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Geotechnical Evaluation of Mine-Induced Earthquakes on Bruce Park Dam <br />Bowie Resources, Limited <br />June 2002 <br />.i Appendix D. The back-calculated friction angle of 22 degrees compares well with the <br />residual friction angle of 22.5 degrees estimated from the published data by Stark and Eid <br />(1994). <br />4.3 Post-Failure Stability Analysis <br />4.3.1 Static Stability Analysis <br />4.3.1.1 Representative Cross Section <br />We performed a two-dimensional static stability analysis of the existing (post-failure) <br />landslide using the surveyed existing ground surface geometry (GEI, 2002). The <br />representative cross section is presented on Figure 4.2. <br />4.3.1.2 Material Properties <br />The material properties used in the static stability analysis are summarized in Table 4.2. We <br />assumed that the glacial till was cracked as a result of previous movement and therefore, <br />apparent cohesion resulting from overconsolidation was neglected. <br />TABLE 4.2 <br />MATERIAL PROPERTIES USED IN STATIC STABILITY ANALYSES OF POST- <br />FAILURE LANDSLIDE <br /> Strength Parameters <br /> <br />Strength Parameters <br />Used in Pseudo-Static Analysis Moist <br />Unit <br />Weight <br />(pcfl Saturated <br />Unit <br />Weight <br />(pc1) <br />Cohesion <br />c' <br />(psf) <br />Friction <br />Angle ?' <br />(degrees) <br />Glacial Till 130 132 0 26 <br />Failure Zone 126 128 0 22 <br />Bedrock 133 139 2000 30 <br />4.3.1.3 Water Pressures <br />We evaluated the stability of the existing landslide for the following three possible <br />groundwater conditions: <br />a. groundwater at the ground surface <br />b. groundwater at the mid-depth of the landslide mass <br />c. groundwater at the top of bedrock <br /> <br />02-05-22 Geotechnical Evaluation of dine-Induced Earthquakes <br />GEI Consultants, Inc. 14