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HomeMy WebLinkAboutSDP 99-07; RANCHO LA COSTA VILLAGE; UPDATE REPORT FOR GRADING AND SITE PLANS; 2001-01-09GEOCON INCORPORATED Project No. 05467-12-06 January 9, 2001 Simac Construction, Inc. 15938 Bernardo Center Drive San Diego, California 92127 Attention: Subject: Mr. Richard Simis RANCHO LA COSTA VILLAGE CARLSBAD, CALIFORNIA UPDATE REPORT GEOTECHNICAL CONSULTANTS References: 1. Preliminary Grading Plan -Rancho La Costa Village, prepared by Stuart Engineering, dated November 11,2000. Gentlemen: 2. Albertsons Drug Store No. 9528, S. w.e. Rancho Santa Fe Rd. & La Costa Ave., Carlsbad, California, Sheet 1.1 (Site Plan), prepared by Courtney + Le Architects, dated December 11, 2000. 3. Update Soil and Geologie Investigation, La Costa Village Retail Center, Carlsbad, California, prepared by Geocon Incorporated, dated December 23, 1997. In accordance with your request and our proposal No. LG-00684 dated December 11,2000, we have reviewed the referenced grading plan and site plan. The purpose of this review was to evaluate the currently proposed grading with respect to the conclusions and recommendations presented in the referenced update soil and geologic investigation report, specifically regarding the design of the soil shear key. Based on our review of the revised grading and site plans, it is our opinion that the conclusions and recommendations as presented in the previous update geotechnical report remain applicable to the currently proposed project development. This includes the recommended dimensional configuration of the soil shear key to be constructed for the buttress/stability remedial grading as well as the recommended grading specifications provided as Appendix D of that report. Should you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, DavidF. Lea RCE 22527 (2) (2/del) Addressee Stuart Engineering Attention: Mr. Stuart Peace 6960 Flanders Drive • San Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159 '. UPDATE SOIL AND GEOLOGIC INVESTIGATION LA COSTA VILLAGE RETAIL CENTER CARLSBAD, CALIFORNIA PREPARED FOR BYCOR GENERAL CONTRACTORS, INC. SAN DIEGO,CALIFORNIA DECEMBER 1997 I I I I I I I I I I I I I I I I I I I -~--~_O_~_P_~_R_~_T_~_D------------------------------GE-O-TE-C-HN-IC-A-L-C-O-NS-U-ITA~N-~·~ Project No. 05467-12-04 December 23, 1997 Bycor General Contractors, Inc. 6867 Nancy Ridge Drive, Suite A San Diego, California 92121 Attention: Mr. Rich Byer '. Subject: LA COSTA VILLAGE RETAIL CENTER CARLSBAD, CALIFORNIA UPDATE SOIL AND GEOLOGIC INVESTIGATION Gentlemen: In accordance with your authorization and our proposal dated December 17, 1997, we have reviewed and updated our original soil and geologic investigation report for the subject .project (dated August 17, 1987 Project No. D3930-H01). The accompanying report presents the findings of our study and our conclusions and recommendations relative to the geotechnical engineering aspects of developing the project as presently proposed, including the stability analysis for remedial grading along the southern property line. If you have any questions regarding this report, of if we may be of further service, please contact the undersigned at your convenience. Very truly yours, RCE22527 DFL:AS:bas (6/del) Addressee 6960 Flanders Drive • San Diego, California 92121·2974 • Telephone (858) 558-6900 • Fax (858) 558·6159 I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS 1. PURPOSE AND SCOPE ................................................................................................................... 1 2. SITE AND PROJECT DESCRIPTION ............................................................................................. 2 3. SOIL AND GEOLOGIC CONDITIONS .......................................................................................... 2 3.1. Previously placed fill (Qaf) ...................................................................................................... 2 3.2. Undocumented fill (Qudf) ........................................................................................................ 3 3.3. Compacted Fill (Qcf) ............................................................................................................... 3 3.4. Topsoils (unmapped) ................................................................................................................ 3 3.5. Slopewash (Qsw) ...................................................................................................................... 3 3.6. Alluvium (Qal) ......................................................................................................................... 3 3.7. Surficial Landslide Debris (Qlsf) ............................................................................................. 3 3.8. Torrey Sandstone (Tt) ................ ; ....................................................................................... : ..... 4 3.9. Delmar Formation (Td) ............................................................................................... , ............ 4 4. GEOLOGIC STRUCTURES ............................................................................................................. 5 5 . GROUNDWATER ............................................................................................................................ 5 6. GEOLOGIC HAZARDS ................................................................................................................... 5 6.1. Faulting and Seismicity ............................................................................................................ 5 6.2. Landslides ................................................................................................................................. 6 7. GEOTECHNICAL LAND USE CHARACTERISTICS ................................................................... 6 8. STABILITY ANALYSIS .................................................................................................................. 7 8.1. General ..................................................................................................................................... 7 8.2. Design Parameter Selection ............................................................................................ -......... 7 9. CONCLUSIONS AND RECOMMENDATIONS ......................................................................... ; ... 8 9.1. General ..................................................................................................................................... 8' 9.2. Groundwater ............................................................................................................................. 8 9.3. Grading ..................................................................................................................................... 8 9.4. Soil and Excavation Characteristics ....................................................................................... 10 9.5. Bulking and Shrinkage Factors .............................................................................................. 10 9.6. Slope Stability ........................................................................................................................ 10 9.7. Foundations ............................................................................................................................ 11 9.8. Retaining Walls and Lateral Loads ........................................................................................ 13 9.9. Slope Maintenance ................................................................................................................. 15 9.10. Drainage ............................................................................................... ~ ............................... 15 9.11. Grading Plan Review ....................................................................................... : .................... 15 LIMITATIONS AND UNIFORMITY OF CONDITIONS I I I I I I I I I I I I I I I I. I I I TABLE OF CONTENTS (continued) MAPS AND ILLUSTRATIONS Figure 1, Geologic Map Figures 2-3, Geologic Cross Sections Figure 4, Typical Shear Key Detail Figure 5, Surficial Slope Stability Analysis APPENDIX A FIELD INVESTIGATION Figures A-I -A-9, Logs of Borings Figures A-lO -A-17, Logs of Trenches APPENDIXB LABORATORY TESTING Table B-1, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table B-II, Summary of Laboratory Expansion Index Test Results Table B-III, Summary of Direct Shear Test Results APPENDIXC SHEAR KEY AND SLOPE STABILITY ANALYSIS APPENDIXD RECOMMENDED GRADING SPECIFICA nONS I I I I I I I I I I I I I I I I I I I UPDATE SOIL AND GEOLOGIC INVESTIGATION 1. PURPOSE AND SCOPE This report presents the findings of our soil and geologic investigation for the proposed La Costa Village Retail Center in the City of Carlsbad, California. The purpose of this study was 10 evaluate the investigation of surface and subsurface soil and geologic conditions at the site and, based on the conditions encountered, provide updated recommendations relative to the geotechnical engineering aspects of developing the site as presently proposed. A site visit was performed on December 17, 1997. The property was observed to be in basically the same condition as reported in the original geotechnical report with the exception of the southern boundary conditions that have changed during the construction of the adjacent Parkview West project. The scope of the investigation included a-review of the following: 1. Soil and Geologic Investigation for Rancho La Costa Plaza, Carlsbad, California, Project No. D-3930-H01, prepare by Geocon Incorporated, dated August 17, 1987. 2. Supplemental Slope Stability Analysis for Rancho La Costa Plaza, Carlsbad, California, Project No. D-3930-H02, prepared by Geocon Incorporated, revised dated September 6, 1988. 3. Revised Supplemental Slope Stability Analysisfor Rancho La Costa Plaza, Carlsbad, California, prepared by Geocon Incorporated, dated December 5, 1994. 4. Geotechnical Investigation for Park View West, Carlsbad, California, Project No. D-3641-M01, prepared by Geocon Incorporated, dated June 2, 1986. 5. Updated Report for Park View West, La Costa Area, Carlsbad, California, prepared' by Geocon Incorporated, dated November 1, 1995. 6. Update Report, Rancho La Costa Plaza, Carlsbad, California, Project No. 05461-12-02, prepared by Geocon Incorporated, dated December 13, 1995. 7. Final Report of Testing and Observation Services for Park View West, Carlsbad, California, prepared by Geocon Incorporated, dated May 28, 1997. The original field investigation consisted of a site reconnaissance by our project geologist, .the drilling of five large-diameter borings and the excavation of 12 exploratory trenches. Laboratory tests were performed on selected soil samples to evaluate pertinent physical properties of the soil conditions encountered. Details of the field exploration and laboratory testing performed for the project are presented in Appendices A and B, respectively. Data collected during the construction of the existing buttress fill along the southern property boundary, within the Parkview West project, has also been utilized in the evaluation for this study. Project No. 05467-12-04 - 1 -December 23, 1997 I I I I I I I I I I I I I I I I I I I The base map used for this investigation consisted of a 40 scale grading plan prepared by Sillman Wyman & Associates, dated November 19, 1997 (Figure I). The results of the field investigation are compiled on Figure 1 depicting the site conditions and geology as well as boring and trench locations. Geologic cross-sections are presented on Figures 2 and 3. The recommendations presented herein are based on the analysis of the data obtained from the exploratory excavations, laboratory tests and our experience with similar soil and geologic conditions. 