Discrete element analysis of uniaxial compression test of EICP cemented sand soil

Enzyme-induced calcium carbonate precipitation (EICP) is a soil solidification and improvement technique with broad prospects. In order to study the mechanical fracture mechanism and meso-properties of EICP stabilized sand, this paper, based on PFC2D, studies the mechanical parameters, particle displacement and microcrack development process of cemented sand samples with different cementation levels and different calcium carbonate distributions in uniaxial compression tests to explain their deformation and failure mechanisms and failure evolution laws. The results indicate that discrete element simulation considering the content, distribution, and particle contact model of calcium carbonate can better reflect the mechanical and deformation characteristics of the cemented sand specimens compared with laboratory tests. Specimens with a low level of cementation undergo local shear failure, and the failure surface emerges in areas with lower calcium carbonate content in the middle. With an increase in cementation level, average particle displacement in sandy soil becomes smaller, and the direction of particle displacement is closer to the axial compression direction of the specimen, leading to splitting failure with better global stability. The higher the level of cementation is, the more uniform the distribution of particle contacts in specimens is observed, resulting in slower extension rates for both crack growth and zones experiencing cementation failure.