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FORWARD LANDFILL <br /> NON-WATER CORRECTIVE ACTION PLAN <br /> 0 4.1.5 Impacts from Slope Failure <br /> 4.1.5.1 Slope Stability Analysis Procedure <br /> To satisfy the requirements of CalRecycle, the existing landfill slopes were evaluated for <br /> dynamic stability by using the calculated horizontal site acceleration of the MCE event. The <br /> calculations for the horizontal acceleration from the MCE event at the site were previously <br /> performed by GLA (2008a) and will be summarized later in this report. <br /> The topographic survey performed by Ausenco Vector(2011) was used as a base map to <br /> evaluate the dynamic slope stability of the existing landfill slopes. An evaluation of the static <br /> stability of the site slopes was not performed since dynamic stability is necessary for this <br /> analysis. The limits of the active landfill footprint are presented in Figure 2. Subsurface <br /> geotechnical information was provided by laboratory testing of soil samples obtained from <br /> several borings and CPTs advanced on the site by GLA(2008a and 2008b). The location of the <br /> site borings and CPTs are also presented on Figure 2. <br /> Five cross sections were prepared to evaluate existing landfill slope stability. Cross section A-A' <br /> was generated to represent the unlined area of the highest landfill slopes in the former Austin <br /> Road Sanitary Landfill area. Cross section B-B' was prepared to represent a lined landfill slope <br /> condition along the highest landfill slope of the Austin Road Sanitary Landfill portion of the site. <br /> Cross Sections C-C' and D-D' were prepared to evaluate the stability of the lined landfill slope at <br /> the area of the highest slope of the southern portion(Forward Landfill) of the site. Cross section <br /> E-E' was constructed to evaluate the stability of the buried Ash Pit cover. The approximate <br /> locations of the cross-sections are presented on Figure 2. Landfill configurations were <br /> constructed from review of plans prepared by R.W. Beck(1993) for the northern(Austin) <br /> landfill portion and conversations with Lewis Engineering and plans by BAS (2001) for the <br /> southern(Forward) landfill portion. <br /> 4.1.5.2 Geotechnical Parameters <br /> The individual components of the composite liner system were previously presented in earlier <br /> sections of the report. The soil materials at the site include: native alluvial soils of the Victor <br /> Formation, municipal solid waste (MSW) fill, textured and smooth high-density polyethylene <br /> (HDPE), non-woven(NW) geotextile, and compacted cover/fill materials. <br /> Geotechnical parameters required for analysis include unit weight and shear strength parameters <br /> ® (angle of friction and cohesion). For the native and compacted cover soils, the angle of friction <br /> M:\2011-012MWFA REPORT.DOCX 1 1 Geo-Logic Associates <br />