2. SITE AND PROJECT DESCRIPTION The roughly triangular-shaped subjec~ site comprises approximately 6 acres of presently undeveloped land located directly southeast of the intersection of Rancho Santa Fe Road and La Costa Avenue (see Figure 1). The site is characterized by moderate southeasterly sloping terrain, with elevations varying from a high of approximately 310 feet above Mean Seal Level (MSL) in the northern corner to a low of approximately 258 feet MSL along the southern boundary. Parkview West project, which has recently been developed, borders the site to the south. The majority of the property is undeveloped, with the exception of a few narrow dirt roads and trails. Fill soils associated with a buttress fill and roadway fill occur at the extreme southwest, south, and southeast portions of the site respectively. Vegetation consists of native grasses and scattered shrubs. Project grading plan prepared by Sillman Wyman & Associates entitled La Costa Retail, dated November 19, 1997 indicates that it is proposed to develop the site into one large sheet-graded commercial lot with maximum fill slope heights of35 feet, at 2 to 1 slope inclinations or flatter. It is anticipated that the site will be graded to receive a service station and a commercial complex consisting of one-and possibly two-story structures. 3. SOIL AND GEOLOGIC CONDITIONS Seven surficial general soil types and two geologic formations were encountered during the investigation. These include, previously placed fill, undocumented fill, compacted fill, topsoil; slopewash, alluvial soils, surficial landslide debris and formation materials associated with the Torrey Formation and Delmar Formation. Each of the surficial and formational soil types are described below. 3.1. Previously placed fill (Qaf) Fill soils are present in the southeast corner of the site and comprise a narrow wedge of fill associated with the existing La Costa Avenue roadway. Project No. 05467-12-04 -2-December 23, 1997 I I I I I I I I I I I I I I I I I I 3.2. Undocumented fill (Qudt) Small areas of end-dumped shallow, rocky, or trashy fill also exist along the slopes and in small ravines in the southeast portion of the site. 3.3. Compacted Fill (Qct) Compacted fill was placed in conjunction with construction of the buttress fill along the southern boundary and under the observation and testing services of Geocon Incorporated during grading of the Parkveiw West project. 3.4. Topsoils (unmapped) Topsoils are present over the majority-of the project area and range in thickness from approximately 1 to 2 feet consisting of soft, dark brown silty to sandy clay. Due to the unconsolidated nature and expansion potential of the surficial topsoils, removal and selective placement in deeper fills will be required as recommended hereinafter. 3.5. Siopewash (Qsw) Accumulations of soft sandy clays and loose clayey sands ranging in thickness from approximately 5 to 9 feet occur in the southeast portion of the site (see Figure 1) along the property boundary the slopewash material becomes undifferentiated with surficial landslide debris which was encountered during the construction of the buttress fill. Due to the unconsolidated nature of these deposits, complete removal and recompaction will be required as recommended hereinafter. 3.S. Alluvium (Qal) The alluvial soils are composed of loose, moist to saturated, medium to dark brown clayey sands and soft, damp, dark brown, silty clays that have accumulated near the base of slopes or within gully bottoms. Due to the unconsolidated nature of these deposits, removal and recompaction will be required as recommended hereinafter. 3.7. Surficial Landslide Debris (Qlsf) Relatively shallow surficial landslide features were encountered in the southeastern portion of the site (see Figure 1). An arcuate-trending fracture system was observed bordering a small promontory on a northeast-facing slope of approximate elevation 272 feet above MSL. Some of the fractures showed a horizontal separation (within approximately one year) of approximately 2 inches. Te~t Trench No.8 located in the upper central portion of the slide debris encountered soft sandy clays and Project No. 05467-12-04 -3-December23,1997 I I I I I I I I I I I I I I I I I I I loose, very clayey fine sands ranging from 4 to 6 feet in thickness. Adverse bedding planes and low- angle sheared surfaces dipping out-of-slope, combined with saturated conditions induced by a perched water table at the underlying Torrey SandstonelDelmar contact are suspected to be responsible for the shallow landslide features. Due to the unconsolidated nature of these deposits, removal and recompaction will be required as recommended hereinafter. 3.8. Torrey Sandstone (Tt) The Tertiary-aged Torrey Sandstone Formation consisting of dense, light tan to reddish-brown, siity fine-grained sandstones interbedded with brown clayey siltstones, was encountered throughout the majority of the site at elevations approximately between 266 to 312 feet above MSL. The sandstones and siltstones are typically t~in-bedded and are near horizontal in attitude, although the coarser-grained sandstones can be massive, or broadly cross-bedded. The interbedded siltstone beds, which occur approximately between 280 and 300 feet above MSL, contain cemented concretion beds with fossil shells. The majority of the excavation of this unit should encounter little difficulty with conventional heavy-duty grading equipment. However, some localized areas of highly-cemented concretions may be encountered requiring heavy ripping to facilitate excavation. Some oversize cemented chunks may be generated and should not be placed within 3 feet of the finish grade The majority of this unit is characterized by low-expansive san?y soils, but may contain interbedded clayey siltstones, particularly across the central portion of the site, and may exhibit moderate to high expansion potential. The clayey portions may require selective grading or specially designed foundations. The moderately to highly expansive material generated from the claystones. should be placed in the deeper canyon fills .. 3.9. Delmar Formation (Td) The Tertiary-aged Delmar Formation consisting of soft to very hard, moist to saturated, greenish- gray to dark gray claystones was encountered generally below elevation 266 feet MSL. Subsurface observations of exploratory borings within the Delmar Formation in this area indicate the presence of low-strength claystones between approximate elevations of 235 and 260 feet above MSL. Inclinations of bedding plane shear zones within the claystones range from a few degrees to as much as 35 degrees in south direction. Remolded clay gouge zones over one inch thick (Boring Nos. B-5 and B-7, D-3641-M01) and dipping 2-5 degrees southward were also along shears in the claystone member. The claystones of the Delmar Formation often posses low shear strength and, as encountered, exhibit both randomly oriented remolded clay seams and bedding plane shear zones. Cut slope stabilization measures as well as deeper, wider fill keys should be anticipated for Project No. 05467-12-04 -4-December 23, 1997 I I I I I I, I I I I I I I I I I I I I excavations within the low-strength claystones. Excavation of this unit should encounter little difficulty with conventional heavy-duty grading equipment. In addition to possessing relatively low-shear strength and adverse structures, the more clayey portions of this formation are highly expansive and often require selective grading or specially designed foundations. The moderately to highly expansive materials generated from the claystones should be placed in the deeper fills. 4. GEOLOGIC 'STRUCTURES Bedding attitudes within the Tertiary-aged sediments are generally horizontal with local variations in dip of several degrees being caused by.hillside creep in claystone or distortions of strata near low- angle shear zones or by drag near faults, A west-northwest striking fracture system was interpreted, from aerial photos and apparent offsetS" of Tertiary-aged strata in the central portion of the site, to represent a fault. 5. GROUNDWATER A number of water seeps were encountered in a majority of the boring excavations, and in several of the trench excavations. The seepage was especially notable along low-angle gypsum filled shears within the Delmar Formation claystones, or in the sandstones near the base ofthe Torrey Sandstone Formation. Elevations of the seepage ranged between approximate elevations of 250 and 280 feet MSL (Mean Sea Level). 6. GEOLOGIC HAZARDS 6.1. Faulting and Seismicity It is our opinion, based on our field investigation and review of aerial photographs andpubl~shed geologic maps, the site is not located on any active or potentially active fault trace as defined by the California Division of Mines and Geology. The Rose Canyon and Elsinore Fault Zones, the closest active faults, lie approximately 7 and 24 miles to the west and northeast, respectively. As shown 'on Table 6.1, a Maximum Probable Earthquake of Magnitude 5.9 occurring on the Rose Canyon fault could result in a peak site acceleration of approximately 0.17g (Table 6.1). Other active faults listed on Table 6.1 are more distant from the site and, hence, ground shaking from earthquakes on those faults will be less intensive. It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of a major earthquake along any of the above-mentioned faults; however, the seismic risk at the site is not considered significantly greater than the surrounding area Project No. 05467-12-04 - 5 -December 23, 1997 I I I I I I I I I I I I I I I I I I I TABLE 6.1. DETERMINISTIC SITE PARAMETERS FOR SELECTED FAULTS (EQFAULT Computer Program-Blake 1996) Approximate Maximum. Credible Event Maximum Probable Event Abbreviated Distance Maximum Peak Site Maximum Peak Site Fault Name (mi.) Credible Acceleration Probable Acceleration (Mag.) (g) (Mag.) (g) Casa Lorna-Clark (S. Jacinto) 48 7.00 0.04 7.00 0.04 Catalina Escarpment 41 7.00 0.05 6.10 0.03 Coronado Bank-Agua Blanca 22 7.50 0.13 6.70 0.09 Elsinore 24 7.50 0.12 6.60 0.07 Glen Helen-Lytle Cr-Clremnt 52 7.00 0.03 6.70 0.03 La Nacion 17 6.50 0.10 4.20 0.03 Newport-Inglewood-Offshore t3 7.10 0.18 5.90 0.10 Rose Canyon 7 7.00 0.30 5.90 0.17 San Diego Trough-Bahia Sol. 32 7.50 0.08 6.20 0.04 6.2. Landslides Our field exploration confirmed the presence of relatively shallow surficial landslides, (see Figure 1. These relatively shallow features were encountered along the southerly property boundary. Recommendations regarding treatment of encountered surficial landslide debris are presented hereinafter. 7. GEOTECHNICAL LAND USE CHARACTERISTICS The results of the field investigation indicate that weak claystones containing bedding plane shear zones and adversely dipping low-angle shear surfaces exist within the Delmar Formation that would create instability conditions for cut slopes. The cut slope located just south of the property within the Parkview West property has already been buttressed due to the presence of such conditions, and possesses an adequate factor of safety. However construction of the proposed fill slope along the southern property margin will create an adverse impact on the integrity of this buttress. Based on our analyses and experience with similar geologic features, this condition may be mitigated by conventional grading techniques, including construction of shear key fill. Project No. 05467-12-04 -6-December 23, 1997 I I I I I I I I I I I .1 I .1 I I I 8. STABILITY ANALYSIS 8.1. General The stability of the existing buttress along the southern property margin and the impact of proposed grading including the fill slope and the surcharge from the proposed building was evaluated utilizing the SLOPEIW computer program, based on the Simplified Jambu method of slices or Spencer method. The analyses are summarized in Appendix C. A review of the as-build conditions of the Parkview West buttress, the results of the subsurface investigation, laboratory testing and existing and future topography were considered in performing the stability analyses. The computer generated cross-sections included herein represent the most critical configurations which were used tn the analyses. The cross-section presented on Figure 2 is the original geologic sections from which the computer generated sections were derived. 