Evaluation of Passive Earth Resistance Using an Improved Limit Equilibrium Method of Slices

Abstract

The present study proposes a new approach to solve passive earth pressure problems using the method of slices, coupled with the limit equilibrium (LE) technique. Unlike existing LE studies that adopted failure surfaces of predetermined shapes, here, the backfill was discretized into thin vertical slices, and the Mohr–Coulomb failure criterion was enforced at each slice. The failure surface was then derived by joining the failure plane of the slices starting from the wall base. Consequently, the failure planes became the base of the respective slices. The outline of the failure surface is governed by the soil, wall, and interslice friction angles. The variation of the interslice friction angle was assumed to follow a power function, and the exponents were achieved by satisfying the static equilibrium of the slices and a boundary condition. The proposed results were verified with the available numerical and experimental results, and they show excellent agreement. Also, the results illustrate that the shape of the failure surface is majorly governed by the wall roughness and interslice friction function. For rough walls, failure surfaces are composite curved planar, and the degree of curvature increases with increasing wall roughness.