A practical stability/instability chart analysis for slope large deformations using the material point method

Abstract

Slope instability and failure may lead to severe geological disasters, which are a primary concern of geotechnical engineering. To estimate the safety of a slope, Taylor (1937) proposed a stability chart that evaluates the factor of safety (FOS) of a homogeneous slope using several simple geometric and material parameters. This study extends the stability chart further into the field of failure, summarising and discussing the failure mode and affected area. A few hundred slope failure simulations have been conducted using the material point method (MPM), which reproduces similar FOSs to traditional stability charts. Three major failure modes, i.e., face failure, toe failure, and base failure, are categorized according to the different positions of the failure bands, and a failure mode distribution spectrum chart is established according to the material parameters of the slope. The affected area of slope failure is characterized by four indicators: the influence distance, run-out distance, sliding depth, and sliding volume. An instability chart is proposed to describe the affected area of slope failure based on simple geometry and material parameters. Further analysis indicates that the internal friction angle plays the most prominent role in the failure modes and slope failure volumes.