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-6- <br /> <br />failure surfaces at the toe with high water table conditions. The third <br />failure class considers a perched water table at the 6800 level. Locations <br />of the six critical circles located in the analysis are presented on Fig. 4, <br />along with resulting lowerbound factors of safety. A summary of the analysis <br />results is presented on the attached Table I. Results are presented for 53 <br />analysis conditions utilizing a circular failure surface and four conditions <br />utilizing a block type failure. <br />Since a deep-seated failure represents the most critical condition, the <br />majority of the analyses emphasized this type of failure. Critical circle <br />C-1 indicates the most probable type failure. Figures 5 through 8 present <br />the results of the Swedish graphical analysis procedures used to determine the <br />factors of safety. Results are. presented for dry slope and three water table <br />• conditions, as well as three strength conditions. The lowest factor of safety <br />obtained was for strength condition No. 1 using water table No. 1. The re- <br />sults indicate the lowerbound factor of safety of approximately 1.67. <br />Analysis of small circular failure surfaces at the toe are represented <br />by critical circle C-4 and C-5. These analyses were conducted and reported <br />under Job No. 5368 utilizing strength condition No. 2 (p=37 degrees) and water <br />table conditions Nos. 1, 2, and 3. The results indicate a high probability <br />of failure with factors of safety ranging from 0.87 to 0.93. <br />Figure 9 presents sliding block failure surfaces Nos. 1 and 2 used in <br />the analysis. The results suggest it is. highly unlikely that a large block- <br />type failure will occur. <br />The analysis of circle C-6 is based upon a possible perched water table <br />developing at a highly compacted bench. For this case we have analyzed the <br />• situation at the 6800 level assuming a 10-foot thick perched water zone <br />