Abstract
Existing three-dimensional (3D) slope stability analysis methods based on limit equilibrium are comprehensively reviewed, and studies which have been conducted to evaluate the computational accuracy of these 3D methods are briefly summarized. The end effect (i.e. ratio of the 3D factor of safety to the 2D value) estimated using different methods of columns is also examined. It may be concluded that simplified analyses based on an extension of the ordinary method of slices (e.g. Hovland method) are not adequate for 3D slope stability computations because they assume zero intercolumn forces, do not satisfy equilibrium conditions, and more importantly, predict overconservative results leading to a partial or complete neglect of the end effect that should be evaluated properly by a 3D analysis. Consequently, the use of a rigorous method of columns that satisfies both force and moment equilibrium is strongly recommended for a realistic 3D evaluation of the slope stability.
