The URL can be used to link to this page

Home My WebLink AboutAMEND 2018-0007; ENCINA WATER POLLUTION CONTROL FACILITY; GEOTECHINCAL INVESTIGATION REPORT; 2017-08-30GEOTECHNICAL INVESTIGATION REPORT 1,400 Square Foot Building Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California Converse Project No. 17-81-153-01 (02) Prepared For: Encinas Wastewater Authority 6200 Avenida Encinas Carlsbad, CA 92001 Prepared By: Converse Consultants 2021 Rancho Drive, Suite 1 Redlands, California 92373 August30,2017 REC -:IV D SEP 2 4 2018 CI TY OF CARLSBAD PLANNING DIVISION Converse Consultants Geotechnical Engineering, Environmental & Groundwater Science, Inspection & Testing Services August30,2017 Mr. James Kearns Capital Project Manager Encinas Wastewater Authority 6200 Avenida Encinas Carlsbad, CA 92001 Subject: GEOTECHNICAL INVESTIGATION REPORT 1,400 Square Foot Building Encina Phase V -Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California Converse Project No. 17-81-153-01 (02) Dear Mr. Kearns: Converse Consultants (Converse) is pleased to submit this geotechnical investigation report to assist with the design and construction of the 1 ,400-square-foot building at the Encina Wastewater Treatment Plant, located at 6200 Avenida Encinas, City of Carlsbad, San Diego County, California. This report was prepared in accordance with our proposal dated June 20, 2017 and your Notice to Proceed, Ref: Admin 17-12783b, dated June 27, 2017. Based on our investigation, testing, and analysis, the proposed building and retaining walls are considered suitable from a geotechnical standpoint provided the recommendations presented herein are incorporated during design and construction. We appreciate the opportunity to be of service to Encina Wastewater Authority. If you have any questions, please do not hesitate to contact us at 909-796-0544". CONVERSE CONSULTANTS ----~~-- Hashmi S. E. Quazi, PhD, PE, GE Principal Engineer Dist.: 1: Addressee (Email) JB/HSQ/kvg 2021 Rancho Drive, Redlands, CA 92373 Telephone: (909) 796-0544 ♦ Facsimile: (909) 796-7675 ♦ www.converseconsultants.com Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page ii PROFESSIONAL CERTIFICATION This report has been prepared by the individuals whose seals and signatures appear herein. The findings, recommendations, specifications, or professional opinions contained in this report were prepared in accordance with generally accepted professional engineering, engineering geologic principles, and practice in this area of Southern California. There is no warranty, either expressed or implied. Zahangir Alam, Ph., EIT Senior Staff Engineer Hashmi S. E. Quazi, PhD, PE, GE Principal Engineer Converse Consultants Jay Burnham, GIT Senior Staff Geologist M:\.JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81 -153-0Z_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Cartsbad, San Diego County, California August 30, 2017 Page iii EXECUTIVE SUMMARY The following is a summary of our geotechnical investigation, conclusions and recommendations, as presented in the body of this report. Please refer to the appropriate sections of the report for complete conclusions and recommendations. In the event of a conflict between this summary and the report, or an omission in the summary, the report shall prevail. • The approximately 5,000 square foot project area is located near the northwest edge of the treatment plant near the existing headworks area, immediately east of the existing screenings building. The project area is bounded by the CEPT chemical storage area to the southwest, influent junction structure and ascending slope to the property line to the northwest, screenings building to the northeast, and grit tank no. 3 southeast. The area is currently developed with access roads and an ascending 3:1 (horizontal:vertical) landscaped slope. • The project consists of a proposed 35-foot by 40-foot (1,400 square-feet) building. We understand that the building will be 12" CMU (solid grouted) with wall height of approximately 28-feet. The south side of the building will have a retaining wall approximately 5-feet tall so that the new building slab finished floor elevation will match the existing screening floor slab elevation. The retaining wall will step up along the east and west side to the finished grade elevation on the north side of the building. A retaining wall up to 5-foot-tall will be constructed within the ascending slope on the northwest side of the project to allow a portion of the area to be flattened and a concrete apron will be constructed for dumpster removal and loading. • Our scope of work included project setup, subsurface exploration, laboratory testing, engineering an,alysis, and preparation of this report. • Four exploratory borings (BH-1 through BH-4) were drilled on July 21, 2017. Borings B- 1 and B-4 were drilled to their maximum planned depths of approximately 19.5 feet bgs. Borings BH-2 and BH-3 were terminated at 4.5 feet and 2 feet bgs respectively due to refusal on unmarked pipelines. Field and laboratory data from Boring BH-8 (Converse, 2005) and Boring BH-1 (Converse, 2017) were substituted for Borings BH-2 and BH-3, respectively. • The site is underlain by artificial fill and alluvial sediment consisting of mostly sand, silt, and clay with scattered gravel to a depth of approximately 19.5 feet bgs. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Car1sbad, San Diego County, California August 30, 2017 Page iv • Groundwater was not encountered during our investigation to the maximum explored depth of 19.5 feet bgs and was not encountered in borings BH-8 (Converse. 2005) or BH-1 (Converse, 2017). The historic high groundwater level in the vicinity of the site is estimated to be approximately 23 feet bgs. Groundwater is not expected to be encountered during the construction of this project based on the depth encountered during our investigation. • The project site is not located within a currently designated State of California or San Diego County Earthquake Fault Zone. There are no known active faults projecting toward or extending across the project site. Seismic design parameters for the design of the proposed building and retaining walls are presented in the text of this report. • Prior to the start of any earthwork, the site should be cleared of all vegetation and debris. The materials resulting from the clearing and grubbing operations should be removed from the site. • Based on our subsurface exploration, we anticipate that the site soils will be excavatable with conventional heavy-duty earthworking and trenching equipment. • The building footprint and any other areas to support structures or retaining walls should be overexcavated to a depth of 24 inches below the bottom of the footings. The depths of overexcavation should be uniform across the entire structures. The overexcavation should extend to at least 2 feet beyond the footprints of the structures. • Excavated onsite earth materials cleared of deleterious matter can be moisture conditioned and re-used as compacted fill. • Fill soils should be placed on properly prepared excavation bottoms, moisture conditioned, and compacted to at least 90 percent of the laboratory maximum dry density. At least the upper 12 inches of fill beneath pavement intended to support vehicle loads should be compacted to at least 95 percent of the laboratory maximum dry density. • The proposed building may be supported on continuous (strip) footing and/or isolated spread footings. Continuous footings should be at least 18 inches in width and embedded to at least 18 inches below the lowest adjacent grade. The footing dimensions and reinforcement should be based on structural design. The footing can be designed based on an allowable net bearing capacity of 2,000 pounds per square foot (psf). Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir eotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Pagev • Lateral earth pressures and asphalt concrete pavement design recommendations are presented in the text of this report. • The total settlement of shallow footings from static structural loads and short-term settlement of properly compacted fill is anticipated to be 1 inch or less. The site has the potential for up to 0.23 inches of dynamic settlement during a large earthquake for the drilled depth of 19.5 feet bgs. However, a total of 2 to 3 inches of dynamic settlement was observed for the drilled depth of 50 feet bgs in the previous report (Converse, 2005). The differential settlement resulting from static and dynamic loads is anticipated to be half of the total settlement over a horizontal distance of 40 feet. • The sulfate and chloride contents of the soils tested correspond to American Concrete Institute (ACI) exposure category SO and C1, respectively. Design recommendations for these categories are provided in the text of this report. • The measured value of the minimum electrical resistivity when saturated was 2,200 Ohm-cm for the project site. This indicates that the soils tested are moderately corrosive to ferrous metals in contact with the soil. A corrosion engineer should be consulted for corrosion mitigation measures for ferrous metals in contact with the soil. • Recommendations for temporary sloped excavations and shoring design are provided in the text of this report. Based on our investigation, it is our professional opinion that the project site is suitable for construction of the proposed tank provided the findings and conclusions presented in this geotechnical investigation report are considered in the planning, design and construction of the project. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02__gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page vi TABLE OF CONTENTS 1 . 0 I NT RO DU CTIO N -----------------------------------------------------------------------------------1 2. 0 PROJECT D ESC RI PTIO N -----------------------------------------------------------------------1 3.0 SITE DESCRIPTION-------------------------------------------------------------------------------1 4. 0 SCOPE OF WORK---------------------------------------------------------------------------------2 4.1 PROJECT SET-UP ----------------------------------------------------------------------2 4 .2 FIELD EXPLORATION--------------------------------------------------------------------2 4. 3 LABO RA TORY TESTING -----------------------------------------------------------------2 4.4 ANALYSIS AND REPORT PREPARATION ----------------------------------------------------3 5. 0 SU BSU RF ACE CONDITIONS ------------------------------------------------------------------3 5.1 SUBSURFACE PROFILE----------------------------------------------------------------3 5.2 GROUNDWATER---------------------------------------------------------3 5. 3 EXCAVAT ABILITY--------------------------------------------------4 5.4 SUBSURFACE VARIATIONS-----------------------------------------4 6.0 LABO RA TORY TEST RES UL TS --------------------------------------------------------------4 6 .1 PHYSICAL TESTING---------------------------------------------------------------------4 6.2 CHEMICAL TESTING -CORROSIVITY EVALUATION----------------------------------------5 7. 0 ENGINEERING GEOLOGY----------------------------------------------------------------------6 7 .1 REGIONAL GEOLOGY --------------------------------------------------------6 7 .2 LOCAL GEOLOGY---------------------------------------------------------6 8.0 FAUL TING AND SEISMICITY-------------------------------------------------------------------6 8.1 FAULTING---------------------------------------------------------------7 8.2 CBC SEISMIC DESIGN PARAMETERS-------------------------------------------------------8 8.3 SECONDARY EFFECTS OF SEISMIC ACTIVITY--------------------------------8 9. 0 EARTHWORK RECOMMEN CATIONS -----------------------------------------------------10 9 .1 GENERAL-----------------------------------------------------------10 9.2 REMEDIAL GRADING-------------------------------------------------------------11 9.3 COMPACTED FILL PLACEMENT----------------------------------------------11 9.4 BACKFILL RECOMMENDATIONS BEHIND RETAINING WALLS---------------12 9.5 FILL MATERIALS---------------------------------------------------12 9.6 SITE DRAINAGE----------------------------------------------------12 Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir eotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page vii 1 0. 0 DESIGN REC OM MEN CATIONS-----------------------------------------------------------13 10.1 GENERAL EVALUATION--------------------------------------------------------13 10.2 SHALLOW FOUNDATION DESIGN PARAMETERS ---------------------------13 10.3 LATERAL EARTH PRESSURES AND RESISTANCE TO LATERAL LOADS-----------14 10.4 SETTLEMENT----------------------------------------------------------------------15 10.5 ASPHALT CONCRETE PAVEMENT-----------------------------------------------15 10. 