A Displacement-Dependent Limit-Equilibrium Slice Method for Slope Stability Analysis

Displacement and factor of safety are two crucial pieces of information about slope stability, but the traditional limit-equilibrium slice method has a significant defect; that is, it cannot reflect slope displacement. In this paper, a displacement-dependent limit-equilibrium slice method is proposed based on the soil shear constitutive model and Morgenstern–Price assumption of interslice forces to establish the relationship between the factor of safety and displacement. In addition to the overall factor of safety, point factors of safety and point displacements can also be obtained using the proposed method to characterize the displacement-dependent slope stability. The point factor of safety and shear displacement of each soil slice calculated using the proposed method are slightly higher and smaller than those calculated by the modified displacement-dependent Janbu method. The iterative process of the proposed method is simpler and more stable than that of the modified displacement-dependent Janbu method. Calculation results of four examples show that the point factors of safety at the upper and lower ends of the slide mass are generally smaller than those at the middle part of the slip body, and the shear displacement of the soil slice near the slope top is generally larger than those at the other positions. The proposed method associates the factors of safety with slope displacements, which allows us to quantitatively assess the slope stability immediately in practice by monitoring the displacements of some key points on it.