtained from the boring, bagged, and transported to our laboratory for testing. LABORATORY TESTING PROCEDURES Moisture Density Tests: Moisture content and dry density determinations performed on relatively undisturbed samples obtained from the test boring. results of these tests are presented on the boring log. were The Maximum Density Tests: The maximum dry density and optimum moisture content of typical materials were determined in accordance with ASTM Test Method D1557-78. The results of these tests are presented in the test data. Expansion Index Test: The expansion potential of a selected material was evaluated by the Expansion Index Test, U.B.C. Standard No. 29-2. Specimens were remolded at near-optimum moisture content to 90 percent relative compaction under a given compactive energy to approximately 50 percent saturation. The prepared specimens (4-inch diameter by l-inch length) were loaded to an equivalent I44 psf surcharge and inundated with tap water until volumetric equilibrium was reached. The results of this test are presented in the test data. Direct Shear Tests: Direct shear tests were performed on relatively undisturbed samples in accordance with ASTM Test Method D3080 at a strain rate of 0.05 inches per minute to determine cohesion and the angle of internal friction of the soil sample. - - C-i 8841485-04 - - - APPENDIX C (continued) Soluble Sulfate Tests: The percent of soluble sulfates in a representative sample was determined by the California Materials Method No. 417 utilizing a hand-held terbidmeter. pH and Minimum Resistivity Tests: Determination of pH and minimum resistivity value for typical subsurface soils was made for analysis of corrosion potential. GENERAL NOTE: All references to the American Society for Testing and Materials (ASTM) imply the latest standards. - - - C - ii : i _I -I 1 _I 1 -i i J 4 4 J 1 I 1 J oJoo 3c4Q zoo0 lw0 0 1000 2ca 3ca ;wco xa NORMAL SFRESS IPSF) DESCRIPTION SYMBOL BORING SAMPLE DEPTH (FEET) COHESION FRICTION SOIL NUMBER NUMBER (PSFI ANGLE TYPE Remoldedat 90%relative l B-Z compaction #I 3' 600 20" m/se DIRECT SHEAR TEST RESULTS Figure C-l - - - - - - - - - - EXPANSION INDEX TEST RESULTS EST SAMPLE INITIAL COMPACTED NO. LOCATION MOISTURE (%) DRY(~om d% (%, VOLUMETRC EXPAKSKJM EXPANSlWE SWELL (%I MEX POTENPAL 1 B-l #3 @8’ 12.8 101.8 26.9 9.2 92 High. 2 B-2 62 @7' 14.0 95.4 27.9 10.5 105 High MAXIMUM DENSITY TEST RESULTS SAMPLE SOIL DESCRIPTION B-2 #l @3' Light to medium gray-brown, clayey sand MAXIMUM OPTIMUM DRY DENSITY MOISTURE (PCF) .CONTENT (%I 119.5 12.0 8841485-04 CALIBER/PACIFIC CENTER, PHASES II AND III - - ‘pH, MINIMUM RESISTlVlTY AND SOLUBLE SULFATE TEST RESULTS SAMPLE LOCATION B-l #l @3’ PH MNMUM RESISTNITY SOLUBLE SULFATE (ohm-cm) bpd 8 6670 110 8841485-04 cmBER/PAcIFIc VENTER, PHASES II AND III Figur*C-3 GENERAL EARTHWORK AND GRADING SPECIFICATIONS - 1.0 General Intent - - These specifications are presented as general procedures and recommendations for grading and earthwork to be utilized in conjunction with the approved grading plans. These general earthwork and grading specifications are a part of the recommendations contained in the geotechnical report and shall be superseded by the recommendations in the geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could supersede these specifications or the reconunendations of the geotechnical report. It shall be the responsibility of the contractor to read and understand these specifications, as well as the geotechnical report and approved grading plans. - - - - - - 2.0 Earthwork Observation and Testinq Prior to the commencement of grading, a qualified geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechni- cal report and these specifications. