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CDP 2022-0008; MARTIN RESIDENCE; REPORT OF GEOTECHNICAL INVESTIGATION - DECEMBER 8 2021; 2021-12-08
REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED MARTIN RESIDENCE LOT 5 BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA PREPARED FOR JOHN MARTIN 3301 LINCOLN STREET CARLSBAD, CALIFORNIA 92008 PREPARED BY CHRISTIAN WHEELER ENGINEERING 3980 HOME AVENUE SAN DIEGO, CALIFORNIA 92105 CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 December 8, 2021 John Martin CWE 2210558.01 3301 Lincoln Street Carlsbad, California 92008 Subject: Report of Preliminary Geotechnical Investigation Proposed Martin Residence, Lot 5 of Buena Vista Circle, Carlsbad, California Dear Mr. Martin: In accordance with your request and our proposal dated September 30, 2021, we have completed a preliminary geotechnical investigation for a proposed residential structure to be constructed at the subject property. We are presenting herewith a report of our findings and recommendations. It is our opinion and judgment that no geotechnical conditions exist at or in the vicinity of the subject property that would preclude the construction of the proposed residential structure provided the recommendations included in this report are implemented. If you have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING Daniel B. Adler, RCE #36037 David R. Russell, CEG #2215 DRR:dba ec: jdmartin999@gmail.com; bknapp@plsaengineering.com CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 CWE 2210558.01 Proposed Martin Residence Lot 5 of Buena Vista Circle Carlsbad, California TABLE OF CONTENTS Page Introduction and Project Description ............................................................................................................................. 1 Scope of Services ................................................................................................................................................................ 2 Findings ................................................................................................................................................................................ 3 Site Description ............................................................................................................................................................... 3 General Geology and Subsurface Conditions ............................................................................................................ 3 Geologic Setting and Soil Description .................................................................................................................... 3 Topsoil ..................................................................................................................................................................... 3 Old Paralic Deposits .............................................................................................................................................. 4 Santiago Formation ................................................................................................................................................ 4 Geologic Structure ...................................................................................................................................................... 4 Groundwater ............................................................................................................................................................... 4 Tectonic Setting .......................................................................................................................................................... 5 General Geologic Hazards ............................................................................................................................................ 5 General ......................................................................................................................................................................... 5 Surface Rupture .......................................................................................................................................................... 5 Landslide Potential and Slope Stability ...................................................................................................................... 6 Slope Stability Analyses ............................................................................................................................................. 6 General ..................................................................................................................................................................... 6 Gross Stability Analyses ............................................................................................................................................ 6 Cross-Sections ......................................................................................................................................................... 6 Strength Parameters ............................................................................................................................................... 7 Method of Analyses ............................................................................................................................................... 7 Results of Stability Analyses ................................................................................................................................. 7 Surficial Slope Stability ............................................................................................................................................... 8 General ..................................................................................................................................................................... 8 Liquefaction ................................................................................................................................................................. 8 Flooding ....................................................................................................................................................................... 8 Tsunamis ...................................................................................................................................................................... 8 Seiches .......................................................................................................................................................................... 8 Conclusions .......................................................................................................................................................................... 8 Recommendations .............................................................................................................................................................. 9 Grading and Earthwork ................................................................................................................................................. 9 General ......................................................................................................................................................................... 9 Pregrade Meeting ........................................................................................................................................................ 9 Observation of Grading ............................................................................................................................................ 9 Clearing and Grubbing .............................................................................................................................................. 9 Site Preparation ......................................................................................................................................................... 10 Excavation Characteristics ....................................................................................................................................... 10 Processing of Fill Areas ........................................................................................................................................... 10 Compaction and Method of Filling ........................................................................................................................ 10 Surface Drainage ....................................................................................................................................................... 10 Foundations ................................................................................................................................................................... 11 General ....................................................................................................................................................................... 11 Dimensions ................................................................................................................................................................ 11 Bearing Capacity ........................................................................................................................................................ 12 Footing Reinforcing .................................................................................................................................................. 12 Lateral Load Resistance............................................................................................................................................. 12 Foundation Excavation Observation ...................................................................................................................... 12 CWE 2210558.01 Proposed Martin Residence Lot 5 of Buena Vista Circle Carlsbad, California Settlement Characteristics ....................................................................................................................................... 