Abstract: To explore the dynamic fracture regularities of coal body under abrupt unloading with consideration of roof subsidence, the discretized virtual internal bond method was used to simulate the dynamic fracture process of the rock-coal-rock body under unloading condition. It was found that the dynamic fracture exhibited three-stage characteristics, namely the initial, the stable and the accelerated failure stage. With consideration of the roof subsidence, a quantitative fracture evolution function was drawn. With the initial in-situ stress increasing, the dynamic fracture in the initial and the accelerated failure stages was more violent, and the duration of the stable failure stage became shorter. The roof subsidence rate had little effect on the initial failure stage. With the roof subsidence rate increasing, the dynamic fracture in the stable and the accelerated failure stages was more violent. With the surrounding rock stiffness increasing, the duration of stable failure became longer. These findings provided valuable reference for the prediction of coal burst.
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2021, Vol. 3 
