Simulation of energy evolution during deformation failure process of the layer-intact structure

To research the failure mechanism of the layer-crack structure of surrounding rock in deep mine roadway, the combination (Layer-Intact structure) of shallow layer-crack coal and deep complete coal was taken as the research object, and the mechanical behavior and energy evolution law of the Layer-Intact structure under uniaxial and biaxial compression were studied by numerical simulation with particle flow code (PFC2D). The results show that: (1) In the Layer-Intact structure, layer-crack specimen is destroyed prior to intact specimen; The degree of fragmentation increases with the increase of confining stress, and decreases with the increase of fissure number; (2) The confining stress and the fissure number have a significant impact on the basic mechanical parameters of the Layer-Intact structure. The peak stress of the structure increases first and then decreases with the increase in the confining stress, and decreases with the increase in the fissure number; (3) When fissure number is constant, the energy ratio of layer-crack specimen (strain energy stored in the layer-crack specimen to the the whole specimen) increases first and then decreases with the increase in confining stress, while the energy ratio of intact specimen (strain energy stored in the intact specimen to the whole specimen) decreases first and then increases. When the confining stress is constant, with the increase in the fissure number, energy storage capacity of the Layer-Intact structure is reduced, the energy ratio of layer-crack specimen decreases, while the energy ratio of intact specimen increases. The research can provide some reference for revealing the energy release for dynamic instability of layer-crack structure.