Laserfiche WebLink
Material Angle of Internal Unit Weight Cohesion <br /> Friction (Ib./cu. Ft.) (Ib./sq. Ft.) <br /> (degrees) <br /> Native soils 1 0 to 33 120 to 125 0 to 2300 <br /> Refuse 2 30 80 200 <br /> Textured HDPE/ Non-Woven 4 to 11 NA O to 950 <br /> Geotextile Interface 3 <br /> Internal Strength Hydrated 5 NA 400 <br /> GCL 4 <br /> Non-Hydrated GCL (Textured 14 NA 0 <br /> HDPE GCL) (3 <br /> (1) CH2MHill(1992) <br /> (2) Singh and Murphy(1990) <br /> (3) Range of Values Considered Obtainable <br /> (4) Cetco Manufacturer Certification <br /> As determined in CH2MHill's geotechniral..evaluation.of..th.e existing Forward <br /> Landfill (1992), the native soils in the area consist of interbedded layers of sand, <br /> silt, and lean clay. The cohesive soils canoe"characterized`as very stiff'to-hard, <br /> and non-cohesive sands are dense to very dense. The stability conditions of the <br /> native subgrade beneath anticipated refuse loads are considered non- <br /> problematic. Assuming a refuse eight of approzcirridtely..,200 feet aboveahe <br /> subgrade, CH2MHill calculated that the factor of safety for failure of a lean clay <br /> layer that is 10 feet below the liner grade would be 2.2-to 2.3. <br /> 5.3.2.3 GROSS STABILITY RESULTS <br /> As shown in Appendix E, the results of the stability analyses indicate that-a-static: <br /> factor-of-safety of 1.5 or more can be achieved for the planned landfill geometry <br /> using a range of liner interface shear strength values (Figure 3). <br /> The pseudo-static analyses that were completed for the project to evaluate <br /> earthquake loading conditions indicate yield accelerations from about 0.1 Og to <br /> 0.11 g for the range of interface shear strength parameters shown in Figure 3. <br /> The yield acceleration is the seismic coefficient (ky) that yields a static factor of <br /> safety of 1.0. As shown in the calculations included in Appendix E, using these <br /> yield accelerations and the Bray & Rathje method (1998), an insignificant amount <br /> of seismic-induced permanent displacement of the landfill liner system is <br /> calculated for the two design earthquake events (i.e., Great Valley and San <br /> Forward Landfill jTD 5-15 <br /> L:\AI I i ed\2000.193\Reports\finaljtd:Sec-5.0:08/22/01 <br /> AQ VAIV A QTOOAT C ACCP1f� ATCC <br />