Document Type : Research Paper



In the past, rock slope stability analysis were performed either graphically or using a hand-held calculator, but nowadays there are variety of slope stability analysis which can be used according to the field condition and potential failure mode. In 2-D analysis, effect of convex and concave walls are neglected, however concave slopes are believed to be more stable than straight walls due to the lateral restraint provided by material on either sides of a potential failure in a concave slope. In open pit mines with general tendency to increase the wall angle, this point is really important. In this study slope stability of western wall of Sarcheshmeh mine in its extension plan is analyzed using 3-D distinct element method (3DEC). For stability analysis, west wall is divided into three structural regions according to the rock type. Rock and joint strength properties are determined from previous and new laboratory tests. Also in Andesite (dominant rock of the west wall) geometrical properties of joint sets are determined. Consequently Slide5.0 software is used to identify rock mass stability and effect of disturbance factor, underground water, horizontal seismic acceleration and rock type on wall stability. In the next step, the mine geometry is modeled in 3DEC and wall stability is investigated in different locations. Results obtained from 3DEC prove failure of several benches at the toe. Also results show drainage may improve stability in some zones but there would still be smaller failures in the toe.