12 Expansive Characteristics ......................................................................................................................................... 13 Soluble Sulfates ......................................................................................................................................................... 13 Foundation Plan Review ........................................................................................................................................... 13 Seismic Design Factors ............................................................................................................................................ 13 Risk Categories .......................................................................................................................................................... 14 On-Grade Slabs ............................................................................................................................................................. 15 General ....................................................................................................................................................................... 15 Interior Floor Slabs.................................................................................................................................................... 15 Under-Slab Vapor Retarders ................................................................................................................................... 15 Exterior Concrete Flatwork .................................................................................................................................... 15 Earth Retaining Walls................................................................................................................................................... 16 Foundations ............................................................................................................................................................... 16 Passive Pressure ........................................................................................................................................................ 16 Active Pressure.......................................................................................................................................................... 16 Waterproofing and Wall Drainage Systems ........................................................................................................... 16 Backfill ........................................................................................................................................................................ 16 Limitations ......................................................................................................................................................................... 17 Review, Observation and Testing .............................................................................................................................. 17 Uniformity of Conditions ............................................................................................................................................ 17 Change in Scope ............................................................................................................................................................ 17 Time Limitations ........................................................................................................................................................... 17 Professional Standard ................................................................................................................................................... 18 Client's Responsibility .................................................................................................................................................. 18 Field Explorations............................................................................................................................................................. 18 Laboratory Testing............................................................................................................................................................ 19 ATTACHMENTS TABLES Table I Seismic Design Factors - 2019 CBC Table II ASCE 7-16 Risk Categories FIGURES Figure 1 Site Vicinity Map, Follows Page 1 PLATES Plate 1 Site Plan & Geotechnical Map Plate 2 Geologic Cross Section A-A’ Plate 3 Cantilever Retaining Wall Drainage Systems APPENDICES Appendix A Subsurface Explorations Appendix B Laboratory Test Results Appendix C Gross Slope Stability Appendix D Surficial Slope Stability CWE 2210558.01 Proposed Martin Residence Lot 5 of Buena Vista Circle Carlsbad, California Appendix E References Appendix F Recommended Grading Specifications-General Provisions Appendix G Data from SGC Report (2000) PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED MARTIN RESIDENCE LOT 5 OF BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA INTRODUCTION AND PROJECT DESCRIPTION This report presents the results of a preliminary geotechnical investigation performed for a proposed residential structure to be located on Lot 5 of Buena Vista Circle, Carlsbad, California. The following Figure No. 1 presents a vicinity map showing the location of the property. We understand that a one- to two-story single-family residence with an attached garage, swimming pool, and other normally associated appurtenances are to be constructed within the upper, pad area of the lot. We anticipate that the proposed residence will be of conventional, wood frame construction with an on-grade concrete floor slab. We also anticipate that the proposed improvements will be supported by conventional shallow foundations and possibly drilled, cast-in-place concrete piers, depending upon the configuration of the proposed pool. Grading to accommodate the proposed improvements is expected to be limited to cuts and fills of less than 2 feet from existing site grades and creating the excavation for the proposed swimming pool. To assist in the preparation of this report, we were provided with architectural drawings prepared by New Modern Design, dated September 20, 2021, and a Preliminary Site Plan prepared by Pasco Laret Suites & Associates (PLSA), dated November, 2021. A copy of the site plan was used as a base map for our Site Plan and Geologic Map, and is included in Plate No. 1 of this report. Our Geologic Cross Section A-A’ has been based on the topographic data presented on the site plan and is included as Plate No. 2 of this report. We were also provided with a report prepared for the subject property titled “Geologic Evaluation of Bluff Property and Soils Investigation for Proposed Single-Family Residence, Vacant Lot Northeast of 2411 Buena Vista Circle, Carlsbad, California” prepared by Southland Geotechnical Consultants (SGC), dated February 17, 2000. Data form the report is included in Appendix G of this report. This report has been prepared for the exclusive use of John Martin, and his design consultants, for specific application to the project described herein. Should the project be modified, the conclusions and CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 PROPOSED SINGLE-FAMILY RESIDENCELOT 5 OF BUENA VISTA CIRCLECARLSBAD, CALIFORNIA DATE:DECEMBER 2021 BY: SRD JOB NO.: 2210558.01 FIGURE NO.: 1 CHRISTIAN WHEELER E N G I N E E R I N G SITE VICINITY © OpenStreetMap contributors PROJECT SITE .p De. Bu na rs agoon Qj t Buena ena Place Dri CWE 2210558.01 December 8, 2021 Page No. 2 recommendations presented in this report should be reviewed by Christian Wheeler Engineering for conformance with our recommendations and to determine whether any additional subsurface investigation, laboratory testing and/or recommendations are necessary. Our professional services have been performed, our findings obtained and our recommendations prepared in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties, expressed or implied. SCOPE OF SERVICES Our geotechnical investigation will consist of surface reconnaissance, subsurface exploration, obtaining representative soil samples, laboratory testing, percolation testing, analysis of the field and laboratory data and review of relevant readily available geologic literature. In consideration of the conditions at the site, the proposed construction, and site access constraints, we anticipate that the following services will be provided as part of our investigation. Obtain a boring permit through the County of San Diego Department of Environmental Health. Drill one small-diameter boring to explore the subsurface conditions of the site and to obtain samples for laboratory testing. Backfill the boring hole using a grout or a grout/bentonite mix as required by the County of San Diego Department of Environmental Health. Evaluate, by laboratory tests and our past experience with similar soil types, the engineering properties of the various soil strata that may influence the proposed construction, including bearing capacities, shear strengths, expansive characteristics and settlement potential. Describe the general geology at the site, including possible geologic hazards that could have an effect on the proposed construction, and provide the seismic design parameters in accordance with the 2019 edition of the California Building Code. Perform computer-assisted slope stability analyses of the proposed lot configuration and bluff in order to quantify the minimum factor-of-safety against global slope failure at the site and, as necessary, to determine the approximate location of the 1.5-factor of safety line. Discuss potential construction difficulties that may be encountered due to soil conditions, groundwater or geologic hazards, and provide geotechnical recommendations to mitigate identified construction difficulties. Provide site preparation and grading recommendations for the anticipated work. Provide foundation