Stability analysis of embankments: comparison of limit analysis with methods of slices

Limit analysis has been firmly established over the past decades and is now considered to be an accurate method for predicting failure mechanisms and for calculating limit loads. A new finite element procedure has been developed, and is briefly described in this paper, to determine automatically the optimal failure mechanism for geometrically complicated structures under applied loads. In limit analysis, the objective is generally to determine the collapse load, whereas the factor of safety is calculated in methods of slices. This paper also shows how the factor of safety introduced in the limit equilibrium analysis can be systematically incorporated into limit analysis. Several computations of stability of embankments were carried out to compare the limit analysis results with those obtained by methods of slices based on the limit equilibrium analysis. Through this investigation, some differences and similarities between these two theories can be demonstrated. The numerical results demonstrate that limit analysis by the present finite element method generally gives factors of safety more accurate than or as accurate as those obtained by methods of slices.