A discrete element simulation considering calcite crystal shape to investigate the mechanical behaviors of bio-cemented sands

Abstract

Microbial-induced calcite precipitation (MICP) is an effective way to stabilize soils, but the microscopic mechanism is unclear. Discrete element method (DEM) models of the mechanical behaviors of bio-cemented sands offer a way to understand this process. This paper used DEM simulations considering calcite crystal shape to understand the microscopic behavior of MICP-cemented sands. Simulation results showed that macrocracks caused by biaxial tests are mainly caused by shear failure. Decreasing calcite content increases the number of high-amplitude acoustic emissions events. The magnitude of the contact force becomes more homogenous with increased calcite. Sand particles initially sustain the load, then calcite particles contribute more to the strong contact force chain. The calcite concentration also affects the magnitude and direction of anisotropy. The proposed DEM model demonstrates its potential to analyze the underlying mechanisms of MICP process.