recommendations for the type of construction anticipated and develop soil engineering design criteria for the recommended foundation designs. CWE 2210558.01 December 8, 2021 Page No. 3 Provide a preliminary geotechnical report presenting the results of our investigation including a plot plan showing the location of our subsurface explorations, excavation logs, field infiltration rates, laboratory test results, and our conclusions and recommendations for the proposed project. Although a test for the presence of soluble sulfates within the soils that may be in contact with reinforced concrete was performed as part of the scope of our services, it should be understood Christian Wheeler Engineering does not practice corrosion engineering. If a corrosivity analysis is considered necessary, we recommend that the client retain an engineering firm that specializes in this field to consult with them on this matter. The results of our sulfate testing should only be used as a guideline to determine if additional testing and analysis is necessary. FINDINGS SITE DESCRIPTION The subject site is an undeveloped residential lot, identified as Assessor’s Parcel Number 155-221-05, which is located adjacent to and north of Buena Vista Circle in in the City of Carlsbad, California. Topographically, the southeast portion of the site is characterized by a relatively level building pad with an elevation of approximately 43 feet. A natural bluff descends from the northwest side of the level pad area of the site to the northwest perimeter of the. Overall, the bluff displays a general inclination of about 3:1 (horizontal to vertical). The bottom of the bluff along the northwest portion of the site is at an approximate elevation of 6 to 8 feet (PLSA). GENERAL GEOLOGY AND SUBSURFACE CONDITIONS GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located in the Coastal Plains Physiographic Province of San Diego County. Based upon the findings of our subsurface explorations and review of readily available, pertinent geologic and geotechnical literature, it was determined that the site is generally underlain by topsoil, old paralic deposits, and Santiago Formation. The subsurface exploration logs are presented in the attached Appendix A. These materials are described below: TOPSOIL: The area of the property investigated was found to be underlain by a relatively thin layer of topsoil extending to a maximum depth of about 2 feet from existing grade. Deeper topsoil may exist in areas of the site not investigated. These materials consisted of dark grayish-brown and dark brown, dry, very loose, silty sand (SM) The topsoil was judged to have a very low expansion potential (EI <20). CWE 2210558.01 December 8, 2021 Page No. 4 OLD PARALIC DEPOSITS (Qop): Quaternary-age very old paralic deposits were found to underlie the surficial soils throughout the area of the property investigated. As encountered in the borings (CWE and SGC), the old paralic deposits range in depth form about 10½ feet to 14 feet below existing site grades. These materials generally consisted of orangish-brown, damp to moist, dense to very dense, silty sand (SM). The old paralic deposits in boring B-1 (CWE) at a depth of 7½ below existing grade consisted of orangish-brown to light gray, damp, very dense, poorly graded sand with silt (SP-SM). Gravels were encountered at the contact with the underlying Santiago Formation. The old paralic deposits were judged to have a very low Expansion Index (EI<20). It is our opinion that this material is competent and typically performs in terms of slope stability. SANTIAGO FORMATION (Tsa): Tertiary-age sedimentary deposits of the Santiago Formation underlie the old paralic deposits across the area of the site to be developed and crop out along the northern portion of the subject lot. As encountered in the subsurface explorations, these materials generally consisted of white to light yellowish-brown and yellowish-green, moist, very dense, clayey sand (SC). The formational deposits were judged to have a low to medium Expansion Index (EI between 21 to 90). GEOLOGIC STRUCTURE: The Santiago Formation materials in the area of the subject site are expected to dip approximately 5° to 10° to the north and northwest as depicted on the local geology map (Kennedy and Tan, 2005). Such bedding is considered to be unfavorable with regards to the stability of the north-facing slope at the site. It should be recognized that such bedding attitudes dipping out of the hillside generally displays unfavorable characteristics with regards to slope stability; however, it is our opinion that the formational materials that underlie the site are very competent and stand well in high, steep slopes. In our opinion, the risk of bedding plane related slope failure at the site can be considered to be very low. GROUNDWATER: No groundwater or seepage was encountered in our subsurface explorations. We do not expect any significant groundwater related conditions during or after the proposed construction. However, it should be recognized that minor groundwater seepage problems might occur after construction and landscaping are completed, even at a site where none were present before construction. These are usually minor phenomena and are often the result of an alteration in drainage patterns and/or an increase in irrigation water. Based on the anticipated construction and the permeability of the on-site soils, it is our opinion that any seepage problems that may occur will be minor in extent. It is further our opinion that these problems can be most effectively corrected on an individual basis if and when they occur. CWE 2210558.01 December 8, 2021 Page No. 5 TECTONIC SETTING: No faults are known to traverse the subject site. However, it should be noted that much of Southern California, including the San Diego County area, is characterized by a series of Quaternary-age fault zones that consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as “active” according to the criteria of the California Division of Mines and Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years). The Division of Mines and Geology used the term “potentially active” on Earthquake Fault Zone maps until 1988 to refer to all Quaternary-age (last 1.6 million years) faults for the purpose of evaluation for possible zonation in accordance with the Alquist-Priolo Earthquake Fault Zoning Act and identified all Quaternary-age faults as “potentially active” except for certain faults that were presumed to be inactive based on direct geologic evidence of inactivity during all of Holocene time or longer. Some faults considered to be “potentially active” would be considered to be “active” but lack specific criteria used by the State Geologist, such as sufficiently active and well-defined. Faults older than Quaternary-age are not specifically defined in Special Publication 42, Fault Rupture Hazard Zones in California, published by the California Division of Mines and Geology. However, it is generally accepted that faults showing no movement during the Quaternary period may be considered to be “inactive”. The City of San Diego guidelines indicate that since the beginning of the Pleistocene Epoch marks the boundary between “potentially active” and “inactive” faults, unfaulted Pleistocene-age deposits are accepted as evidence that a fault may be considered to be “inactive.” It should be recognized that the active Newport-Inglewood-Rose Canyon Fault Zone is located approximately 2¼ miles southwest of the site. Other active fault zones in the region that could possibly affect the site include the Coronado Bank Fault Zone to the southwest, the San Diego Trough and San Clemente Fault Zones to the west; the Palos Verdes Fault Zone to the northwest; and the Elsinore, San Jacinto and San Andreas Fault Zones to the northeast. GENERAL GEOLOGIC HAZARDS GENERAL: The site is located in an area where the risks due to significant geologic hazards are relatively low. No geologic hazards of sufficient magnitude to preclude the construction of the subject project are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable for the proposed improvements. SURFACE RUPTURE: There are no known active faults that traverse the subject site; therefore, the risk for surface rupture at the subject site is considered low. CWE 2210558.01 December 8, 2021 Page No. 6 LANDSLIDE POTENTIAL AND SLOPE STABILITY: As part of this investigation, we reviewed the publication “Landslide Hazards in the Northern Part of the San Diego Metropolitan Area" by Tan and Giffen, 1995. This reference is a comprehensive study that classifies San Diego County into areas of relative landslide susceptibility. The subject site is located in Relative Landslide Susceptibility Area 3-1. The 3-1 classification is assigned to areas considered “generally susceptible” to slope movement. Natural slopes within the 3-1 classification are considered at or near their stability limits due to their steep inclinations and can be expected to fail locally when adversely modified. Sites within this classification are located outside the boundaries of known landslides. Due to the very competent nature of the Quaternary and Tertiary-age sedimentary deposits forming the sloping portions of the site, the potential for deep-seated landslides is considered low. In addition, the near- vertical slopes are comprised of the very competent Quaternary and Tertiary-age sandstones and are considered to possess a low potential in their natural state for landsliding. Based on the implementation of proper drainage to channel water away from the bluff top, it is our opinion that the potential for slope failures within the bluff will remain low after the proposed construction. It is further our opinion that the proposed construction will not significantly affect the stability of the existing bluff if the recommendations presented here within are implemented. SLOPE STABILITY ANALYSES GENERAL: In consideration of the existing inland bluff at the subject site, we have performed a series of quantitative