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Abstract To study rock dynamic fracture，the two-dimensional Discontinuous Deformation Analysis for Rock Failure(DDARF) is implemented to simulate the whole process of the Brazilian disc specimen dynamic fracture in the Split Hopkinson Pressure Bar(SHPB) experiment. It is concluded that the results reproduce the whole fracture process from the initiation，propagation to failure of the specimen under the different incident waves，which fits well with the experimental results. The fracture extension mechanism，crack propagation and concomitant phenomenon are explained. The results show that：(1) The improved micro-fracture criterion applies not only to simulate static load failure，but also to simulate the dynamic load failure. (2) When the sample subjected to impact loading，the main cracks initiate from one end，gradually extend to the center along the radial load direction and propagate together to the other end. The tensile stress at the crack tip is the cause of rock crack. (3) The propagation process of the main cracks is accompanied by the generation of the secondary damage micro-cracks that focus on the region near both sides of the main cracks. (4) The triangular fracture zone is generated in the contact part of both ends of the specimen，the incident and transmission bars and the zone has the tendency of increase with the increase of incident wave amplitude.
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2015, Vol. 34 
