Versatile coupling of MPM and FEM: A case study of the stability of vegetated slope

Abstract

Evaluating root reinforcement in the root–soil composite is challenging due to the complex interactions among its components and the variable configurations of the roots. A proposed FEM-MPM coupled model is dedicated to examining the influence of roots on slope stability. The FEM component employed the Truss structural element type to model the dynamics and physics of the root, coupled with a damaged constitutive model, which sheds light on the effects of orientation, cohesion, and friction on the brittle or progressive failure modes of the root. The MPM counterpart provided the capability for large deformation simulation in the post-failure phase of the slope. The framework’s integration was achieved through a penalty method, correcting the dynamics of its members (translation and orientation) and linking the decay of the root with the plastic behavior of the soil through updated geometrical and mechanical properties. Several geotechnical tests and examples, such as pull-out tests, direct shear tests, and vegetated slope collapse simulations, were conducted to validate and verify the robustness of the proposed approach. The results demonstrate the methodology’s capability to capture the mechanism of root reinforcement in vegetated slope stability.