slope stability analyses to determine the factors-of-safety against deep-seated slope failure for the slope that descends to the project area. It is our professional opinion that the cross section modeled in our stability analyses, oriented perpendicular to the steepest portion of the slope, represents the worst-case scenario with regards to gross slope stability at the subject site. We have also performed a surficial stability analysis to determine the minimum factor-of-safety against surficial failure. Descriptions of our stability analyses are presented in the following “Gross Stability Analyses” and “Surficial Stability Analyses” sections of this report. GROSS STABILITY ANALYSES CROSS-SECTIONS: As presented on our Site Plan and Geotechnical Map, included herein as Plate No. 1, we have created geologic cross section A-A’ to depict the topography and subsurface conditions at the subject site. The geologic cross section is included on Plate No. 2 of this report. The location of the geologic cross section was chosen to be oriented perpendicular to the slope and included the steepest portions of the slope. CWE 2210558.01 December 8, 2021 Page No. 7 To analyze the stability of the subject site we have performed a series of quantitative slope stability analyses incorporating the topography and geologic conditions presented on our geologic cross section A-A’. The on-site earth materials incorporated in our stability analyses are described above in the “Geologic Setting and Soil Description” section of this report. Based on the configuration of the site and the composition of the underlying formational material, circular- and block-type failure mechanisms were modeled in our analyses. The results of our quantitative slope stability analyses are presented below in the results of Stability Analyses Section of this report. STRENGTH PARAMETERS: The strength parameters for the earth materials underlying the subject site were estimated by the direct shear test method and our experience and judgment with similar soil types. The results of our direct shear testing are presented in Appendix B of this report. The unit weights of the earth materials that underlie the subject site and adjacent areas utilized in our stability analyses were chosen based on the results of our laboratory testing and our experience with similar materials in the vicinity of the subject site. It is our professional opinion that the strength parameters and unit weights presented below and utilized in our stability analyses provide for conservative slope stability analyses. Soil Type Unit Weight, Phi, Cohesion, c Artificial Fill (Qaf) 120 pcf 32 150 psf Very Old Paralic Deposits (Qvop) 120 pcf 35° 300 psf Santiago Formation (Tsa) (across bedding) 125 pcf 38° 600 psf Santiago Formation (Tsa) (along bedding) 125 pcf 28° 450 psf METHOD OF ANALYSES: The analyses of the gross stability of the proposed site topography were performed using Version 2 of the GSTABL7 computer program developed by Garry H. Gregory, PE. The program analyzes circular, block, specified, and randomly shaped failure surfaces using the Modified Bishop, Janbu, or Spencer’s Methods. The STEDwin computer program, developed by Harald W. Van Aller, P. E., was used in conjunction with this program for data entry and graphics display. The proposed topography of the subject site along geologic cross section A-A’ was analyzed for circular- and block-type failures and each failure analysis was programmed to run at least 2,000 random failure surfaces. The most critical failure surfaces were then accumulated and sorted by value of the factor-of-safety. After the specified number of failure surfaces were successfully generated and analyzed, the ten most critical surfaces were plotted so that the pattern may be studied. RESULTS OF STABILITY ANALYSES: Appendix C of this report presents the results of our static, gross stability analyses. As demonstrated on the printouts of these analyses, the proposed site topography CWE 2210558.01 December 8, 2021 Page No. 8 along our geologic cross section A-A’ demonstrates minimum factors-of-safety of 3.8 and 2.4 for static and pseudo-static slope failures, respectively. These values are in excess of the minimums that are generally considered to be stable of 1.5 and 1.1 for static and pseudo-static failures, respectively. SURFICIAL SLOPE STABILITY GENERAL: Appendix D of this report presents the results of our surficial slope stability analysis of the steepest portions of the natural slopes on-site. As demonstrated on the printout of this analysis, the natural slope demonstrates a factor-of-safety of 2.2 against shallow, surficial failures, which is above the minimum generally considered to be stable (1.5). LIQUEFACTION: The earth materials underlying the site are not considered subject to liquefaction due to such factors as soil density, grain-size distribution, the absence of shallow groundwater conditions. FLOODING: As delineated on the Flood Insurance Rate Map (FIRM) prepared by the Federal Emergency Management Agency, the developable area of the site is not located within either the 100-year flood zone or the 500-year flood zone. TSUNAMIS: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. Due to the site’s setback from the ocean and elevation, it will not be affected by a tsunami. SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Due to the elevation of the proposed building pad, the risk of seiches affecting the site is considered to be very low. CONCLUSIONS In general, it is our professional opinion and judgment that the subject property is suitable for the construction of the subject project provided the recommendations presented herein are implemented. The main geotechnical conditions affecting the proposed project consists of potentially compressible topsoil. The flat-lying portion of the subject site was found to be underlain by potentially compressible topsoil extending to a maximum depth of about 2 feet below existing grade. Deeper potentially compressible soils may exist in areas of the site not investigated. These materials are considered unsuitable, in its present CWE 2210558.01 December 8, 2021 Page No. 9 condition, for the support of settlement sensitive improvements and will have to be removed and replaced as compacted fill as described hereinafter. It is anticipated that the proposed development scheme will involve very minor cuts and fills. This, coupled with the recommended site preparation may result in a cut/fill transition underlying the proposed structure at foundation level. Cut/fill transitions are not recommended due to the potential for differential settlement due to the different compression characteristics of compacted fill and old paralic deposits. Special recommendations are provided hereinafter to mitigate this condition. The site is located in an area that is relatively free of geologic hazards that will have a significant effect on the proposed construction. The most likely geologic hazard that could affect the site is ground shaking due to seismic activity along one of the regional active faults. However, construction in accordance with the requirements of the most recent edition of the California Building Code and the local governmental agencies should provide a level of life-safety suitable for the type of development proposed. RECOMMENDATIONS GRADING AND EARTHWORK GENERAL: All grading should conform to the guidelines presented in the current edition of the California Building Code, the minimum requirements of the City of Carlsbad, and the recommended Grading Specifications and Special Provisions attached hereto, except where specifically superseded in the text of this report. PREGRADE MEETING: It is recommended that a pre-grade meeting including the grading contractor, the client, and a representative from Christian Wheeler Engineering be performed, to discuss the recommendations of this report and address any issues that may affect grading operations. OBSERVATION OF GRADING: Continuous observation by the Geotechnical Consultant is essential during the grading operation to confirm conditions anticipated by our investigation, to allow adjustments in design criteria to reflect actual field conditions exposed, and to determine that the grading proceeds in general accordance with the recommendations contained herein. CLEARING AND GRUBBING: Site preparation should begin with the removal of any vegetation in areas to receive proposed improvements or new fill soils. CWE 2210558.01 December 8, 2021 Page No. 10 SITE PREPARATION: It is recommended that all existing underlying the proposed structure, associated improvements, and new fills be removed and replaced as compacted fill. Based on our findings, it is anticipated that maximum removal depth will extend to a depth of about 2 feet below existing grade. Deeper removals may be necessary in areas of the site not investigated or due to unforeseen conditions. Lateral removal limits should extend at least 5 feet from the perimeter of the structure, any settlement sensitive improvements, and new fills or equal to removal depth, whichever is more. No removals are recommended beyond property lines or within 5 feet from the top of the bluff. All excavated areas should be approved by the geotechnical engineer or his representative prior to replacing any of the excavated soils. The excavated materials can be replaced as properly compacted fill in accordance with the recommendations presented in the “Compaction and Method of Filling” section of this report. EXCAVATION CHARACTERISTICS: Based on our findings, it is our opinion that it is likely that the proposed grading may be performed with conventional heavy-duty grading equipment in good working condition. However, localized hard concretions requiring special handling may be encountered within the very old paralic deposits. In addition, trenching with light equipment within the very old paralic deposits may be difficult. PROCESSING OF FILL AREAS: Prior to placing any new fill soils or constructing any new improvements in areas that have been cleaned out to receive fill, the exposed soils should be scarified to a depth of 12 inches, moisture conditioned, and compacted to at least 90 percent relative compaction. This recommendation applies to the area of the site outside the perimeter of the proposed residence. COMPACTION AND METHOD OF FILLING: In general, all structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of its maximum laboratory dry density as determined by ASTM Laboratory Test D1557. Structural fills underlying the proposed structure should be compacted to at least 95 percent. