Seismic Analysis of Slopes with Tension Cutoff Considering Vertical Seismic Excitation

Abstract

The Mohr–Coulomb (M-C) yield criterion provides an exaggerated tensile strength of bonded soils, leading to misestimation of slope stability, particularly under seismic excitation. In this paper, the concept of tension cutoff is introduced to eliminate the tensile strength from the M-C yield criterion. A discrete kinematic approach, incorporating both the pseudostatic method and Newmark’s method, was utilized to comprehensively evaluate the seismic stability of slopes, including yield seismic acceleration, displacement coefficient, and earthquake-induced displacement. Both the vertical and horizontal seismic excitation were considered. The calculated results were compared with those obtained by introducing a tension crack. The proposed method was applied to seismic stability analysis of both homogeneous and heterogeneous slopes. The results revealed that the vertical seismic excitation has a significant influence on slope stability, which should not be ignored. Steep slopes are more vulnerable to vertical seismic excitation than gentle slopes. Earthquake-induced displacement caused by a tension crack is the largest, followed by that of tension cutoff, with the lowest displacement resulting from the M-C yield criterion. Furthermore, mild slope geometry and soils with strong shear strengths can reduce the discrepancy of the results calculating by tension crack and tension cutoff methods.