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1 <br />' material's relatively low friction angle (28 degrees) and <br />cohesion (200 psf), it was felt that the bench fill material will <br />' be the dictating material for the slope stability analysis and, <br />therefore, the use of these charts is appropriate. <br />1 <br />' With respect to the rock slopes, as has been mentioned <br />previously, it has been assumed that the stability of the rock <br />slopes on the site will be controlled by either a circular <br />failure mode assuming a failure of the overall rock mass, or by <br />' structural discontinuities. The data collected on the spacing <br />' and attitude of existing planes of weakness have been presented <br />graphically for each outcrop on-site utilizing equal area <br />' stereonets where concentrations of the poles of planes observed <br />have been contoured. The stereonets may be seen in Figures 6 <br />' through 10. The associated outcrop locations may be found on <br />' Figure 11. All these plots show a very highly ordered structure. <br />Percent occurrence contours of pole concentrations typically <br />range from 5 to 20 percent for peak concentrations. This highly <br />ordered structure would be felt to be typical of most of the <br />' areas on-site. <br /> <br /> S.4 AN AT.y TT('AT. T HN70 i .C <br />' The circular failure mode for the rock slope analysis was <br /> performed using a computer assisted limit equilibrium method of <br />' slices. This particular program utilized Spencer's method of <br />' analysis. The program is capable of analyzing stability <br /> conditions under circular and randomly specified shear surfaces. <br />' The factor of safety associated with the circular failure for the <br />' 11 <br />