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3.3.2 Results of Slope Stability Analyses A discussion of the results of the slope stability analyses performed for the critical conditions are presented below. Calculations, output data, and plots are presented in Appendix B. WMU FU-04 Central Portion As shown on the Construction Drawings (Appendix A), WMU FU-04 is directly south of the former Austin Road Landfill and directly west of WMU FU-03. The southern boundary is offset from the southern property line by approximately 50-feet. The site development plan (BAS, 2001) includes development of future modules to the east of WMU FU-04. The slope stability analysis was performed for a maximum Forward Landfill refuse fill elevation of 150-ft with a 3:1 slope. The critical slope configuration is in the east-west direction. Other sections were considered but assessed to be less critical. As indicated in Appendix B, a minimum factor of safety of 1.7 is obtained for a sliding block shear surface along the base liner and through the refuse in the east-west direction. A factory of safety of 1.7 is acceptable for the temporary east-west slope. The maximum refuse fill height and slope for WMU FU-04 should be re-evaluated based on actual CQA direct shear tests results on the base and slope liner interfaces. Because the east slope of WMU FU-04 is a temporary slope, a seismic deformation analysis was not performed. WMU FU-04 Northeastern Portion The slope stability analysis was performed for a 150-ft refuse fill elevation with a 3:1 slope. The elevation at the base of the cell ranged from 80 ft to 96 ft and grades at approximately 3 percent to the south. The critical slope configuration is in the south direction. Other sections were considered but assessed to be less critical. As indicated in Appendix B, a minimum factor of safety of 1.8 is obtained for a sliding block shear surface along the base liner and through the refuse in the south direction. A factory of safety of 1.8 is acceptable for this temporary refuse fill configuration. The maximum refuse fill height and slope for WMU FU-04 should be re-evaluated based on actual CQA direct shear tests results on the base and slope liner interfaces. Seismic deformation analyses were not performed because this slope represents an interim condition. Forward Landfill Final Buildout As shown on the Construction Drawings (Appendix A), WMU FU-04 is directly south of the former Austin Road Landfill and directly west of WMU FU-03. The southern boundary is offset from the southern property line by approximately 50-feet. The site development plan (BAS, 2001) includes development of future modules to the east of WMU FU-04. The slope stability analysis was performed for a maximum Forward Landfill refuse fill elevation of 170-ft with a 3:1 final slope and 20 ft wide benches every 50 vertical feet (effective slope 3.25:1) on the southern side. The critical slope configuration is in the north-south direction. Other sections were considered but assessed to be less critical. FU-04 REPORT.DOC 3-7