8.2. Design Parameter Selection The shear strength parameters used in analysis are based on the laboratory test result~ and experience with similar soils and geologic conditions. The following table presents the soil strength parameters utilized for this study. TABLE 8.2. SOIL STRENGTH PARAMETERS Soil Type Description Angle of Internal Cohesion Friction <I> (degrees) c (pst) Compacted fill-non-select (Qcfl) 20 300 Compacted fill -select (Qcf2) 30 450 Torrey Sandstone (Tt) 30 400 Delmar Formation (highly fractured claystone) (Tdl) 20 200 Delmar Formation (massive claystone) (Td2) 25 500 Bedding Plane Shear (BPS) 5 200 The results of the evaluation indicates that in order to accommodate the grading as currently proposed, a shear key fill with a minimum bottom width of 20 feet and a minimum penetration of 3 feet below the bedding plane shear is required. Select soils with specified strength parameters, available on site, will be required for grading the shear hey. Details of the construction are discussed in Section 9.6 below. Project No. 05467-12-04 -7-December 23, 1997 I I I I I I I I I I I I I I I I I I I 9.1. 9.1.1. 9.1.2. 9.1.3. 9. CONCLUSIONS AND RECOMMENDATIONS General No soil or geologic conditions were encountered which, in our opinion, would preclude the development of the property as presently planned, provided the recommendations of this report are followed. The site is underlain by surficial soils consisting of existing fill soils, topsoils, slopewash, alluvium, surficial landslide debris and by two formational soil units. The surficial soils, except compacted fill, are not considered suitable for the support of fill or structural loads in their present condition and will require remedial grading. A shear key should be constructed during grading along the southern boundary in order to achieve an adequate factor of safety for the proposed fill slope as recommended hereinafter. 9.2. Groundwater 9.2.1. 9.3. 9.3.1. 9.3.2. 9.3.3. Active water seepage was encountered along the contact between the Torrey Sandstone Formation and the underlying Delmar Formation. The recommendations that follow provide for the installation of subsurface drains within the recommended shear-key fill along the southerly property boundary to reduce the potential for groundwater buildUp. Grading All grading should be performed in accordance with the attached Recommended Grading Specifications (Appendix D) and the City of Carlsbad grading ordinance. Where the recommendations of this section conflict with Appendix D, the recommendations of this section take precedence. Prior to commencing grading, a pre-construction conference should be held at the site with the owner or developer, grading contractor, civil engineer, and geotechnical engineer in attendance. Special soil handling and/or the grading plans can be discussed at that time. Site preparation should begin with the removal of all deleterious matter and vegetation. The depth of removal should be such that material to be used in fills is free of organic matter. Material generated during stripping operations and/or demolition should be exported from the site. Project No. 05467-12-04 -8-December 23,1997 I I I I I I I I I I I I I I I I I I I 9.3.4. The site should then be brought to final subgrade elevations with structural fill compacted in layers. In general, soils native to the site are suitable for reuse as fill if free from vegetation, debris and other deleterious matter. Layers of fill should be no thicker than will allow for adequate bonding and compaction. All fill, including backfill and scarified ground surfaces, should be compacted to at least 90 percent of maximum dry density at approximately 2 percent over optimum moisture content, as determined in accordance with ASTM Test Procedure D1557-91. 9.3.5. Grading operations on the site should be scheduled so as to place oversize rock and expansive soils in the deeper fills and to "cap" the building pads and fill slopes with granular materials having a low expansion potential. 9.3.6. All potentially compressible surficial deposits including existing undocumented fill soils, topsoil, slopewash, alluvium -and surficial landslide debris not removed by planned grading operations should be removed to firm natural ground and properly compacted prior to placing additional fill andlor structures. Deeper than normal benching andlor stripping operations for sloping ground surfaces will be required where thicknesses of potentially compressible surficial deposits are greater than 3 feet. The actual extent of removals will be determined in the field by the soil engineer. Overly wet excavated materials will require drying andlor mixing with drier soils to facilitate proper compaction. Extensive benching operations on the order of 10 feet horizontally should' be anticipated where proposed fills are placed adjacent to the existing fill slope along La Costa Avenue. 9.3.7. The upper 3 feet of all building pads (cut or fill) and 12 inches in pavement areas should be composed of properly compacted or undisturbed formational "very low" to "low" expansive soils. The more highly expansive soils should be placed in the deeper fill areas and properly compacted. "Very low" to "low" expansive soils are defined as those soils that have an Expansion Index of 50 or less when tested in accordance with UBC Table 18- I-B. Cobbles, cemented concretions, and small boulders greater than 12 inches in maximum dimension should not be placed within 3 feet of finish grade. 9.3.8. To reduce the potential for differential settlement, it is recommended that the cut portion of cut/fill transition building pads be undercut at least 3 feet and replaced with properly compacted low expansive fill soils. The undercut should extend from the back of the pad to the street and be graded at a gradient of at least 1 percent towards the street. 9.3.9. Special grading procedures for constructing the shear-key within the fill slope at the south boundary are discussed below. Project No. 05467-12-04 -9-December 23, 1997 I I I I I I I I I I I I I I I I, I I I 9.4. 9.4.1. 9.4.2. 9.5. 9.5.1. Soil and Excavation Characteristics The soil conditions encountered vary from low expansive, silty fine sands derived from the Torrey Sandstone Formation to the medium to highly expansive clayey soils of the Delmar Formation and surficial deposits. In our opinion, the surficial deposits can be excavated with light to moderate effort with conventional heavy-duty grading equipment. Excavation of the formational soils will require moderate to heavy effort. Cemented chunks may be generated during the excavation of each of the formational units. Bulking and Shrinkage Fa~tors Estimates of embankment b~lking and shrinkage factors are based on comparing laboratory compaction tests with the density of the material in its natural state as encountered in the test borings. It should be emphasized that variations in natural soil density, as well as in compacted fill densities, render shrinkage value estimates very approximate. As an example, the contractor can compact the fill soils to any relative compaction of 90 percent or higher of the maximum laboratory density. Thus, the contractor has approximately a 10 percent range of control over the fill volume. Based on the limited work performed to date, in our opinion, the following shrinkage factors can be used as a basis for estimating how much the on-site soils my shrink or swell (bulk) when excavated from their natural state and placed as compacted fills: TABLE 9.5 Soil Unit ShrinklBulk Factor Surficial Deposits 10 to 15 percent shrink Torrey Sandstone, Delmar Formation 4 to 8 percent bulk 9.6. Slope Stability 9.6.1. The slope stability analyses indicates that in order to create an adequate factor of safety for the proposed fill slope along the southern property margins, a 20 feet wide shear key should be constructed in this area. The shear key should penetrate at least 3 feet below the bedding plane shear with a back-cut inclination of 1;1 (horizontal to vertical) see Figures 2 and 3. Project No. 05467-12-04 -10-December 23, 1997 I I I I I I I I I I, I I I I I I 9.6.2. 9.6.3. 9.6.4. 9.6.5. 9.6.6. 9.7. 9.7.1. A subdrain system consisting of a heel drain and panel drains should be installed within the shear key to reduce the potential for groundwater buildup. It is understood that the heel drain will be lower than the storm drain· inlets in the area. The drain may be connected to the existing subdrain of the Parkview West buttress. A typical shear-key (buttress) fill configuration is presented on Figure 4. It should be recognized that the excavation for the shear key involves risk of back-cut failure. In order to reduce the potential for back-cut failure, it is recommended that the shear key be constructed in segments. With a 1:1 back-cut inclination, the, maximum exposure at the bottom of the shear key should be limited to a length of 100 feet. The stability analyses indicates that select materials with minimum soil strength parameters of c = 450 psf and <l> = 30 degrees is required to fill the shear key to an approximate elevation of270 feet MSL. It is our opinion that such material can be derived from the sandy portion of the Torrey Sandstone Formation. The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill slopes should be composed of properly compacted granular "soil" fill to reduce the potential for surface sloughing. All fill slopes should be compacted by back-rolling with a sheepsfoot roller at vertical intervals not to exceed 4 feet and should be track-walked at the completion of each slope such that the fill soils are uniformly compacted to at least 90 percent relative compaction. Surficial Slope stability analysis is presented on Figure 5. All slopes should be planted, drained and properly -maintained to reduce erosion. Foundations The foundation recommendations that follow are for one-to two-story commercial structures and are separated into categories dependent on the thickness and geometry of the underlying fill soils as well as the Expansion Index of the prevailing subgrade soils of a particular building pad. The recommended minimum foundation and interiQr concrete slab design criteria for each Category is presented below. These recommendations are preliminary and will be finalized after the site is graded. Project No. 05467-12-04 -11 -December 23,1997 I I I I I I I I I I I I I I I I I TABLE 9.7. FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Footing Continuous Footing Interior Slab Category Depth 1-to 2-Story Reinforcement Reinforcement I 12 Inches One No.4 bar top and bottom 6 x 6 -10/10 welded wire mesh at slab mid-point II 18 Inches Two No.4 bars top and bottom No.3 bars at 24 inches on center, both directions III 24 Inches Two No.5 bars top and bottom No.3 bars at 18 inches on center, both directions CATEGORY CRITERIA Category I: Maximum fill thickness is less than 20 feet and Expansion Index is less than or equal to 50. Category II: Maximum fill thickness is less than 50 feet and Expansion Index is less than or equal to 90. Category III: Fill thickness exceeds 50 feet, or variation in fill thickness exceeds 10 feet, or Expansion Index exceeds 90, but is less than 130. Notes: 1. All footings should have a minimum width of 12 inches. 2. Footing depth measured from lowest adjacent fmish grade. 3. All concrete slabs should be at least four inches thick for Categories I and II and 5 inches thick for Category III. 4. All interior concrete slabs should be underlain by at least four inches of clean sand (or crushed rock). 5. All slabs expected to receive moisture sensitive floor coverings or used to store moisture sensitive materials should be underlain by a Visqueen moisture barrier covered with at least 2 inches of the clean sand recommended in No.4 above. 