Laserfiche WebLink
- 15 - <br />Stability Analysis: ltie stability of the opal refuse embanlanent was <br />• analyzed for several loading conditions to determine the factor of <br />safety of the compacted material and the natural foundation materials <br />ayainst a mass rotational failure. Static and dynamic (pseudo-static) <br />analyses of the waste snbanlanent were conducted assuming a 3:1 and a <br />5:1 slope. The strength of the foundation material and the friction <br />angle of the Dual refuse material were maintained ronstant, and the <br />cohesive strength of the coal refuse material was varied between <br />200 and 600 psf. The configuration of the slopes analyzed, the <br />strength parameters and the various loading conditions are shown on <br />Fig. 7. <br />These studies indicate that enbanlanents constructed to a maximum <br />height of 100 feet will have a factor of safety greater than 1.5 under <br />• static loading conditions provided the strength of the coal waste <br />material is greater than or equivalent to a friction angle of 22° and <br />' a cohesion of 200 psf. Analysis of the same 100-foot high slope with <br />a 3 horizontal to l vertical face and an earthqualoe croefficient of <br />0.05 results in a factor of safety of 1.3. Factors of safety for <br />other strength values and slope heights and angles are presented in <br />Fig. 7. The shear strength of the coal waste material should be <br />' confirmed by sampling and testing the coal refuse material after the <br />mine begins operation. <br />The slope stability analyses were conducted utilizing a computer <br />program based on the si~lified Bishop's method of analysis. Subse- <br />ll- --_- _ =quent to-eanputer analysis,- the. results were checked using published - - _ <br />stability charts. <br />• <br />