Study on the spatio-temporal relationship between ground fracturing and underground drainage holes arrangement

Based on the respective technical advantages of ground fracturing and underground gas drainage, a joint drainage mode of ground wells and underground is proposed, which focuses on utilizing the large-scale advantages of ground fracturing to promote underground gas drainage. Experimental study of two kinds of ground fracturing and underground drainage connection Mode, that is "Ground fracturing lags behind drilling construction" and "drilling construction lags behind the ground fracturing". Through the micro-seismic method and the underground hole exposure method, it is concluded that the cracks in the coal seam are mainly horizontal cracks with a small northeast opening, and the crack length is about 158 similar to 203m. According to the law of crack distribution, fracturing investigation schemes of two modes were designed. The reasonable time connection between the ground fracturing and underground drainage is preliminarily determined by the engineering practice, it is effective in increasing the permeability of the coal seam, reducing the abnormal gas emission from the coal seam and the risk of coal and gas outburst by using "ground fracturing lags behind drilling construction"; the gas drainage effect is remarkable when the underground drilling is delayed within 3 months of ground fracturing by using "drilling construction lags behind the ground fracturing".