Experimental dynamic testing demonstrates how impact velocity and gas pressure alter mechanical and energy responses in gas-bearing coal, highlighting disaster prevention strategies.
Key Points
To investigate the dynamic mechanical behavior and energy evolution characteristics of gas-containing coal under varying impact velocities and gas pressures.
Dynamic compression tests conducted using a 50 mm diameter split Hopkinson pressure bar (SHPB) system.
Experimental matrix structured using a two-factor, five-level central composite design (CCD) within response surface methodology (RSM).
Statistical damage modeling developed by combining RSM, the effective stress criterion, and the Drucker–Prager criterion.
Dynamic compressive strength increased with impact velocity, with strength attenuation slowing when gas pressure exceeded 1.2 MPa, modeled with an R² ≥ 0.93 regression model.
Energy consumption density rose by up to 48% with increasing impact velocity due to accelerated fracture propagation, but decreased by more than 25% under higher gas pressure as coal structure loosened.
Constructed statistical damage model achieved a correlation coefficient of R² ≥ 0.92, showing dominant control of impact velocity followed by gas pressure effects.