9.7.2. Foundations for either Category I, II, or III may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (pst) (dead plus live load). This bearing pressure may be increased by up to one-third for transient loads such as wind or seismic forces. 9.7.3. 9.7.4. No special sub grade pre saturation is deemed necessary prior to lacing concrete, however, the exposed foundation and slab subgrade soils should be sprinkled, as necessary, to maintain a moist condition as would be expected in any such concrete placement. Where buildings or other improvements are planned near the top of a slope steeper than 3: 1 (horizontal:vertical), special foundations andlor design considerations are recommended due to the tendency for lateral soil movement to occur. Project No. 05467-12-04 -12-December 23, 1997 I I I I I I I' I I I 'I I I, I I I I I' I • For fill slopes less than 20 feet high, building footings should be deepened stich that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. • Where the height of the fill slope exceeds 20 feet, tpe minimum horizontal distance should be increased to Hl3 (where H equals the vertical distance from the top of the slope to the toe) but need not exceed 40 feet. For composite (fill over cut) slopes, H equals the vertical distance from the top of the slope to the bottom of the fill portion of the slope. An acceptable alternative to deepening the footings would be the .use of a post-tensioned slab and foundation system or increased footing and slab reinforce- ment. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. • For cut slopes in dense formational materials, or fill slopes inclined at 3;'1 (hori- zontal;vertical) or flatter, the bottom outside edge of building footings should be at least 7 feet horizontally from the face of the slope, regardless of slope height. • Although other improvements which are relatively rigid or brittle, such as concrete flatwork or masonry walls may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures which would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 9.7.5. The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soils (if present), differential settlement of deep fills or fills of varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entry slab corners occur. 9.8. 9.8.1. Retaining Walls and Lateral Loads Retaining walls not restrained at the top and having a level backfill surface shOUld be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of30 pounds per cubic foot (pct). Where the, backfill will be inclined at no steeper than 2.0 to 1.0, an active soil pressure of 40 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1; 1 plane extending upward from the base of the wall possess an Expansion Index of less than 50. For those lots with finish grade soils having an Expansion Index greater than 50 and/or Project No. 05467-12-04 -13 -December 23, 1997 I I I I I I I I I I I 'I I I I I I I I 9.8.2. 9.8.3. 9.8.4. 9.8.5. 9.8.6. where backfill materials do not conform to the above criteria, Geocon Incorporated should be consulted for additional recommendations. Unrestrained walls are those that are allowed to rotate more than O.OOlH at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf (where H equals the height of the retaining wall portion of the wall in feet) should be added to the above active soil pressure. All retaining walls should be provided with a drainage system adequate to prevertt the buildup of hydrostatic forces and should be waterproofed as required by the project architect. The use of drainage openings through the base of the wall (weep holes, etc.) is not recommended where the seepage could be a nuisance or otherwise adversely impact the property adjacent to the base of the wall. The above recommendations assume a properly compacted granular (Expansion Index less than 50) backfill material with no hydrostatic forces or imposed surcharge load. If conditions different than those described are anticipated, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. In general, wall foundations having a minimum depth and width of one foot may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet below the base of the wall has an Expansion Index of less than 90. The proximity of the foundation to the top of a slope steeper than 3: 1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is anticipated. For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid density of 3 00 pcf is recommended for footings or shear keys poured neat against properly compacted granular fill soils or undisturbed natural soils. The allowable passive pressure assumes a horizontal surface extending at least 5 feet or three times the surface generating the passive pressure, whichever is greater. The upper 12 inches of material not protected by floor slabs or pavement should not be included in the design for lateral resistance. An allowable friction coefficient of 0.4 may be used for resistance to sliding between soil and concrete. This friction coefficient may be combined with the allowable passive earth pressure when determining resistance to lateral loads. The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon Incorporated should be consulted for additional recommendations. Project No. 05467-12-04 -14-December 23, 1997 I I I I I I I I I I I I I I I I I I 9.9. 9.9.1. 9.10. Slope Maintenance Slopes that are steeper than 3: I (horizontal:vertical) may, under conditions which are both difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The instability is typically limited to the outer three feet of a portion of the slope and usually does not directly impact the improvements on the pad areas above or below the slope. The occurrence of surficial instability is more prevalent on fill slopes and is generally preceded by a period of heavy rainfall, excessive irrigCltion, or the migration of subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result from root growth, soil expansion, or excavation for irrigation lines and slope planting, may also be a significant contributing factor to surficial instability. It is, therefore, recom- mended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or properly recompacted, (b) irrigation systems be periodically inspected and maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be periodically maintained to preclude ponding or erosion. Although the incorporation of the above recommendations should reduce the potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it may be nec~ssary to rebuild or repair a portion ofthe project's slopes in the future. Drainage 9.10.1. Adequate drainage provisions are imperative. Under no circumstances should water be allowed to pond adjacent to footings. The building pads should be properly finish graded after the buildings and other improvements are in place so that drainage water is directed away from foundations, pavements, concrete slabs, and slope tops to controlled drainage devices. 9.11. Grading Plan Review 9.11.1. The soil engineer and engineering geologist should review the grading plans prior to finalization to verify their compliance with the recommendations of this report ~nd determine the need for additional comments, recommendations and/or analysis. The recommended shear key fill should be shown on the final grading plans. Project No. 05467-12-04 -15 -December 23, 1997 I I' I I I I I I I I I I I 1 I I I: I I 1. 2. 3. LIMITATIONS AND UNIFORMITY OF CONDITIONS The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If any variations or undesirable conditions are encountered during construction, or if the proposed construction will differ from that anticipated herein, Geocon Incorporated should be notified so that supplemental recommendations can be given. The evaluation or identification of the potential presence of hazardous or corrosive materials was not part of the scope of services provided by Geocon Incorporated. 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 contain~d 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, 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. Project No. 05467-12-04 December 23, 1997 m r m < l> -i o Z A 300' 280' 260' 240' 220' , ,. I: it 11 { \'1 I PROPOSED GRADE BUILDING PAD ~ ~I PARKVIEW WEST PROJECT ~" «~'-------. 8-4 ---------....~ I "~ QISf I ~ '--........~ -~,--....9Cf I ~ . ~7""" LJl Td 1 ~ Tt Td1 Td2 Td2 Td2 ?=======:::=:::::::: ,0' BEDING PLANE SHEAR (BPS) ?=~~=::::::::=:~==?~~==~=== CROSS-SECTION A-A' SCALE: 1" = 20' (HORIZ. = VERT.) LEGEND QCf ........ COMPACTED FILL Qlsf ......... SURFICIAL LANDSLIDE DEBRIS Tt .......... TORREY SANDSTONE Td ......... DELMAR FORMATION I I,' I I , LA COSTA VILLAGE RETAIL CENTER lCARLSBAD, CALIFORNIA I Td AI 260' 240' 220' GEOCON INCORPORATED e GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE· SAN DIEGO, CAUFORNIA 92121·297.4 PHClN: 619 558-6900 • FAX 619 558·6159 PROJECT NO. 05467-12-04 FIGURE 2 DATE 12 -23 - 1997 8 300' Tt ~ Ull-1 ~ T)V ....J w 260' 240' 220' .. '0':·.' ."0 -_ :~. :." ., '." ~ ..•.. , . .: ...... . : ... ;.' i r ".-.>' ·:.:".0· ..... " ._. I I . LA C<DST A VILLAGE RETAIL CENTER !CARLSBAD, CALIFORNIA I I -• l I PROPOSED BUILDING PAD I ' PROPOSED GRADE ........................ / I-PARK VIEW WEST PROJECT • ...... Tt ......... ...... ............ ... , ......... ............ ...... ...... ............ Tt ~ .." ... , .................. -n \~ Td2 Td2 1D 1 PROPOSED SHEARKEY ~ ~L-----------------B-E-OO-I-NG---P~ESH~(BPS) Td1 \ ?==~===~~~=~~?~===~==~~==~ \ . Td1' w, , , Td2 CROSS-SECTION B-B' SCALE: 1" = 20' (HORIZ. = VERT.) LEGEND QCf ........ COMPACTED FILL Tt ......... TORREY SANDSTONE Td ......... DELMAR FORMATION iJ1 Td~----__ Qcf 1 ---... '< Td1 ~=~=~~=~=~=~ Td2 8' 260' 240' 220' GEOCON INCORPORATED o GEOTECHNICAL CONSULTANTS 6960 FLANCERS DRIVE· SANDEGO, CALIFORNIA 92121·2974 PHONE 619 558·6900 • FAX 619 558-6159 PROJECT NO. 05467 -12 -04 FIGURE 3 DATE 12 -23 -1997 I __ ----------------------------~ I I I I I I I I I I NOTES; I 1-E=:aace. baci:z:izt ar: 1.0 m 1.0 fndinarina., ~. Base of tbe marb:rsDaaJ4l)e-3 (ccbdalrdlaJatN:Kst.c:oaear2S'" liljii!i!d bysail. .'gi"-c Sapia(.a ali"· Fin af5&pwCiiilCiIa ct...... " .. -, I ~ SJlar-kl:r-CO be g:""l'-~ of P''''4*ti, "."tN-' p:bP'fersail widt. .. sIIar: . :..... . .sa:eaagctLPWO'h '., Qc+"-&1!c.-~~. <-: .. : ... :;,., ':: .'.' ;.' ... ;.:: ........ . . ~'.;: 4:. sz..: • .,. L ,c aa::aa:iaa&*-iIlbeptGiididwidt.l* " h j ,Jw. ,., .... ~ (Mif""'n;n. l"=-; a&"~'~:appc . ..,.3IJIIIK • a ..... _ ar,~ I by24-iadts.xsau.twidl1!br.iCi iwi ~NaIa~ A"""" .... clmiawlit.ZM(IIilwd . wDare-uas of ""P'P mrci. • cL. D .. i '.' pIIIId:I.*-iILlIei i '. "111ra-: !ram tbII-tDp of m.cmr ......... ciaa:\L . I S-Ha: i i i'l to _l~ opcD'8I:adt:d;c:msizcd.radI: en d !)N!~ Draltappaoverd>l!JI:et1abtic:: (Mizadl4ON or~ . . .' 0.. CoiJ.el:l:!:pq.CObe~"·' 'Aih elf. 'i.Pctbi 1 .. rf;i.....,..!VC':sc:fiIerlpIe=., .or~am1Sapel:t.to cDiu.:l.paCiiiiLOh ..• h aupptUNd;:~ .' I~---------------TY--p-IC-~...-~-S~H-~--·m-~-~---.~D~·~~·~:~~~·i~~.~-.. ~~~ .. ~ .. -.. ...-------~ I LA COSTA VILLAGE RETAIL CI;NTER CARJ,.SBAD, CALlFOR~IA I ~~----------------··~------~~~ FIGURE 4 I I I I I I I I I I I I I I I I I I I I PROJECTNO 05467-12-04 ASSUMED CONDITIONS: Slope Height Depth of Saturation Slope Inclination Slope Angle = Infinite = 3 feet (Horizontal :Vertical) = 26.5 degrees Unit Weight of Water Total Unit Weight of Soil Angle of Internal Friction Apparent Cohesion H Z 2:1 i Yw YI = 62.4 pounds per cubic foot = 135 pounds per cubic foot = 30 degrees $ C = 200 pounds per square foot Slope saturated to vertical depth Z below slope face. Seepage forces parallel to slope face ANALYSIS: FS= = 1.85 r I Z sini cosi REFERENCES: (1) Haefeli, R. The Stability a/Slopes Acted Upon by Parallel Seepage, Proc. Second International Conference, SMFE, Rotterdam, 1948, 1,57-62. (2) Skempton, A. W., and F. A. Delory, Stability a/Natural Slopes in London Clay, Proc. Fourth International Conference, SMFE, London, 1957,2,378-81. SURFICIAL SLOPE STABILITY ANALYSIS LA COSTA VILLAGE RETAIL CENTER CARLSBAD, CALIFORNIA FIGURES , , ~: I':' :"<-:" ':, , .. :', ~. ," I' ..... ;. ,., " .' . ~. -'.: :;.. , ':~. -:, "'~"I-" .. ,';: -,:,;,:.