Preliminary DEM Analysis on Micro-Mechanical Behavior of the Composite Cemented Granules Under Complex Stress Conditions

The micro-mechanical properties of the idealized composite cemented granules are numerically investigated by the Distinct Element Method. The composite cemented granules system, which consists of two particles and two bond materials, is discretized as a rectangular assembly of very fine particles connecting two edges. Then a series of loading tests, including compression, tension, shear, torsion and their combinations, are performed on the composite cemented granules system. The results show that both the compression force and tension force increases almost linearly with the displacement from 0 to a peak force at first. Then the compression force drops sharply to 0 and the tension force drops to a non-zero residual value. The normal force shows significant effects on the shear force and torsion force. The shear force and torsion increases linearly with the increasing displacement and then fluctuates around the peak force under large normal force. Both the peak shear force and the peak torsion increase with the increasing normal force at first and then decreases when the normal force exceeds a critical value. The failure envelope in the shear-torsion space is in an elliptical shape. It expands with the normal force firstly and then shrinks when the normal force exceeds a critical value.