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes, at least 24 hours in advance, so that he may schedule his personnel accordingly. No grading operations should be performed without the knowledge of the geotechnical consultant. The contractor shall not assume that the geotechnical consultant is aware of all grading operations. It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes and agency ordinances, recommendations in the geotechnical report, and the approved grading plans not withstanding the testing and observation of the geotechnical consultant. If, in the opinion of the consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than recommended in the geotechnical report and the specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the conditions are rectified. Maximum dry density tests used to evaluate the degree of compaction should be performed in general accordance with the latest version of the American Society for Testing and Materials test method ASTM D1557. 3.0 Preparation of Areas to be Filled 3.1 Clearing and Grubbing: Sufficient brush, vegetation, roots, and all other deleterious material should be removed or orooerlv disoosed of in a method acceptable to the owner, design engineer, 'governing agencies and the geotechnical consultant. -i- - - - - - -_ - - - - - - - - - - The geotechnical consultant should evaluate the extent of these removals depending on specific site conditions. In general, no more than 1 percent (by volume) of the fill material should consist of these materials and nesting of these materials should not be allowed. 3.2 Processing: The existing ground which has been evaluated by the geotechnical consultant to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory should be overexcavated as specified in the following section. Scarification should continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform, flat, and free of uneven features which would inhibit uniform compaction. 3.3 Overexcavation: Soft, dry, organic-rich, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overex- cavated down to competent ground, as evaluated by the geotechnical consultant. For purposes of determining quantities of materials overexcavated, a licensed land surveyor/civil engineer should be utilized. 3.4 Moisture Conditioning: Overexcavated and processed soils should be watered, dried-back, blended, and/or mixed, as necessary to attain a uniform moisture content near optimum. 3.5 Recompaction: Overexcavated and processed soils which have been properly mixed, screened of deleterious material, and moisture- conditioned should be recompacted to a minimum relative compaction of 90 percent or as otherwise recommended by the geotechnical consultant. 3.6 : Where fills are to be placed on ground with slopes steeper (horizontal to vertical), the ground should be stepped or The lowest bench should be a minimum of 15 feet wide, at least 2 feet into competent material as evaluated by the geotechnical consultant. Other benches should be excavated into competent material as evaluated by the geotechnical consultant. Ground sloping flatter than 5:l should be benched or otherwise overexcavated when recommended by the geotechnical consultant. 3.7 Evaluation of Fill Areas: All areas to receive fill, including processed areas, removaf areas, and toe-of-fill benches, should be . evaluated by the geotechnical consultant prior to fill placement. - - - - 4.0 Fill Material 4.1 General: Material to be placed as fill should be sufficiently free of organic matter and other deleterious substances, and should be evaluated by the geotechnical consultant prior to placement. Soils of poor gradation, expansion, or strength characteristics should be placed as recommended by the geotechnical consultant or mixed with other soils to achieve satisfactory fill material. 