Research on gas leakage mechanism and detection technology of coal mine gas drainage

Aiming at the low concentration of gas in the percolation borehole, the paper analyzes the mechanism of gas leakage in the sealing hole of the pumping hole based on the multi- physics coupling theory based on the distribution of the surrounding rock stress field of the mining borehole and the roadway. The drilling hole sealing detection device and the determination method are used to detect gas concentration at different depths in the borehole in the normal extraction state, and analyze the variation law of the gas drainage concentration along the hole depth distribution to achieve fast and accurate judgment of the leak position and sealing test of the pumping hole. The test proves that the method and the device can effectively detect the leaking position and sealing effect of the extraction drilling hole, and can provide a simple and rapid detection method and science for the improvement of the sealing process, the adjustment of the sealing depth and the fine management of the coal mine site.