6 CONCRETE FLA TWORK --------------------------------------------------------16 10. 7 SOIL CORROSIVITY --------------------------------------------------------------17 11.0 CONSTRUCTION RECOMMENDATIONS----------------------------------------------17 11.1 GENERAL --------------------------------------------------------------------------------18 11.2 SHORING DESIGN-----------------------------------------------------------------------18 12.0 GEOTECHNICAL SERVICES DURING CONSTRUCTION -------------------------21 13. 0 CL OS URE ---------------------------------------------------------------------------------------21 14. 0 REFERENCES ---------------------------------------------------------------------------------23 FIGURES Following Page No. Figure No. 1, Approximate Site Location Map .......................................................................... 1 Figure No. 2, Approximate Boring Location Map ............................................................ 2 Figure No. 3, Lateral Earth Pressures for Temporary Braced Excavation ........................... 19 Figure No. 4, Lateral Earth Pressures on Temporary Cantilever Wa/1 ................................. 20 TABLES Page No. Table No. 1, Seismic Characteristics of Nearby Active Faults ............................................. 7 Table No. 2, CBC Seismic Parameters ................................................................................... ? Table No. 3, Recommended Foundation Design Parameters ........................................... 13 Table No. 4, Active and At-Rest Earth Pressures .............................................................. 14 Table No. 5, Recommended Preliminary Pavement Sections ........................................... 16 Table No. 6, Lateral Earth Pressures for Temporary Shoring ........................................... 18 APPENDICES Appendix A .............................................................................................. Field Exploration Appendix,B ............................................................................ Laboratory Testing Program Appendix C ............................................................................ Seismic Settlement Analysis Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81 -153-02_gir 1.0 INTRODUCTION Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Car1sbad, San Diego County, California August30,2017 Page 1 This report presents the results of our geotechnical investigation performed for the proposed 1,400 square foot building and retaining walls at the Encina Wastewater Treatment Plant, located at 6200 Avenida Encinas, City of Carlsbad, San Diego County, California, as shown in Figure No. 1, Approximate Site Location Map. The purposes of this investigation were to determine the nature and engineering properties of the subsurface soils, and to provide design and construction recommendations for the proposed structures. Data has been incorporated into this report from two prior investigations conducted by Converse in the area of the proposed new building. The prior investigations were conducted in 2005 (Converse, 2005) and 2017 (Converse, 2017). This report is prepared for the project described herein and is intended for use solely by Encina Wastewater Authority and their authorized agents for design purposes. It should not be used as a bidding document but may be made available to the potential contractors for information on factual data only. For bidding purposes, the contractors should be responsible for making their own interpretation of the data contained in this report. 2.0 PROJECT DESCRIPTION Detailed project plans were not available at the time of this report. We understand that the project consists of a proposed 35-foot by 40-foot (1,400 square-feet) building. The building will be 12" CMU (solid grouted) with a wall height of approximately 28 feet. The south side of the building will have a retaining wall approximately 5-feet-tall so that the new building slab finished floor elevation will match the existing screening floor slab elevation. The retaining wall will step up along the east and west side to the finished grade elevation on the north side of the building. A retaining wall up to 5-feet-tall will be constructed within the ascending slope on the northwest side of the project to allow a portion of the area to be flattened and a concrete apron will be constructed for dumpster removal and loading. 3.0 SITE DESCRIPTION The approximately 5,000 square foot project area is located near the northwest edge of the treatment plant near the existing headworks area, immediately east of the existing screenings building. The project area is bounded by the CEPT chemical storage area to the southwest, influent junction structure and ascending slope to the property line to the northwest, screenings building to the northeast, and grit tank no. 3 southeast. The ~. Converse Consultants W' M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Q Project: Location: For: M1gu Is Coclna McOonalds • I I ' ' ' • Gren ragonQ v r1 M em "D 0, Ill ff) 0 0 ~ z 0 ~ It) Palomar Airport Rd 0 t of California M tntenanc Stat ons Co cow ol sa le, T p Top Me t , "' ' \ ... .. ' 1 ' • I I I \ .. I ' .. _____ ,,. Approximate Site Location Approximate Site Location Map Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad , San Diego County, California Encina Wastewater Authority ,,,' .,,, Pas Can Project No. 17-81-153-02 i) Converse Consultants Figure No. 1 Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Car1sbad, San Diego County, California August 30, 2017 Page2 area is currently developed with access roads and an ascending 3:1 (horizontal:vertical) landscaped slope. The project area has a maximum elevation of approximately 38 feet above mean sea level (amsl) in the area of_ the retaining wall within the northwest slope and a minimum elevation of approximately 28 feet amsl along the southeast edge. , 4.0 SCOPE OF WORK The scope of this investigation included set-up, subsurface exploration, laboratory testing, engineering analysis, and preparation of this report, as described in the following sections. 4.1 Project Set-up As part of the project setup, we conducted the following. • Marked the borings at locations approved of Encina Wastewater Authority in the field such that drill rig access to all the locations was available. • Notified Underground Service Alert (USA) at least 48 hours prior to investigation to clear the locations of any conflict with existing underground utilities. • Engaged a drilling subcontractor. 4.2 Field Exploration Four exploratory borings (BH-1 through BH-4) were drilled on July 21 , 2017 at the site of the proposed building. Borings B-1 and B-4 were drilled to their maximum planned depths of approximately 19.5 feet bgs. Borings BH-2 and BH-3 were terminated at 4.5 feet and 2 feet bgs respectively due to refusal on unmarked pipelines. Field and laboratory data from Boring BH-8 (Converse, 2005) and Boring BH-1 (Converse, 2017) were substituted for Borings BH-2 and BH-3, resp~ctively. Approximate boring locations are fndicated in Figure No. 2, Approximate Boring Location Map. For a description of the field exploration and sampling program see Appendix A, Field Exploration. 4.3 Laboratory Testing Representative samples of the site soils were tested in the laboratory to aid in the soils classification and to evaluate the relevant engineering properties of the site soils. These tests included the following. • In-situ moisture contents and dry densities (ASTM D2216) • Expansion index test (ASTM D4829) ~ Converse Consultants ~ M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir EXPLANATION BH-4 Number and Approximate Location of S Exploratory Boring (This lnvestgation) BH-8 Number and Approximate Location of ~ Exploratory Boring (Converse 2005 '\J and 2017) Project: · Location: For: 20' Approximate Boring Location Map Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad, San Diego County, California Encina Wastewater Authority (i Converse Consultants Project No. 17-81-153-02 Figure No. 2 Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Page3 • Soil corrosivity tests (California Tests 643, 422, and 417) • Grain size distribution (ASTM D422) • Maximum dry density and optimum-moisture content (ASTM D1557) • Direct shear (ASTM D3080) • Consolidation (ASTM D2435) For in-sftu moisture and dry density data, see the Logs of Borings in Appendix A, Field Exploration. For a description of the laboratory test methods and test results, see Appendix B, Laboratory Testing Program. 4.4 Analysis and Report Preparation Data obtained from the field exploration and laboratory testing program were compiled and evaluated. Pertinent data from previous investigations (Converse, 2005 and 2017) were reviewed and incorporated. Geotechnical analyses of the compiled data were performed and this report was prepared to present our findings, conclusions and recommendations for the proposed rehabilitation project. 5.0 SUBSURFACE CONDITIONS A general description of the subsurface conditions, various materials and groundwater conditions encountered at the site during our field exploration is discussed below. 5.1 Subsurface Profile Based on the exploratory borings and laboratory test results, the site is underlain by an approximately 5-to 10-foot-thick layer of artificial fill consisting of mixtures of silty sand and sandy clay. The fill is underlain by mixtures of clay, silt, sand, and gravel to the maximum explored depth of 21.5 feet bgs. For a detailed description of the subsurface materials encountered in the exploratory borings, see Drawing Nos. A-2 through A-7, Logs of Borings, in Appendix A, Field Exploration. 5.2 Groundwater Groundwater was not encountered during our investigation to the maximum explored depth of 19.5 feet bgs, and was not encountered in Boring BH-8 (Converse, 2005) or Boring BH-1 (Converse, 2017). The GeoTracker database (SWRCB, 2017) was reviewed for groundwater data from sites within close proximity of the project. One site was identified within a 1.0-mile radius of the project site that contained groundwater elevation data. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir eotechnical Investigation Report En-,,., a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page4 • STILLMAN SEAL (Site No. T0608143131 ), located approximately 1,200 feet northwest of the project site, reported groundwater at a depth ranging from 23 to 32 feet bgs in 2004. • CAL TRANS/CARLSBAD (Site No. T0607302364 ), located approximately 1,700 feet northeast of the project site, reported groundwater at a depth of 26 feet bgs in 2005. Based on available data, the historical high groundwater level in the vicinity of the project site is approximately 23 feet bgs, and the current depth to groundwater at location of the proposed new building is deeper than 19.5 feet bgs. Groundwater is not expected to be encountered during construction. Shallow perched groundwater may be present locally, particularly following precipitation or irrigation events. 5.3 Excavatability Based on our field observations, subsurface materials at the site are anticipated to be readily excavatable by conventional heavy-duty earth moving equipment such as excavators, scrapers, and trenching machines. 5.4 Subsurface Variations Based on results of the subsurface exploration and our experience, some variations in the continuity and nature of subsurface conditions within the project site should be anticipated. Because of the uncertainties involved in the nature and depositional characteristics of the earth material, care should be exercised in interpolating or extrapolating subsurface conditions between or beyond the boring locations. 6.0 LABORATORY TEST RESULTS Results of physical and chemical tests performed for this project are presented below. 6.1 Physical Testing Results of the various laboratory tests are presented in Appendix B, Laboratory Testing Program, except for the results of in-situ moisture and dry density tests, which are presented on the Logs of Borings in Appendix A, Field Exploration. The results are also discussed below. • In-situ Moisture and Dry Density -In-situ dry density and moisture content of the site soils were determined in accordance to ASTM Standard D2216. Dry densities of soils ranged from 96 to 127 pcf with moisture contents of 7 to 17 percent. Results are presented in the log of borings in Appendix A, Field Exploration. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 5 • Expansion Index -Two representative samples from the upper 10 feet of the site soils were tested to evaluate the expansion potential in accordance with ASTM Standard D4829. The test results indicated El of 1 and O corresponding to very low expansion. • R-Value -One representative bulk sample was tested (Converse, 2017) in accordance with Caltrans Test Method 301. The result of the R-value test was 11. • Collapse Potential -The collapse potential of one relatively undisturbed sample from the upper 15 feet was tested under a vertical stress of up to 2.0 kips per square foot (ksf) in accordance with the ASTM Standard D5333 test method. The test result showed collapse potential of 0.6 percent, indicating slight collapse potential. A consolidation test result showed a collapse potential of 2.0 percent, also indicated slight collapse potential. • Grain Size Analysis -Two representative samples were tested to determine the relative grain size distribution in accordance with the ASTM Standard D422. The test results are graphically presented in Drawing No. B-1, Grain Size Distribution Results. • Maximum Dry Density and Optimum Moisture Content -Two typical moisture- density relationship of a representative soil samples were tested, according to ASTM Standard D1557-B, with the results presented in Drawing No. B-2, Moisture- Density Relationship Results, in Appendix B, Laboratory Testing Program. The laboratory maximum dry density was 133 pounds per cubic feet (pcf), with an optimum moisture content of 6 percent. • Direct Shear -Two direct shear tests were performed in accordance with ASTM Standard D3080 on relatively undisturbed ring samples. The results of the direct shear tests, including the test result from BH-1 (Converse, 2017) are presented in Drawing Nos. B-3 through B-5, Direct Shear Test Results in Appendix B, Laboratory Testing Program. • Consolidation Test -One consolidation test was performed on relatively undisturbed samples of the site soil, in accordance to ASTM Standard D2435. The test result is shown on Drawing No. B-6, Consolidation Test Results, in Appendix B, Laboratory Testing Program. 6.2 Chemical Testing -Corrosivity Evaluation One representative soil sample was tested to determine minimum electrical resistivity, pH, and chemical content, including soluble sulfate and chloride concentrations. The purpose of the test was to determine the corrosion potential of site soil when placed in contact with common pipe materials. These tests were performed by EG Labs in accordance with California Test Methods 643, 422, and 417. The test result is summarized in the table below and is presented in Appendix B, Laboratory Testing Program. • The pH measurement of the sample was 8.72. ~ Converse Consultants ~ M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report En...,_ a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page6 • The soluble sulfate content of the sample was 0.021 percent by weight. • The chloride concentration of the sample was 150 ppm. • The minimum electrical resistivity of the sample when saturated was 2,200 ohm-cm. 7.0 ENGINEERING GEOLOGY The regional and local geology within the proposed project area are discussed below. 7.1 Regional Geology The project site is located along the central coastal margin of the Peninsular Ranges Geomorphic Province of Southern California. The Peninsular Ranges Geomorphic Province consists of a series of northwest-trending mountain ranges and valleys bounded on the north by the San Bernardino and San Gabriel Mountains, on the west by the Los Angeles Basin, and on the southwest by the Pacific Ocean. The province is a seismically active region characterized by a series of northwest- trending strike-slip faults. The most prominent of the nearby fault zones include the Rose Canyon and Elsinore Fault Zones, which have been known to be active during Quaternary time. Topography within the province is generally characterized by broad alluvial valleys separated by linear mountain ranges._ This northwest-trending linear fabric is created by the regional faulting within the granitic basement rock of the Southern California Batholith. Broad, linear, alluvial valleys have been formed by erosion of these principally granitic mountain ranges. 7 .2 Local Geology The project site is located on the coastal plain across from the mouth of the Canyon de las Encinas channel. The channel was downcut into the terrace platform during the Pleistocene glacial stage and then gradually filled with alluvial deposits to form the shallow, broad valley. The underlying sediments consist mostly of fine-grained marine and non-marine sediments. These sediments are in turn underlain by fine-to medium-gained sandstone of the Bay Point Formation. 8.0 FAULTING AND SEISMICITY The approximate distance and seismic characteristics of nearby faults as well as seismic design coefficients are discussed in the following subsections. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 8.1 Faulting Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Page 7 The project site is not located within State of California or San Diego County designated Earthquake Fault Zones (CGS, 2007; San Diego County, 2010a). There are no known active faults projecting toward or extending across the project site. The potential for surface rupture resulting from the movement of nearby major faults is not known with certainty but is considered low. The proposed site is situated in a seismically active region. As is the case for most areas of Southern California, ground shaking resulting from earthquakes associated with nearby and more distant faults may occur at the project site. During the life of the project, seismic activity associated with active faults can be expected to generate moderate to strong ground shaking at the site. The following table contains a list of active and potentially active faults within one- hundred (100) kilometers of the subject site. The fault parameters and distances presented in the following table are based on the output from EQFAUL T (Blake, 2000), revised in accordance with CGS fault parameters (Cao et. al., 2003). T bl N 1 S . . Ch t . f f N rb A f F It Fault Name Approximate Distance Moment Magnitude (mi (km)) (Mw) Rose Canyon 4.3 (6.9} 7.2 Newport-Inglewood (Offshore) 7.0 (11.3) 7.1 Coronado Bank 19.9(32.1) 7.6 Elsinore-Julian 25.4 (40.9} 7.1 Elsinore-Temecula 25.4 (40.9} 6.8 Elsinore-Glen lvv 36.4 (58.6) 6.8 Palos Verdes 37.6 (60.5} 7.3 Earthquake Valley 43.1 (69.3} 6.5 San Jacinto-Anza 48.2 (77.5) 7.2 Newport-Inglewood (L.A. Basin) 48.7 (78.3) 7.1 San Jacinto-San Jacinto Valley 49.0 (78.9} 6.9 Chino-Central Ave. (Elsinore) 50.6 (81.5) 6.7 San Jacinto-Coyote Creek 52.6 (84.7) 6.8 Whittier 54.1 (87.1) 6.8 Elsinore-Coyote Mountain 56.5 (91.0} 6.8 Compton Thrust 58.3 (93.9} 6.8 Elvsian Park Thrust 61.5 (98.9) 6.7 Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 8.2 CBC Seismic Design Parameters eotechnical Investigation Report En . , Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Pages Seismic parameters based on the California Building Code (CBSC, 2016) were determined using the Seismic Design Maps application (USGS, 2017) and are provided in the following table. Table No. 2, CBC Seismic Parameters Seismic Parameters Site Coordinates 33.1170 N, 117.3213 W Site Class D Mapped Short period (0.2-sec) Spectral Response Acceleration, 1.163g Ss Mapped 1-second Spectral Response Acceleration, S1 0.448g Site Coefficient (from Table 1613.5.3(1 )), Fa 1.0 Site Coefficient (from Table 1613.5.3(2)), Fv 1.5 MCE 0.2-sec period Spectral Response Acceleration, SMs 1.204g MCE 1-second period Spectral Response Acceleration, SM1 0.695g Design Spectral Response Acceleration for short period Sos 0.802g Design Spectral Response Acceleration for 1-second period, So1 0.463g Maximum Peak Ground Acceleration, PGAM 0.484g 8.3 Secondary Effects of Seismic Activity In general, secondary effects of seismic activity include surface fault rupture, soil liquefaction, landslides, lateral spreading, and settlement due to seismic shaking, tsunamis, seiches, and earthquake-induced flooding. The site-specific potential for each of these seismic hazards is discussed in the following sections. Surface Fault Rupture: The site is not located within State of California or San Diego County designated earthquake fault zones (CGS, 2007; San Diego County, 201 0a). There are no known faults projecting toward or through the project site. The risk of surface fault rupture is considered low. Liquefaction: Liquefaction is defined as the phenomenon in which a cohesionless soil mass within the upper 50 feet of the ground surface, suffers a substantial reduction in its shear strength, due the development of excess pore pressures. During earthquakes, excess pore pressures in saturated soil deposits may develop as a result of induced cyclic shear stresses, resulting in liquefaction. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 9 Soil liquefaction generally occurs in submerged granular soils and non-plastic silts during or after strong ground shaking. There are several general requirements for liquefaction to occur. They are as follows: • Soils must be submerged. • Soils must be loose to medium-dense. • Ground motion must be intense. • Duration of shaking must be sufficient for the soils to lose shear resistance. The site is not located within an area designated as having liquefaction risk by San Diego County (San Diego County, 2010b). During the 2005 investigation, Converse identified isolated sandy layers below the water table that were potentially liquefiable. A calculated liquefaction potential of 2 to 3 inches for the isolated sandy layers was provided. A previous report by Law Crandall (reference unavailable) also indicated the potential liquefaction of less dense sandy soils at the project site (Converse, 2005). Seismic Settlement Seismically-induced settlement occurs in unsaturated, unconsolidated, granular sediments during ground shaking associated with earthquakes. The analysis presented in Appendix C, Settlement Analysis indicates that the site has the potential for up to approximately 0.23 inches of dry seismic settlement. Landslides: Seismically induced landslides and other slope failures are common occurrences during or soon after earthquakes. There is an ascending slope on the northwestern portion of the project area. Properly compacted fill slopes are expected to be stable. Due to the relatively flat nature of the remainder of the project site, the risk of landsliding is considered low. Lateral Spreading: Seismically induced lateral spreading involves primarily lateral movement of earth materials over underlying materials which are liquefied due to ground shaking. It differs from the slope failure in that complete ground failure involving large movement does not occur due to the relatively smaller gradient of the initial ground surface. Lateral spreading is demonstrated by near-vertical cracks with predominantly horizontal movement of the soil mass involved. The potential for lateral spreading is not known with certainty, however, due to the relatively flat nature of the project site, the risk of lateral spreading is considered low. Tsunamis: Tsunamis are large waves generated in open bodies of water by fault displacement or major ground movement. The project site is located approximately 1, 150 feet from the Pacific Ocean. The Tsunami Inundation Map for Emergency Planning, Encinitas Quadrangle (CGS, 2009) indicates that the project site is not located within a designated tsunami inundation zone. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir ootechnical Investigation Report En . Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 10 Seiches: Seiches are large waves generated in enclosed bodies of water in response to ground shaking. Seiching within onsite reservoirs onsite is possible during a major seismic event. The site is not considered at risk for damage from off-site seiching. Earthquake-Induced Flooding: Dams or other water-retaining structures may fail as a result of large earthquakes. The project site is not located with a designated San Diego County designated dam inundation area (San Diego County, 2010a and 2010b). The risk of earthquake induced-flooding at the reservoir site due to failure of offsite dams is considered low. 9.0 EARTHWORK RECOMMENDATIONS Earthwork recommendations for the project are presented in the following sections. 