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by the Geotechnical Consultant. Fill material should be free of rocks or lumps of soil in excess of 3 inches in maximum dimension. Utility trench backfill within 5 feet of the proposed structure and beneath all concrete flatwork or pavements should be compacted to a minimum of 90 percent of its maximum dry density. SURFACE DRAINAGE: The drainage around the proposed improvements should be designed to collect and direct surface water away from proposed improvements toward appropriate drainage facilities and the CWE 2210558.01 December 8, 2021 Page No. 11 top of slopes. Rain gutters with downspouts that discharge runoff away from the structure into controlled drainage devices are recommended. The ground around the proposed improvements should be graded so that surface water flows rapidly away from the improvements without ponding. In general, we recommend that the ground adjacent to structure slope away at a gradient of at least 5 percent for a minimum distance of 10 feet. If the minimum distance of 10 feet cannot be achieved, an alternative method of drainage runoff away from the building at the termination of the 5 percent slope will need to be used. Swales and impervious surfaces that are located within 10 feet of the building should have a minimum slope of 2 percent. Pervious hardscape surfaces adjacent to structures should be similarly graded. Drainage patterns provided at the time of construction should be maintained throughout the life of the proposed improvements. Site irrigation should be limited to the minimum necessary to sustain landscape growth. Over watering should be avoided. Should excessive irrigation, impaired drainage, or unusually high rainfall occur, zones of wet or saturated soil may develop. FOUNDATIONS GENERAL: Based on our findings and engineering judgment, the proposed structure may be supported by conventional shallow continuous and isolated spread footings extending into very old paralic deposits. Footings supporting associated exterior improvements may be supported by conventional shallow continuous and isolated spread footings founded on old paralic deposits or newly compacted fill soils. The following recommendations are considered the minimum based on the anticipated soil conditions, and are not intended to be lieu of structural considerations. All foundations should be designed by a qualified engineer. Depending upon the configuration of the proposed pool and its proximity to the descending slope along the north side of the building pad, the proposed pool may need to be supported by drilled, cast-in-place concrete piers. DIMENSIONS: Spread footings supporting the proposed structure should be embedded at least 18 inches below lowest adjacent finish pad grade, and should extend at least 6 inches into old paralic deposits, whichever is more. Spread footings supporting light miscellaneous exterior footings should be embedded at least 12 inches below lowest adjacent finish pad grade. Continuous and isolated footings should have a minimum width of 12 inches and 24 inches, respectively. Retaining wall footings should be at least 18 inches deep and 24 inches wide. Property line footings should also extend at least 6 inches into competent very old paralic deposits. CWE 2210558.01 December 8, 2021 Page No. 12 BEARING CAPACITY: Spread footings supporting the proposed structure with a minimum depth of 18 inches and a minimum width of 12 inches may be designed for an allowable soil bearing pressure of 3,000 pounds per square foot (psf). This value may be increased by 700 psf for each additional foot of embedment and 500 psf for each additional foot of width up to a maximum of 6,000 psf. Spread footings supporting the proposed light exterior improvements with a minimum depth of 12 inches and a minimum width of 12 inches may be designed for an allowable soil bearing pressure of 2,000 psf. This value may be increased by 500 psf for each additional foot of embedment and 300 psf for each additional foot of width up to a maximum of 4,000 pounds per square foot. These values may be increased by one-third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCING: Reinforcement requirements for foundations should be provided by a structural designer. However, based on the expected soil conditions, we recommend that the minimum reinforcing for continuous footings consist of at least 2 No. 5 bars positioned near the bottom of the footing and 2 No. 5 bars positioned near the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be 0.30. The passive resistance may be considered to be equal to an equivalent fluid weight of 300 pounds per cubic foot. These values are based on the assumption that the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one-third. PROPOSED SWIMMING POOL: It is recommended that the proposed swimming pool be founded in very old paralic deposits. The swimming pool may be founded on conventional shallow foundations; however, revised recommendations may be necessary depending on the final swimming pool location relative to the top of the existing bluff. FOUNDATION EXCAVATION OBSERVATION: All footing excavations should be observed by Christian Wheeler Engineering prior to placing of forms and reinforcing steel to determine whether the foundation recommendations presented herein are followed and that the foundation soils are as anticipated in the preparation of this report. All footing excavations should be excavated neat, level, and square. All loose or unsuitable material should be removed prior to the placement of concrete. SETTLEMENT CHARACTERISTICS: The anticipated total and differential settlement for the proposed structure is expected to be less than about 1 inch and 1 inch over 40 feet, respectively, provided the CWE 2210558.01 December 8, 2021 Page No. 13 recommendations presented in this report are followed. For swimming pool design, the total and differential settlement may be assumed to be less than about ¼ inch and ¼ inch over 40 feet, respectively. It should be recognized that minor cracks normally occur in concrete slabs and foundations due to concrete shrinkage during curing or redistribution of stresses, therefore some cracks should be anticipated. Such cracks are not necessarily an indication of excessive vertical movements. EXPANSIVE CHARACTERISTICS: The prevailing foundation soils are assumed to have a very low expansive potential (EI<20). The recommendations within this report reflect these conditions. SOLUBLE SULFATES: The water-soluble sulfate content of a selected soil sample from the site was determined in accordance with California Test Method 417. The test results indicate that the soil sample had a soluble sulfate content of 0.003 percent. Soils with a soluble sulfate content of less than 0.1 percent are considered to be negligible. However, it should be recognized that the sulfate content of surficial soils may increase with time due to soluble sulfate in the irrigation water or fertilized use. It should be understood Christian Wheeler Engineering does not practice corrosion engineering. If a corrosivity analysis is considered necessary, we recommend that the client retain an engineering firm that specializes in this field to consult with them on this matter. The results of our corrosion testing should only be used as a guideline to determine if additional testing and analysis is necessary. FOUNDATION PLAN REVIEW: The final foundation plan and accompanying details and notes should be submitted to this office for review. The intent of our review will be to verify that the plans used for construction reflect the minimum dimensioning and reinforcing criteria presented in this section and that no additional criteria are required due to changes in the foundation type or layout. It is not our intent to review structural plans, notes, details, or calculations to verify that the design engineer has correctly applied the geotechnical design values. It is the responsibility of the design engineer to properly design/specify the foundations and other structural elements based on the requirements of the structure and considering the information presented in this report. SEISMIC DESIGN FACTORS The seismic design factors applicable to the subject site are provided below. The seismic design factors were determined in accordance with the 2019 California Building Code. The site coefficients and adjusted maximum considered earthquake spectral response acceleration parameters are presented in the following Table I. CWE 2210558.01 December 8, 2021 Page No. 14 TABLE I: SEISMIC DESIGN FACTORS Site Coordinates: Latitude Longitude 33.167° -117.351° Site Class C Site Coefficient Fa 1.2 Site Coefficient Fv 1.5 Spectral Response Acceleration at Short Periods Ss 1.073 g Spectral Response Acceleration at 1 Second Period S1 0.388 g SMS=FaSs 1.287 g SM1=FvS1 0.583 g SDS=2/3*SMS 0.858 g SD1=2/3*SM1 0.388 g Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed improvements. RISK CATEGORIES The project structural engineer and architect should evaluate the appropriate Risk Category and Seismic Design Category for the planned structures. The values presented herein assume a Risk Category of II and a Seismic Design Category D. Table II presents a summary of the risk categories in accordance with ASCE 7- 16. TABLE II ASCE 7-16 RISK CATEGORIES Risk Category Building Use Examples I Low risk to Human Life at Failure Barn, Storage Shelter II Nominal Risk to Human Life