SLOPE FAILURE RISK ANALYSIS FOR HIGHWALLS IN COMPLEX GEOTECHNICAL CONDITIONS
Limit equilibrium methods have been shown to be ineffective in predicting the potential for highwall failure in many instances in coal mines around the world. Slope engineers have for many years recognised a Block Thrust Failure Mechanism for slope failures, but little work had been done before 2000 on the actual mechanisms which must be responsible for the failure. The purpose of this paper is to extend the practical application of the analytical method developed from mechanism studies to provide an objective assessment of the risk of slope failure, and therefore guidelines for more stable slope designs. This work is based on studies carried out on three failures in an open pit coal mine in South Africa, and provides a methodology to assess the potential for failure more objectively than is possible with currently accepted methods, while at the same time remaining sufficiently simple to allow a “back of the cigarette box” assessment by geotechnical engineers on site.