> ." ", " "... .. " ; :.: ... ; .... !.,,: -',', ~;. ,", .. . . ;' . -,' I I I I I I I I I I I I I I I I I I I APPENDIX A FIELD INVESTIGATION The field investigation was perfonned during the period of July 22 through July 24, 1987, and consisted of a visual site reconnaissance and the excavation of 5 large-diameter borings and 12 backhoe trenches. The approximate locations of the exploratory borings and trenches are shown on Figure 1. The large-diameter borings were advanced to depths ranging from 31 to 39.5 feet below existing grade using an E-IOO truck-mounted drill rig equipped with a 30-inch-diameter bucket auger. Relatively undisturbed samples were obtained by driving a 3-inch split-tube sampler 12 inches into the undisturbed soil mass with blows from the drill rig Kelly bar. The sampler was equipped with I- to 6-inch by 23/s-inch brass sampler rings to facilitate removal and testing. Bulk samples were also obtained. The backhoe trenches were advanced to depths of 8 to 15 feet using a JD 555 trackhoe equipped. with an I8-inch-wide bucket. Disturbed bulk and chunk samples were o~tained at selected locations in the trenches. The soils encountered in the borings and backhoe trenches were visually examined, classified, and logged. Logs of the borings and backhoe trenches are presented on Figures A-I through A-17. The logs depict the soil and geologic conditions encountered and the depth at which samples were obtained. Project No. 05467-12-04 December 23, 1997 I File No. D-3930-HOl IAugust 17, 1987 a: I I I I I I I I I I I I I ::: ... li:%w w-w o ... -0 -- -2 --- I-4 ----6 --.' I-8 - ~ - 1-10- ~ - ... 12 - -- ~ 14 - I-- -16 --- -18 - ~ . I-20 - ~ - -22 --- I-24 • I-- I-26 • -- d z w .... ... ::l: ~ B1-1 Bl-2 Bl-3 Bl-4 Bl-5 Bl-6 Bl-7 >-I!! 8 ~ .... 0 0 % j!; ~ :l 0 Vf I I IX I I I' .' , xV '. '/ .. ' . · ' ... · . :-I·:/:·j·: ·r·lf · .... .... :·fft .' . :-i':r 'l-r. .. ',:1'<1:: j~: :'(('l " . :J:I:{ :--·I:J· ~:"·CI·:·. :.fT:I:: ':I:rl:' .' . ' ' /jl l~ % I I J.X 1 1 ~iii u cJ .... cd -:;) ~- CH CL ,- SM CL-CH ~--, '\ " / I I -28 ... lli 11)/ // EII_~I~ / .--. B1-S BORING 1 sw, ?: wI-j:ut: 311 7/23/87 ~~U! ~,.; a:..: ELEVATION DATE DRILLED :;)% tu!!l~ wcJ ~~ 30" Bucket Rig ffi:ai5 eo: 0% EQUIPMENT a: ::l:8 ... a:. c , , MATERIAL DESCRIPTION TOPSOIL Soft, moist to wet, dark brown, Silty CLAY - - TORREY SANDSTONE 4 105.0 18.9 Hard, moist, orange-brown, Sandy ~ ~ULK. ~ AMPLE CLAYSTONE l- i\ ~ Dense, moist, light tan-white, Silty, - fine SANDSTONE; massive ~, I- 6 I--BULK :iAMPLE --. l- I--6 112.9 17.0 ~ontact/bedding nearly horizontal, - ±1-2° w/!s." thick gypsum layers - DELMAR FORMATION Stiff, moist, medium greenish-gray-brown, I- Silty CLAYSTONE; 1/16-1/2" thick gypsum 3 106.7 20.0 .. layers common ~ULK AHPLE --,-cemented zone 2-3" - J _gypsum layers 1/8-1/2" very common as -r laminations 1-2" apart l- I 0- J ~rd, wet, medium to dark gray, very Clayey -.i. SILTSTONE; carbonaceous (lignitic); (potential low pH) - ,_seepage along ~" thick gypsum layer - lJ 9 1,17.2 16.4 Figure A~l, Log of Test Boring 1 CONTINUED NEXT ~AGE I' SAMPLE SYMBOLS 0_ SAMPl.ING UNSUca:SSFUL ~ _ DISTURBED OR BAG SAMPt.E I1_STANDARD PENETRATION TEST il_CHUNK SAMPt.E • :... DRIVE SAMPt.E (UNDISTURBEDI ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDtnONS SHOWN HEREON APPLIES ONLY ATTHESPECIFICBORING OR TRENCH LOCATION AND ATTHE DATE INDICATED. ITIS NOTWARRANTEDTO BE REPRESENTAnvEOFSUBSURFACECONDmONSATOTHER LOCATIONS AND TIMES. I File No. D-3930-H01 I August 17, 1987 a: ~ 0 > :x: ... z 8 ~ tzw w -' ... 0 z w-w a. o ... ~ i!: :::> ~ ::::; ~ CI I -30 en ~;;; -'d (Jill ==s g- BORING 1, CONTINUED Sw. !; ~~t wl# 311 7/23/87 ~..: a:.., ELEVATION DATE DRILLED a:~Us :::>z wtj "w tu~~ 011: en __ 30" Bucket Rig zen ... > gg EQUIPMENT ~~CD a: 0 MATERIAL DESCRIPTION I I B1-9 X/ dark gray, Clayey SILTSTONE; -BULK AMPLE I I I I I I I I I I I I -~ -32 - ... -, ... 34 - -.. ... 36- ... · I-38· ... · I'"' 40 --- -- ... - i-- I'"' .. -· ... --- l-· ... --· I'"' --- i-- l-· I-- i---... -.. Figure 'T ML Hard, moist, i/ massive, carbonaceous (lignitic), possible -.... V low pH / ~ l/ ~(: .. 1---.... --becomes sandy !- .:;/. -:-: .' ' .. ~:'-.. · . / - '.~."" -~' .. . · . L'~ . . ~<' ' . i-· . .. :,:t ... . I- \ Very dense, moist, medium gray, Clayey SILTSTONE: cemented zone with fossil shells ~ -- 1 BORING TERMINATED AT 39.5 FEET l- --... - I- ------... ... ---. - A-2, Log of Test Boring 1, continued I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL 18l_ DISTURBED OR BAG SAMF't.E I)_STANDARD PENETRAnON TEST iii_CHUNK SAMF't.E • _ PRIVE SAMF't.E (UNDISTUI;IBEDI ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OFSUBSURFACECONDInONS SHOWN HEREON APPLIES ONLY ATTHESPECIFICBORING OR TRENCH LOCATION AND ATTHE DATE INDICATED. ITISNOTWARRANTEDTOBEREPRESENTATIVEOFSUBSURFAC ECONDInONSATOTHER LOCAnONSAND nMES. I File No. D-3930-H01 I August 17 , 1987 cr BORING 2 0 >-... rn Z 8 i m-aw . ~ w# J: .. '" _uti: I tztj w ..J Q -0 296 7/23/87 ~~., ~&&; cr,.: ..J 0 u'" ELEVATION DATE DRILLED ~z w-w CI. Z a;>-~ wo >-w c ... ~ J: ::J =::J !a~ ~ ... ~ ~-!ij!ao CC1: ~ 30" Bucket RiS zl/)..J >-~8 Cl EQUIPMENT wWIll a; Q.a; c MATERIAL DESCRIPTION I~ 0 /,1 I TOPSOIL --I~ CL Soft, damp, dark brown, Silty CLAY - I I 2 -V. .. .. TORREY SANDSTONE I--I: ~~: ~: ML Stiff soft, B2-1 ;. to moist, medium-light brown, 2 108.2 19.3 ~ I: 4 --v~ :. ~~ , ' , ' '~ . ' -6 -" ;, " I-~ ;,: " '/ , , , . ,~ -8 -' ,~ 1 ~ -~: :: ',; " ' -. '. .~ '. -10 -B2-2 i~: ' ' .. 1:12 -" :/ .... '~ -: -;~~' ' , . ' ' , ~ -I ' . " .'/ '/ ' 1-14 :. '~ , ' , . :' < ~~ , . --'. " 1 ' '/, "'16 -, '~ -: . '. X ' . --" :~ I t-18 .. .;.::- >\: I' ,l"- =--::(, :r' I 1"20 -1:.1 ::1.:,' B2-3 f--"'1'1' I' I -22 -::(1 :,,:~ I--:.r fl, -24 -:rr,I~' J f--: {{'I.: -26 -. 'I: 1'.1'. I I--'~r "I ::1> -28 .. :-I~ " :-1': , , ' , I~ -',I' I' I'. , I.' 1.'1, Figure A-3, Log of I SAMPLE SYMBOLS Sandy, Clayey SILTSTONE i- i----- ML Hard, moist, light brown, Sandy, Clayey 5 123.9 SILTSTONE f-------cemented zone SM Dense, moist to wet, reddish-brown, Silty, fine SANDSTONE -----becomes saturated ~ t--. ...... ...... " strong seepage /~ ----1-' ........ Jr--nense , wet, light grayish-tan, Silty, fine SANDSTONE ,- SH Test Boring 2 0_ SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR SAG SAMPLE Il_STANDARD PENETRATION TEST iI_CHUNK SAMPLE ---.. -. - ;. I--7 114.9 --. ---- ~ --.. CONTINUED NEXT PAGE • _-DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIESONL Y ATTHESPECIFICBORING OR TRENCH LOCATION AND ATTHE DATE INDICATED.ITIS NOTWARRANTEDTO BE REPRESENTATIVEOFSUBSURFACECONDmONSATOTHER LOCATIONSAND TIMES. 6.2 16.4 I File No. D-3930-HOI II August 17, 1987 a: BORING 2, CONTINUED 0 >-w '" z 8 < ~;;; ,Zw ?: ::t: ... ~ Qut: ~zw w .... ....(.) 296 7/23/87 <~~ '" I .... u", w-w ... 0 z ELEVATION DATE DRILLED z..: a ... ~ i: § =:::1 ~r!i~ W(.) ~-an; ~ ::::i 30" Bucket Rig z"' .... >- C) EQUIPMENT ~~m a: a If-30 MATERIAL DESCRIPTION ".,-'.1-:1'", ... . :-1: ·1:-1:' l- III-32 • ~ DELMAR FORMATION l- I-- CL-CH Hard, moist to wet, medium greenish-gray, ~ I I Silty CLAYSTONE; massive, some fractures II-34 -: l- I-• :J} l- t-36 I BORING TER}fINATED AT 36.0 FEET l-· l- I-· l- I l-· I- l-· l- I l-· l- I-· l- I I--l- t-· l- I-· l- I l-· I- ... · ... I i--l- I-· l- I I--l- i--l- I: -to- · I-- l-· "'" II--l- I--l- I: -l- · I- II--I- Figure A-4, Log of Test Boring 2, continued SAMPLE SYMBOLS 0_ SAMPt.ING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPt.E [I_STANDARD PENEmAnON TEST "_CHUNK SAMPt.E • _ DRIVE SAMPt.E (UNOISTURBED) ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OFSUBSURFACECONomONSSHOWN HEREON APPLIES ONLY ATTHESPECIFICBORING OR TRENCH LOCAnONAND ATTHE DATE INOICATED.ITIS NOTWARRANTEDTO BE REPRESENTAnVEOFSUBSURFACE CONomONSATOTHER LOCAnONSANO nMES. wI-a:,.: :::Iz "'w "' ... ~8 - I File No. D-3930-HOl I August 17 1987 , • cr BORING 3 d >-~ en Z ~ Z 8 ~ en_ Q~t:: w# I :r ... ~III li:z'" w .... 0 (.)cJ 286 7/23/87 ~z ~&&: cr.., .... 0 Z .... 111 ELEVATION DATE DRILLED IZ:~~ j:!z w-w CI. WcJ o ... ::E ;: :> -:> ti~o 0,.; ",j!:! ;:; ::; !f ~-. 30" Bucket Ri~ zll)iiI >-~8 <!I EQUIPMENT ~l!! IZ: Q I 0 MATERIAL DESCRIPTION i-/-'-' -TOPSOIL : " .' .' . .. .. 0, --:< :./: CL Soft, damp, medium brown, Sandy CLAY - ,0 ..... " " •• I -2 --I' .'. ., .... ", TORREY SANDSTONE r--B3-1 i .... ::: ML Hard, moist, light tan, Sandy SILTSTONE; - I ~ ..... ' trace of clay, gypsum 6 105.3 9.2 i-4 -...... -• I • ': .. i"--.' ., - \ , ~ 6 -. , I .' . -I ,- I -, . ' . . ---, " . . . · ' to-8 ' t, . --" , I I' ' . .. , , ~ , ' -, " I r -i-1O -B3-2 J .... , " 6 18.8 12.7 I " i--, I - I I ~ 12 -, • I ' , -. ' ' , ----I v ' --:. c · ., fossil shells, cemented zone 4-6" thick -Co .' " ~--I. . ' 1-14 -. .. ~ -· -I -i--I , I -16 -I •• - "0°, "\ .1 .' . ---I ' , , , ~ ............... ~18 -, 'I' '\. ,\" -. " . " SM Dense, moist to wet, light grayish-tan --. \' 1',' . with orange bands, Silty, very fine i- , ',,':,1 :',',: I -20 -" . SANDSTONE -'.' 1::1:,1' ' ---c:: ::-:...;> Break in Log - I -24 -" (:\'."1".: - --":'(1':1:: ,r--contactlbedding nearly horizontal (°1_2°) -;:~ :-tl.:· !. - -26 -~ - I DELMAR FORHATION ~ -.J. Q:::~~-~ Hard, moist to wet, medium greenish-gray, .. "28 -1 \ Silty CLAYSTONE; gypsum layers 1/8-{/2" ~ I I thick common --Z: I - 1 I : 1 I seepage along 1/2" thick gypsum layer -30 .. '--- I -I v BORING TERMINATED AT 31.0 FEET Figure A-5, Log of Test Boring 3 I SAMPLE SYMBOLS 0 -SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPLE Il_STANDARD PENETAAnON TEST ~_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED! ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDmONSSHOWN HEREON APPLIES ONLY ATTHESPECIFIC80RINGORTRENCH LOCAnONAND ATTHE DATE INDICATED,ITIS NOTWARRANTEDTO BE REPRESENTATlVEOFSUBSURFACECONDmONSATOTHER LOCAnONSAND nMEs. I File No. D-3930-H01 ugust 17, 1987 a: d ::J: Z ~z~ '" ..... w-'" CL Q u.. ~ ~ 8 ~ ;;: ..... Q 0 z i: :J ::i lil (:J 0 22 24 26 28 <Il <Il_ <rn ..... u Urn ~::; &1- SM-SC SM BORING 4 ELEVATION 278 DATE DRILLED 7/23/87 EQUIPMENT 30" Bucket Rig MATERIAL DESCRIPTION T PSOIL Soft, damp, dark brown, Sandy CLAY TORREY SANDSTONE Dense to medium dense, moist, light brown to tan, very Silty, very fine SANDSTONE to SILTSTONE; some clay in fractures, thin beds' Dense to medium dense, moist, light brown-grayish tan', Silty, fine SAND becomes wet r-strong seepage I DELMAR FORMATION Soft to stiff, saturated, medium to dark greenish-gray, Silty CLAYSTONE; fractured \L_ remolded zone 1/4" thick gough; E-IV, \ 5-rS \ L_ slickensided fractures N40-50W, 30-35°SW; ·water seeps along these surfaces L-_ slickensided fractures N25W, 18°SW; grooved ,_ slickensided fractures E-W, 20-25°S Stiff to hard, moist, dark greenish-gray, Silty CLAYSTONE; more massive, less fracturing, but still randomly oriented discontinuous slickensided surfaces generally dipping southward 3 109.0 16.3 3 106.5 18 .. 0 2 101.8 22.6 BULK AMPLE 2 103.8 22.5 3101.723.9 Figure A-6, Log of Test Boring 4 CONTINUED NEXT PAGE SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL 1:82_ DISTURBED OR SAG SAMPLE Il_STANDARD PENETRATION TEST IiiJ _ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OFSUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHESPECIFICBORING OR TRENCH LOCATION AND ATTHE DATE INDICATED. IT IS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACECONDmONSATOTHER LOCATIONS AND TIMES. I File • A ugus No. D-3930-H01 t 17 1987 , • tr >-W 0 ~ z 8 J: ... I !i:z'" W .... 0 .... 0 w-w 0.. Z o ... ~ j!: ~ ~ :J <:J I!-30 /,1 I -I I I -~ r-32 -100 _ B4-7 0 1:34 - J: ---- I !-- i-- I I-- 100 - I ~ .. l-- ~ -J I---- I I-..: F-- I ... - '"" ---I l--.. . I~ .. l-. I: .. -.. '" BORING 4, CONTINUED "'-<01 ....0 ELEVATI0 N..--1.7 S 7/23/87 °01 DATE DRILLED =~ g-30" EQUIPMENT Bucket Rig MATERIAL DESCRIPTION -L Hard, moist, dark greenish-gray, Silty CLAYSTONE; massive~ some fractures ·BORING TERMINATED AT 34.0 FEET - I~ Figure A-7, Log of Test Boring 4, cont~nued ~w . ?: _0t;: <z ...... '" z"; e:a3! Wd ll:1iiig QQ; >-... WIII tr o..tr '0 '~ - ~ 5 106.5 i- .