Slope stability analysis and discontinuous slope failure simulation by elasto-plastic smoothed particle hydrodynamics (SPH)

TLDR

Slope stability analyses typically use LEMs or FEM, but these methods cannot model the discontinuous soil failures that accompany slope instability. The study extends SPH to evaluate slope stability and simulate post‑failure soil behavior, and proposes its use for future saturated‑soil SPH developments. The authors use a shear‑strength‑reduction technique with a modified failure criterion to compute safety factors and slip surfaces, develop a pore‑water‑pressure‑aware SPH formulation, and apply the method to multiple slope analyses and failure simulations compared with conventional solutions. The method yields safety factors and slip surfaces that agree with traditional techniques, while uniquely enabling large‑deformation post‑failure simulations for a broad range of geomechanical applications.

Abstract

Most slope stability analyses have employed limit equilibrium methods (LEMs) or the finite-element method (FEM) as the standard approach. However, slope instability is often accompanied by discontinuous failure of the soil, which cannot be modelled by either LEMs or FEM. To overcome this limitation, this paper presents an extension of the smoothed particle hydrodynamics (SPH) method to evaluate the stability of a slope, and to simulate the post-failure behaviour of soil. For the slope stability analysis, the shear strength reduction technique with a modified failure criterion for distinguishing convergent from non-convergent solutions is applied to estimate the safety factor of a slope, and the critical slip surface is determined from a contour plot of accumulated plastic strain. To take the pore water pressure into account, a new SPH formulation for soil motion is developed. It is suggested that this equation can be applied to further developments of SPH for saturated soil. As an application of the proposed method, several smoothed particle slope stability analyses and corresponding slope failure simulations are presented, and compared with other solutions. The results show good agreements with other methods in terms of the safety factor and the critical slip surface. As compared with such traditional methods, however, an advantage of SPH is that it can simulate large deformation and post-failure of soil, and can thereby treat a wide range of applications in computational geomechanics, especially those that include large deformation and failure of geomaterials.