Performance of Sheet Pile Walls With Rubber-Modified Backfill

Abstract

This study investigates the behavior of clean sand and sand-rubber mixtures used as backfill materials behind sheet pile walls under vertical loads. Physical model experiments were conducted to assess lateral displacement and pressure for backfills containing 10% granulated rubber (2.5-5 mm) under both dry and saturated conditions, and across varying backfill inclination angles. To complement the experiments, discrete element method (DEM) simulations were performed to capture the micromechanical behavior of sand-rubber mixtures, enabling analysis of particle-scale interactions. Material stiffness and friction parameters were calibrated through direct shear tests to ensure computational efficiency and accurate representation. Comparative analyses were conducted between the DEM simulations and the physical sheet pile tests across various sand-rubber backfill configurations. The results suggest that sand-rubber mixtures offer a practical and sustainable alternative for backfill applications, improving both mechanical performance and pressure mitigation. Furthermore, force chain development and deformation patterns were thoroughly examined to understand the role of micro parameters; such as particle contact behavior, porosity, internal friction, and stiffness of the rubber-sand composite backfill in reducing active earth pressure against sheet pile walls.