- .- .- ~ .. .- -- ~ .- .. -- ~ i-.. -.. - ' .. ---.. - SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPLE I)_STANDARD PENETRAnON TEST IW_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHE SPECIFIC BORING OR TRENCH LOCATION AND ATTHE DATE INDICATED.ITlS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACE CONDmONSATOTHER LOCAnONSANDl1MES. w# tr..: ~z ~~ OZ :lEg 19.9 I File No. D-3930-H01 I August 17, 1987 a: BORING 5 d > ~ ~_ Zw J: .... ~ \. § ~ <Ul Q0t: ~ ",oj! I !ii?!:::l ~ 0 0 d~ ELEVATIONL. __ ...:2"-'7r...7!..-___ DATE DRILLED, __ ..t.7..t./.=.2.:t4..t./:¥8..t.7__ !C~ii} ~..; §i Q ... ~ i: 5 52 --------~!2i~ ~~ ~I!! ~ ::::; g r/) zU)~ >-OZ ~----~----~----+=~~----~E~Q~U~I~P~M~E~N:T~::~3:0:"::B~U~C:k~e:t::R~i~~::::::::::::::::::::~~!~:~:m~-!~~~-=~~8~ I MATERIAL DESCRIPTION I-0 V· ..... SLOPEWASH .<~ ... : .. : !cL-CH Soft, moist to wet, medium to dark brown, · I ~ 2 • I--BS-1 I ~ 4 - ~ - I-6 -I~ · I-8 -II-- 1-10 -BS-2 -BS-3 - - - -1-18 - ~ . BS-4 · . .. :.. Sandy CLAY 10·:{··<:: ... -.. -... . . ' .. r~ ~! I:~ fi:~ /Ii I' ~/. SC-SM SM Loose, moist, light orange-brown, Silty, Ciayey, fine SAND TORREY SANDSTONE Medium dense to dense, moist to wet, light tan-orange, Silty, fine SANDSTONE r---nearly horizontal, very soft clay zone I with gypsum, wet to saturated 1-_ II _::::->f.S 1-----n DELJ.'1AR FORHATION CH,CL I Soft to stiff, wet, dark to medium I green-gray-yellow, Silty CLAYSTONE; gypsum \ along fractures, extremely fractured, I almost brecciated; can punch pick in wall I several inches I 1-.__ abundant gypsum r--1-2" thick remolded zone I NSOW, SOSW; throughgoing 1---1-1 shear; wet to saturated of clay-gouge bedding-plane l- I- I-_ 1 - ~ l- I- ~ ~ .- I- ~ l- I-- I- ~ 2 2 ~: I ,"' i I ~ '" ~26 • 109.2 1l0.S IBULK 19.2 10.4 AMPLE rn~ i, Hard, moist, dark greenish gray, Silty 1-28 • I I CLAYS'J;ONE;massive, blocky with fewer ~ ~. I CL fractures I~ ___ .B_S_-_S ___ I.y __ ~ ___ ~ _____________________________________________________ .~ ___ 6 ___ ~ ___ ~ ___ ~ Figure A-8, Log of Test Boring 5 CONTINUED NEXT PAGE I I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPl.E Il_STANDARD PENETRATION TEST ,,_ CHUNK SAMPl.E • _ DRIVE SAM~E (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONOITIONS SHOWN HEREON APPLIES ONLY ATTHE SPECIFIC BORING ORTRENCH LOCATION ANO ATTHE OATE INOICATEO.ITIS NOTWARRANTEOTO BE REPRESENTATIVE OF SUBSURFACE CONomONSATOTHER LOCATIONS AND TIMES. I File No. D-3930-H01 I August 17. 1987 a:: BORING 5, CONTINUED d >-w '" >- :z: ... Z 8 ~ ~iij 1 ~ZLU W ... 0 "'0 277 ... 0 Z u'" ELEVATION DATE DRILLED w-w ... o ... ::e ;: :;) :::!:;) ~ ~ ~ 0-'" 30" 0 EQUIPMENT ~lJs::k.et Ri~ MATERIAL DESCRIPTION 1--30 ~V ... - I I I ,.. 32 BORING TERMINATED AT 32.0 FEET ~ - I I-- I-- I-- I --. I-- I I-- F-- I I-- I-- --I I-- I-- I I-- I-- I I-M "-- I r-- I-- I--I ~ --· I ~ · -· I I-- "-- I !-- Figure A-9, Log of Test Boring 5, continued I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPLE I1_STANDARD PENETRATION TEST iiJ _ CHUNK SAMPLE Zw ~ Qut 7/24/87 ~~U! ~....: W(j >-"'~ w-o Co; z"'''' ?i wWm (La:: C ~: l- ... 0- -- .1- i- l- .- -- 0- -- - - 0- ----- l- I- l- ... l-- •. _ DRIVE SAMPLE (UNDisTuRBED) ~ _ WATER TABLE OR'SEEPAGE I NOTE: THE LOGOF SUBSURFACE CONDITIONS SHOWN HEREON APPLIESONL Y ATTHESPECIFICBORING ORTRENCH LOCATION AND AJTHE DATE INDICATED-ITIS NOTWARRANTEDTO BE REPRESENTATlVEOFSUBSURFACECONDI:rJONSATOTHER LOCATIONS AND TIMES. w# a::,.: :;)z S!i~ OZ ::e8 I File No. D-3930-HOl t 17,1987 d z III ..J 0.. :::E ~ Tl-l Tl-2 '" Ul_ <u:l -'u Uo1 =:::l g- TRENCH 1 ELEVATION 290 DATE DRILLED 7 /22/87 EQUIPMENT Trackhoe MATERIAL DESCRIPTION . Medium hard, damp, light brown, Sandy SILT H Very soft, wet, medium to dark reddish- brown, Silty CLAY; slickensides on random surfaces; creep TORREY SANDSTONE ~~~~~-----+~ Hard, moist, green-gray-brown, Clayey, Tl-3 SM Sandy SILTSTONE; in-place with gypsum \ bedded layers 1/2-1" every 12 to 18" ~----------------------------------- Hard, moist, green-gray-mottled yellow, Clayey SILTSTONE horizontal to 2°± attitude of bedding Very dense, damp, medium brown, highly cemented (CaC03-Si02) fossiliferous concretion layer; gastropods, 10-12" thick Dense, moist, light grayish-brown, Silty fine SANDSTOME TRENCH TERMINATED AT 15.0 FEET Figure A-lO, Log of Test Trench 1 I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL 181_ DISTURBED OR BAG SAMPLE IJ_STANDARD PENETRAnON TEST IW_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED)· ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OFSUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHESPECIFIC80RINGORmENCH LOCATION AND ATTHE DATE INOICATEO. ITiS NOTWARRANTEOTO BE REPRESENTAnVE OF SUSSURF ACECONOITIONSATOTHERLOCAnONSANOnMEs, I I I I I I I I I I File No. D-3930-H01 August 17, 1987 ~ ~ J: ... tzw w-w a ... 0 · --2 - ~ -.. 4 - I-- ~ 6 . ~ I-8 ~ -10 - --12 l- 1-14 ... -16 - · · - -- · · · - · -- ---- · · · · · d z w .... Cl. ~ ~ 12-1 > 8 .... 0 J: ... :; VI I I I i.l 1/1 a: ~ a z ::l !f " TRENCH 2 rn ~w . rn_ ~ wI-<., _ut: ~t.l 302 7/22/87 i~0 rn a:..: urt.l ELEVATION DATE DRILLED z..: ::lz =:::l :U!!l~ wt.l "'w &)-OQ; a:Z Trackhoe zrn .... > EQUIPMENT wwcn a: . ~8 Cl.a: Q MATERIAL DESCRIPTION TOPSOIL Medium hard, damp, dark brown, Silty CLAY CL ML TORREY SANDSTONE MIl Medium, moist, orange, Sandy Clayey SILTStONE - -~\ -SM I\~ ________________________________________ -+ ____ ~ ____ ~ __ ~ I Hard, moist to wet, brown green gray, very Clayey SILTSTONE; slickensided discontinuous I shear surfaces lL-:= horizontal bedding contact Dense, moist, white to light tan, Silty fine SANDSTONE TRENCH TERMINATED AT 15.0 FEET .. I- ---.. ~ULK ~ AMPLE I-.. --- I- ~ I----- I- 0- I- ... II ~I-.... _-L-__ .... ~ __ .... ~~ .... -L--.... --------............ ------------.... --........ --.... --~ .... ~~~~--~ I I Figure A-ii, Log of Test Trench 2 SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL 181_ DISTURBED OR BAG SAMPLE Il_STANDARD PENETRATION TEST iI_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED' ~ _ WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHE SPECIFIC BORING OR TRENCH LOCATION AND ATTHE DATE INOICATEO.ITIS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACECONOmONSATOTHER LOCATIONS AND TIMES. I File No D-3930-H01 I 'August . 17, 1987 cr TRENCH 3 0 >-~ '" z"" ~ z 8 "'-will I 1: ... <'" Qot li:z"" "" .... 0 .... 0 301MSL 7/22/87 ~z~ '" cr,.: .... 0 0", ELEVATION DATE DRILLED zu; :::>z ",,-w 0.. Z cr~ o ... ~ i!: :::> =:::> :u~o W(j ~~ ~ 0-00.; ~ ::l '" Trackhoe z"' .... >-Oz CI EQUIPMENT ~~m cr :::1:8 0 I.-MATERIAL DESCRIPTION 0 1" MH TOPSOIL It-' I--:y I."':' Soft, damp, dark yellow-brown, Clayey SILT I- I~ I-2-:.('-T. SM ~ --: I ~'I", (, TORREY SANDSTONE I: 4-',I-'!>I: Dense, moist, light tan white, Silty, fine --: f:I-} : 1----1\, SANDSTONE; massive r- I: 6 -"J'~{' r--",1.'1.-1: L_ beddin,g N60-70W, 2-4°SE 1 -: .1:: I. '.":: l- I-8-l- I I .. ML Hard, moist, medium to light green gray, .. Sandy SILTSTONE massive in-place ,~ I-lO-r- I .. -TRENCH TERMINATED AT 9.0 FEET I--I- 'I .. -I- ~ . ~ I~ 0 TRENCH 4 Elev. 308HSL ~ . , '0 FILL I--O.Oj~ Loose, dry damp, medium brown, Clayey SAND l- I '·0 ;):",~ J-2 -• oX • " ' and BOULDERS; oversize fill and trash l-I-~'O" I--... , .. ~: 1 a. 4 :,,: "I< /" '. TORREY SANDSTONE --I·i·,:: SM Dense, moist, light banded with orange -l tan, --:1'·1:.1> red, Silty fine SANDSTONE - I r 6 -".,\.,:. 1------nearly horizontal bedding -:·1:('(' .. -I--.. Hard, moist, light brown, Sandy Clayey I-8 -~ ML ... I T4-1 . / ~MlPLE I ~ .. ~~ SILTSTONE BULK .. -., .. ---n -J ' ... 1-10 v,' ... L_ bedding N80E,2-4°SE --" " . J ' . ":~. t-. ' . 1;.-:' ' . TRENCH TERMINATED AT 11.0 FEET -12 -I- I~ -I- Figure A-12, Log of Test Trenches 3 and 4 , , I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL Il_STANDARD PENETRATION TEST • _ DRIVE SAMPLE (UNDISTURBED) !81_ DISTURBED OR BAG SAMPLE IW_ CHUNK SAMPLE =f -WATER TABLE'OR SEEPAGE 'I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHE SPECIFIC BORING OR TRENCH LOCATION AND ATTHE DATE INDICATED,ITIS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACE CONDITIONSATOTHER LOCATIONS AND TIMES. I File No. D-3930-HOl I ugust l7, 1987 0 >-8 J: ... Z I Q:zW w ..... ..... 0 w-w 0.. J: o ... :::!: ... ~ ;;; I~ 0 :1:)(1" ~ -;.:(:,-: I:: I: 2 -:',:T.;):':- "J:' ·1:' .. . >:, . .. . . . I: 4 .. • * •• .. .. . . .. . . . . , .. i-6 .. ' . I ''.1':'':1 :: I--"'I :'1-:1 :--8 -:t',I'.1 .- I '.'I".I·.t·.· I--l!:I··I·'· " .. " .. -lO .. ~ I I-.. .. , I ...... ". ... l2 .. ~:'I:,:ly I ... -l4 ---I I-.. I J. 0 .. /.. . V" .'. ' .. --V. I 2 - Oo .. " 0. I-........ .. • .. 0° Ia -: .. " .. °0 .: .... ( ~ 4 -.. /. . I ~ I--if I-6 - I t -Ily i-8 I I-- !:. 10- II-.. I F:gUre A-13, Log of SAMPLE SYMBOLS 0: TRENCH 5 w rn ... rn_ ~w , ~ ~ <'" _ut: 0 ""'0 289MSL 7/22/87 !<~;,;; ~~ z u'" ELEVATION DATE DRILLED :::) =:::) ~!ii~ W(j Oa; ~ ~-Trackhoe zC/) ..... >-I!l EQUIPMENT ~~m a: 0 MATERIAL DESCRIPTION ALLUVIUM Loose, dry damp, medium brown, Silty Clayey ~ SM-SC fine SAND i- TORREY SANDSTONE ML Hard, moist, light brown, very Sandy - SILTSTONE - l-\L bedding horizontal l- SM Dense, moist, tan white, Silty fine SANDSTONE, massive -- CL Hard, moist, medium greenish gray with - yellow layers, Sandy Silty CLAYSTONE, ,l- massive, blocky l- TRENCH TERMINATED AT l3.0 FEET -.-- TRENCH 6 Elev.258MSL ALLUVIUM SC-CI Loose to medium dense, damp, medium brown, ... very Clayey SAND to Sandy CLAY -- l- -DELMAR FORMATION CL-CE Hard, moist, dark greenish gray, Silty ~ CLAYSTONE, massive, moderate fractures l--- TRENCH TERMINATED AT 8.0 FEET I- Test Trenches 5 and 6 0_ SAMPLING UNSUCCl:SSFUL ~ _ DISTURBED OR SAG SAMPLE Il_STANDARD PENETRATION TEST IW_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE 'I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTH ESPECIFIC BORING OR TRENCH LOCATION AND AT!HE DATE INDICATED.ITIS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACE CONDmONSATOTHER LOCATIONS AND TIMES. w~ 0:,.: :::)z ... w rn ... o,z :::!:8 I File No. D-3930-H01 I August 17, 1987 I :t: .... !i:zw w-w Q ... 0 - 2- - 0 z w ... CI. ::I: ~ > 8 ... o ~ ::; ~:~ .. '.: l/ cr w ~ C z ::> ~ Cl en TRENCH 7 en_ <'" ..... u 268MSL 7/22/87 u'" ELEVATION DATE DRILLED =::> 0-Trackhoe r.tJ EQUIPMENT MATERIAL DESCRIPTION SLOPEWASH Loose, damp, medium brown, very Clayey SC-CL fine SAND to Sandy CLAY 4- ...... : -> :-./.' '+, --+--.-f-------------------"-------- - 6- - 8- I~ - :.U:r :·1·:1· J: ."\""'.j'. <I :J:'I': >1:-1'.:( .... .... SM CL-CH TORREY FORHATION Dense, mQist, light brown, very Silty finel SANDSTONE Hard, moist, dark greenish gray with yellow bands, Silty CLAYSTONE . ~w . ~ w# _ut ~z_ en cr..: cr~~ z..: ::>z wu .... w t;j!!lo Co: ~~ zen ... > ~8 ~~m cr Q ~ I- ... - ~ ~ I- ~ l- i- ... I : 10: r: :1 l{1L ~ 124---~~~~+----+--------~ __ ----------------------------~---r---;--~ TRENCH TERMINATED AT 12.0 FEET I ~ ~ 14- -~ ~ I I TRENCH 8 Elev.268MSL SURFICIAL LANDSLIDE Soft, damp, dark brown, Sandy CLAY; fractured ~ CL disturbed (insipient backs carp surface ring ~ ~-;"-/'o~~-.-\. crack 2-3" wide _ ~----------------------.-----~ --SC Loose, moist, medium brown very Clayey fine __ ~ SAND; fractured disturbed and brecciated CH ~ contact dips 1-50 out-of-slope DELMAR FORMATION .. . --~ Medium stiff, moist to wet, mottled white, CL-CH \ orange green gray, Silty CLAYSTONE; fractured - ~-----+-'---+~------h\ and weathered with gypsum and random slickens'~ed Hard, moist, dark greenish-gray, Silty CLAYSTONE; less frac·tured and more massive in-place - .. st: rfacel Figure ~14, Log of Test Trenches 7 and 8 TRENCH TERMIN~TED AT 10.0 FEET SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL jgJ _ DISTURBED OR BAG SAMPLE Il_STANDARD PENETRAnON TEST iI_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDIstuRBED) ~ _ WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREONAPPLIESONL Y ATTHESPECIFICBORING OR TRENCH LOCATION AN'D ATTHE DATE INDICATED. ITIS NOTWARRANTED TO BE REPRESENTAnvE OFSUBSURFACECONDmONSAToTHER LOCATIONS AND TIMES. I File No. D-3930-HOl I August 17, 1987 d > l: .... z 8 I !i:zw w -' -' 0 w-w <1-o ... ::f J: .... ~ ::; a:: TRENCH 9 ~ Ul ,Zw ~ Ul_ ~ w# <en g~t 0 -'tj 255 7/22/87 Ul §..: z uen ELEVATION DATE DRILLED ~~iiJ zu.: ::l ~:; tu!!l~ wu .... ~ ~ g-OQ; cr. ... Trackhoe z"'-' ?c oz 0 EQUIPMENT ~I!!ID ::f8 0 I~ o~----~~~-7----~------------------------------------------r----+----+---~ ~~'f j',:(T' ALLUVIUH MATERIAL DESCRIPTION I--:'1,'1, SM-SC Loose, moist to saturated, medium brown, Ir-2 -T9-1 ' ,y. Silty, Clayey, fine SAND - I-BULK SAlfPLE ~ II'" 4· 1 .