Abstract

A numerical study was conducted on the damage behaviors of sandstone specimens with an embedded rough fracture under triaxial stress conditions. The discrete element method was used to study the deformation and cracking characteristics, and the effects of triaxial stress state, fracture width and inclination angle on the mechanical properties were also investigated. The results are as follows: (1) The strength of fractured rock decreased with the increase of fracture width ratio and the yield stress under conventional triaxial stress is higher than those under true triaxial tests with the same mean confinement; (2) For fractured rock models with small width ratios (0.2, 0.4 and 0.6), the strength increases as the fracture angle turning towards the principal stress direction. The shear damaged bond ratio decreased with the increase of confining pressure when σx=σy, while its ratio increased slightly with the fracture angle when σx≠σy; (3) For the large-width fractured rock model with a width ratio 1.0, the strength first decreased and then increased with the increasing inclination angle. At inclination angles of 0° and 30°, damage first occurred near fracture surface, then it propagated along the diagonal direction, and the ratios of bond damage caused by tension and shear failure were almost equal. While the shear damaged bond ratio was much higher than that by tension at inclination angles of 60° and 90°.