Spatial–Temporal Response Law and Main Controlling Factors of Temperature During Coal-and-Gas Outburst

Abstract

One of the most common catastrophes that occur during the coal mining process is the coal-and-gas outburst. However, due to the complexity of this phenomenon, there are many variables affect it, and the degree of synergistic coupling of various factors is deep, and so the mechanism of its occurrence cannot be fully grasped so far. Existing research mainly focused on the temperature variation law of coal-and-gas outburst under a single influencing factor, which is limited in understanding of the temperature evolution law in the outburst process under the coupling of multiple influencing factors. In this study, the temperature change of the whole process of the outburst was monitored by carrying out physical simulation experiments under different conditions (gas pressure, in-situ stress and permeability). According to the experimental results and theoretical analysis, it was found that the temperature of the coal seam and the roadway following an outburst follows an evolutionary pattern of first rapid decrease, then rapid rise, and finally slow change in time. Then, the weights of three influencing factors were determined by the analytic hierarchy process—criteria importance through inter-criteria correlation (AHP–CRITIC) mixed weighting method, and it was concluded that the temperature evolution of coal-and-gas outburst was mainly controlled by gas pressure. Finally, further fitting was conducted to obtain the exponential variation of temperature drop peak and outburst propagation distance under various conditions of gas pressure, and the physical meanings of different fitting parameters were discussed. On this basis, the abnormal change of coal seam temperature can be detected, and the roadway temperature can be predicted, thereby studying the influence range of the two-phase flow and further evaluating the disaster-causing effect, and providing a new idea for the prediction and prevention of coal-and-gas outburst disaster.