Laserfiche WebLink
• safety of the slope with the addition of the out-of-pit spoil <br />results in a reduced factor of safety, but the stability of the <br />slope remains above the minimum factor of safety of 1.5. The <br />REAME analysis resulted in a slightly lower factor of safety than <br />the SWASE analysis, making the circular failure surface more <br />critical than a sliding block failure surface in this analysis. <br />This is most likely the result of the conservative soil properties <br />used in this analysis for sandstone and shale. <br />Figure 7 is a graphical representation of the factor of <br />safety for the entire slope with the out-of-pit spoil using the <br />REAMS analysis. As shown on this graph, at a distance of 160 feet <br />from the toe of the creek bank, the existing slope has a factor of <br />safety of 1.5. The toe of the proposed out-of-pit spoil has been <br />located 180 feet from the toe of the creek bank, to insure the <br />factor of safety of the slope at this location will be at least <br />1.5 or greater with the addition of the out-of-pit spoil material. <br />SUMMARY <br />A stability analysis was completed to determine the factor of <br />safety of the proposed out-of-pit spoil slope using the REAME <br />computer program and soil properties determined by WWL in previous <br />studies. Based on the stated soil properties and a 3:1 slope, the <br />out-of-pit spoil has a calculated factor of safety of 1.875. A <br />• stability analysis was also completed using the REAME and the <br />SWASE computer program to determine the affect the proposed <br />out-of-pit spoil would have on the entire slope. The cylindrical <br />failure of the REAMS program resulted in a slightly lower factor <br />of safety than the SWASE failure surface. The existing slope had <br />a calculated factor of safety of 1.5 at approximately 160 feet <br />from the toe of the creek bank. Bp placing the out-of-pit spoil <br />toe 180 feet from the toe of the creek bank, the factor of safety <br />of the entire slope is calculated to be 1.5 or greater. <br />The results of this study indicate general stability based on <br />the parameters and for the configurations used to generate this <br />report. The parameters selected for this study were based on <br />information collected from former studies and assumptions made <br />from recent and past field explorations. If conditions are <br />encountered different from those assumed in this report, these <br />observations should be noted and an evaluation made to determine <br />if the new conditions affect the stability of the slope. <br />r1 <br />U <br />11 <br />