9.1 General This section contains our general recommendations regarding earthwork and grading for the proposed building and retaining walls. These recommendations are based on the results of our field exploration, laboratory tests, our experience with similar projects, and data evaluation as presented in the preceding sections. These recommendations may require modification by the geotechnical consultant based on observation of the actual field conditions during grading. Prior to the start of construction, all underground existing utilities and appurtenances should be located at the project site. Such utilities should either be protected in-place or removed and replaced during construction as required by the project specifications. All excavations should be conducted in such a manner as not to cause loss of bearing and/or lateral support of existing structures or utilities. All debris, surface vegetation, deleterious material, and surficial soils containing roots and perishable materials should be stripped and removed from the site. Deleterious material, including organics, concrete, and debris generated during excavation, should not be placed as fill. The final bottom surfaces of all excavations should be observed and approved by the project geotechnical consultant prior to placing any fill. Based on these observations, localized areas may require remedial grading deeper than indicated herein. Therefore, some variations in the depth and lateral extent of excavation recommended in this report should be anticipated. Converse Consultants M:\JOBFILE\2017\81\17-81 -153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 9.2 Remedial Grading Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Page 11 Building and retaining wall footings, slabs-on-grade, and other shallow or at-grade structures and pavements should be uniformly supported by compacted fill. In order to provide uniform support, structural areas should be overexcavated, scarified, and recompacted as follows. The building footprints and any other areas to support structures or retaining walls should be overexcavated to a depth of 24 inches below the bottom of the footings. The depths of overexcavation should be uniform across the entire structures. The overexcavation should extend to at least 2 feet beyond the footprints of the structures. All areas to receive asphalt or concrete pavement should be overexcavated to a depth of 12 inches below finish grade. The overexcavation should extend at least 1 foot beyond the edge of pavement. If isolated pockets of very soft, loose, or pumping subgrade are encountered, the overexcavation should be locally deepened, as needed, to expose undisturbed, firm, and unyielding soils. 9.3 Compacted Fill Placement All surfaces to receive structural fills should be scarified to a depth of 6 inches. The soil should be moisture conditioned to within ±3 percent of optimum moisture content for coarse soils and 0 to 2 percent above optimum moisture content for fine soils. The scarified soils should be recompacted to at least 90 percent of the laboratory maximum dry density. Fill soils should be evenly spread in horizontal lifts not exceeding 8 inches in uncompacted thickness. All fill placed at the site should be compacted to at least 90 percent of the laboratory maximum dry densities as determined by ASTM Standard D1557 test method, unless a higher compaction is specified herein. At least the upper 12 inches of subgrade soils underneath pavements intended to support vehicle loads should be scarified, moisture conditioned, and compacted to at least 95 percent of the laboratory maximum dry density. Fill materials should not be placed, spread or compacted during unfavorable weather conditions. When site grading is interrupted by heavy rain, filling operations should not resume until the geotechnical consultant approves the moisture and density conditions of the previously placed fill. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02__gir Geotechnical Investigation Report E -.. a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 12 9.4 Backfill Recommendations Behind Retaining Walls Compaction of backfill adjacent to structural walls can produce excessive lateral pressures. Improper types and locations of compaction equipment and/or compaction techniques may damage the walls. The use of heavy compaction equipment should not be permitted within a horizontal distance of 5 feet from the wall. Backfill behind any structural walls within the recommended 5-foot zone should be compacted using lightweight construction equipment such as handheld compactors to avoid overstressing the walls. 9.5 Fill Materials Excavated on-site soils are generally considered suitable for re-use as compacted fill. Prior to re-use, excavated soils should be cleared of all debris, vegetation, rocks larger than 3 inches in maximum dimension, and other deleterious materials. Rocks larger than 1 inch in the largest dimension should not be placed within the upper 12 inches of fill beneath footings and slabs. We anticipate that import fill soils will be required to achieve the proposed grade. Imported soils, if used as fill, should be predominantly granular and meet the following criteria. • Movement does not occur due to the relatively smaller gradient of the initial ground surface. Lateral spreading is demonstrated by near-vertical cracks with predominantly Expansion Index less than 20. • Free of all deleterious materials. • Contain no particles larger than 3 inches in the largest dimension. • Contain less than 30 percent by weight retained on ¾-inch sieve. • Plasticity Index of 10 or less. • Corrosivity not greater than the onsite soils. Any imported fill should be tested and approved by geotechnical representative prior to delivery to the site. 9.6 Site Drainage Adequate positive drainage should be provided away from the building, retaining walls, and excavation areas to prevent ponding and to reduce percolation of water into the foundation soils. A desirable drainage gradient is 1 percent for paved areas and 2 percent in landscaped areas. Surface drainage should be directed to suitable non-erosive devices. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 10.0 DESIGN RECOMMENDATIONS Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 13 General design recommendations, resistance to lateral loads, bearing pressures, and soil corrosivity are discussed in the following subsections. 10.1 General Evaluation Based on our field exploration, laboratory testing and analyses of subsurface conditions at the project site, the structure may be placed on compacted fill materials as described in this report. The various design · recommendations provided in this section are based on the assumption that in preparing the site, the above earthwork recommendations will be implemented. 10.2 Shallow Foundation Design Parameters The proposed building and retaining walls may be supported on continuous (strip) footing and/or isolated spread footings. The design of the shallow foundations should be based on the recommended parameters presented in the table below. Minimum continuous spread footing width Minimum isolated footin width Minimum continuous or isolated footing depth of embedment below lowest ad·acent rade Allowable net bearing capacity 18inches 18 inches 18inches 2,500 psf The footing dimensions and reinforcement should be based on structural design. The allowable bearing capacity can be increased by overburden pressure of 150 psf for each foot of width or depth of footing embedment to the maximum of 3,500 psf. The net allowable bearing values indicated above are for the dead loads and frequently applied live loads and are obtained by applying a factor of safety of 3.0 to the net ultimate bearing capacity. If normal code requirements are applied for design, the above vertical bearing value may be increased by 33 percent for short duration loadings, which will include loadings induced by wind or seismic forces. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Enc, a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 14 10.3 Lateral Earth Pressures and Resistance to Lateral Loads In the following subsections, the lateral earth pressures and resistance to lateral loads are estimated by using on-site native soils strength parameters obtained from laboratory testing. 10.3.1 Active Earth Pressures The active earth pressure behind any buried wall or foundation depends primarily on the allowable wall movement, type of backfill materials, backfill slopes, wall or foundation inclination, surcharges, and any hydrostatic pressures. The recommended lateral earth pressures for the site are presented in the following table. Table No. 4, Active and At-Rest Earth Pressures L d. c d·t· Lateral Earth Pressure oa mg on I ions (psf) Active earth conditions (wall is free to deflect at least 0.001 radian) 50 At-rest (wall is restrained) 70 The equivalent fluid seismic pressure was calculated using Seed and Whitman (1970) procedure. The seismic force applied to the wall is based on a horizontal seismic acceleration coefficient equal to one-third of the peak ground acceleration in accordance with Caltrans Bridge Design Specifications (Caltrans, 2004 ). An equivalent fluid seismic pressure of 22H pcf may be assumed under active loading conditions at the top of an inverted triangle pressure distribution where H is the height of the backfill behind the wall. Under at-rest conditions, the active equivalent fluid seismic pressure should be increased by 30 percent. These pressures assume a level ground surface behind the walls for a distance greater than the walls height, no surcharge and no hydrostatic pressure. If water pressure is allowed to build up behind the walls, the active pressures should be reduced by 50 percent and added to a full hydrostatic pressure to compute the design pressures against the walls. 10.3.2 Passive Earth Pressure Resistance to lateral loads can be assumed to be provided by a combination of friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.30 between formed concrete and soil may be used with the dead load forces. An allowable passive earth pressure of 220 psf per foot of depth may be used for the sides of footings poured against recompacted soils. A factor of safety of 1.5 was applied in Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 15 calculating passive earth pressure. The maximum value of the passive earth pressure should be limited to 2,500 psf for compacted fill. Vertical and lateral bearing values indicated above are for the total dead loads and frequently applied live loads. If normal code requirements are applied for design, the above vertical bearing and lateral resistance values may be increased by 33 percent for short duration loading, which will include the effect of wind or seismic forces. Due to the low overburden stress of the soil at shallow depth, the upper 1 foot of passive resistance should be neglected unless the soil is confined by pavement or slab. 10.4 Settlement The total settlement of shallow footings from static structural loads and short-term settlement of properly compacted fill is anticipated to be 1 inch or less. The differential settlement resulting from static loads is anticipated to be 0.5 inches or less over a horizontal distance of 40 feet. Our analysis of the potential dynamic settlement is presented in Appendix C, Settlement Analysis. We estimate that the site has the potential for up to 0.23 inches of dynamic settlement during a large earthquake for the maximum drilled depth of 19.5 feet bgs. However, a total of 2 to 3 inches of dynamic settlement was observed for the drilled depth of 50 feet bgs in the previous report (Converse, 2005). Differential settlement is expected to be limited due to the uniform soil conditions at the site. The dynamic differential settlement is anticipated to be half of the total settlement over a horizontal distance of 40 feet. The static and dynamic settlement estimates should not be combined for design purposes. The maximum combined static and dynamic settlement is not anticipated to exceed the maximum anticipated dynamic settlement. We recommend the planned structure should be designed based on the maximum settlement. 10.5 Asphalt Concrete Pavement Laboratory testing indicated an R-value of 11. Preliminary asphalt concrete pavement sections corresponding to Traffic Indices (Tis) ranging from 5 to 8 and an R-value of 11 are presented in the table on the following page. Converse Consultants M:UOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Table No. 5, Recommended Prelimina Geotechnical Investigation Report Enc, a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 16 Pavement Section Traffic Index (Tl) Asphalt Concrete (inches) Aggregate Base (inches) R-value 11 7 8 3.5 10.0 4.0 12.0 5.0 14.0 At or near the completion of grading, subsurface samples should be tested to evaluate the actual subgrade R-value for final pavement design. Prior to placement of aggregate base, at least the upper 12 inches of subgrade soils should be scarified, moisture-conditioned if necessary, and recompacted to at least 95 percent of the laboratory maximum dry density as defined by ASTM Standard D1557 test method. Base materials should conform with Section 200-2.2,"Crushed Aggregate Base," of the current Standard Specifications for Public Works Construction (SSPWC; Public Works Standards, 2015) and should be placed in accordance with Section 301.2 of the SSPWC. Asphaltic concrete materials should conform to Section 203 of the SSPWC and should be placed in accordance with Section 302.5 of the SSPWC. 