Assessing the Stability of Rock Slopes with Respect to Block-Flexure Toppling Failure Using a Force-Transfer Model and Genetic Algorithm

Abstract

Block-flexure toppling is the commonest type of failure in anti-dip bedding rock slopes. In this work, a new model called the force-transfer model (FTM) for this kind of failure is proposed, which is based on cantilever beams and limit equilibrium theory. A genetic algorithm (GA) was further employed to predict the safety factor and failure surface of the rock slope. A centrifuge test was also conducted to check the feasibility of using the combined FTM–GA method to model block-flexure toppling failure. The centrifugal results showed that a complex failure surface was produced in a slope undergoing block-flexure toppling. The failure surface is stepped and has a step height approximately equal to the spacing of the cross joints. Comparing these results with the theoretical ones shows that it is eminently feasible to use the FTM–GA method to analyze the stability of slopes liable to undergo block-flexure toppling failure. Moreover, the safety factor (i.e., failure load in the centrifugal test) and failure surface of the slope can be accurately determined using the new method. The newly proposed method can, therefore, be used as a theoretical tool for evaluating and designing anti-dip bedding rock slopes.