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<br /> <br />Foothill Sanitary Landfill Page 12 of 53 San Joaquin County DPW - Solid Waste <br />Joint Technical Document Revised 6/09/2020 <br /> <br />ground acceleration in rock determined from the analysis conducted for this report generally <br />agree with those values established during the preparation of the 2002 report. <br /> <br />4.9. Engineering and Chemical Properties of Soil <br />Soil samples were collected and analyzed by Kleinfelder in 1985 (Appendix D) and 1990 <br />(Appendix E). Laboratory testing included moisture content, unit weight, sieve size/gradation <br />analyses, moisture density, plasticity index, dry density, hydraulic conductivities, and Atterberg <br />Limits. Soil properties are as follows: <br /> <br />Dry unit weights of soil samples varied between 73 to 82 pounds per cubic foot <br />Moisture contents ranged from 9 to 41% <br />Plasticity limits ranged from 8 to 29 (PI) <br />Liquid limit of soil ranged from 35 to 45 <br /> <br />4.9.1. Stability Analysis <br />Requirements for seismic stability are found in Title 27 Chapter 3 Subchapter 5, addressing <br />requirements for landfill closure. According to Section 21090 of that subchapter, “Designs <br />having any slopes steeper than a horizontal to vertical ratio of three to one, or having a <br />geosynthetic component [under ¶(a)(2)], shall have these aspects of their design specifically <br />supported in the slope stability report required under §21750(f)(5).” Because the final landfill <br />slope configuration is three to one (Figure 6), a stability analysis is required for this site. A <br />stability analysis had been performed previously by EMCON/OWT in 2002 for the overall refuse <br />slope stability of both Modules “I” and 1, and the long-term partial cover of Module “I”. The <br />refuse fill, and cover soils were found to be stable under design conditions (Appendix F). The <br />2002 EMCON/OWT report discusses the regional geology and site geology as well. <br /> <br />Shaw Environmental, Inc. performed an update of the slope stability analyses reported by <br />EMCON/OWT in 2002 and has provided the results of the updated analysis in Appendix L of <br />this report (2012). The updated slope stability analysis for Foothill Sanitary Landfill investigated <br />both the global stability of the final landfill configuration, and the stability of two interim waste <br />slopes that will be created between landfill modules 1 and 2 and modules 2 and 3 within the <br />expansion area. The global and interim slopes were all analyzed for stability under static