10.6 Concrete Flatwork Except as modified herein, concrete walks, driveways, access ramps, curb and gutters should be constructed in accordance with Section 303-5, Concrete Curbs, Walks, Gutters, Cross-Gutters, Alley Intersections, Access Ramps, and Driveways, of the Standard Specifications for Public Works Construction (Public Works Standards, 2015). The subgrade soils under the above structures should consist of compacted fill placed as described in this report. Prior to placement of concrete, the upper 12 inches of subgrade soils should be moisture conditioned to between within 3 percent of optimum moisture content for coarse-grained soils and 0 and 2 percent above optimum for fine- grained soils. The thickness of driveways for passenger vehicles should be at least 4 inches, or as required by the civil or structural engineer. Transverse control joints for driveways should be spaced not more than 10 feet apart. Driveways wider than 12 feet should be provided with a longitudinal control joints. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 17 Concrete walks subjected to pedestrian and bicycle loading should be at least 4 inches thick, or as required by the civil or structural engineer. Transverse joints should be spaced 15 feet or less and should be cut to a depth of one-fourth the slab thickness. Positive drainage should be provided away from all driveways and sidewalks to prevent seepage of surface and/or subsurface water into the concrete base and/or subgrade. 10.7 Soil Corrosivity The result of chemical testing of a representative sample of site soil was evaluated for corrosivity with respect to common construction materials such as concrete and steel. The test result is presented in Appendix B, Laboratory Testing Program in Table No. B- 3, Summary of Corrosivity Test Result, and is discussed below. The sulfate content of the sample tested corresponds to American Concrete Institute (ACI) exposure category SO for this sulfate concentration (ACI 318-11, Table 4.2.1). ACI recommends a minimum compressive strength of 2,500 psi for exposure category SO in ACI 318-11, Table 4.3.1. No concrete type restrictions are specified. We anticipate that concrete structures will be exposed to moisture from precipitation and irrigation. Based on the project location and the result of chloride testing of the site soil, we do not anticipate that concrete structures will be exposed to external sources of chlorides, such as deicing chemicals, salt, brackish water, or seawater. ACI specifies exposure category C1 where concrete is exposed to moisture, but not to external sources of chlorides (ACI 318-11, Table 4.2.1 ). ACI provides concrete design recommendations in ACI 318-11, Table 4.3.1, including a minimum compressive strength of 2,500 psi, and a maximum chloride content of 0.3 percent. The measured value of the minimum electrical resistivity when saturated was 2,200 Ohm-cm. This indicates that the majority of the soils at the project site are corrosive for ferrous metals in contact with the soil (Romanoff, 1957). Converse does not practice in the area of corrosion consulting. A qualified corrosion consultant should provide appropriate corrosion mitigation measures for ferrous metals in contact with the site soils. 11.0 CONSTRUCTION RECOMMENDATIONS Temporary sloped excavation and shoring design recommendations are presented in the following sections. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 11.1 General Geotechnical Investigation Report '-· a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Page 18 Both sloped and vertical braced excavations can be considered for the continuous foundations at the proposed project site. Recommendations pertaining to temporary excavations are presented in this section. Excavations near existing streets or structures may require vertical side wall excavation. Where the side of the excavation is a vertical cut, it should be adequately supported by temporary shoring to protect workers and any adjacent structures. All applicable requirements of the California Construction and General Industry Safety Orders, the Occupational Safety and Health Act, and the Construction Safety Act should be met. The soils exposed in cuts should be observed during excavation by the geotechnical consultant and the competent person designated by the contractor. If potentially unstable soil conditions are encountered, modifications of slope ratios for temporary cuts may be required. 11.2 Shoring Design Temporary shoring may be required where open sloped excavations will not be feasible due to unstable soils or due to nearby existing structures or facilities. Temporary shoring may consist of conventional soldier piles and lagging or sheet piles. The shoring for the pipe excavations may be laterally supported by walers and cross bracing or may be cantilevered. Drilled excavations for soldier piles will require the use of drilling fluids to prevent caving and to maintain an opened hole for pile installation. The active earth pressure behind any shoring depends primarily on the allowable movement, type of backfill materials, backfill slopes, wall inclination, surcharges, and any hydrostatic pressures. The lateral earth pressures to be used in the design of shoring is presented in the following table. Active Earth Pressure (Braced Shoring) (psf) {A) 30 Active Earth Pressure (Cantilever Shoring) (psf) (B) 50 At-Rest Earth Pressure (Cantilever Shoring) (psf) (C) 70 Passive earth pressure (psf per foot of depth) (D) 220 Maximum allowable bearing pressure against native soils (psf) (E) 2,500 Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir I Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 19 Lateral Resistance Soil Parameters* Values Maximum allowable bearing pressure against native soils (psf) (E) 2,500 Coefficient of friction between sheet pile and native soils, fs (degree) (F) 0.30 Parameters A through F are used in Figures No. 3 and 4 below. Restrained (braced) shoring systems should be designed based on Figure No. 3, Lateral Earth Pressures for Temporary Braced Excavation to support a uniform rectangular lateral earth pressure. Figure No. 3, Lateral Earth Pressures for Temporary Braced Excavation q (Surcharge) t t t t :;;:;II H, Pq = 0.5q Pa= (A)H1 Pp = (D) H2 ~ (E) psf 1,1=(F) Total Earth Pressure P P= Pq+ Pa -incremental surcharge pressure -active earth pressure (Braced walls) Lateral Pressure Resistance -passive earth pressure (on native soils) -ultimate friction coefficient between steel sheet piles and soil _1__/ All values of height (H) in feet, pressure (P) and surcharge (q) in pounds per I I ~ i-l ___ P_p_----<■-1 ___ P_q_. +--• _P_o _ ____,•--i-square foot (psf). Unrestrained (cantilever) design of cantilever shoring consisting of soldier piles spaced at least two diameters on-center or sheet piles, can be based on Figure No. 4, Lateral Earth Pressures on Temporary Cantilever Wall. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81 -153-02_gir Geotechnical Investigation Report Eric., a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August30,2017 Page 20 Figure No. 4, Lateral Earth Pressures on Temporary Cantilever Wall Pa, Po Pq =O.Sq Pa= (B)H1 Po= (C)H1 Pp= (DI H2 :S (E) psf Total Earth Pressure P P= Pq+ Pa, Po -incremental surcharge pressure -active earth pressure (Un-restrained) -at rest earth pressure (Restrained) Lateral Pressure Resistance -passive earth pressure ( on native soils) µ = (F) -ultimate friction coefficient between steel sheet piles and N.ote.; All values of height (H) in feet, pressure (P) and surcharge (q) in pounds per souare foot (psf). The provided pressures assume no hydrostatic pressures. If hydrostatic pressures are allowed to build up, the incremental earth pressures below the ground-water level should be reduced by 50 percent and added to hydrostatic pressure for total lateral pressure. Passive resistance includes a safety factor of 1.5. The upper 1 foot for passive resistance should be ignored unless the surface is confined by a pavement or slab. In addition to the lateral earth pressure, surcharge pressures due to miscellaneous loads, such as soil stockpiles, vehicular traffic or construction equipment located adjacent to the shoring, should be included in the design of the shoring. A uniform lateral pressure of 100 psf should be included in the upper 10 feet of the shoring to account for normal vehicular and construction traffic within 10 feet of the trench excavation. As previously mentioned, all shoring should be designed and installed in accordance with state and federal safety regulations. The contractor should have provisions for soldier pile and sheet pile removal. All voids resulting from removal of shoring should be filled. The method for filling voids should be selected by the contractor, depending on construction conditions, void dimensions and available materials. The acceptable materials, in general, should be non- deleterious, and able to flow into the voids created by shoring removal (e.g. concrete slurry, "pea" gravel, etc). Excavations should not extend below a 1 :1 horizontal:vertical (H:V) plane extending from the bottom of any existing structures, utility lines or streets. Any proposed excavation should not cause loss of bearing and/or lateral supports of the existing utilities or streets. Converse Consultants M:IJOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 21 If the excavation extends below a 1 :1 (H:V) plane extending from the bottom of the existing structures, utility lines or streets, a maximum of 10 feet of slope face parallel to the existing improvement should be exposed at a time to reduce the potential for instability. Backfill should be accomplished in the shortest period of time and in alternating sections. 12.0 GEOTECHNICAL SERVICES DURING CONSTRUCTION The project geotechnical consultant should be present to observe conditions and test the density and moisture of the backfill during the earthwork for this project. The excavations and backfill should be observed and tested for compliance with project specifications. 13.0 CLOSURE This report is prepared for the project described herein and is intended for use solely by Encina Wastewater Authority to assist in the design and construction of the proposed project. Our findings and recommendations were obtained in accordance with generally accepted professional principles practiced in geotechnical engineering. We make no other warranty, either expressed or implied. Converse Consultants is not responsible or liable for any claims or damages associated with interpretation of available information provided to others. Site exploration identifies actual soil conditions only at those points where samples are taken, when they are taken. Data derived through sampling and laboratory testing is extrapolated by Converse employees who render an opinion about the overall soil conditions. Actual conditions in areas not sampled may differ. In the event that changes to the project occur, or additional, relevant information about the project is brought to our attention, the recommendations contained in this report may not be valid unless these changes and additional relevant information are reviewed and the recommendations of this report are modified or verified in writing. In addition, the recommendations can only be finalized by observing actual subsurface conditions revealed during construction. Converse cannot be held responsible for misinterpretation or changes to our recommendations made by others during construction. As the project evolves, a continued consultation and construction monitoring by a qualified geotechnical consultant should be considered an extension of geotechnical investigation services performed to date. The geotechnical consultant should review plans and specifications to verify that the recommendations presented herein have been appropriately interpreted, and that the design assumptions used in this report are valid. Where significant design changes occur, Converse may be required to augment or modify the recommendations presented herein. Subsurface conditions may differ in ~ Converse Consultants W M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02__gir Geotechnical Investigation Report En ,a Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 22 some locations from those encountered in the explorations, and may require additional analyses and, possibly, modified recommendations. Design recommendations given in this report are based on the assumption that the recommendations contained in this report are implemented. Additional consultation may be prudent to interpret Converse's findings for contractors, or to possibly refine these recommendations based upon the review of the actual site conditions encountered during construction. If the scope of the project changes, if project completion is to be delayed, or if the report is to be used for another purpose, this office should be consulted. