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SECTION 3 Sloe Stability In accordance with Title 27 regulations, both static and seismic stability analyses were performed for WMU FU-06. The seismic stability analysis is based on a seismic hazard analysis performed in 2001 (GeoSyntec,2001). WMU FU-06 will be filled with designated wastes (Class II) in the southern portion and municipal solid wastes (Class III) in the northern portion. Refuse placed in portions of WMU FU-06 will overlie existing municipal solid waste fill (Class II1). Interface liners will be placed in these areas to separate the designated and municipal solid wastes. Refuse placed on the southern side of the southern portion and on the northern side of the northern portion of WMU FU-06 will eventually form the final landfill slopes and will be constructed at a 3:1 (horizontal:vertical) slope with 20-ft wide benches every 50 vertical feet. The eastern refuse fill slopes are temporary and will be constructed at a 3:1 grade. Refuse will be placed against the 3:1 eastern slope once future WMUs to the east of WMU FU-06 are constructed. The western slopes will be filled against existing refuse slopes. The following slope stability conditions were considered for the WMU FU-06 design: • WMU FU-06 Southern Portion. This condition represents the planned fill configuration of the southern portion of WMU FU-06. Based on the geometry, construction against adjacent WMUs, and site development plans, the planned fill elevation in the southern portion of WMU FU-06 is currently approximately 150-feet. The critical section is through the eastern slope. • WMU FU-06 Northern Portion. This condition represents the maximum fill configuration of WMU FU-06 in the northern portion. Based on the geometry and construction against adjacent WMUs, the maximum fill elevation in northern portion of WMU FU-06 is approximately 150- feet. The critical section is through the southern slope. • Forward Landfill Final Grades. This condition represents the maximum fill configuration for the landfill once adjacent WMUs have been constructed and the entire landfill is at its maximum fill configuration. The maximum elevation in WMU FU-06 at the final grade condition is at an approximately 170-foot elevation. The critical section is through the southern slope. The critical stability configurations were selected based on the Construction Drawings and WMU FU- 06 refuse grading plans in Appendix A and B,respectively. The internal stability of the interface and side slope lining system was also considered. On a portion of the north slope in the southern portion of WMU FU-06,the GCL, HDPE geomembrane, and GDN will be placed on a maximum 2:1 slope. A protective operations soil layer will be placed against the slope as WMU FU-06 filling operations progress(i.e., the operations layer will not be "hung" on the side slope). To minimize interface liner loads, it was assumed that the operations layer would be placed up to a maximum height of 10 feet above the refuse fill level using a wheel loader3. Minimal equipment loads will, therefore, be applied to the slope. To maintain the stability of the slope lining 3 The protective operations layer will be placed on the slope using a Caterpillar 966F Series Wheel Loader with a 4.5 cy bucket. WMU FU-06 REPORT 3-1