The Effects of Confining Stress on Rock Fragmentation by TBM Disc Cutters

Abstract

In this paper, General Particle Dynamics (GPD3D) is developed to simulate rock fragmentation by TBM disc cutters under different confining stress. The processes of rock fragmentation without confining pressure by one disc cutter and two disc cutters are investigated using GPD3D. The crushed zone, initiation and propagation of cracks, and the chipping of rocks obtained from the proposed method are in good agreement with those obtained from the previous experimental and numerical results. The effects of different confining pressure on rock fragmentation are investigated using GPD3D. It is found that the crack initiation forces significantly increase as the confining stress increases, while the maximum angle of cracks decreases as the confining stress increases. The numerical results obtained from the proposed method agree well with those in previous indentation tests. Moreover, the effects of equivalent confining stress on rock fragmentation are studied using GPD3D, and it is found that rock fragmentation becomes easier when the equivalent confining stress is equal to 15MPa.