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1 <br />' The maximum embankment height analyzed by this procedure was 300 feet, <br />because it is believed that the time for construction of very high em- <br />' bankments (greater than 300 feet) would become sufficiently long to <br />allow for consolidation of the foundation, and thus, a subsequent in- <br />crease in undrained shear strength. <br />Factors of safety for several potential failure surfaces were computed <br />in each case. The lowest computed factor of safety represents the <br />critical sliding surface, and is reported as the minimum factor of <br />safety for that case. <br />' Summary curves plotting embankment height versus factor of safety are <br />shown on Figure IV-1 for wedge type failure through the embankment and <br />' topsoil. Separate plots are presented for slope angles of 30 and 40 <br />degrees. Each plot shows a family of curves, representing different <br />values~of seismic coefficient (K) used for analysis (0, 5, 10, and 15, <br />percent of gravity force). For the static case, where K'= O%, safety <br />factors are computed for a horizontal foundation, and for the foundation <br />' inclined at 10 degrees. <br />Factors of safety computed by the "infinite slope" method of analysis <br />are listed in Table IV-1. Summary curves plotting slope angle versus <br />' factor of safety are shown on Figure IV-2. Separate plots are shown for <br />assumed angles of internal friction, ~', of the embankment material, of <br />35 and 40 degrees. Each plot shows a family of curves representing different <br />values (0, 5, 10, and 15 percent of gravity force) of seismic coefficient <br />used in the analysis. <br />C. STABILITY OF PIT SLOPES <br />' Loads caused by the waste dump being placed near the crest of the pit <br />slope could reduce the stability of the pit slope. To avoid a potential <br />failure, the waste dump should be located outside the critical wedge <br />' area as determined in the rock slope stability analysis presented in the <br />W. A. Wahler and Associates' design report "Preliminary Design of Open <br />Pit Slopes." The top widths of critical wedges for pit slopes were <br />WR.WANLER Project 0823 IV-2 <br />& RSSOCII~S <br />