Laserfiche WebLink
S[abili[y <br />• <br />Pre failure cross sections were generated in an attempt to simulate pre-slide conditions. <br />The SB•SLOPE Stability computer program was used [o approximate conditions prior to the <br />slide, in effect, back calculate until a safety factor of 1.0 was attained. This exercise <br />was conducted to verify assumptions that were to be used in the future stability and slide <br />remediation design. <br />Slope reconstruction options were discussed internally and slope stability calculations <br />were generated based on possible remediation techniques (discussed in detail under the <br />heading of Reconstruction). Please refer to Appendix 13-48 for computer analysis and <br />reference material. <br />Materiel strengths were based on published data (Huang 1983) and from geotechnical <br />information gained from the 7990 slide near Pond 006. The log of Borehole Gw-42-S2w-Sw <br />(Table 13-463) indicates that the underlying material in the Road A slide area is <br />claystone. Shear values obtained from the tri axial tests conducted (Table 13-482) on the <br />Pond 006 slide show that the claystone has a cohesion of 945 psi and a phi angle of 31°. • <br />This same data was used in the SB-SLOPE calculations. If the material has to be replaced <br />in lifts or benches, the as-compacted cohesion of 1200 psi and phi angle of 28° (Table <br />13-481) should be used for a sandy clay (SC) type material (Huang 1983). <br />Stability analysis results indicated that either method of reconstruction will result in <br />safety factors approaching 1.9, which is greater than the 1.25 required by 4.03(2)(d)(ix). <br />This was based on the "worst case" analysis that the toe of the fill would be saturated <br />and a loaded haul truck (b)00 lbs/ft) would stop at the head of the potential failure arc <br />(see Figures 73-48-5 and 13-4B-b). <br />General Construction Notes <br />The uphill slope of Road p will be kept as moderate as possible during and after <br />construction. <br />If obvious seep areas are encountered either above or below Road A, measures will be taken <br />to release the water by the most expedient, prudent methods. This could include • <br />construction of French drains, piping, Mirafi fabric, or any tombine[ion [o alleviate <br />potential water problems. <br />13-48-4 <br />