Three-dimensional distinct element analysis of mechanical properties of structured sands

The three-dimensional (3D) distinct element method (DEM) is employed to investigate the behaviours of cemented sands at the macro-scale in triaxial tests. A 3D bond contact model is implemented in a DEM commercial software (PFC^3D) to simulate the triaxial tests on cemented specimens, and the simulated data are compared with the experimental results. Finally, the underlying mechanism behaviour is discussed at the macroscopic scale. The DEM results show that, the structured sands and uncemented loose sands have different macroscopic behaviours. In the conventional triaxial compression tests, the strain softening and the shear dilation are more pronounced in the structured sands with the increasing cement content or decreasing confining pressure. Under high confining pressures, the specimens show strain hardening and shear contraction. Both the cohesion and the peak friction angle increase with the increasing cement content under relative low-mean stresses. As the mean stress increases, the strength envelops for cemented sands converge gradually to those for uncemented geomaterials.