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir 14.0 REFERENCES Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 23 AMERICAN CONCRETE INSTITUTE (ACI), 2011, Building Code Requirements for Structural Concrete (ACI 318-11 ), dated August, 2011 . AMERICAN SOCIETY OF CIVIL ENGINEERS (ASCE), 2010, Minimum Design Loads for Buildings and Other Structures, SEI/ASCE Standard No. 7-10, dated January 1, 2010. CALIFORNIA BUILDING STANDARDS COMMISSION (CBSC), 2016, California Building Code (CBC). CALIFORNIA DEPARTMENT OF TRANSPORTATION (Caltrans), 2004, Bridge Design Specifications, Section 5, Retaining Walls, dated August, 2004. CALIFORNIA GEOLOGICAL SURVEY (CGS), 2009, Tsunami Inundation Map for Emergency Planning, Encinitas Quadrangle, State of California, County of San Diego, scale 1 :24,000, dated June 1, 2009. CALIFORNIA STATE WATER RESOURCES CONTROL BOARD (SWRCB), 2017, GeoTracker database (http://geotracker.waterboards.ca.gov/), accessed August, 2017. CONVERSE CONSULTANTS, 2005, Geotechnical Investigation Report; Proposed Phase V Expansion Project, Encina Wastewater Authority, Carlsbad, California, Project No. 04-32-139-01, dated July 8, 2005. CONVERSE CONSULTANTS, 2017, Geotechnical Investigation Report, Encina Phase V Wastewater Expansion -New Parking Lot, 6200 Avenida Encinas, City of Carlsbad, San Diego County, California, Project No. 17-81-153-01, dated May 24 2017. CIVILTECH SOFTWARE, 2011, LiquefyPro: Liquefaction and Settlement Analysis Software, version 5.2E. DIBBLEE, T.W., and MINCH, J.A., 2002, Geologic map of the Mescal Creek quadrangle, Los Angeles and San Bernardino Counties, California, Dibblee Foundation Map DF-81, scale 1 :24,000. DIBBLEE, T.W., and MINCH, J.A., 2008, Geologic map of the Shadow Mountains & · Victorville 15 minute quadrangles, San Bernardino & Los Angeles Counties, California, Dibblee Foundation Map DF-387, scale 1 :62,500. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir eotechnical Investigation Report En .. _ hase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page 24 MORTON, D.M. and MILLER, F.K., 2006, Geologic Map of the San Bernardino and Santa Ana 30' x 60' Quadrangles, California, U.S. Geological Survey Open-File Report 2006-1217, scale 1 :100,000. PUBLIC WORKS STANDARDS, INC., 2015, Standard Specifications for Public Works Construction ("Greenbook"), 2015. ROMANOFF, MELVIN, 1957, Underground Corrosion, National Bureau of Standards Circular 579, dated April, 1957. SAN DIEGO COUNTY, 201 0a, San Diego County General Plan Safety Element, dated August, 2011. SAN DIEGO COUNTY, 2010b, San Diego County Multi-Jurisdictional Hazard Mitigation Plan, dated 2010. SOUTHERN CALIFORNIA EARTHQUAKE CENTER (SCEC), 2008, Recommended Procedures for Implementation of DMG Special Publication 117 A: Guidelines for Analyzing and Mitigating Liquefaction Hazards in California, dated September, 2008. U.S. GEOLOGICAL SURVEY (USGS), 2017a, National Water Information System: Web Interface (http://nwis.waterdata.usga.gov/nwis/gwlevels), accessed on May 5, 2017. U.S. GEOLOGICAL SURVEY (USGS), 2017b, U.S. Seismic Design Maps Tool: Web . Interface (http://earthquake.usgs.gov/hazards/designmaps/usdesign.php ), accessed on August 14, 2017. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Appendix A Field Exploration eotechnical Investigation Report En Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 APPENDIX A FIELD EXPLORATION •. Page A-1 Our field investigation included a site reconnaissance and a subsurface exploration program consisting of drilling soil borings. During the site reconnaissance, the surface conditions were noted and the boring locations were marked. The borings were located in the field using approximate distances from onsite buildings as a guide and should be considered accurate only to the degree implied by the method used to locate them. Four exploratory borings (BH-1 through BH-4) were drilled on July 21, 2017 at the site of the proposed building. Borings B-1 and B-4 were drilled to their maximum planned depths of approximately 19.5 feet bgs. Borings BH-2 and BH-3 were terminated at 4.5 feet and 2 feet bgs respectively due to refusal on unmarked pipelines. Field and laboratory data from Boring BH-8 (Converse, 2005) and Boring BH-1 (Converse, 2017) were substituted for Borings BH-2 and BH-3, respectively. The borings were advanced using a truck-mounted drill rig equipped with 6-inch diameter hollow-stem augers for soils sampling. Encountered materials were continuously logged by a Converse geologist and classified in the field by visual classification in accordance with the Unified Soil Classification System. Where appropriate, the field descriptions and classifications have been modified to reflect laboratory test results. Relatively undisturbed samples were obtained using California Modified Samplers (2.4 inches inside diameter and 3.0 inches outside diameter) lined with thin sample rings. The steel ring sampler was driven into the bottom of the borehole with successive drops of a 140-pound driving weight falling 30 inches. Blow counts at each sample interval are presented on the boring logs. Samples were retained in brass rings (2.4 inches inside diameter and 1.0 inch in height) and carefully sealed in waterproof plastic containers for shipment to the Converse laboratory. Bulk samples of typical soil types were also obtained. The exact depths at which material changes occur cannot always be established accurately. Unless a more precise depth can be established by other means, changes in material conditions that occur between drive samples are indicated on the logs at the top of the next drive sample. Following the completion of logging and sampling, the borings were backfilled with soil cuttings and patched with cold asphalt concrete. The surface of the borings may settle over time. If construction is delayed, we recommend the owner monitor the boring locations and backfill any depressions that might occur, or provide protection around the boring locations to prevent trip and fall injuries from occurring near the area of any potential settlement. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, California August 30, 2017 Page A-2 For a key to soil symbols and terminology used in the boring logs, refer to Drawing No. A-1, Unified Soil Classification and Key to Boring Log Symbols. For logs of borings see Drawing Nos. A-2 through A-7, Logs of Borings. Converse Consultants M:\JOBFILE\2017\81\17-81 -153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir MAJOR DIVISIONS COARSE GRAINED SOILS MORE THAN 50% 01 MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE FINE GRAINED SOILS MORE THAN 50% OF MATERIAi.iS SMALLER THAN NO. 200 SIEVE SIZE GRAVEL AND GRAVELLY SOILS MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE SAND AND SANDY SOILS MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE SILTS AND CLAYS SILTS AND CLAYS CLEAN GRAVELS (LITnE OR NO FINES) GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINES) CLEAN SANDS (LITn.E OR NO FINES) SANDS WITH FINES (APPRECIABLE AMOUNT OF FINES) LIQUID LIMIT LESS THAN SO LIQUID LIMIT GREATER THAN 50 HIGHLY ORGANIC SOILS SYMBOLS GRAPH LETTER ---· ·•· .. ••••• ·:_•:_: .. -· ... ·,:·: -~-------------- GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT TYPICAL DESCRIPTIONS WELL-GRADED GRAVELS, GRAVEL · SANO MIXTURES, UTTI..E OR NO FINES POORL Y-GRADEO GRAVELS, GRAVEL -SANO MIXTURES, LITTLE OR NO FINES SL TY GRAVELS, GRAVEL -SAND • SLT MIXTIJRES CLAYEY GRAVELS, GRAVEL- SANO -Cl.AYMIXTURES WELL-GRADEO SANOS, GRAVELLY SANOS, LITTlE OR NO FINES POORL Y-GRADEO SANOS, GRAVELLY SAND, LITTLE OR NOFNES SL TY SANDS, SANO -SL T MIXTURES CLAYEY SANDS, SAND-CLAY MIXTURES NORGANIC SIL TS ANO VERY FINE SANDS, ROCK FLOUR, SL TY OR CLAYEY FINE ~DS -~~-~~~~~~S NORGANIC CLAYS OF LOW TO MEOIUM PLASTICrTY, GRAVELLY CLAYS, SAI\IDY CLAYS, SL TY CLAYS, LEAN r••= ORGANIC SLTS ANO ORGANIC SLTYCLAYSOFLOW PlASTICrTY NOR GAN IC SIL TS, MICACEOUS OR OIATOMACEOUS FINE SANO OR SIL TY SOLS NORGANIC CLAYS OF HIGH PLASTICrTY ORGANIC CLAYS OF MEOIUM TO HIGH PLASTICITY, ORGANIC SLTS PEAT, HUMUS, SWAMP SOLS WITH HIGH ORGANIC CONTENTS NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS SAMPLE TYPE STANDARD PENETRATION TEST Split barrel sampler in accordance with ASTM D-1586--84 Standard Test Method -DRIVE SAMPLE 2.42" I.D. sampler (CMS). D DRIVE SAMPLE No recovery ~ BULK SAMPLE BORING LOG SYMBOLS LABORATORY TESTING ABBREVIATIONS ~ SJBl;t;GIH (Results shown in Appendix B) Pocket Penetrometer Direct Shear Direct Shear (single point) CLASSIEICATION Unconfined Compression Triaxlal Compression Plasticity pl Vane Shear Grain Size Analysis ma Consolidation Passing No. 200 Sieve wa Collapse Test Sand Equivalent se Resistance (R) Value ..Y_ GROUNDWATER WHILE DRILLING _I_ GROUNDWATER AFTER DRILLING E,cpanslon Index Compactlon curve Hydrometer Disturb el Chemical Analysis max Electrical Resistivity h Penneabillty Dist. Soil Cement =' Very Loose Loose Medium Dense Very Dense SPT IN\ <4 4-11 11-30 31-50 >50 Very Soft Soft Medium Stiff Very Stiff CASamDio, <5 5-12 13-35 36-60 >60 R-<20 20-40 40-60 60-80 >80 Den.,.;1%1 <2 2--4 9-15 16-30 <3 3--6 7-12 13-25 26-50 UNIFIED SOIL CLASSIFICATION AND KEY TO BORING LOG SYMBOLS p ds ds" UC Ix vs C col ca er penn SC Haro > 30 >50 ~ Converse Consultants Encina Phase V Wastewater Expansion 1,400 Square Foot Building Project No. 17-81-153-02 Drawing No. Project ID: 17-81-153--02.GPJ; Template: KEY 6200 Avenida Encinas City of Carlsbad, San Diego County, California For: Encina Wastewater Authority A-1 Log of Boring No. B-1 Dates Drilled: ------------7/21/2017 Logged by: James Burnliam Checked By: Scot Mathis ------- Equipment: __ 6_"_H_O_L_L_O_W_S_T_E_M_A_UG_ER_ Ground Surface Elevation (ft)_: __ 3_1 __ _ Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): NOT ENCOUNTERED -!E.. -~ .s:::. .s:::. -a. a. nl Cl Q) ... 0 Cl (!) ...J 5 10 15 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. 5.0" ASPHALT CONCRETE/ 8" AGGREGATE BASE ARTIFICIAL FILL SIL TY SAND with CLAY (SM): fine to coarse-grained, yellowish brown. ALLUVIUM SANDY CLAY (CL): fine to medium-grained, olive yellow. ---------------------------------CLAY (CL): olive gray. End of boring at 19.5 feet bgs. No groundwater encountered. Borehole backfilled with soil cuttings and patched with asphald concrete on 7/21/2017. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ 6200 Avenida Encinas ~ Converse Consultants City of Carlsbad, San Diego County, California ~ For: Encina Wastewater Authority ProJed lb: 1/-81-153-02.GPJ; Template: LOG SAMPLES ~ w a: I- en ::::, z a: ~ I-::::, :.: 3,:: en w ii: ...J 0 0 ~u' J: ::::, ...J I-0 al al ::. oE, 0 ei, ma, max 23/10/10 13 96 col 7/14/15 10 116 ds 5/11/12 16 112 3/6/10 17 93 3/6/10 17 103 Project No. Drawing No. 17-81-153-02 A-2 Log of Boring No. B-2 Dates Drilled: -------------7/21/2017 Logged by: James Burnha Checked By: --------Scot Mathis Equipment: __ 6_"_H_O_L_L_O_W_S_T_E_M_A_UG_ER_ Driving Weight and Drop: 140 lbs/ 30 in Ground Surface Elevation (ft)_: __ 3_2 __ _ Depth to Water (ft): NOT ENCOUNTERED SUMMARY OF SUBSURFACE CONDITIONS SAMPLES This log is part of the report prepared by Converse for this project £ and should be read together with the report. This summary applies ~ -u only at the location of the boring and at the time of drilling. w t-:c a: .c Subsurface conditions may differ at othe~ locations and may change U) => z ..., C. ~ ~ t-=> a: C. Cll c, at this location with the passage of time. The data presented is a :.,: U) w Cl) ... 0 ...J 0 0 ~i i= 0 C)_i simplification of actual conditions encountered. a: => ...J 0 al al :::; o~ 0 -6.0" ASPHALT CONCRETE/ 8.0" AGGREGATE BASE ARTIFICIAL FILL ?'. \l' ~x>c ::>c SIL TY SAND with CLAY (SM): fine to coarse-grained, 3/4/50-4.5" 14 110 olive brown. ?'. 