at Failure (Buildings Not Designated as I, III or IV) Residential, Commercial and Industrial Buildings III Substantial Risk to Human Life at Failure Theaters, Lecture Halls, Dining Halls, Schools, Prisons, Small Healthcare Facilities, Infrastructure Plants, Storage for Explosives/Toxins IV Essential Facilities Hazardous Material Facilities, Hospitals, Fire and Rescue, Emergency Shelters, Police Stations, Power Stations, Aviation Control Facilities, National Defense, Water Storage CWE 2210558.01 December 8, 2021 Page No. 15 ON-GRADE SLABS GENERAL: It is our understanding that the floor system of the proposed structure will consist of a concrete slab-on-grade. The following recommendations are considered the minimum slab requirements based on the soil conditions and are not intended in lieu of structural considerations. These recommendations assume that the site preparation recommendations contained in this report are implemented. INTERIOR FLOOR SLABS: The minimum on-grade slab thickness for the structure should be 5 inches (actual) and the slab should be reinforced with at least No. 4 bars spaced at 12 inches on center each way. Slab reinforcement should be supported on chairs such that the reinforcing bars are positioned at mid-height in the floor slab. The slab reinforcement should extend down into the perimeter footings at least 6 inches. UNDER-SLAB VAPOR RETARDERS: Steps should be taken to minimize the transmission of moisture vapor from the subsoil through the interior slabs where it can potentially damage the interior floor coverings. Local industry standards typically include the placement of a vapor retarder, such as plastic, in a layer of coarse sand placed directly beneath the concrete slab. Two inches of sand are typically used above and below the plastic. The vapor retarder should be at least 15-mil Stegowrap® or similar material with sealed seams and should extend at least 12 inches down the sides of the interior and perimeter footings. The sand should have a sand equivalent of at least 30, and contain less than 10% passing the Number 100 sieve and less than 5% passing the Number 200 sieve. The membrane should be placed in accordance with the recommendation and consideration of ACI 302, “Guide for Concrete Floor and Slab Construction” and ASTM E1643, “Standards Practice for Installation of Water Vapor Retarder Used in Contact with Earth or Granular Fill Under Concrete Slabs.” It is the flooring contractor’s responsibility to place floor coverings in accordance with the flooring manufacturer specifications. EXTERIOR CONCRETE FLATWORK: Exterior concrete slabs on grade should have a minimum thickness of 4 inches and be reinforced with at least No. 3 bars placed at 18 inches on center each way (ocew). Driveway slabs should have a minimum thickness of 5 inches and be reinforced with at least No. 4 bars placed at 12 inches ocew. Driveway slabs should be provided with a thickened edge a least 12 inches deep and 6 inches wide. All slabs should be provided with weakened plane joints in accordance with the American Concrete Institute (ACI) guidelines. Special attention should be paid to the method of concrete curing to reduce the potential for excessive shrinkage cracking. It should be recognized that minor cracks occur normally in concrete slabs due to shrinkage. Some shrinkage cracks should be expected and are not necessarily an indication of excessive movement or structural distress. CWE 2210558.01 December 8, 2021 Page No. 16 EARTH RETAINING WALLS FOUNDATIONS: Foundations for any proposed retaining walls should be constructed in accordance with the foundation recommendations presented previously in this report. PASSIVE PRESSURE: The passive pressure for the anticipated foundation soils may be considered to be 300 pounds per square foot per foot of depth. The upper foot of embedment should be neglected when calculating passive pressures, unless the foundation abuts a hard surface such as a concrete slab. The passive pressure may be increased by one-third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.30 for the resistance to lateral movement. When combining frictional and passive resistance, the friction should be reduced by one-third. ACTIVE PRESSURE: The active soil pressure for the design of “unrestrained” and “restrained” earth retaining structures with level backfill may be assumed to be equivalent to the pressure of a fluid weighing 41 and 63 pounds per cubic foot, respectively. These pressures do not consider any other surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values are based on a drained backfill condition. Seismic lateral earth pressures may be assumed to equal an inverted triangle starting at the bottom of the wall with the maximum pressure equal to 12H pounds per square foot (where H = wall height in feet) occurring at the top of the wall. WATERPROOFING AND WALL DRAINAGE SYSTEMS: The need for waterproofing should be evaluated by others. If required, the project architect should provide (or coordinate) waterproofing details for the retaining walls. The design values presented above are based on a drained backfill condition and do not consider hydrostatic pressures. The retaining wall designer should provide a detail for a wall drainage system. Typical retaining wall drain system details will be presented in Plate No. 3 for informational purposes. Additionally, outlet points for the retaining wall drain system should be coordinated with the project civil engineer. BACKFILL: Retaining wall backfill soils should be compacted to at least 90 percent relative compaction. However, retaining wall backfill underlying the on-grade portion of the structure should be compacted to at least 95%. Expansive or clayey soils should not be used for backfill material. The wall should not be backfilled until the masonry has reached an adequate strength. CWE 2210558.01 December 8, 2021 Page No. 17 LIMITATIONS REVIEW, OBSERVATION AND TESTING The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the geotechnical engineer and engineering geologist so that they may review and verify their compliance with this report and with the California Building Code. It is recommended that Christian Wheeler Engineering be retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. UNIFORMITY OF CONDITIONS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the geotechnical engineer so that he may make modifications if necessary. CHANGE IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they be due to natural processes or the work of man on this or CWE 2210558.01 December 8, 2021 Page No. 18 adjacent properties. In addition, changes in the Standards-of-Practice and/or Government Codes may occur. Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations. PROFESSIONAL STANDARD In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations, and recommendations be based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of the Client, or her representatives, to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to ensure that the contractor and his subcontractors carry out such recommendations during construction. FIELD EXPLORATIONS One subsurface exploration was made under the direction of our firm on October 13, 2021 at the location indicated on the Site Plan and Geotechnical Map included herewith as Plate No. 1. The exploration consisted of a small diameter boring drilled utilizing a truck mounted drill rig (IR A-300). The fieldwork was conducted under the observation and direction of our engineering geology personnel. The explorations were carefully logged when made. The boring logs are presented on Appendix A. The soils are described in accordance with the Unified Soils Classification. In addition, a verbal textural description, the wet CWE 2210558.01 December 8, 2021 Page No. 19 color, the apparent moisture, and the density or consistency is provided. The density of granular soils is given as very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. Relatively undisturbed drive samples were collected using a modified California sampler. The sampler, with an external diameter of 3.0 inches, is lined with 1-inch long, thin, brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into the ground with the weight of a 140-pound hammer falling 30 inches in general accordance with ASTM D 3550-84. The driving weight is permitted to fall freely. The number of blows per foot of driving, or as indicated, are presented on the boring logs as an index to the relative resistance of the sampled materials. The samples were removed from the sample barrel in the brass rings, and sealed. Bulk samples of the earth materials encountered were also collected. Samples were transported to our laboratory for testing. LABORATORY TESTING Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed and the subsequent results are presented in Appendix B. B-2 B-1 B-4 B-3 B-1 Qop Tsa Tsa Qop Tsa A'A Approximate Boring Location (CWE 2021) Approximate Boring Location(SGC 2000) Old Paralic Deposits overSantiago Formation Santiago Formation Geologic Contact Geologic Cross Section QopTsa CWE LEGEND B-1 B-4 Note: Topsoils Not Mapped Tsa DATE: DECEMBER 2021 BY: SD JOB NO.: 2210558.01 PLATE NO.: 1 SITE PLAN AND GEOTECHNICAL MAP PROPOSED SINGLE-FAMILY RESIDENCELOT 5 OF BUENA VISTA CIRCLECARLSBAD, CALIFORNIA CHRISTIAN WHEELER E N G I N E E R I N G 00 30'60' SCALE: 1" = 30' I / • LOT6 BUENA VISTA GARDENS MAP2492 PLAN VIEW -PRELIMINARY SITE PLAN EX/STINGSmucnJRE TOREJIAIN r'1¼.,../r ; • <:;: ,,r~ " PASCO LAREY SUITER <I ~SSIOC!