Study on the Multi-Field Coupling Effect and Temperature Evolution Law of Coal and Gas Outburst Incubation Process in the Fault-Affected Area

Abstract

The multi-field coupling relationship and temperature evolution mechanism of gas-containing coal in areas affected by geological structures were investigated, focusing specifically on the engineering aspects of a reverse fault in the No. 3 coal seam at the Xinjing Coal Mine. An analysis was conducted to examine the thermal-fluid-solid coupling behavior of gas-containing coal. A thermal-fluid-solid coupling model for gas-containing coal, accounting for the effects of damage, was developed to simulate the incubation process of coal and gas outbursts within the fault zone during the advancement of the working face. The study has indicated that faults not only degrade the mechanical properties of the surrounding coal-rock mass, but also disrupt the continuity of coal seam stress. Gas tends to accumulate near fault zones, resulting in differences in the gas pressure and content on either side of the fault, thereby substantially increasing the likelihood of coal and gas outbursts. The primary factors influencing temperature variations include deformation energy, energy from gas expansion, thermal convection, thermal conduction, and the thermal effects associated with adsorption and desorption. Among these factors, the endothermic effect associated with adsorption and desorption significantly influences the temperature fluctuations in coal. The results of this study provide a theoretical foundation for exploring the mechanisms underlying coal and gas outbursts, improving the interdisciplinary coupling theory for coal and gas systems and employing temperature metrics to predict such outbursts.