DEM Modeling Mechanical Behavior of Unsaturated Structural Loess under Constant Stress Increment Ratio Compression Tests

Abstract

AbstractThis paper presents a numerical investigation into the macromechanical and micromechanical behavior of unsaturated structural loess under constant stress increment ratio compression using the distinct-element method (DEM). Loess is typically a kind of clayey silt with a metastable structure composed of interparticle bonding and large voids. To represent the interparticle bonding, a published bond contact model proposed by the authors was used. Three samples with different water contents were tested under six incremental stress ratios to study the influence of water content and stress increment ratio on the mechanical response of loess. The DEM results qualitatively agree with available experimental observations in the literature. The observed macromechanical properties can be explained by the velocity field, force-chain distribution, bond breakage events, and contact orientation at the microscopic scale. When the stress increment ratio is low, the force chains exhibit a column-like pattern. As the...