~iilES San Diego I Solana Beach I Orange County Phone 858.259.82121 www.plsaengineering.com A 60 - PL I I 40 _ I i--Buena ~ Vista Lagoon 20 - I ------------------N 64° W----------------- T B-2 (SGC) Projected 36' Southwest_ Proposed Site Retaining Wall--~1 I I LJ Tsa Tsa B-1 (SGC) Projected -40' Northeast Proposed Grade B-1 (CWE) Proposed ,___ __ Residence _____ 1 Qop Tsa Qop -- B-3 (SGC) Projected 20' Southwest PL I I I A' -60 I I 40 20 y-I !' OL--W-a~t1/~r--'-'----~•l _____ ._, ____ ._, ____ ._, ____ ._, ____ ._, ____ ._, ____ ._,-_-____ ._, ____ ._, ____ ._, ____ ._, ___ ----'0 0 W ~ @ ~ ~ ~ ~ ™ ~ ~ ~ ~ ~ ~ CWELEGEND B 1 & B2 Approximate Boring Location (CWE 2021) B3 Approximate Boring Location (SGC 2000) Qop Old Paralic Deposits Tse Santiago Formation '! Groundwater GEOLOGIC CROSS SECTION A-A' DATE: BY: PROPOSED SINGLE-FAMILY RESIDENCE LOT 5 OF BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA 0 DECEMBER 2021 JOB NO.: 2210558.01 SD PLATE NO.: 2 20' 40' SCALE: 1" = 20' CHRISTIAN WHEELER ENGINEERING 1 3 5 5 5 1 1 3 2 2 3 4 NOTES AND DETAILS 1 GENERAL NOTES: 1) THE NEED FOR WATERPROOFING SHOULD BE EVALUATED BY OTHERS.2) WATERPROOFING TO BE DESIGNED BY OTHERS (CWE CAN PROVIDE A DESIGN IF REQUESTED).3) EXTEND DRAIN TO SUITABLE DISCHARGE POINT PER CIVIL ENGINEER.4) DO NOT CONNECT SURFACE DRAINS TO SUBDRAIN SYSTEM. 4 2 3 4 5 UNDERLAY SUBDRAIN WITH AND CUT FABRIC BACK FROMDRAINAGE PANELS AND WRAP FABRIC AROUND PIPE. COLLECTION DRAIN (TOTAL DRAIN OR EQUIVALENT)LOCATED AT BASE OF WALL DRAINAGE PANEL PERMANUFACTURER'S RECOMMENDATIONS. 4 3 6 4 4 4 4 4 4 7 4-INCH PERFORATED PVC PIPE ON TOP OF FOOTING, HOLESPOSITIONED DOWNWARD (SDR 35, SCHEDULE 40, OR EQUIVALENT). 34 INCH OPEN-GRADED CRUSHED AGGREGATE. GEOFARBRIC WRAPPED COMPLETELY AROUND ROCK. PROPERLY COMPACTED BACKFILL SOIL. WALL DRAINAGE PANELS (MIRADRAIN OR EQUIVALENT)PLACED PER MANUFACTURER'S REC'S. DETAILS: 6 7 12" 12"12" 12" 12" MIN.6" MIN. 6" MIN.6" MIN. 1 DETAIL 2 2 DETAIL DETAIL DETAIL PROPOSED SINGLE-FAMILY RESIDENCELOT 5 OF BUENA VISTA CIRCLECARLSBAD, CALIFORNIA DATE: DECEMBER 2021 BY: SRD JOB NO.: 2210558.01 PLATE NO.: 3 CANTILEVER RETAINING WALLDRAINAGE SYSTEMS CHRISTIAN WHEELERE N G I N E E R I N G □----- i~~~~ 4 . cl 4 • /•~' ,, ' ~/, ~~ cl cl ~ ~ ~---------~~ □----- 0 Q; 0 0 0 □----- ~~~~ 4 cl /a · ,,;z« / ~ ~" /~ cl □----- 0 0 Appendix A Subsurface Explorations 0 -- -- -- -- 5-- -- -- -- -- -- -- -- -- 15-- -- -- -- -- -20-- -- -- -- -- 25-- -- -- -- -- 30-- LOG OF TEST BORING B-1 Date Logged: Logged By: Existing Elevation: Proposed Elevation: rJ'J u rJ'J :;:i SM -·: SM : .. ·., .. :,-,•;-~ "l, ~ .... -. :·: .. •-,ti:· m-tr.· SP- SM SC 10/13/21 DJF ±43' ±43' Equipment: Auger Type: Drive Type: Depth to Water: IRA-300 8 inch Hollow Stem 140lbs/30 inches 35' SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) Topsoil: Dark grayi~h-brown, dry, ve!!Y loose, very fine-to medium-grained, SICTY SAND with rootlFts O1d Paralic Deposits (Qop): Orangish-brown, damp, very dense,vety fine-to medium-grained, SILTY SANp. Orangish-brown to light gray, damp, very dense, very fine-to coarse-grained, SAND with silt and trace gravels, mottled. I J Gravel bed at 10' top•. Santiago Formation (Tsa): White to light yellowish-brown, moist, very dense, fine-to very coarse-grained, CLAYEY SAND with reddish iron staining. Sample Type and Laboratory Test Legend Cal Modified California Sampler SPT Standard Penetration Test ST Shdby Tube MD Max Density S04 Soluble Sulfates SA Sieve Analysis HA Hydrometer SE Sand Equivalent PI Plasticity Index CP Collapse Potential 50/4" Cal 50/6" Cal - 50/5" Cal 50/5" Cal - 50/4" SPT 50/3" Cal 50/3" Cal - 5.2 4.1 8.7 9.3 9.1 CK Chunk DR Drive Ring DS Direct Shear Con Consolidation El Expansion Index R-Val Resistance Value Ch1 Soluble Ch1orides Res pH & Resistivity SD Sample Density l_ll.4 99.8 ~18.4 118.8 114:-3 ISA MD 1S04 OS OS SA Notes: Continues on A-2 * ** Symbol Legend Groundwater Level During Drilling Groundwater Level After Drilling Apparent Seepage No Sample Recovery Non-Representative Blow Count (rocks present) DATE: BY: PROPOSED SINGLE-FAMILY RESIDENCE LOT 5 OF BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA DECEMBER 2021 JOB NO.: 2210558.01 SRO APPENDIX: A-1 " CHRISTIAN WHEELER. ENGINEEIUNG LOG OF TEST BORING B-1 (Cont.) SamI!le Tree and Laborato!)'. Test Legend Cal Modified California Sampler CK Chunk SPT Standard Penetration Test DR Drive Ring ST ShdbyTube Date Logged: 10/13/21 Equipment: IRA-300 MD Max Density DS Direct Shear Logged By: DJF Auger Type: 8 inch Hollow Stem S04 Soluble Sulfates Con Consolidation SA Sieve Analysis El Expansion Index Existing Elevation: ±43' Drive Type: 140lbs/30 inches HA Hydrometer R-Val Resistance Value SE Sand Equivalent Chi Soluble Ch1orides Proposed Elevation: ±43' Depth to Water: 35' Pl Plasticity Index Res pH & Resistivity CP Collapse Potential SD Sample Density g ~ ~ Z,::-i:.:i ,-.. z ~ ~ z s 0 0 0 ~ ~~ 0 g 0 i:Q i::.s ;;,.t~ ~~ 0 .... u ~ SUMMARY OF SUBSURFACE CONDITIONS ~[ oZ ~ ::c: E-s 5= (based on Unified Soil Classification System) ~ ii,:: Cl) (J E-s ~ ~ Cl) tl ; ~ ~ ~ ~ o~,e, E-s:J~ 0~ ~ ~ u ZS ~ .... z A ~,-.. j~ i:.:i Cl) 0 Oo ~o~ A i:.:i ~ 0 i:.:i ,tl i:Q ~u ~ '-' us:.., 30 SC Santiago Formation (Tsa): White to light yellowish-brown, moist, very dense, - - . -~ fine-to very coarse-grained, CLAYEY SAND with reddish iron staining. 50/3" Cal 9.6 ~16.0 SD - - - -- - -g -!' J ----35- Saturated. GroundJater at 35' . 110.~ .. ~ - -50/4" Cal 13.4 OS - - - - - - 40 --,:;p 50/3" Cal ~ 1.7 a 17.4 - - Boring terminated at~:1 eet. - -Groundwater encountered at 35 J eet. - - - - 45 -- - - - - - - - - 50 -- - - - - - - - - 55 -- - - - - - - - - 60-- Notes: Symbol Legend PROPOSED SINGLE-FAMILY RESIDENCE y Groundwater Level During Drilling LOT 5 OF BUENA VISTA CIRCLE " !' Groundwater Level After Drilling CARLSBAD, CALIFORNIA '' Apparent Seepage DATE: DECEMBER 2021 JOB NO.: 2210558.01 CHRISTIAN WHEELER. * No Sample Recovery ENGINEER.ING ** Non-Representative Blow Count BY: SRO APPENDIX: A-2 (rocks present) Appendix B Laboratory Test Results Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. Brief descriptions of the tests performed are presented below: a) CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System and are presented on the exploration logs in Appendix A. b) MOISTURE-DENSITY: MOISTURE-DENSITY: In-place moisture contents and dry densities were determined for selected soil samples in accordance with D 2937. The results are summarized in the boring logs presented in Appendix A. c) MAXIMUM DENSITY & OPTIMUM MOISTURE CONTENT: The maximum dry density and optimum moisture content of typical soils were determined in the laboratory in accordance with ASTM Standard Test D1557, Method A. d) DIRECT SHEAR: Direct shear tests were performed on selected samples of the on-site soils in accordance with ASTM D3080. e) GRAIN SIZE DISTRIBUTION: The grain size distribution of selected samples was determined in accordance with ASTM C136 and/or ASTM D422. f) SOLUBLE SULFATE CONTENT: The soluble sulfate content of selected samples were determined in accordance with California Test Methods 417. CWE 2200558.01 December 8, 2021 Appendix B-2 LABORATORY TEST RESULTS PROPOSED MARTIN RESIDENCE LOT 5 BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT (ASTM D1557) Sample Location Boring B-1 @ 1’-6’ Sample Description Orangish-Brown Silty Sand (SM) Maximum Density 132.0 pcf Optimum Moisture 8.2 % DIRECT SHEAR (ASTM D3080) Sample Location Boring B-1 @ 1’-6’ Boring B-1 @ 4½’ Boring B-1 @ 26’ Boring B-1 @ 36’ Sample Type Remolded to 90% Undisturbed Undisturbed Undisturbed Friction Angle Cohesion 32° 200 psf 35° 350 psf 38° 650 psf 38° 550 psf GRAIN SIZE DISTRIBUTION (ASTM D4226) Sample Location Boring B-1 @ 1’-6’ Boring B-1 @ 28’-33’ Sieve Size Percent Passing Percent Passing #4 100 100 #8 100 99 #16 99 93 #30 95 72 #50 77 52 #100 46 41 #200 34 34 SOLUBLE SULFATES (CALIFORNIA TEST 417) Sample Location Boring B-1 @ 1’-6’ Soluble Sulfate 0.003 % (SO4) APPENDIX C GROSS STABILITY ANALYSES 0 40 80 120 160 200 240 280 0 40 80 120 160 200 Martin Residence - CWE 2210558.01 A-A' Static c:\users\drussell\desktop\martin stability\a-a'.pl2 Run By: DRR 12/7/2021 02:57PM 3 3 2 2 1 1 1 22 3 W1 W1 W1 bcdefghija # FS a 3.8 b 3.8 c 3.8 d 3.8 e 3.8 f 3.8 g 3.8 h 3.8 i 3.9 j 3.9 Soil Desc. Qaf Qop Tsa Soil Type No. 1 2 3 Total Unit Wt. (pcf) 120.0 120.0 125.0 Saturated Unit Wt. (pcf) 130.0 130.0 135.0 Cohesion Intercept (psf) 150.0 300.0 Aniso Friction Angle (deg) 32.0 35.0 Aniso Piez. Surface No. 0 0 W1 GSTABL7 v.2 FSmin=3.8 Safety Factors Are Calculated By The Modified Bishop Method 0 40 80 120 160 200 240 280 0 40 80 120 160 200 Martin Residence - CWE 2210558.01 A-A' Static Block c:\users\drussell\desktop\martin stability\a-a' static block.pl2 Run By: DRR 12/7/2021 03:20PM 3 3 2 2 1 1 1 22 3 W1 W1 W1 bcde fghija # FS a 3.8 b 3.8 c 3.8 d 3.8 e 3.8 f 3.9 g 3.9 h 3.9 i 3.9 j 3.9 Soil Desc. Qaf Qop Tsa Soil Type No. 1 2 3 Total Unit Wt. (pcf) 120.0 120.0 125.0 Saturated Unit Wt. (pcf) 130.0 130.0 135.0 Cohesion Intercept (psf) 150.0 300.0 Aniso Friction Angle (deg) 32.0 35.0 Aniso Piez. Surface No. 0 0 W1 GSTABL7 v.2 FSmin=3.8 Safety Factors Are Calculated By The Simplified Janbu Method for the case of c & phi both > 0 - - - - - - - - - - - - - - ---- - - - -~ - - - - - - - --- - - - - - - - - - - - - - - - - - - -~ - - - - - - - - - - - - - - - 0 40 80 120 160 200 240 280 0 40 80 120 160 200 Martin Residence - CWE 2210558.01 A-A' Pseudo Static c:\users\drussell\desktop\martin stability\a-a' pseudo static.pl2 Run By: DRR 12/7/2021 03:00PM 3 3 2 2 1 1 1 22 3 W1 W1 W1 bcde fgh ija # FS a 2.5 b 2.5 c 2.5 d 2.5 e 2.5 f 2.5 g 2.5 h 2.5 i 2.5 j 2.5 Soil Desc. Qaf Qop Tsa Soil Type No. 1 2 3 Total Unit Wt. (pcf) 120.0 120.0 125.0 Saturated Unit Wt. (pcf) 130.0 130.0 135.0 Cohesion Intercept (psf) 150.0 300.0 Aniso Friction Angle (deg) 32.0 35.0 Aniso Piez. Surface No. 0 0 W1 Load Value Peak(A) 0.570(g) kh Coef. 0.150(g)< GSTABL7 v.2 FSmin=2.5 Safety Factors Are Calculated By The Modified Bishop Method 0 40 80 120 160 200 240 280 0 40 80 120 160 200 Martin Residence - CWE 2210558.01 A-A' Pseudo Static Block c:\users\drussell\desktop\martin stability\a-a' pseudo static block.pl2 Run By: DRR 12/7/2021 03:19PM 3 3 2 2 1 1 1 22 3 W1 W1 W1 bcdefghij a # FS a 2.4 b 2.4 c 2.4 d 2.4 e 2.4 f 2.5 g 2.5 h 2.5 i 2.5 j 2.5 Soil Desc. Qaf Qop Tsa Soil Type No. 1 2 3 Total Unit Wt. (pcf) 120.0 120.0 125.0 Saturated Unit Wt. (pcf) 130.0 130.0 135.0 Cohesion Intercept (psf) 150.0 300.0 Aniso Friction Angle (deg) 32.0 35.0 Aniso Piez. Surface No. 0 0 W1 Load Value Peak(A) 0.570(g) kh Coef. 0.150(g)< GSTABL7 v.2 FSmin=2.4 Safety Factors Are Calculated By The Simplified Janbu Method for the case of c & phi both > 0 1 '--=-~-- - - -~ - - - - - - - --- - - - - - - - - - - - - - - - - - - -~ - - ---- - ---- - Anisotropic Soil Definition c=600., phi=38. s· ---lf-----------::==---t-=--------t-'.:::0~450., phi=28. c=600., phi=38. Soi13 Martin Residence -CWE 221 0558. 