4.2 - -, 4.3 Oversize: Oversize material, defined as rock or other irreducible material with a maximum dimension greater than 6 inches, should not be buried or placed in fills, unless the location, materials, and disposal methods are specifically recommended by the geotechnical consultant. Oversize disposal operations should be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densified fill. Oversize material should not be placed within 10 feet vertically of finish grade, within 2 feet of future utilities or underground construction, or within 15 feet horizontally of slope faces, in accordance with the attached detail. Import: If importing of fill material is required for grading, the import material should meet the requirements of Section 4.1. Sufficient time should be given to allow the geotechnical consultant to observe (and test, if necessary) the proposed import materials. 5.0 Fill Placement and Compaction - 5.1 - -- -~ 5.2 5.3 Fill Lifts: Fill material should be placed in areas prepared and previously evaluated to receive fill, in near-horizontal layers approximately 6 inches in compacted thickness. Each layer should be spread evenly and thoroughly mixed to attain uniformity of material and moisture throughout. Moisture Conditioning: blended, and/or mixed, content near optimum. Fill soils should be watered, dried-back, as necessary to attain a uniform moisture Compaction of Fill: After each layer has been evenly spread, moisture- conditioned, and mixed, it should be uniformly compacted to not less than 90 percent of maximum dry density (unless otherwise specified). Compaction equipment should be adequately sized and be either specifi- cally designed for soil compaction or of proven reliability, to efficiently achieve the specified degree and uniformity of compaction. . . . - 111 - - - 5.4 Fill Slopes: Compacting of slopes should be accomplished, in addition to normal compacting procedures, by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the fill out to the slope face should be at least 90 percent. 5.5 Compaction Testing: Field tests of the moisture content and degree of -of fill soils should be performed by the geotechnical - consultant. The location and frequency of tests should be at the consult- ant's discretion based on field conditions encountered. In general, the tests should be taken at approximate intervals of 2 feet in vertical rise - and/or 1,000 cubic yards of compacted fill soils. In addition, on slope faces, as a guideline approximately one test should be taken for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. - 6.0 Subdrain Installation - - - Subdrain systems, if recommended, should be installed in areas previously evaluated for suitability by the geotechnical consultant, to conform to the approximate alignment and details shown on the plans or herein. The subdrain location or materials should not be changed or modified unless recommended by the geotechnical consultant. The consultant, however, may recommend changes in subdrain line or grade depending on conditions encountered. All subdrains should be surveyed by a licensed land surveyor/civil engineer for line and grade after installation. Sufficient time shall be allowed for the surveys, prior to commencement of filling over the subdrains. 