'V \l' End of boring at 4.5 feet bgs due to refusal on unmarked steel pipe. No groundwater encountered. Borehole backfilled with soil cuttings and patched with asphald concrete on 7/21/2017. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ Converse Consultants 6~00 Avenida Encinas . . . City of Carlsbad, San Diego County, California Project No. Drawing No. 17-81-153-02 A-3 For: Encina Wastewater Authority Pm1ecl ID: 1 /.JJi.153-02.GPJ; I emplaie: LOG Log of Boring No. B-3 Dates Drilled: ------------7/21/2017 Logged by: James Burnham Checked By: __ S_co_t_M_a_t_h_is __ Equipment: __ __::_6_" .:....:H--=-O-=L-=-LO-=--:....W'-S-=--T.:....:E=Mc:..:....:....A=U--=-G--=E:..:....c.R Ground Surface Elevation (ft)'-: __ 2_9 __ _ Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): NOT ENCOUNTERED SUMMARY OF SUBSURFACE CONDITIONS SAMPLES This log is part of the report prepared by Converse for this project g and should be read together with the report. This summary applies ~ 0 only at the location of the boring and at the time of drilling. w :c Cl'. f-.c Subsurface conditions may differ at other locations and may change en ::::> z Cl'. -a. w s: f-::::> a. at this location with the passage of time. The data presented is a !><: en w Q) CU Cl <!: ...J 0 0 ~u :I: ._ 0 simplification of actual conditions encountered. Cl'. ::::> ...J f-Cl CL..J 0 al al ::;; o.S 0 ~ 3.0" ASPHALT CONCRETE/ 3.0" AGGREGATE BASE r ~ ARTIFICIAL FILL SIL TY SAND with CLAY (SM): fine to coarse-grained, r olive yellow. End of boring at 2 feet bgs due to refusal on unmarked steel pipe. No groundwater encountered. Borehole backfilled with soil cuttings and patched with asphald concrete on 7/21/2017. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ 6200 Avenida Encinas ~ Converse Consultants City of Carlsbad, San Diego County, California ~ For: Encina Wastewater Authority Project No. Drawing No. 17-81-153-02 A-4 ProJeci lb: 1/-81.153-02.GPJ; lemplaie: LOG Log of Boring No. B-4 Dates Drilled: 7/21/2017 ------------Logged by: James Bumhar. Checked By: Scot Mathis -------- Equipment: 6" HOLLOW STEM AUGER ------------- Ground Surface Elevation (ft)_: __ 3_5 __ _ Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): NOT ENCOUNTERED -~ -.c -C. Q) 0 5 10 15 -~ .c C. ('Q C) .... 0 C) ...J ·\\/?// ::::_;(;::}:::\ . . :-::.-.::.-:.:-.:-::.-. -:_:_::-. .-·.-::,:-._:_::· .. SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. 6.0" ASPHALT CONCRETE/ 8.0" AGGREGATE BASE ARTIFICIAL FILL SIL TY SAND with CLAY (SM): fine to coarse-grained, gravel up to 3" in largest dimension, olive brown. ALLUVIUM SAND (SP): fine-grained, gray. End of boring at 19 feet bgs. No groundwater encountered. Borehole backfilled with soil cuttings and patched with asphald concrete on 7/21/2017. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ Converse Consultants ~~~0 0:~:~~:a~~~:~sDiego County, California ~ For: Encina Wastewater Authority Pro1ecl lb: 17:a\.153-02.GPJ; I emplate: LOG SAMPLES ~ w a:: f- en :::l z a:: w :!: f-:::l ~ ~ en w ...J 0 0 ~'R J: a:: :::l ...J f-□ al al :::; □~ 0 ca, er, ei, ma 27/10/6 11 104 ds 3/4/5 12 104 col 3/3/2 11 103 5/20/49 9 127 18/50-5.5" 7 124 Project No. Drawing No. 17-81-153-02 A-5 f Boring No. BH-1 (Conve 2017) Dates Drilled: Lo 5/3/2017 ------------Logged by: James Bumliam Checked By: Scot Mathis -------- Equipment: 8" HOLLOW STEM AUGER ------------- Ground Surface Elevation (ft)_: __ 2_9 __ _ Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): NOT ENCOUNTERED -ii::: • !:2 -.c .c -a. a. ca c, Q) .... 0 0 (.9 ...J ·:,:.~/ ;_.::,:-.:·- .•.· -_.·:· . . ... •,•,· ·.··-: •.: -:_:_/ .-_.::,:-·./·. •·.· ?) ,• ::::_::_:~ <: ,•: .-.-::.:: ·-• .. -:: 5 10 15 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling . Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. ALLUVIUM SIL TY SAND (SM): fine to coarse-grained, trace clay, brown. ---------------------------------SANDY CLAY (CL): fine to medium-grained sand, olive brown. End of boring at 19.5 feet bgs. No groundwater encountered. Borehole backfilled with soil cuttings and tamped on 5/3/2017. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ C r e Cons ltants 6200 Avenida Encinas ~ On Ve S U City of Carlsbad, San Diego County, California ~ For: Encina Wastewater Authority ProJeci lb: 17:S1.153-o2.GPJ; I emplaie: LOG SAMPLES ~ w a:: I- rn ::> z w I-::> a:: ~ ~ :i: rn w ...J 0 6 ~'R :I: a:: ::> ...J I-0 al al :::. o~ 0 r 4/5/10 14 112 ds 5/8/9 24 110 3/5/8 14 103 3/6/10 21 95 6/10/12 24 91 Project No. Drawing No. 17-81-153-02 A-6 Dates Drilled: Log 8/9/2004 oring No. BH-8 {Convers ------------Logged by: KN 005) Checked By: JW -------- Equipment: 8" HOLLOW STEM AUGER ------------- Ground Surface Elevation (ft)_: __ 3_2 __ _ Driving Weight and Drop: 140 lbs/ 30 in Depth to Water (ft): NOT ENCOUNTERED -~ (.) -:c .J::. -c.. c.. m c, Q) ... 0 0 C)_J 5 10 15 20 SUMMARY OF SUBSURFACE CONDITIONS This log is part of the report prepared by Converse for this project and should be read together with the report. This summary applies only at the location of the boring and at the time of drilling. Subsurface conditions may differ at other locations and may change at this location with the passage of time. The data presented is a simplification of actual conditions encountered. 4" ASPHALT CONCRETE OVER 12" AGGREGATE BASE ALLUVIUM CLAYEY SAND (SC): fine-grained, light brown. SIL TY SAND (SM): fine-grained, yellowish brown. SANDY CLAY (CL): fine-grained sand, gray. SILTY SAND (SM): fine-grained, gray. End of boring at 21.5 feet bgs. Groundwater not encountered. Borehole backfilled with soil cuttings and patched with asphalt concrete. Encina Phase V Wastewater Expansion ~ 1,400 Square Foot Building ~ Converse Consultants 6~00 Avenida Encinas . . . City of Carlsbad, San Diego County, California For: Encina Wastewater Authority Pro1ed lb: 17-81-153-02.GPJ; I emplaie: LOG SAMPLES ~ w t--a: en ::> z w t--::> a: > ~ 3: ti) w ...J 0 0 ~'R :i: a: ::> ...J t--0 al al ::; 0-0 ca, er 4t6n 15 117 ds 9/20/32 8 97 ma,ds 7/9/16 26 99 wa 6nt16 Project No. Drawing No. 17-81-153-02 A-7 Appendix 8 Laboratory Testing Program eotechnical Investigation Report En .. , Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, CA August 30, 2017 Page B-1 APPENDIX B LABORATORY TESTING PROGRAM Tests were conducted in our laboratory on representative soil samples for the purpose of classification and evaluation of their physical properties and engineering characteristics. The amount and selection of tests were based on the geotechnical parameters required for this project. Test results are presented herein and on the Logs of Borings, in Appendix A, Field Exploration. The following is a summary of the various laboratory tests conducted for this project, including laboratory data from Boring BH-8 (Converse, 2005) and Boring BH-1 (Converse, 2017). In-Situ Moisture Content and Dry Density Results of these tests performed on relatively undisturbed ring samples were used to aid in the classification and to provide quantitative measure of the in situ dry density and moisture content. Data obtained from this test also provides qualitative information on strength and compressibility characteristics of the site soils. For test results, see the Logs of Borings in Appendix A, Field Exploration. Expansion Index Test Two representative bulk samples were tested to evaluate the expansion potential of the materials encountered at the site. The tests were conducted in accordance with ASTM Standard D4829. The test results are presented in the following table. T bl N B 1 R It f E • I d T t Boring No. Depth (feet) Soil Description Expansion Expansion Index Potential BH-1 1.0-7.0 Silty Sand with Gravel (SM) 1 Very Low BH-4 1.0-7.0 Silty Sand with Gravel (SM) 0 Very Low R-value One representative bulk soil sample was tested for resistance value (R-value) in accordance with State of California Standard Method 301-G. This test is designed to provide a relative measure of soil strength for use in pavement design. The test result is shown in the following table. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, CA August 30, 2017 Page B-2 Table No. B-2, R-Value Test Result Boring No. BH-1 (Converse, 2017) Soil Corrosivity Tests Depth (feet) 1.0-5.0 Soil Classification Sandy Clay (CL) Measured R-value One representative soil sample was tested to determine minimum electrical resistivity, pH , and chemical content, including soluble sulfate and chloride concentrations. The purpose of these tests was to determine the corrosion potential of site soils when placed in contact with common construction materials. The test was performed by EG Laboratory in accordance to California Test Methods 643, 422 and 417 . Test result is presented in the f9llowing table. • • a • : Boring No. Depth (feet) 1.0-5.0 Collapse Tests Soluble Sulfates (CA417) (% by weight) 0.021 Soluble Chlorides (CA 422) (ppm) Min. Resistivity (CA643) (Ohm-cm) 2,200 To evaluate the moisture sensitivity (collapse/swell potential) of the encountered soils, one collapse test was performed in accordance with the ASTM Standard D5333 laboratory procedure. The sample was loaded to approximately 2 kips per square foot (ksf), allowed to stabilize under load, and then submerged. The test result including the consolidation test is presented in the following table. T bl N B-4 C II • T t R It Boring Depth Percent Swell + Collapse Soil Classification No. (feet) Percent Collapse -Potential BH-1 2.5-4.0 Silty Sand with Grav~I -0.6 Slight (SM) *BH-4 5.0-6.5 Silty Sand with Gravel -2.0 Slight (SM) * result from consolidation test Grain-Size Analyses To assist in classification of soils, mechanical grain-size analysis was performed on two select samples in accordance with the ASTM Standard D422 test method. Grain-size curves are shown )n Drawing No. B-1 , Grain Size Distribution Results. ~ Converse Consultants ~ M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81 -153-02_gir Laboratory Maximum Density Tests eotechnical Investigation Report Enc,t, Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, CA August 30, 2017 Page B-3 Laboratory maximum dry density-optimum moisture content relationship test was performed on two representative bulk samples. These tests were conducted in accordance with the ASTM Standard D1557 test method. The test results are presented in Drawing No. 8-2, Moisture-Density Relationship Results, and are summarized in the following table. T bl N B 5 S f M . t D "t RI f h" R It • Boring No. Depth Soil Description Optimum Maximum (feet) Moisture (%) Density (pcf) BH-1 1.0-7.0 Silty Sand with Gravel 133.0 6.0 (SM) BH-4 1.0-7.0 Silty Sand with Gravel 128.0 12.5 (SM) BH-1 (Converse, 2017) 1.0-5.0 Sandy Clay (CL) 127.5 9.0 Direct Shear Tests Three direct shear tests were performed on relatively undisturbed samples in soaked moisture condition in accordance with the ASTM D3080 procedure. For each test, three samples contained in brass sampler rings were placed, one at a time, directly into the test apparatus and subjected to a range of normal loads appropriate for the anticipated conditions. The samples were then sheared at a constant strain rate of 0.02 inch/minute. Shear deformation was recorded until a maximum of about 0.25-inch shear displacement was achieved. Ultimate strength was selected from the shear-stress deformation data and plotted to determine the shear strength parameters. For test data, including sample density and moisture content, see Drawings No. 8-3 through 8-5, Direct Shear Test Results, and the following table. T bl N B 6 S f D" t Sh T t R It Boring Depth Peak Strength Parameters Soil Description No. (feet) Friction Angle Cohesion (degrees) (psf) BH-1 5.0-6.5 Silty Sand with Gravel (SM) 30 300 BH-4 2.5-4.0 Silty Sand with Gravel (SM) 26 190 BH-1 (Converse, 2.5-4.0 Silty Sand (SM) 34 60 2017) Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir Consolidation Tests Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, CA August 30, 2017 Page B-4 Data obtained from this test performed on one relatively undisturbed ring sample was used to evaluate the settlement characteristics of the on-site soils under load. The test was conducted in accordance with ASTM Standard 02435 method. Preparation for this test involved trimming the sample, placing it in a 1-inch-high brass ring, and loading it into the test apparatus, which contained porous stones to accommodate drainage during testing. Normal axial loads were applied to one end of the sample through the porous stones, and the resulting deflections were recorded at various time periods. The load was increased after the sample reached a reasonable state of equilibrium. Normal loads were applied at a constant load-increment ratio, successive loads being generally twice the preceding load. For test results, including sample density and moisture content, see Drawing No. B-6, Consolidation Test Results. Sample Storage Soil samples presently stored in our laboratory will be discarded 30 days after the date of this report, unless this office receives a specific request to retain the samples for a longer period. