Progressive Failure Behavior: Energy Evolution and Self-Inhibition in Mining-Stressed Coal with Borehole-Cracked Fractures

To explore the impact of the crack angle around the gas extraction borehole on the stability of coal, its internal energy change and self-inhibition mechanism in the process of energy transfer are important indicators during progressive destruction. Therefore, this paper combined with the elastic strain energy accumulation rate and the input total strain energy density established a self-inhibition evolution model between the elastic strain energy and axial strain and explored the influence on the macroscopic energy self-inhibition. The results show that the elastic strain energy is similar to that of the stress-strain curve, with "step" and "cliff" decreases at 0° and 30°, a yield platform at 45°, and a "double peaks" phenomenon evident at 60°. An energy self-inhibition evolution model is used to characterize the macroscopic energy accumulation processes. The key parameters <i>p</i> and <i>q</i> of the model are verified to be accurate, and the fit is above 0.99, indicating that the proposed energy self-inhibition evolution model can accurately characterize the basic law of force-deformation-destruction of the specimens. However, the mechanism inhibiting the energy conversion effect is crucial for the final outcome of prepeak energy accumulation.