Analytical technique for stability analyses of rock slopes subjected to block toppling failure
In the traditional analytical models for evaluating block toppling failure mechanisms of the slope, a single weak plane angle is assumed, running from upper rock columns and daylighting on the slope face. However, for some physical rock slopes, the weak plane bounding the potential toppling blocks may be dipping at two diverse angles within the rock masses and may not daylight on the predictable point on the face of the slope due to varying characteristics of the weak plane. The mathematical technique for estimating the counter-tilted angle of the weak plane has been proposed and incorporated into the modified analytical technique for evaluating slope stability subjected to block toppling failure. The physical slope with pre-existing weak plane dipping at two diverse angles within the rock slope subjected to block toppling was analysed using the modified analytical technique and results were validated using the discrete element method. The obtained simulated failure mode zones are consistent with those obtained by the modified analytical technique. The influence of the relative counter-tilted angles of the weak plane on slopes stability was studied and the results show that, progressive increase in the counter-tilted angles of the weak plane lead to gradual increase in slope instability.
Keywords: Block toppling, counter-tilted weak plane, modified analytical technique, numerical simulation model