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slopes under varying conditions. This program is a comprehensive slope stability program for <br />Is microcomputers and uses a variety of methods for factor of safety calculations. <br />The slope configurations used in our analyses were obtained from the cross sections shown on the drawings <br />provided by the client. A discussion and summary of the slope stability evaluations for the proposed cut <br />and fill slopes results are discussed below. <br />Cuttings Pit - Cut Slone (Station 0+50 to 0+75): A slope stability analysis was completed for the largest <br />of the proposed cut slopes to be constructed at this site, which appears to be located along the northern end <br />of the Cuttings Pit and from approximately Station 0+50 to 0+75. It appears that the proposed cut slope <br />will be approximately 24 feet in height and be constructed to approximately a 1.4 (horizontal) to 1 <br />(vertical) slope configuration. The slope stability analysis was completed under the assumption that the <br />Cuttings Pit is empty, which is the worst case scenario for this type of cut slope. <br />For this evaluation a unit weight (soil density) of 135 pcf, a cohesion value of 11000 psf and a phi angle of <br />0 were used for the claystone bedrock materials, which were encountered from 5 to 10 feet below the <br />existing ground surface. In addition, a unit weight (soil density) of 127 pcf, a cohesion value of 500 psf <br />and an effective phi angle of 0 were used for the natural clays that were encountered above the bedrock <br />materials. <br />Based on our calculations and analysis, the minimum calculated theoretical factor of safety for a failure of <br />the maximum cut slope section will be 1.74 under static conditions. The slope stability analysis data and a <br />cross section showing the slip (failure) surface are presented in Appendix B. <br />Cuttings Pit - Embankment Fill Slone (Station 3+25 to 3+80): A slope stability analysis was completed <br />for the largest section of the proposed embankment fill slope to be constructed at the southern end of the <br />cuttings pit, which appears to be located from approximately Station 3+25 to 3+80. It appears that the <br />proposed embankment fill slope will be constructed with the upstream face being approximately 11 feet in <br />height and constructed to a 1 (horizontal) to 1 (vertical) slope configuration; whereas, the downstream face <br />will be approximately 24 feet in height and constructed to approximately a 1.4 (horizontal) to 1 (vertical) <br />slope configuration. <br />A phreatic surface has also been added to this model to analyze the embankment under a full reservoir <br />condition with steady state seepage, which is considered to be the worst case scenario. Therefore, a failure <br />of the downstream face of the embankment during peak water storage was analyzed. <br />For this evaluation a unit weight (soil density) of 135 pcf, a cohesion value of 1,000 psf and a phi angle of <br />• 0 were used for the underlying, natural claystone bedrock materials. A unit weight (soil density) of 127 <br />Job Number: 08-8241 NWCC, Inc. Page 10