Strain Rate Effect and Mechanical Constitutive Model of Coal Samples Under Dynamic Load

The failure characteristics and mechanism of coal under dynamic and static loading are a basic problem for studying the mechanism of rock burst. It is also a basic research problem to solve the protection of deep underground engineering. By using the split Hopkinson bar system, the mechanical behavior and energy change of coal were analyzed. The law of stress and energy evolution during coal sample failure were analyzed. Combined with a high-speed camera, the analysis of a coal sample after failure showed that, in the process of dynamic loading, it produced cracks along its axial direction. The critical strain rate in the dynamic damage process of coal samples was also analyzed, and the damage degree of coal samples intensified gradually within a certain range of strain rate. Finally, a dynamic mechanical constitutive model was established by considering the influence of strain rate, and the damage changes of coal samples were analyzed. The research results provide a reference basis for further revealing the mechanism of rock burst and preventing coal rock dynamic disaster.