DEM modeling of mini-triaxial test on soil-rock mixture considering particle shape effect

Soil-rock mixture (SRM) that is seriously affected by multiple factors such as particle morphology, grading, and composition has been widely used in geotechnical engineering. In this study, a series of discrete element method (DEM) simulations of mini-triaxial tests on SRM were carried out considering the particle shape effect. First, micro-computed tomography, advanced image processing, and spherical harmonics analysis techniques were successively used to obtain the natural particle shapes of grains which were used to build the particle shape template by the clumping algorithm in DEM. Then, a flexible membrane with constant confining pressure loading was made allowing free deformation of the SRM specimens. After that, a set of micro-parameters involved in the DEM model were calibrated by the uniaxial compression tests, and 9 DEM models of mini-triaxial tests were established to investigate the effects of particle shape, size (gradation), and the percentage of irregularly shaped particles on the deformation and failure characteristics of SRM under shearing. Lastly, the mechanical behaviors of SRM, e.g., stress-strain, macroscopic deformation, and cracks generation and evolutions, were comprehensively analyzed. The simulation results provide new insights into the discrete element study of SRM and contribute to the development of soil stabilization materials for geotechnical engineering.