7.0 Excavation - Excavations and cut slopes should be evaluated by a representative of the geotechnical consultant (as necessary) during grading. If directed by the geotechnical consultant, further excavation, overexcavation, and refilling of cut areas and/or remedial grading of cut slopes (i.e., stability fills or slope buttresses) may be recommended. - 8.0 Quantity Determination For purposes of determining quantities of materials excavated during grading - and/or determining the limits of overexcavation, a licensed land surveyor/civil engineer should be utilized. - iv - - - - - - - - 0 - ! - - - - N - I 1 - 1 1 - .- - .- KEY IE~TH , STABILITY FILL / BUTTRESS DETAIL OUTLET PIPES 4’ 0 NONPERFORATED PIPE. 00’ MAX. O.C. HORIZONTALLY. SO’ MAX. O.C. VERTICALLY -------------------------------z-z ---~-~------------ ----- -- ==-c..-YL=====~~~~-&~-~- =-------.-.-.------- ------ - --__-___-____-___ -:~A-z~.,,.,,z~z=-z-y...y~ - LOWEST SUBDRAIN SHOULD -><~~6~i,Ac~&,~<<<- BE SITUATED AS LOW AS -i-.-:-..<-:-E-~m> F,L Lz<<<<<< P08SlSLE TO ALLOW - -===========--------------- ===============----==- SUITABLE OUTLET - =-L-L-Z======~~-=--~- ----- -- ==========----------- ------ - - ---=-============------- ---- -Z--z=======- --_-__ ----em- ---------- - --_-_-__ --L-L=y;---~ -_____-_ PERFORATED OUTLET PIPEyAp NON-PERFORATED KEY WIDTH AS NOTED ON QRADING PLAN8 15’ MIN. / 8EE T-CONNECTION 6’ MIN. DETAIL 3/4*-l-112’ CLEAN QRAVEL (3ttih. MIN.)- :ON-P>R&RATEO A MIN. VER PIPE PERFORATED :ILTER FABRIC iNVELOPE MR SUBDRAIN TRENCH DETAIL T-CONNECTION DETAIL *IF CALTRANS CLASS 2 PERMEABLE MATERIAL IS USED IN PLACE OF 3/4,-l-1/2’ QRAVEL. FILTER FABRIC MAY SE DELETED SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size % Passing 1” 100 3/4” 90-100 3/a” 40- 100 No. 4 25-40 No. a 18-33 No. 30 5-15 No. 50 o-7 No. 200 o-3 Sand Equivalent>75 NOTES: For buttrose dim~nelonr. see geotechnlcrl report/plans. Actual dlmenaione of buttress and. rubdrai may b. charwed by the gwtechnlcal consultant bawd on field condltlona. SUBDRAIN INSTALLATION-Subdrain pipe rhould be installed with perfCratlCn0 down aa dmplcted. At locatIona recommended by the gectechnlcal,ccnsuItant. nonperforated pipe ahculd b* InMaIled SUBDRAIN TYPE-Subdraln type should be Acrylonitrll~ Eutadlene Styrene (A.S.S.), PolYvlnYt Chlorlde (PVC) or l ppioved wulvalent. Clara 12S,8OR 32.8 should ba urad for maximum fill depth* of 36 1.0 Clam 20D,8OR 21 should be wed for maxImum fill depth* of 100 fwt. - - TRANSITION LOT DETAILS TRANSITION LOT DETAILS CUT-FILL LOT CUT-FILL LOT EXISTINQ EXISTINQ QROUND SURFACE WOUND SURFACE 3 L m L I I II II .+‘,/ .+‘,/ ,’ ,’ I I I I , ’ -I& , ’ -I& OVEREXCAVATE OVEREXCAVATE AN0 RECOMPACT AN0 RECOMPACT COMPETENT BEDROCK COMPETENT BEDROCK OR MATERIAL EVALUATED OR MATERIAL EVALUATED BY THE QEOTECHNICAL BY THE QEOTECHNICAL CONSULTANT CONSULTANT CUT LOT EXISTINQ GROUND SURFACE COMPETENT BEDROCK R MATERIAL EVALUATED BY THE QEOTECHNICAL CONSULTANT *NOTE: Deeper or laterally more extensive overexcavation and reoompaction may be recommended by the geotechnical concrultant based on actual field conditions encountered’ and locatlonr of proposed improvement8 ROCK DISPOSAL DETAIL r FINISH GRADE SLOPE FACE- L OVERSIZE WINDROW DENSIFIED IN PLACE BY FLOODINQ DETAIL --_- ---we-- ---- --_-- __---- --- ----_------- --- ___-_----- ----- ------ --- -- --- --------- _--em- TYPiCAL PROFILE ALONQ WINDROW 1) Rock with maximum dimensions greater than 8 Inches should not be used within 10 feet vertically of.finish grade (or 2 feet below depth of lowest utility whichever is greater), and 15 feet horizontally of slope faces. 2) Rocks with maximum dimensions greater than 4 feet should not be utiltzed In flllS. 