Seismic Stability of Heterogeneous Slopes with Tensile Strength Cutoff Using Discrete-Kinematic Mechanism and a Pseudostatic Approach

Abstract

Frequently, the Mohr–Coulomb (M-C) yield criterion is used to determine slope stability. It offers an exaggerated, unreliable, and cautious assessment of the tensile strength of bonded materials, which are composed primarily of compressive elements, especially when subjected to seismic excitation. This work modifies the M-C yield criterion to integrate the concept of tensile strength cutoff, which involves restricting or eliminating the tensile strength of bonded materials. Analyses of the seismic stability of heterogeneous slopes use the discrete kinematic approach. Using a pseudostatic method of analysis, vertical and horizontal forces simulating seismic excitation are characterized. The primary objective of this study is to provide an insight into the effect of tensile strength cutoff on critical failure surfaces. For steep slopes, seismic excitation increases the range of base failure and decreases stability by 45%, while tensile strength cutoff exacerbates the decline. On steep slopes, an overturning failure is guided by the tensile strength cutoff; however, on mild slopes, it is indifferent to such a cutoff. Its application to two nonhomogeneous slopes indicates that a face failure may occur when a relatively weak layer exists in the slope and that the introduction of a tension crack yields the most conservative estimates, while its failure surface corresponds to the critical failure surface with tensile strength cutoff under the strong seismic excitation.