The Effects of Thermal-mechanical Coupling on the Thermal Stability of Coal

Abstract

ABSTRACT As the depth of coal mining continues to increase, the weight of the overlying strata and the ground stress on the residual coal in goaves also increase. At the same time, the temperature of the coal rocks continues to rise, and the high ground temperature environment of the mining and heading faces becomes more severe. As a result, coal oxidation and spontaneous combustion disasters become more prominent. In this work, an anaerobic heating experiment of coal under the thermal-mechanical coupling effect was performed. The effects of thermal-mechanical coupling on the thermal stability of coal were studied by analyzing parameters such as the heat flow peak temperature, endothermic peak value, heat absorption, and activation energy. The results showed that the heat flow peak temperature exhibited hysteresis as the initial temperature and the initial stress increased. At the same time, the endothermic heat flow peak value and the heat absorption decreased. Under the same initial stress, the activation energy gradually decreased as the initial temperature of the coal sample increased; the higher the initial stress, the lower the decrease in the activation energy. At the same initial temperature, the activation energy first increased and then decreased as the initial stress increased; the higher the initial temperature, the more sensitive this change in the activation energy was to stress. In this study, the influence of thermal-mechanical coupling on the thermal stability of coal was obtained. This work provides on-site guidance for the prevention and control of spontaneous coal combustion in deep mining.