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The interface shear strength for the base lining system of WMU FU-17 was estimated using <br /> laboratory testing performed for the construction of the WMUs D-95 through WMU FU-14 lining <br /> systems. These interface shear strength results were assumed to be representative of those in WMU <br /> FU-17 because WMU FU-17 will be constructed using onsite soils and geosynthetic materials very <br /> similar to those used in these previously constructed WMUs. <br /> TABLE 3-1 <br /> Material Properties Used for Stability Analysis <br /> Forward Landfill <br /> Stockton, Cali ornia <br /> Friction Apparent Unit <br /> Angle Cohesion Weight <br /> Material/Shear Surface (degrees) or Shear (pct) <br /> Stress <br /> s <br /> WMU FU-17 Base Liner <br /> Clay liner/textured geomembrane interface(Normal Stress 0 to 6,500 psf) 18 0 120 <br /> Clay liner/textured geomembrane interface(Normal Stress 6,500 to 17,000 psf) 10 1,000 120 <br /> Textured geomembrane/cushion geotextile(Normal Stress 2,000 psf) - 700 120 <br /> Textured geomembrane/cushion geotextile(Normal Stress 4,000 psf) - 1,110 120 <br /> Textured geomembrane/cushion geotextile(Normal Stress 8,000 psf) 1,950 120 <br /> Textured geomembrane/cushion geotextile(Normal Stress 12,000 psf) - 2,780 120 <br /> Waste Materials <br /> Wastes(Normal Stress 0 to 770 s 0 500 75 <br /> Wastee (Normal Stress 770 to 17,000 PSO 33 0 75 <br /> Notes: <br /> 3 Waste properties based on literature values(Kavazanjian,1999). <br /> 'Based on previous soil investigations(CH2M HILL,1994e),the foundation materials are relatively strong. Critical shear surfaces therefore <br /> occur within the lining system and refuse and do not extend through the foundation <br /> 3.2.2 Results of Slope Stability Analyses <br /> As shown on the Construction Drawings(Appendix A), WMU FU-17 is directly east of WMUs FU- <br /> 13 and 14. The site development plan (BAS, 2001) includes development of future modules to the <br /> east of WMU FU-17. <br /> The slope stability analysis was performed for an interim refuse fill elevation of 170-ft with a 3:1 <br /> slope. The critical slope configuration is in the east-west direction. <br /> A minimum factor of safety of 1.57 was obtained for a sliding block shear surface along the base liner <br /> and through the slope liner and refuse in the east-west direction. This factory of safety of 1.57 is <br /> acceptable for the temporary WMU FU-17 slope. <br /> Calculations,output data,and plots are presented in Appendix B. <br /> The maximum refuse fill height and slope for WMU FU-17 should be re-evaluated based on actual <br /> CQA direct shear tests results on the base and slope liner interfaces. <br /> WMU FU-17 DESIGN REPORT 3-2 <br />