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FORWARD LANDFILL <br /> NON-WATER CORRECTIVE ACTION PLAN <br /> The five refuse cross-sections were analyzed to determine the yield acceleration (ky)to achieve a <br /> pseudo-static factor of safety equal to 1.0. The pseudo-static (dynamic) analysis was performed <br /> for Cross Section E-E' with two different possible critical interfaces for each of the two possible <br /> weaker GCL interfaces for the Ash Pit cover. <br /> The results of the pseudo-static slope stability analysis are presented in Figures 3 through 8 and <br /> are summarized below. <br /> Pseudo-Static Slope Stability Analysis <br /> Figure No. Description of Analysis Yield Acceleration,ky <br /> 3 Section A-A' 0.39g <br /> 4 Section 13-13' 0.25g <br /> 5 Section C-C' 0.23g <br /> 6 Section D-D' 0.25g <br /> 7 Section E-E'(GCL internal strength) 0.3g <br /> 8 Section E-E'(HDPE/GCL interface) 0.29g <br /> The results of the seismic induced permanent displacement calculation for the refuse fill <br /> configuration are presented in Table 1 and indicate negligible permanent dynamic displacement <br /> for the MCE design earthquake for all cross sections analyzed. <br /> 4.1.5.4 Landfill Cover System <br /> The proposed final landfill cover system will include two different types of covers (one for the <br /> decks and one for the side slopes) to facilitate construction and provide a cost-effective method <br /> of compliance with regulations. The deck will include geosynthetic components (HDPE and <br /> GCL), while the slopes will incorporate a 4-foot monolithic cover system design; the same as <br /> was approved on the Stage I area. However, the current landfill final cover is composed of 2 <br /> feet of protective soil layer, over a foot of daily cover(3 feet total cover) on MSW. Slope <br /> inclinations currently vary across the site from about 2.5:1 (horizontal to vertical)to 5:1 with the <br /> southeastern landfill slope as steep as 2:1 (Ausenco Vector, 2011). Accordingly, the landfill <br /> cover slope stability has been analyzed using the infinite slope method for the most critical <br /> (steepest) slope configuration(2:1 slope inclination). <br /> The stability of the final cover system is dependent on the interface shear strength developed <br /> between the cover/foundation layer and the underlying MSW. The friction generated between <br /> ® these two materials is anticipated to be an average of the strengths of both materials, but the <br /> M:\2011-0129vNWFA REPORT.DOCX 14 Geo-Logic Associates <br />