3) Rock placement, flooding of granular soil, and fill placement should be observed by th, geotechnical consultant. 4) Maxlmum size and spacing of wlndrows should be in accordance with the above detail Width of windrow should not exceed 4 feet. Windrows should be staggered vertically (as depicted). 5) Rock should be placed in excavated trenches. Qranular soil (S.E. greater than Or equs to 30) should be flooded in the windrow to completely fill voids around and beneath rocks. CANYON SUBDRAIN DETAILS - QROUNO SURFACE MATERIAL TRENCH SEE BELOW SUBDRAIN TRENCH DETAILS 8’ MIN. OVER FILTER FABRIC ENVELOPE m YIN. OVERLAP 3/4’-t-112’ CLEAN GRAVEL (0fk31ft. MIN.) PERFORATED PIPE IF CALTRANS CLASS 2 PERMEASLI MATERIAL IS USED IN PLACE. OF 3/4*-l-112’ QRAVEL. FILTER FAERI MAY BE DELETE0 DETAIL OF CANYON SUBDRAIN TERMINAL DESIQN FINISH SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size % Passfng 1" 3/4" 3/B" No. 4 No. a 18-33 No. 30 5-15 No. 50 o-7 No. 200 o-3 Sand Equivalent>75 SubdraIn l hould be constructed only on compotont motorlol aa l wluotod by the 2ootoohnlcol Eonwltont. SUeDRAiN fN8TALLATfON SubdraIn plpo l hould bo lnotollod with porforotlona dOWn .o dopktod. At locotlon~ rocommondod By the gootochnlcal conoultont, nonpwforotod plpo rhould bo Inotollod. SUeDRAiN TYPE-Subdroin typo should bo AcrylOnlt~llo Sutodlono Styrono (A.S.S.). POiyVlnyi ChlOrldO (PVC) or opprovod l oulwlont. Cloas 124 SDR 32.8 *hoold bo unod for maxImum flff doptha of 3S foot. Claw 200,SDR 21 should bo uood for morlmum 1111 doptho of tOO’foot, - - - - SIDE HILL STABILITY FILL DETAIL EXISTINQ QROUNO I -..--_ a- -A - ,3 0’ 0 0’ 0 FINISHED SLOPE FACE .- PROJECT 1 TO 1 LINE FINISHED CUT PAD FROM TOP OF SLOPE TO OUTSIDE EDGE OF KEY - PAD OVEREXCAVATION DEPTH AND RECOUPACTION MAY BE RECOMMENDED BY THE QEOTECHNICAL CONSULTANT - ‘BENCH BABED ON ACTUAL FIELD CONDITIONS ENCOUNTERED. I /tZ~~lf”TENT BEDROCK OR I MATERIAL AS EVALUATED BY THE QEOTECHNICAL CONSULTANT - - -A L---A NOTE: Subdrain details and key width recommendations to be provldeu oaseo on exposed subsurface conditions I - - - - - - - .- - - - - - - - - L KEY AND BENCHING DETAILS FILL SLOPE EXISTING QROUND SURF NOTE: Back drain may be recommended by the geotechnical consultant based on actual field conditions encountered. Bench dimension recommendations may also be altered based on field conditions encountered. DEPTH BENCH (KEY) FILL-OVER-CUT SLOPE MATERIAL -CUT SLOPE (TO SE EXCAVATED PRIOR TO FILL PLACEMENT) CUT-OVER-FILL SLOPE PE AVATED PRIOR TO FILL PLACEMENT) PROJECT 1 TO 1 LINE FROM TOE OF SLOPE TO RETAINING WALL DRAINAGE DETAIL RETAINING WALL> WALL WATERPROOFINQ PER ARCHITECT’S SPECIFICATIONS FINISH GRADE . SOIL BACKFILL. COMPACTED TO SO PERCENT RELATIVE COMPACTION+ = FILTER FABRIC ENVELOPE (YIRAFI 140~ OR APPROVED -z EQUIVALENT)* ---- zzzz _===- .c-.r.r: gg---- 3/4’-l-112. CLEAN QRAVEL* --- :31+ z.Yz _==-. --- 4=~(MIN.) DIAMETER PERFORATED ---r’PVC PIPE (SCHEDULE 40 OR EQUIVALENT1 WITH PERFORATIONS ORIENTED DOWN AS DEPICTED z.Yzz zzzz MINIMUM 1 PERCENT GRADIENT =_==- -===’ TO SUITABLE OUTLET mWALL FooT’NQ+~$‘l 3’ MIN. SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size % Passing 1” 100 3/4” go-100 3/ail 40- 100 No. 4 25-40 No. a la-33 No. 30 5-15 No. 50 No. 200 ::: Sand Equivalent>75 Y COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE QEOTECHNICAL CONSULTANT *BASED ON ASTM 01657 **IF CALTRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/4*-l-112’ GRAVEL. FILTER FABRIC MAY SE DELETED. CALTRANS CLASS 2 PERMEABLE MATERIAL SHOULD SE COMPACTED TO 90 PERCENT RELATIVE COMPACTION l N0.T TO SCALE