~ seepage, caving " ..... ----.. ... -~:':f:~~: f---,---probe penetrates 3' with body weight . I--' 1 I' I ............ ....... I I-I-6. -~ ':' ~--+-D-E-LMAR--F-O-RMA--T-I-O-N---------------f---I----+-~ 1 1 CH Hard, wet" dark greenish-gray, Silty ~I CLAYSTONE; fractured moderately, but l- i- I-8 -massive .. I~ 1 1 -10 - TRENCH TERHINATED AT 9.0 FEET - I- I- -- i- i- TRENCH 10 EL. 276 v: : ',' SLOP EWASH ~~~~ __ C_L_~_S_O_f_t_'_d_am_p_'_d_a_r_k_b_r_own __ ,_s_a_n_d_y_CL_A_Y _____ -r: __ ~-~~--_4 >1"1' ,I.: TORREY SANDSTONE - I ~ 10 - :.. - ... 12 - I: 14- .'1>1:,1', SM Dense, moist, light tan, Silty, fine '.:1:: 1'-'1:: SAND STONE ':1 :,1 ::1:- Y'L·I:: __ _ r-becomes wet J CH-CI DELMAR FORHATION r-_-.... Hard, moist to saturated, dark greenish-~---~ gray-brown, Silty CLAYSTONE L-__ cemented fossiliferous concretion-zone 6-8" ~ _ seepage, caving --- .. -- I- TRENCH TERMINATED AT 13.0 FEET I ... -----~-----~----~~~--~-----------------------------------------------~---~,~----~----~ Figure A-IS, Log I SAMPLE SYMBOLS of Test Trenches 9 and 10 0_ SAMPLING UNSUCC£SSFUL r81_ DISTURBED OR BAG SAMPLE IJ_STANDARD PENETRAnON TEST ii_CHUNK SAMPLE • _ DRIVE SAMPLE I\,INDISTURBEOI ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOGOF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHESPECIFICBORING ORTRENCH LOCATION AND ATTHE DATE INDICATED,ITIS NOTWARRANTEDTO BE REPRESENTAnVE OFSUBSURFACECONDmONSATOTHER LOCAnONSAND nMEs. I File No. D-3930-HOl I August 17, 1987 a: TRENCH 11 d >-w '" aw , z 8 !< "'-~ :c .... ~ <Ul _UI;: I w ..... ej ~u; !i:zw ..... ..... C uUl ELEVATION 282 7/22/87 ~z_ 0 z DATE DRILLED o:~~ w-W Q. iE =:::l Wej Q .... ::!! :::l &! Sl-t;j!!!o Ca; ~ :::; Trackhoe z"' ..... >- <!l EQUIPMENT ~~CD a: C I MATERIAL DESCRIPTION -0 ~I ALLUVIUM -... I~ CL Soft, damp, dark brown, Silty CLAY - 'I J I i-2 -- <1"1 '·1:' i-->.1:: I:: 1-: TORREY SANDSTONE I "'" 4 -"1'·1'.1" SH Dense, moist, light tan, Silty, fine -.. I' "'" -:I.f: : SANDSTONE - -6 -: :1."1 :."1:: L horizon:tal bedding - I :.I':I:{· --.}'.I -:1': -. . i-8 -:-, :.1 :., .. SM Dense, moist, medium orange, Silty, fine - I i---:1'·1.\' SANDSTONE; massive -'.1",'.,' . . . . . -"'"10 - I «I·J· SM Dense, moist to wet, grayish-tan, Silty, --·fl'·'< -fine SANDSTONE (laminated) -12 -'''I':I~' (. - :/. t:I.- I i-TRENCH TERMINATED AT 13.0 FEET 1-14 -"" -i--I i---. --- I --- ... -l- I --- I ----I --------.: ----0-- '1--------- -Figure A-16, Log of Test Trench 11 I SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL ~ _ DISTURBED OR BAG SAMPLE 1l_'~T~~~ARD PE~~~~ON TEST ~_ CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TABLE OR SEEPAGE I NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHESPECIFlCBORING ORTRENCH LOCATION AND ATTHE DATE INDICATED.ITIS NOTWARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS ATOTH ER LOCATIONS AND TIMES. wI-0:,..: :::lz ~~ Oz ::!!8 - I File Nq. D-3930-HOl IA 17 98 Ugust . 1 7 a: TRENCH 12 " I I I I I I I l I I I _I I I I I I I d > w rn .. 5w . J: .. z 8 ~ ~iii _uti: ?; !i:zw w ..J 0 ..JcJ 270 7/22/87 ~z ...... en ..J 0 Uuj ELEVATION DATE DRILLED z...: w-w 11. Z l:~~ o ... ::!l ~ ~ =;:) WcJ 00,; ~ 5)-w-o :::; Trackhoe zrn..J > Cl EQUIPMENT wWG) a: 11.a: Q MATERIAL DESCRIPTION -a V. . . · . ".-TOPSOIL -.. · "' ... CL Soft, moist, dark brown, -./ Sandy CLAY · .. -2 · ..... .. · .1'.1< 1 '. f-... '·1'·1"1'· >1"":-1:' SM TORREY SANDSTONE f-4 .. · . .-l\ Dense, moist, orange, Silty, very fine - ~ .. -:U·J· SANDSTONE - ~ 6 ... J'I}: L --:1:1 :t SM -.. .J-:I:.I·: ~--\ Dense, mo'ist, light tan, Silty, fine .. I-8 .. '.(1.'., :: SANDSTONE I- \ ~ .. >1,".1" f L-horizontal - ',1'.1 }. bedding I-10 .. - :.. .. Jf':: .. -12 .. -:1:.1-".1:-.. ',1'-1'.,< I-.. · ... ~I ~ DELMAR FORK~TION I-14 .. 'W" 1-_'"'::".:> h Hard, wet to saturated, dark greenish-brown, - I I I f--- l-I Silty CLAYSTONE -\ \ .. !-16 .. \ -.. L_ cemented fossiliferous concretion layer; - seepage follows this zone --.. I-.. TRENCH TERMINATED AT 15.0 FEET -I-.. -I-.. . .. I-.. --.. -' -I-.. I-... I- -.. I- --.. --.. :.. .. - Figure A-17, Log of Test Trench 12 SAMPLE SYMBOLS 0_ SAMPLING UNSUCCESSFUL 181_ DISTURBED OR SAG SAMPLE I]_;!T~~PARD PE~ETR,ATlON TEST il_CHUNK SAMPLE • _ DRIVE SAMPLE (UNDISTURBED) ~ _ WATER TASLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY ATTHE SPECIFIC BORING OR TRENCH LOCATION AND ATTHE DATE INDICA TEo..lTIS NOTWARRANTEDTO BE REPRESENTATIVE OF SUBSURFACECONomONSATOTHER LOCATIONS AND TIMES. w# a:,.: ;:)z .. w rn .. ~8 I' . ' . , .. , .. ". -:.-I,. -. ~ -.' ,', . " "', . .. '::.-' , .,.-. " .', . "~ I I I I I I I I I I I I I I I I I I APPENDIX B LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. Selected, relatively undisturbed, drive samples were tested for their in-place dry density, moisture content, and shear strength. A residual shear strength test was performed to assist in the determination of appropriate soil strength parameters for slope stability analyses. The maximum dry density and optimum moisture content of selected bulk samples 'were determined in accordance with ASTM Test Procedure D1557-78. Portions of the bulk samples were then remolded to selected densities and subjected to direct shear and expansion tests. The results of our laboratory tests are presented in tabular form hereinafter. In-place density and moisture characteristics are presented on the logs of the exploratory boring logs. Sample No. Bl-4 B4-4 TABLE B-1 SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557-78 Description Maximum Dry Optimum Moisture Density (pet) Content (% dry wt.) Gray, white, Silty, very fine to fine SAND 116.2 14.3 Green, Silty CLAY 112.8 16.8 TABLE B-II SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS Moisture Content Dry - Sample No. Before Test After Test Density Expansion Classification (pet) Index (%) (%) Bl-2 14.6 30.5 94.3 43 low Bl-4 12.1 36.9 102.8 153 very high Bl-7 13.4 28.1 98.2 46 low B4-4 15.1 35.2 92.4 95 . high Project No. 05467-12-04 -B-1 -December 23, 1997 I I I I I I I I I I I I I I I I I I I TABLE B-III SUMMARY OF DIRECT SHEAR TEST RESULTS Sample No. Dry Density Moisture Content Unit Cohesion Angle of Shear (pet) (%) (pst) Resistance (degrees) BI-4* 104.3 14.6 310 32 B4-2 106.5 18.9 570 40 B4-3 101.8 22.6 1390 4 B4-4* 101.7 16.6 420 15 B4-7 106.5 19.9 320 37 Soil sample remolded to 90 percent relative density at near optimum moisture content. Project No. 05467-12-04 -B-2-December 23,1997 '1"> " . ~".' . " .ro " '.' I I I I I I I I I I I I I I I I I I I APPENDIX C SHEAR KEY AND SLOPE STABILITY ANALYSIS SLOPEIW VERSION 3 for LA COSTA VILLAGE RETAIL CENTER CARLSBAD, CALIFORNIA PROJECT 05467-12-04 ------------------- ~ ~ "-'" ~ o .~ ~ ;> Q) ~ ~ Project No. 5467-12-04 30 LA COSTA VILLAGE RETAIL CENTER CROSS SECTION A -A' Graded Conditions with Bldg. Surcharge Pressure As Proposed -No Shear Key 50 100 Factor of Safety = 1.239 • PL 150 200 250 300 Distance( ft) File: RLCA1.slp Soil * Unit Wt (pet) ~ (deg) Cohesion (pst) ! Qefl 125 20 300 Qefl 125 30 450 Tt 125 30 400 Tdl 120 20 200 Td2 120 25 500 B.P.S. 110 5 200 * For description see Table 8.2 Figure C-l ------------------- ~ ~ "'-" o o • P""'4 ~ > 0) ~ ~ Project No. 5467-12-04 30 Soil Qefl Qet2 Tt Tdl Td2 B.P.S. LA COSTA VILLAGE RETAIL CENTER CROSS SECTION A -A' Graded Conditions with 20 ft. Shear Key using Low Strength Fill & Bldg. Surcharge Pressure 50 Unit Wt (pet) 125 125 125 120 120 110 Factor of Safety = 1.292 • PL Building 100 150 200 250 Distance( ft) 9 (deg) Cohesion (pst) 20 300 30 450 30 400 , 20 200 25 500 5 200 ~ 300 File: RLCA2a.slp Figure C-2 ------------------- ~ '--" ~ o • ,.....,-t ~ :> Q) ..--4 ~ Project No. 5467-12-04 o Soil Qcfl Qct2 Tt. Td1 Td2 B.P.S. LA COSTA VILLAGE RETAIL CENTER CROSS SECTION A -A' Graded Conditions with 20 ft. Buttress using Higher Strength Fills to Elevation 270 ft. (MSL) & Bldg. Surcharge Pressure Factor of Safety = 1.517 IYe-f I • PL 50 100 150 200 250 300 Distance(ft) File: RLCA2f.slp Unit Wt (pct) ~ (deg) Cohesio.n (pst) 125 20 300 125 30 450 125 30 400 120 20 200 120 25 500 110 5 200 Figure C-3 - - - - - - -_.-- - - - - - - - - - ,.,-,. ~ '--'" ~ o • '1""'4 ~ > (]) ~ ~ Project No. 5467-12-04 Soil Qefl Qcf2 Tt Tdl ITd2 B.P.S. LA COSTA VILLAGE RETAIL CENTER CROSS SECTION A -A' Graded Conditions with 20 ft. Buttress using Higher Strength Fills to Elevation 270 ft. (MSL) & Bldg. Surcharge Pressure Factor of Safety = 9.298 • PL Building Qefl 50 100 150 200 250 Qef2 ~ 300 Distance(ft) File: RLCA2.slp Unit Wt (pet) ~ (deg) Cohesion (pst) 125 20 300 125 30 450 125 30 400 120 ·20 200 120 25 500 110 5 200 Figure C-4 ------------------- ~ ~ "'-" ~ o .~ ~ :> (]) ~ ~ Project No. 5467-12-04 LA COSTA VILLAGE RETAIL CENTER CROSS SECTION A -At Temporary 1:1 Backcut Factor of Safety = 0.788 • PL 50 100 150 200 250 300 Distance( ft) File: RLCA3.slp Soil Unit Wt (pet) ~ (deg) Cohesion (pst) I Qefl 125 20 300 Qefl 125 30 450 Tt 125 30 400 Tdl 120 20 200 T~2 120 25 500 B.P.S. 110 5 200 Figure C~5 " "I " , . ,..", . ." -,.. --' ~' . , " ' ..... :., , " .. ,~-, " r._. I I I I I I I I I I I I I I I' I. I I I APPENDIX D RECOMMENDED GRADING SPECIFICATION for LA COSTA VILLAGE RETAIL CENTER CARLSBAD, CALIFORNIA PROJECT 05467-12-04 I I I ,I I I I I I I I I I I I I I I I RECOMMENDED GRADING SPECIFICATIONS 1 GENERAL 1.1 These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Geocon Incorporated. The recom- mendations contained in the text of the Geotechnical Report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial conformance wit!1 the recommendations of the Geotechnical Report and these specifications. It will be necessary that the Consultant provide adequate testing and observation services so that he may determine that, in his opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep him apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3 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 or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture condition, inadequate compaction, adverse weather, and so forth, result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the work and recommend to the Owner that construction be stopped until the unacceptable conditions are corrected. 2 DEFINITIONS 2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading work is being performed and who has contracted with the Contractor to have grading performed. 2.2 Contractor shall refer to the Contractor performing the site grading work. 2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as-graded topography. 2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. I I I I I I I I I I I I I I I I I I I 3 2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the ' Owner, who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be responsible for having qualified representatives on-site to observe and test the Contractor's work for conformance with these specifications. 2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site grading. 2.7 Geotechnical Report shall refer to a soil report (including all addendums) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended t? apply. MATERIALS 3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant, is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as defined below. 3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than 3/4 inch in size. 3.1.2 Soil-rock fills are defmed as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. 3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3- feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than 3/4 inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. 