Energy Consumption Characteristics and Dynamic Damage Constitutive Model of Gas-Bearing Coal under Dynamic Loading

To explore the damage evolution law of gas-bearing coal under impact, a split Hopkinson pressure bar (SHPB) test system for gas-bearing coal was used to conduct dynamic compression tests on coal with gas pressures of 0, 0.5, 1.0, 1.5, and 2.0 MPa. Based on the energy theory, the deformation and failure processes of gas-bearing coal under impact were analyzed, and the influence of gas pressure on energy parameters of coal was discussed. Using the SMP strength criterion and Weibull distribution function, a dynamic damage constitutive model of gas-bearing coal considering gas-impact coupling damage was established by combining the energy consumption index. The results indicate that during the impact compression process, the energy curve of gas-bearing coal can be divided into a slow growth stage, an accelerated growth stage, and a stable stage. With the increase of gas pressure, the reflected energy of coal shows a linear increase trend, while the transmitted energy and dissipated energy show a linear decrease trend. The theoretical curve based on the gas-impact coupling damage constitutive model is highly consistent with the test curve, indicating that the model can accurately describe the damage evolution law of the entire stress-strain process of gas-bearing coal under impact.