01 APPENDIX D SURFICIAL SLOPE STABILITY ASSUMED PARAMETERS z Depth of Saturation (ft)5 a Slope Angle (H:1)3 gW Unit Weight of Water (pcf)62.4 gT Saturated Unit Weight of Soil (pcf)130 f Angle of Internal Friction Along Plane of Failure (degrees) 30 c Cohesion Along Plane of Failure (psf)250 FACTOR OF SAFETY c + T (tan f)c + (gT - gW)(z)(cos a)2(tan f) T FS = 2.2 Reference: Skempton, A., and Delory, F., 1957, “Stability of Natural Slopes in London Clay,” Proceedings 4th International Conference on Soil Mechanics and Foundation Engineering, London, England, Butterworths, Vol. 2. BY: DRR DATE: Dec-21 JOB NO.:APPENDIX: D2210558.01 PROPOSED SINGLE-AMILY RESIDENCE Lot 5 Buena Vista Circle, Carlsbad, California CHRISTIAN WHEELER SURFICIAL SLOPE STABILITY FS =FS =(gT)(z)(sin a)(cos a) E n g i n e e r i n g z SEEPAGE PARALLEL TO SLOPE a -, ,, , , , !,,,"" ,, ✓ ✓,,,' ,, , ,, , , , ,, , , ✓ ,,' , ,,' ,, , , , , , , ,, , ► I I -~,= :Ii Appendix E References CWE 2210558.01 December 8, 2021 Appendix E-1 REFERENCES American Society of Civil Engineers, ASCE 7 Hazard Tool, https://asce7hazardtool.online Bryant, W. A. (compiler), 2005, Digital Database of Quaternary and Younger Faults from the Fault Activity Map of California, version 2.0: California Geological Survey Web Page, http://www.consrv.ca.gov/CGS/information/publications/QuaternaryFaults_ver2.htm California Emergency Management Agency, 2009, Tsunami Inundation Map for Emergency Planning, San Luis Rey Quadrangle, scale 1:24,000, June 1, 2009. Countywide Flood Insurance Rate Map, Map No. 06073C761F (panel 761F of 2375), prepared by the Federal Emergency Management Agency, effective date June 19, 1997. Gregory Geotechnical Software, 2002, GSTABLE7 v.2 Historic Aerials, NETR Online, historicaerials.com Jennings, C.W. and Bryant, W. A., 2010, Fault Activity Map, California Geological Survey, Geologic Data Map No. 6, http://www.quake.ca.gov/gmaps/FAM/faultactivitymap.html Kennedy, M.P. and Tan, S.S., 2005, Geologic Map of the Oceanside 30’ X 60’ Quadrangle, California; California Department of Conservation and California Geological Survey. Kern, P., 1989, Earthquakes and Faults in San Diego County, Pickle Press, 73 pp. New Modern Design, 2021, Preliminary Architectural Plans, Martin Residence, Lot 5 Buena Vista Circle, Carlsbad, CA, APN: 155-221-05-00. Pasco Laret Suiter & Associates, 2021, Preliminary Site Plan, Martin Residence, Buena Vista Circle, scale 1”=10’. Tan, S.S., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, California Division of Mines and Geology Open-File Report 95-04. CWE 2210558.01 December 8, 2021 Appendix E-2 REFERENCES (continued) Southland Geotechnical Consultants (SGC), 2000, Geologic Evaluation of Bluff Property and Soils Investigation for Proposed Single-Family Residence, Vacant Lot Northeast of 2411 Buena Vista Circle, Carlsbad, California, Project No. 106D41, dated February 17, 2000. Tan, S.S. and Kennedy, M.P., 1996, Geologic Map of the Oceanside, San Luis Rey, and San Marcos 7.5’ Quadrangles, San Diego County, California, California Division of Mines and Geology Open-File Report 96-02. U.S. Geological Survey, Quaternary Faults in Google Earth, http://earthquake.usgs.gov/hazards/qfaults/google.php Weber, F. Harold, 1982, Recent Slope Failures, Ancient Landslides, and Related Geology of the North-Central Coastal Area, San Diego County, California, California Division of Mines and Geology Open-File Report 82-12. Appendix F Recommended Grading Specifications – General Provisions CWE 2210558.01 December 8, 2021 Appendix F, Page F-1 RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS PROPOSED MARTIN RESIDENCE LOT 5 BUENA VISTA CIRCLE CARLSBAD, CALIFORNIA GENERAL INTENT The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary geotechnical investigation report and/or the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Geotechnical Engineer. OBSERVATION AND TESTING Christian Wheeler Engineering shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further recommendations. If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: CWE 2210558.01 December 8, 2021 Appendix F, Page F-2 Maximum Density & Optimum Moisture Content - ASTM D1557 Density of Soil In-Place - ASTM D1556 or ASTM D6938 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the specified minimum degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is defined as natural soil which possesses an in-situ density of at least 90 percent of its maximum dry density. When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil. The lower bench shall be at least 10 feet wide or 1-1/2 times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recommendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 CWE 2210558.01 December 8, 2021 Appendix F, Page F-3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and/or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLACING AND COMPACTION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical Engineer and until the desired relative compaction has been obtained. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of CWE 2210558.01 December 8, 2021 Appendix F, Page F-4 two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over-built and cut- back to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions section of this specification. The compaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be surficially stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Geotechnical Engineer. CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints, or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Geotechnical Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or the observation and testing shall release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. CWE 2210558.01 December 8, 2021 Appendix F, Page F-5 SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be compacted to at least 95 percent relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29-2. OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material are provided by the Geotechnical Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. Appendix G Data from SGC Project No. 106D41, dated February 17, 2000 I I I I I I I. I, I: 1: ·1, ,·:: l I I Scholl/Buena Vista Circle Project No. 1060 41 December 21, 1999 Depth Graphic Sample Blows in Per Feet Log No. Foot 0 --------__ ,.. ___ ------ -I DS-1 63 -I -Bulk 1 - 5-_L DS-2 I 81 - -- -- -1-- 10- -55.y I -------40/6'' -50/4.5' -- -- -- 15-..... -- -- -I- -1-- 20-1-- -- -I- -- -- 25-- -1-- -- -- -I-- 30 GEOT ECHNICAL BORING LOG Dry Water Density Content (pcfJ (%) ------·---- 104.9 5.2 108.6 4.4 ---------- F & C Drilling Boring No. 1 Logged by GAR Sampled by GRR 8-inch Hollow Stem A uger Sampler 140 lbs., 30-inch drop uses Soil Geotechnical Descript ion Type TOPSOIL SM @ 0 -18" -Dark brown, dry, medium dense to dense, - - ---silty fine to medium sand -... ------------------~------------------- -----· ---- SM TERRACE DEPOSITS @ 18" -Dark orange-brown, moist, dense, silt y fine to - medium sand; with occasional gravel - I- - - - ,- - --------------------------------------------------- SM SANTIAGO FORMATION - @ 10.5' -Yellow-brown, moist, dense, silty medium to ~ coarse sand - ... Total depth = 11 . 5 feet No groundwater encountered ... No refusal I- Backfilled on 12/21 /99 - - - ... 1-- ,.. - ... - - - ... - SGC I I I I I I I I I I I I I I I I I I I Scholl/Buena Vista Circle Project No. 106041 December 21, 1999 Depth Graphic Sample Blows in Per Feet Log No. Foot 0 ~ - -------on-• -50/4'' -I ,_ Bulk 1 -J_ ~ 5 -I 05-2 33/6" -43/4" -L- ~ - -,_ 10--~~-~-1 45/6" -------_§_3J1.''.... -- -L- 15-,_ -,_ -~ -~ -,_ 20-I- -L- -,_ -~ -,_ 25 -L... -I- -L- -,_ -,_ 30 GEOTECHNICAL BORING LOG Dry Water Density Content lpcf) (%) -92.4---4-:s - 108.3 3.8 ---------- F & C Drilling Boring No. 2 Logged by GAR Sampled by GRR 8-inch Hollow Stern A uger Sampler 140 lbs., 30-inch drop uses Soil Geotechnical Description Type SM TOPSOIL @ O -.2' -Dark brown, dry, loose, silty fine to medium ... -----___ sand;. with rootlets --------·-------------------- SM-SP TERRACE DEPOS ITS @ 2' -Orange-brown, dry to moist, dense, slightly silty I- fine to medium sand; micaceous; with occasional gravel >- - - I- - ._ ---------------------------------------------------~ SM-SP SANTIAGO FORMATION @ 11' -Yellow-brown, moist, very dense, silty medium I- to coarse sand - Tot al depth = 13 feet ... No groundwater encountered >-No refusal Backfilled on 12/21/99 I- I- - I- - - ... - >-- I- .... I- ... SGC I I I I I I I l I I I 1: Scholl/Buena Vista Circle Project No. 106D41 December 21, 1999 Depth Graphic Sample Blows in Log No. Per Feet Foot 0 -----------------...... -- -- -- 5-I 05-1 36 - -...... -- -- 10- -155.2-1 -------2-576"--50/5.5" -,- -I- 15-- -,- -- -- -- 20-- -...... -- -- -- 25-- -- -- -- -f- 30 GEOTECHNICAL BORING LOG Dry Water Density Content (pcf) (%) ---------- 109.8 3.7 T20:-o--11.4- F & C Drilling Boring No. 3 Logged by GRR Sampled by GRR 3-inch Hollow Stem Auger Sampler 140 lbs., 30-inch drop uses Soil Geotechnical Description Type SM TOPSOIL ' @ 0 -8" -Dark brown, dry, medium dense, silty fine to ' ... ' ' ' medium sand; with rootlets ' ----------------------------------------------- SM-SP TERRACE DEPOSITS @ 8" -Orange-brown, moist to wet, medium dense, slightly silty fine to medium sand; micaceous - '- - @ 7' -Gravel layer - - @ 9' -Gravel layer - - --------------------------------------------------- SC SANTIAGO FORMATION - @ 10. 5' -Yellow-green, moist, very dense, clayey f ine to coarse sand ... Total depth = 13 feet No groundwater encountered - No refusal '- Backfilled on 12/21 /99 - - - ... ..... ... - - - - ... ... ... ... SGC