Contact erosion of soil layers with different water table levels under cyclic loading using VOF-DEM coupled method

Abstract

In the process of using transportation infrastructure, contact erosion between different particle sizes soil layers can easily occur under complex hydro-mechanical coupling, leading to deformation and damage of structures. To investigate indirect erosion between soil layers under cyclical load effects from a microscopic perspective, a volume of fluid-discrete element method (VOF-DEM) coupled method was adopted in this study. The influence of different water table levels and particle size ratios (PSR) was considered. The study found that: (1) The compressive effect of coarse particles during loading and the stress relaxation effect during unloading can both cause migration of fine particles within one loading–unloading cycle; (2) Immersion of the contact surface between coarse and fine particles is a key factor in inducing particle migration, with the interaction between particles being the most intense at the contact surface; (3) Fully saturated soil experiences the most severe particle erosion and macroscopic deformation; (4) Reducing PSR can effectively improve the integrity of soil structure and suppress erosion of fine particles; (5) Particle migration inevitably leads to axial deformation of the soil, resulting in reduced stiffness and increased energy dissipation during loading–unloading cycles. This study provides new insights into contact erosion under complex hydraulic coupling from a microscopic perspective.