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-02_gir • Ill • Ill U.S. SIEVE OPENING IN INCHE U.S. SIEVE NUMBERS HYDROMETER 6 4 3 2 1.5 2, IA 112318 3 6 8 10 14 16 20 30 40 50 60 100 140 200 I I I I II I I I 100 I II T~II II 951--+---+----l----1-j...j....j.-+-1---+--+---+-~'"'\~l-1-1-~+-+--+--~1-+-1--+-,.1---4-+--++++++-+-+----t------lf++-1-+--f-+-+--+----1 901-+--4----l-------ll++-l-+-+-+-+---4~---'flll1c+-'~+-+-+-----lf---++++++-4---l--1---+++++-Hr-+-+---+H+++-t-;-+-------I ' ,. ' ........ 851-+-+---4--++++++-+-+-----lf---++++-P-.....+..::.....iac..l---+++++-Hr-+-+---+H+++-t-;-+---+t-H-t-+-+-t---t------1 ~r---.., .... r------... aoH-+--1--+++:+++-+-+-f------++++++·++"--:m-1-1---' ....._"""t1f++++--+-+---+--+t+++-t-++--+---+tti-+-,--+-+--+----t ~ ~ 751-+--4----1-------lH+l-+-+-+-+---4;.._-+++++~-+-----lf--~+++-N.,-+-+---l--1---+++++-Hr-+-+---+H+++-t-;-+-------I Ill ~ ~ 701-+--4----+------lH+l-+-+-+-+---4;.._-+++++~---1------lf---+-N-++-l'<.;+---l--1---+++++-Hr-+-+---+H+++-t-;-+-------I ~ I\ . : ~ 65 , :\ Q 60 l-+--4----+------lf+l.:-l-+-+-+-+---4;---++++++-+---1------lf---+++++-+'l\'4: -4+-l---+++i+-+-Hf--+-+---+H+++-t-;-+-------1 w \ ' S: : I I 1;:i 551--1-~----+----l~+-l--l---+---+------l~-144-+++-4--+---lf----l+++++-4: +-\~-+-----+1H'+++-+--+--+----++++-+-+-+--+---+---i a:: w 501-+--+--I--H++++-+-+--l-:---H++++-t-+-----lf------t++++B-'lll\-t----+t++++-,H-t----tti-tt+-H-+------i ~ 451-+-+---+--H-+1-+-+-+-+---4--++++++-+---1------lf---++++++-+---I---\J~f-+-----+,H+++-+-+--+----I-H-t+-t-+-+--+----t ~ 40 l--l-~----+--144-+-1--l---+---+------1--144-++-l--4--+---lf----1++++-l--l---1--\4-, l---+H++-+-,i----+-+--~-++-+-l----l-+-------i w 0.. 351--1-~----+--144-+-l--l---+---+------l.;..._-144-++-l--4--+---lf----l++++-l--l---l--H\---+"H+++-+--+--+----++++-+-+-+--+---+---i \\ 301-+-+---+--H-+1-+-+-+-+---4;.._-+++++~---l------ll---++++++-+---l--++-~+++++-Hr-+-+---+H+++-t-;-+-------I 251--+---+--+----++,+;++-+--+-+-----1.--~++++-+--+----+++-r++,;.1---!--t--'\t-\---f'l<al-+++-+--t-++t+i-;-t-;---+----i ' ~ 201-+---1------lf---++++++-+---l--l;---++++++.-i---l--+---+H++-+-;-i---4-+-+-+Hfi+-+-+-~f--+---++-t-+-1-+-+-l--+-----I \ w 151-+---l------lf---++++++-+---l--l;---++++++.-ir-+-+---+H++-+-;-r-+-+---FH~•.+-+-+-+--+-r-+++-t-+-,f-+-+---l-------l 101--+--+---lf----l++++-l--l---1--1---+H+++--,1----+-+--+H++-+-1----+-+--~H-+-+-f----lf--+-----++t-+-1-+-+-l---+-----I 51-+---l------lf---++++++-+---l--l---+++++~---l--+---+H+++-1---4-+--+HH-+-+-~f--+---++-t-+-1-+-+-l--+-----I 0 L....L---L.--Jf---.u..i....L..L. ........ --L.-L---.u....L...I...L. .......... L....../,-..___ ................ _.__ ........ _.,___..........,u...,........_ ......... '---'---....U.. .................. .,__..__.......___, 100 10 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY Boring No . Depth (ft) Description LL PL Pl Cc Cu B-1 1.0-7.0 SIity Sand with Gravel (SM) 8-4 1.0-7.0 SIity Sand with Gravel (SM) Boring No. Depth (ft) D100 D60 D30 D10 %Gravel %Sand %Silt I %Clay B-1 1.0-7.0 19 0.35 0.174 13.0 72.0 15.0 8-4 1.0-7.0 25 0.476 0.136 16.0 60.0 24.0 GRAIN SIZE DISTRIBUTION RESULTS ~ Converse Consultants Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad, San Diego County, California For: Encina Wastewater Authority Project No. 17-81-153-02 Drawing No. B-1 Project ID· 11 81 153 02 GR I· Iemplalff GRAIM SIZE 150 145 140 135 130 0 125 a. ~ ci5 120 z w 0 >-a: 0 115 110 105 100 95 90 0 5 SYMBOL BORING NO. DEPTH (ft) • B-1 1.0-7.0 Curves of 100% Sat ation for Specific Gravity E ual to: 10 DESCRIPTION 15 WATER CONTENT, % SIity Sand with Gravel (SM), Olive Brown 20 25 ASTM OPTIMUM TEST METHOD WATER,% 01557-B 6 MOISTURE-DENSITY RELATIONSHIP RESULTS Encina Phase V Wastewater Expansion C C It t 1,400 Square Foot Building OnVerSe OnSU an $ 6200 Avenida Encinas City of Carlsbad, San Diego County, California Project ID: 17-81-153--02.GPJ; Template: COMPACTION For: Encina Wastewater Authority Project No. 17-81-153-02 30 MAXIMUM DRY DENSITY, pcf 133 Drawing No. B-2 4,000 3,500 3,000 -2,500 "' C. ::c I-(!) z w Cl'.: I-2,000 (/) Cl'.: i'.5 :I: (/) 1,500 1,000 500 ....-1 .. V V V V •• V V / /' V • ./ / 0 0 1,000 2,000 3,000 4,000 SURCHARGE PRESSURE, psf BORING NO. B-1 DEPTH (ft) DESCRIPTION Silty Sand with Gravel (SM) COHESION (psf) 300 FRICTION ANGLE (degrees): MOISTURE CONTENT(%) 10.0 DRY DENSITY (pcf) NOTE: Ultimate Strength. DIRECT SHEAR TEST RESULTS ~ Converse Consultants Project ID: 17.a1-153-02.GPJ; Template: DIRECT SHEAR Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad, San Diego County, California For: Enc1na Wastewater Authonty 5 30 115.8 Project No. 17-81-153-02 Drawing No. B-3 'ti a. ::i I-(!) z w a:: I-Cl) a:: <( w J: Cl) 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 V 0 0 BORING NO. DESCRIPTION COHESION (psf) /' MOISTURE CONTENT(%) NOTE: Ultimate Strength. 0 / V v V ~ V V V / 4 / 1,000 2,000 3,000 4,000 SURCHARGE PRESSURE, psf B-4 DEPTH (ft) 2.5-4.0 Silty Sand with Gravel (SM) 180 FRICTION ANGLE (degrees): 26 : 11.0 DRY DENSITY (pcf) 104.4 DIRECT SHEAR TEST RESULTS ~ Converse Consultants Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad, San Diego County, California For: Enema Wastewater Autfionty Project No. 17-81-153-02 Drawing No. B-4 Project ID: 17-81-153-02.GPJ; Template: DIRECT SHEAR -(/) a. :i I-(!) z w CX'. I-(/) CX'. t5 I (/) 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 V 0 0 BORING NO. DESCRIPTION COHESION (psf) .,,,,, MOISTURE CONTENT(%) NOTE: Ultimate Strength. / V ,) / / V ,/ V V / 1,000 2,000 3,000 4,000 SURCHARGE PRESSURE, psf BH-1 (Converse 2 17) DEPTH (fl) : 2.5-4 Silty Sand with Clay (SM) 60 FRICTION ANGLE (degrees): 34 : 13.6 DRY DENSITY (pcf) : 113.1 DIRECT SHEAR TEST RESULTS ~ Converse Consultants Encina Phase V Wastewater Expansion 1,400 Square Foot Building 6200 Avenida Encinas City of Carlsbad, San Diego County, California For: Enema Wastewater Authonty Project No. 17-81-153-02 Drawing No. B-5 Project ID: 17-81-153-02.GPJ; Template: DIRECT SHEAR 0 2 4 6 8 10 100 BORING NO. DESCRIPTION : MOISTURE G- -- CONTENT(%) INITIAL 12.4 FINAL 14.9 t--11 I ~ ~ I"- rs.I'< ~ \ \. \ \ ~ ~ \ It I\ i ~ ~ ---· ....... 1,000 10,000 STRESS, psf B-4 I DEPTH (ft) : Silty Sand with Clay (SM) DRY DENSITY l PERCENT l (pcf) SATURATION 103.9 56 110.8 100 NOTE: SOLID CIRCLES INDICATE READINGS AFTER ADDITION OF WATER CONSOLIDATION TEST RESULTS ~ Converse Consultants Project ID: 17-81-153-02.GPJ; Template: CONSOLIDATION Enclna Phase V Wastewater Expansion 6200 Avenlda Endnas City of Carlsbad, San Diego County, California For: Enclna Wastewater Authority 5.0-6.5 VOID RATIO 0.591 0.492 Project No. 17-81-153-02 105 Drawing No. B-6 BH-8 Laboratory Test Results (Converse 2005) I l I ;J ] ..J J _j • Iii .. * 0 • CG .. * 0 100 9 5 0 5 0 9 8 8 7 7 5 0 i 65 £! 60 ~ ~ 55 ffi 50 z a: !z 45 w ~ 40 w o. 35 30 25 20 15 10 5 0 U.S. SIEVE OPENING IN INCHES " ◄ 2 3 1.5 _ 3/◄ 1/2 3/8 I II T' ~I ... 100 10 COBBLES GRAVEL coarse fine Boring No. Depth (ft) BH-1 0-5 BH-1 15 BH-8 10 BH-9 5 BH-9 15 Boring No. Depth (ft) 0100 BH-1 0-5 25.4 BH-1 15 2 BH-8 10 0.42 BH-9 5 4.76 BH-9 15 4.76 3 II ~t-, 6 a U.S. SIEVE NUMBERS 10 19 30 50 14 20 4 60 100 1◄0 ~ ~ ~ 1-,1---\ I I I t-.. i\ t-,1' -[\ 1 "r---.. "\ ~ I r-,,._ [\ ' :\ 1~ I\ ' I~ \ I ' ! ' [\ ' . \ \ ' -~ I ~ \ ' \ \ \ \ ~ \ \ \ I \ \ ' \ \ \ ' 1 0.1 GRAIN SIZE IN MILLIMETERS SAND coanse medium fine Description CLAYEY SAND fSC) CLAYICLI SIL TY SAND (SM) SANDfSPI SIL TY SAND ISM' 200 g I • LL 32 31 060 030 010 %Gravel 0.344 0.084 11.0 o.o 0.188 0.119 0.0 0.525 0.281 0.154 0.0 0.164 0.0 GRAIN SIZE DISTRIBUTION RESULTS . J \!) Project Name . Converse Consultants EWA.PhaH V Expansion Carlabad, CA For: Black And Veatch J HVOROMETER 0.01 0.001 SILT OR CLAY PL Pl Cc Cu 24 8 0.97 3.40 26 6 %Sand %Silt I %Clay 60.9 27.8 86.8 96.3 60.0 Project No. 04-32139-01 28.1 72.2 13.2 3.7 40.0 Drawing No. B-1 . I . I I C B. ........ .J ~ f -[] (I') J (I') , .. ! I 4000 3000 Upper Bound 2000 1000 0 0 1000 2000 3000 Surcharge Pressure (psf) Note: Values plotted are based on Ultimate Shear Strength Lower Bound 4000 LEGEND + SH-1 • 0 • BH-7 BH-e Bti-9 . l J J J J J _] DIRECT SHEAR TEST RESULTS -SINGLE POINT EWA -PHASE V EXPANSION CARLSBAD, CALIFORNIA For: Black And Veatch j ~ · Geotechnlcal Engineering _ ~ Converse Consultants and Applied Sciences J Project No. 04-32139-01 Drawing No. 8-4 J ·.1 - J J J _] J .J _J J 1000 -t-----,-----,.------,,---.------.-----.-----.-----.---.----- (\ I\ " 900 +----r----+----s=--1·-\-~-\-·H------+----+----+----i>-------- 1 /~\.... V\_ ' ~ BOO ,J \ I I 700 +----+--~;'-+---+-------+---+---+---....----+-i __ +---J / I I r .1soo 1-----+1----+----t---t-----!--------+----+------11----+-----4 I ~400 +--~/'----+----+--------+-------+---------1-----+-------+----+-------+---~ 300 ➔-( ~---~ I 200 / 100 ➔----+-------+----+---1----+--------+----+---------f---+----I 0 +----+----+-----+---1--------+-------+-----+--------11---------------1 0% 1% 2% Boring No: BH-8 Depth: 5 feet Soll Description: Clay {CL) 3% 4% 5% 6% 7% 8% 9% Axial Strain Unconfined Compressive Strength, qu (psf): 900 Undrained Shear Strength, c.., (psf): 4S0 Ory Unit Weight (pcf): 117.0 Moisture Cont•nt (¾): 15.0 UNCONFINED COMPRESSIVE TEST RESULTS 10% EWA -Phase V Expansion Carlsbad, CA For: Black And VHtch Project No • 04-32139-01 ~ Geotechnlcal Engineering ~ Converse Consultants & Applied Sciences Drawing No. B-6 Appendix C Settlement Analysis Geotechnical Investigation Report Encina Phase V Wastewater Expansion 6200 Avenida Encinas City of Carlsbad, San Diego County, CA August 30, 2017 Page C-1 APPENDIX C SETTLEMENT ANALYSIS The subsurface data obtained from borings BH-1 and BH-4 drilled during the field investigation were used to evaluate the dynamic settlement due to potential densification of relatively loose sediments subjected to ground shaking during earthquakes. The dynamic analysis was performed using Liquefy Pro (Civiltech, 2012). An earthquake magnitude of M7.2 and a peak ground acceleration (PGA) of 0.484g, where g is the acceleration due to gravity, were selected for this analysis. The PGA was based on the CBC seismic design parameters presented in Section 8.2, CBC Seismic Design Parameters. An analysis considering both historical and current groundwater conditions were performed for each boring. The results of our analyses are presented on Plates C-1 and C-2, and summarized in the following table. Table C-1, Estimated D namic Settlement Location BH-1 BH-4 Groundwater Conditions (feet bgs) >19.5 >19 Dynamic Settlement (inches) 0.03 0.23 Differential Dynamic Settlement (inch/40 linear feet) >0.01 0.13 Based on our current analysis, the site has the potential for up to 0.23 inches of dynamic settlement for the drilled depth is 19.5 feet bgs. However, a total of 2 to 3 inches of dynamic settlement was observed for the drilled depth 50 feet bgs in the previous report (Converse, 2005). The dynamic differential settlement is anticipated to be half of the total settlement over a horizontal distance of 40 feet. Converse Consultants M:\JOBFILE\2017\81\17-81-153 EWA, Encinitas WTP Parking Lot Expansion\Report\17-81-153-0Z_gir ~ :::, I!! m i? ell 0 !;; "' 0 S! ~ §" LIQUEFACTION ANALYSIS Encina Phase V Wastewater Expansion Hole No.=BH-1 Water Depth=31 ft Surface Elev.=31 Magnitude=7.2 Acce/eration=0.484g Rew Unit Fines (ft} SPT Weight % O 12 108.5 5 5 17.4119.245 10 13.8129.9Nolq 15 9.6 11 8.2Nolq 9.6 120.2Nolq 20 25 30 35 CivirTech Corporation Soil Description Silty Sand with Clay Silty Send wilh Clay Sandy Clay Clay Clay Shear Stress Ratio 0 I I I I \.... / fs1 1 fs2 1.30 I I I I Factor of Safety 2 0 1 5 'IIIIIIII I I I I I I I I I I I I I I I CRR -CSR fs1-fs2 - Shaded Zone has Liquefaction Potential Dynamic Settlement Settlement 0 (in.) 111111111 s = 0.03in. Saturated Unseturat. - Plate C-1 a u ~ .. " ,. ,. .. iii ::, I!! .. I u ~ :.; u e ; S" LIQUEFACTION ANALYSIS Encina Phase V Wastewater Expansion Hole No.=BH-4 Water Deprh=19 ft Surface Elev.=31 Magnitude=7.2 Accelerarion=0.484g Raw Untt Fines (ft) SPT Weight % O 9.6 110 45 5 5. 110 45 10 3.0 11-4.545 15 41.41:}0 15 30 133.515 20 25 30 35 Soil Oescr.iption Silly Sand with Clay Silly Sand with Clay Silly Sand w Ith Clay 1:1 , > .. ~,}Y Sand ,-f~-~-·f CivilTech Corporation She.ar Stress Ratio 0 fs1=1 fs.2=1 .30 CRR -CSR fs1-fs2 - Factor ,of Safety 0 1 5 'l'IIIIII I Shaded Zone has Liquefaction Potential Dynamic Settlement Settlement 0 (in.) I 1111111 S = 0.23 in. Saturated Un.saturat. - Plate C-2