HJC constitutive model and numerical simulation of hammer damage with gas-containing coal

Determining the dynamic constitutive relationship of gas containing coal is the basis for understanding the mechanism of coal-rock dynamic disasters. Based on the “ deformation effect” characteristics and the Mohr-Coulomb strength theory of coal adsorption gas,the weakening effect of adsorbed and free gas on the strength of coal is theoreti-cally analyzed and quantified,and the “static damage variable method” is proposed. The main parameters of the HJC constitutive model of gas-containing coal are determined,and the numerical simulation of the hammer damage of the gas-containing coal is carried out. The results show that ① under the same impact velocity,the damage form of gas-containing coal sample and common coal sample is obviously different and the former damage degree is more serious. ② Under the same gas pressure,the greater the impact velocity is,the more serious the damage of the coal-bearing coal sample is. With the increase of impact velocity,the failure transits from the tensile-compressive failure to the com-pressive stress-induced destruction,and shows the characteristic of central swelling and destruction. ③ When the im-pact velocity is the same,the gas pressure in gas-bearing coal is bigger and the damage degree is larger. The main pa-rameters of the HJC model of gas-containing coal can simulate the dynamic process of the impact damage of gas-containing coal well.