CFD-DEM simulation of consolidated undrained triaxial test of completely decomposed granite

Particle morphology significantly influences the mechanical properties of soils. A coupled CFD-DEM method is developed in this paper to simulate consolidated undrained (CU) triaxial tests considering real morphologies of completely decomposed granite (CDG) particles. This method incorporates fluid compressibility into the volume-averaged Navier-Stokes equations, synchronizes CFD and DEM boundaries, and corrects elementary sphere overlaps when using clumps. The 3D morphologies of CDG particles are obtained using in-situ X-ray micro tomography (μCT) CU triaxial tests, image processing techniques, and spherical harmonic analysis. Validation of this CFD-DEM model is performed by comparing simulation results with experimental data and those obtained from the coupled fluid method. Based on the simulation results, the effects of particle morphology on the macro and microscopic undrained behavior of CDG are systematically investigated.