Analysis of 2D and 3D Slope Stability Using the Bishop Simplified Method

Abstract

Most limit equilibrium studies in slope engineering are done in two dimensions (2D). Assuming that plane strain conditions are true, a two-dimensional slope formula has been developed. But if the plane strain assumptions are wrong, three-dimensional (3D) slope analysis has to be done. It would be interesting to study the differences between 2D slope analysis and 3D slope analysis. This study used 2D and 3D formulations based on Bishop's Simplified Method (BSM) to examine the effects of a homogeneous soil slope comprising a pore pressure ratio (ru) and horizontal seismic loading kh. The 3D geometry of the slope is made using a digital elevation model method. Plots show the nature of failure surfaces, malpha (mα), the change of base dip angles, and the distribution of normal force parallel to the failure surface's base. According to the findings, a two-dimensional slope analysis typically produces more conservative estimates of the factor of safety (FS) than a 3D analysis of slope does. Compared to a 3D slope stability problem, it is generally agreed that a 2D analysis of slope gives a more conservative estimate of the problem.