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-15- <br />• Our stability analyses for cross section A were performed using the <br />program Geoslope (tm) developed by Geocomp Corp. This computer program <br />is based upon the slope stability analysis procedure STABL developed at <br />Purdue University. Geoslope offers Modified Bishop Analysis Methods for <br />circular-shaped failure surfaces and Janbu's ~Ylethod of Generalized Slices for <br />non-circular surfaces. The analysis employs a limit equilibrium procedure of <br />slices. We believe the numerical values selected for strength of The various <br />materials and the water surface assumptions control the computed factor of <br />safety. We have performed a parametric study using conservative values of <br />strength conditions in order to assess slope stability. <br />Appendix C contains detailed results of our slope stability <br />calculations. We performed 18 trials which compared factor of safety for 100 <br />• failure surfaces each. The results indicated the most likely mode of failure <br />would be a shallow, circular-type failure occurring at the toe of the proposed <br />spoil fill. Table C-I summarizes the analyses results and Fig. C-I shows the <br />"critical" slip surface for each analysis. Figure C-2 shows results of our <br />parametric study considering the effects of the angle of internal friction of <br />the spoil, clay cohesion, spoil and clay uniT weight, and the groundwater level <br />above the natural ground surface. The fill is to be constructed within a <br />confined V-shaped canyon where the effect of arching will act to increase the <br />stability. This increase in stability was not considered in our analyses and the <br />calculated factors of safety will tend to be somewhat conservative. <br />The basis of our parametric studies was an assumption the clay would <br />remain in place and free groundwater would develop at the existing clay <br />surface. The results of our stability calculations indicated the impact of the <br />• <br />