An extended limit analysis of three-dimensional slope stability

A three-dimensional rotational failure mechanism for earth slope is extended from toe failure to include face failure and base failure. An efficient optimisation method is simultaneously employed to find the least upper bounds to the critical height in order to avoid missing the global minimum. Compared with the results from analysis based on toe failure alone, best estimates of the critical height and the critical failure mechanism are obtained. The calculated results are given in the form of graphs and tables for a wide range of parameters. The critical failure surfaces are also investigated to assess the influences of geometrical constraint and soil property on failure mechanism.