Three-Dimensional Stability of a Slope Subjected to Seepage Forces

Three-dimensional (3D) stability of a slope subjected to seepage forces is studied in this work in light of the kinematic approach of limit analysis. The widely used horn model for 3D stability of slopes is presented and discretized for the first time. To compute the seepage forces developed in a slope, 3D numerical calculations are used to solve the seepage-flow problem. The discretization makes it possible to calculate the seepage force acting on each element of the discretized horn mechanism by using the numerical results. The safety factors obtained by the proposed approach agree well with those given by numerical calculations. The influence of soil properties, 3D slope geometry, and anisotropic permeability is discussed in this work. Numerical results show that the 3D effect is important for B/H ratios lower than 10.0, beyond which the two-dimensional (2D) plane-strain analysis can be used for a 3D slope, and that a larger horizontal permeability with respect to the vertical one is a favorable factor for the slope stability.