3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the Consultant shall not be used in fills. I I I I I I I I I I I I I I I I I I I 3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defmed by applicable laws and regulations. 3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face,: provided that the slope is not steeper than 2: 1 (horizontal:vertical) and a soil layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This procedure may be utilized, provided it is acceptable to the governing agency, Owner and Consultant. 3.5 Representative samples of soil materials to be used for fill shall be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and, where appropriate, shear strength, expansion, and gradation characteristics of the soil. 3.6 During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the Significance of the unanticipated condition. 4 CLEARING AND PREPARING AREAS TO BE FILLED 4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, brush, vegetation, man-made structures and similar debris. Grubbing shall consist of removal of stumps, roots, buried logs and other unsuitable material and shall be performed in areas to be graded. Roots and other projections exceeding 1:'112 inches in diameter shall be- removed to a depth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. 4.2 Any asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility. Concrete fragments which are free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this document. I I I I I I I I I I I I I I I I I I I 4.3 After clearing and grubbing of organic matter or other unsuitable material, loose or porous soils shall be removed to the depth recommended in the Geotechnical Report. The depth of removal and compaction shall be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.4 Where the slope ratio of the original ground is steeper than 6: 1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. NOTES: TYPICAL BENCHING DETAIL NO SC~L.s: (1) Key width "B" should be a minimum of 10 feet wide, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the bottom key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. I I I I I I I I 'I I I I I I I I I I I 4.5 After areas to receive fill have been cleared, plowed or scarified, the surface should be disced or bladed by the Contractor until it is uniform and free from large clods. The area should then be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6.0 of these specifications. 5 COMPACTION EQUIPMENT 5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented- steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a desig~ that it will be capable of compacting the soil or soil-rock fill to the specified relative compaction at the specified moisture content. 5.2 Compaction of rock fills shall be performed in accordance with Section 6.3. 6 PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: 6.1.1 Soil fill shall be placed by the Contractor in. layers that, when compacted, should generally not exceed 8 inches. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock materials greater than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. 6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTM D1557-91. 6.1.3 When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. 6.1.4 When the moisture content of the soil fill is above the range specified by the Consultant or too wet to achieve proper compaction, the soil fill shall be aerated.- by the Contractor by blading/mixing, or other satisfactory methods until the moisture content is within the range specified. 6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 . percent. Relative compaction is defined as the ratio (expres:sed in percent) of the in-place dry density of the compacted fill to the maximum laboratory dry density as determined in accordance with ASTM D1557-91. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum density has been achieved throughout the entire fill. I ,I I I I I I I I I' I I I' I I ,I I I I 6.2 6.1.6 Soils having an Expansion Index of greater than 50 may be used iIi fills if placed at least 3 feet below finish pad grade and should be compacted' at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D.,8 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, roc~ or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading, as specific cases arise and shall be approved by the Consultant prior to placement. 6.2.3 For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. 6.2.4 For windrow placement, the rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around ,and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 oc greater and should be compacted by flooding. Windrows may also be placed utilizing an "open-face" method in lieu of the trench procedure, however, this' method should first be approved by the Consultant. 6.2.5 Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center-to-center with a 5-foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. J I .1 I I I I I I I I I I I I I I I, I I 6.3 6.2.6 All rock placement, fill placement and flooding of approved granular soil in the windrows must be continuously observed by the Consultant or his, representative. Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: 6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent, maximum slope of 5 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not, develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-construction infiltration of water. 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the required compaction or deflection as recommended in Paragraph 6.3.3 shall be utilized. The number of passes to be made will be determined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. 6.3.3 Plate bearing tests, in accordance with ASTM D1196-64, may be performed in both the compacted soil fill and in the rock fill to aid in determining the number of passes of the compaction equipment to be performed. If performed, a minimum of three plate bearing tests shall be performed in the properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be performed on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the reslj.lts of the plate bearing tests for the soil fill and the rock fill and by evaluating the deflection variation with number of passeS. The required number of passes of... the compaction equipment will be performed as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted soil fill. In no case will the required number of passes be less than two. 6.3.4 A representative of the Consultant shall be present during rock fill operations to verify that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate bearing tests will be determined by the Consultant during grading. In general, at least one test should be performed for each approximately 5,000 to 10,000 cubic yards of rock fill placed. I I I I I I I I I I I I I I I 6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that, in his opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In-place density testing' will not be required in the rock fills. 6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying soil fill material, a 2-foot layer of graded filter material shall be placed above the uppennost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to corpmencing grading. The gradation of the graded filter material will be determined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the graded filter prior to the commencement of rock fill placement. 6.3.7 All rock fill placement shall be continuously observed during placement by representatives of the Consultant. 7 OBSERVATION AND TESTING 7.1 The Consultant shall be the Owners representative to observe and perfonn tests during clearing, grubbing, filling and compaction operations. In general, no more than 2 feet in vertical elevation of soil or soil-rock fill shall be placed without at least one field density test being perfonned within that interval. In addition, a minimum of one field density test shall be perfonned for every 2,000 cubic yards of soil or soil-rock fill placed and compacted. 7.2 The Consultant shall perfonn random field density tests of the compacted soil or soil-rock fill to provide a basis for expressing an opinion as to whether the fill material is compacted as specified. Density tests shall be perfonned in the compacted materials below any disturbed surface. When these tests indicate that the density of any layer of fill or portion thereof is below that specified, the particular layer or areas represented by the test shall be reworked until the specified density has been achieved. 7.3 During placement of rock fill, the Consultant shall verify that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant shall request the excavation of observation pits and may perfonn plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for... expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. If perfonned, plate bearing tests will be perfonned randomly on the surface of the most-recently placed lift. Plate bearing tests will be perfonned to provide a basis for expressing an opinion as to whether the rock fill is adequately seated. The maximum deflection in the rock fill determined in Section 6.3.3 shall be less than the maximum deflection of the properly compacted soil fill. When any of the above criteria indicate that a layer of rock fill or any portion thereof is below that specified, the affected layer or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. I I I I I I I I I I I 'I I I I 7.4 A settlement monitoring program designed by the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services performed during grading. 7.5 The Consultant shall observe the placement of subdrains, to verify that the drainage devices have been placed and constructed in substantial conformance with project specifications . 7.6 Testing procedures shall conform to the following Standards as appropriate: 7.6.1 Soil and Soil-Rock Fills: 7.6.1.1 Field Density Test, ASTM D1556-82, Density of Soil In-Place By the Sand-Cone Method. 7.6.1.2 Field Density Test, Nuclear Method, ASTM D2922-81, Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 7.6.1.3 Laboratory Compaction Test, ASTM D1557-91, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-Inch Drop. 7.6.1.4 Expansion Index Test, Uniform Building Code Standard 29-2, Expansion Index Test. 7.6.2 Rock Fills: 7.6.2.1 Field Plate Bearing Test, ASTM D1196-64 (Reapproved 1977) Standard Method for Nonrepresentative Static Plate Load Tests of Soils and Flexible Pavement Components, For Use in Evaluation and Design of Airport and Highway Pavements. 8 PROTECTION OF WORK 8.1 During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with th~ Specifications prior to placing additional fill or structures. 8.2 After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. I I I I I -I I I I I I I I I I I I I I 9 CERTIFICATIONS AND FINAL REPORTS 9.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and! or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as-built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstructions. 9.2 The Owner is responsible for furnishing a final as-graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as-graded report should be prepared and signed by a California licensed Civil Engineer experienced in geotechnical engineering and by a California Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were performed in substantial conformance with the Specifications or approved changes to the Specifications. Gcocon Incorporated Form, Revision date: 08/93 ~ __ ' . ~: f' ~""" ~.J! • .,:' ." J l' ~ I I I' 1 I 1 I I I I I I I I I I I I I it...;; ------.' --.. , , ;' \ .' I , , .. " I I I -f--- , I· '. "~.' • I / / . I '" .' • '~~ '-?>U-,~-_.,L / , /. \ / / / / . GRADING PLAN SCALE: , .. -40' ,/ / 2':j6. I _ .-.. Tt ,. . '. ,. • ". ~>' -.~ I I / / , \~ . <..' ,/ c' . ~ I, i' ------~ ---- " \ '-'---, , '\ B-4ffi Td \ \I7 ~1. ", \ , tJ ~)4;'6.8() E J7I296 [LEV ~ J 1j :'0 \ \ , ,/. ---- -''0'''' • , , ----- " " . \.~' , \' ~ .' \' ~. " ......... "---~ , NORTH \ \ , , . . \ ''-iN , I ) . 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