Optimal stability analysis of homogenous soil slopes with an irregular geometric morphology

Abstract

The common morphologies of slope surfaces in nature include linear, stepped, convex, concave, and their combination types. Many researchers have investigated the stability of slopes with simple linear, stepped convex, or concave geometric morphologies, disregarding the effect of combination of convex and concave morphology. In this paper, slope surfaces with convex-concave characteristics are considered. A model of a slope surface composed of n segments is constructed to realize the arbitrary generation of irregular geometric morphologies. Based on the upper bound limit analysis and the log-spiral failure mechanism, a formula for the factor of safety of slopes with irregular geometric morphology is obtained. Optimal stability analysis of convex, concave and convex-concave combination slopes with different characteristics is carried out. This paper mainly focuses on the effect of the location and extent of convex-concave sections on slope stability and sliding surfaces. In addition, a comparative analysis is carried out from both theoretical and numerical perspectives. The local stability of convex and convex-concave combination slopes is discussed. The results show that the effect of convex-concave characteristics on slope stability is related to the equivalent straight-slope angle. Moreover, some abnormal phenomena have been identified. For example, under certain conditions, the stability of a convex slope is better than that of a straight slope, and a concave morphology is not conducive to slope stability. In addition, when the equivalent straight-slope angle is small, convex-concave combinations can yield the worst or best slope stability. Therefore, the location and extent of convex-concave sections should be comprehensively considered to achieve an optimal design scheme in slope reinforcement design and construction.