Laserfiche WebLink
or <br />• Tmb= ~ + 9Tan~ <br />F F <br />where Tmb = shear stress mobilized along the failure surface <br />The following steps were used to determine the factor of safety for the <br />fill slope of the access road: <br />Step 1: The fill is fully drained because of the location which is <br />confirmed by field inspection. Attached as Figure 1 is the circular <br />failure chart utilized in the calculations. <br />Step 2: The following assumptions for the slope are made:l <br />Maximum slope height <br />Slope angle <br />• Material density <br />Minimum friction angle <br />Minimum cohesion <br />Maximum friction angle <br />Maximum cohesion <br />H = 15 ft - field measurement <br />1~/= 34° average -field measurement <br />7'= 120 lb/ft3 - estimate <br />~ = 16° -from Rocky Mountain <br />Geotechnical <br />c = 210 lb/ft2 - from Rocky Mountain <br />Geotechnical <br />~ = 23° -from Rocky Mountain <br />Geotechnical <br />c = 360 lb/ft2 - from Rocky Mountain <br />Geotechnical <br />Step 3: The value of thz following dimensionless ratio was calculated <br />based on the assumptions in Step 2: <br />c = 0.41 Minimum <br />7 H Tan ~ <br />• = 0.47 Maximum <br />1 Data from Rocky Mountain Geotechnical "Stability Analysis of Portal <br />and Access Road Areas, Bear Mine No. 3, Somerset, Colorado"; 4-16-82 <br />