Effect of a Gas Environment on the Crack Propagation of Coal Impact Failure

Abstract

Mining disasters such as coal and gas outbursts and rock bursts seriously threaten safe coal mining. Accordingly, it is important to analyze the dynamic damage characteristics of gas-bearing coal and achieve safe coal mining. In the present study, the criterion of crack arrest for gas-bearing coal was set in accordance with the theory of gas dynamics and fracture mechanics. Then, the impact failure characteristics of gas-bearing coal subjected to an impact load were investigated. In this regard, different parameters, including the impact energy, gas pressure, and gas type, were considered. Moreover, the transient effect of the free gas on the coal destruction was analyzed. The influence of free gas-induced damage on the coal structure was also simulated using ANSYS 17.0 software. The obtained results show that, during the impact crushing of gas-bearing coal, the gas moves in the coal body, which tears the coal body and increases the crushing effect of coal. The crushing effect of gas-bearing coal has a linear correlation with gas pressure, impact energy, and gas adsorption strength. It was concluded that the proposed crack arrest criterion and numerical methods are powerful measures for analyzing the failure characteristics of gas-bearing coal.