Laserfiche WebLink
• <br />B.0 STABILITY MODELLING <br />8.1 ANALYTICAL METHOD <br />Slope stability was analyzed using STABL, the computer program <br />developed by Purdue University and the Indiana State Highway <br />Commission. STABL uses limit equilibrium equations utilizing <br />either the Janbu or the Modified Bishop Method of Slices. <br />Circular, non-circular shear surfaces and wedge failures can be <br />analyzed. <br />8.2 PRE-SUBSIDENCE CONDITIONS <br />Cross-sections AA' and BB' were used to analyze the pre- <br />subsidence stability with regard to deep-seated failures in the <br />• bedrock for the permit area. These cross-sections are shown in <br /> Figures B4 and B5. The models utilize formation properties <br />(both typical and conservative values) as shown in Tables 1 and 3 <br />and determined from the laboratory testing. Several failure <br />modes were analyzed and their results are shown in Table 2. <br />Analyses involved circular failure search routines to find the <br />minimum or critical failure circle as well as the evaluation of <br />various potential wedge failure mechanisms through weak rock <br />layers (shales) in the geologic profile. Factors of safety <br />ranged from 1.82 to 5.90' for the typical strength parameters and <br />from 1.98 to 2.01 for the conservative strength parameters. <br />It should be noted that these analyses assume the bedrock profile <br />. above the C seam on-site to be dry (i.e., we have assumed no <br />21 <br />