Fluid Coupled-DEM Simulation of Lateral Loading Experiment for Buried Pipe in Saturated Sand

Abstract

Two-dimensional simulation was carried out using a fluid coupled-DEM (discrete element method) analysis on lateral loading experiments for a pipe buried in saturated sand. The interaction between soil and pore water was reproduced by dividing the model into solid and fluid phases. The variation of the excess pore water pressure was calculated on a fluid mesh based on the pore volume change and was then given to the soil particles in the solid phase. The head difference between the fluid meshes produced upward seepage to the soil model. Liquefaction was reproduced by the decrease of the contact force between the soil particles due to the upward seepage. The force-displacement curves obtained from lateral loading simulations showed good agreement with the experimental results under various effective stress conditions. Distribution maps of contact force and displacement of soil particles revealed displacement mechanism of the buried pipe and its surrounding soil. The variation of the void ratio and the excess pore water pressure with the pipe displacement could be reproduced to some extent, and the applicability of this analysis method to interaction problems has been verified.