Research and engineering practice on key spatial parameters of long borehole group along coal seam strike

YANG Peng

doi:10.11799/ce202312016

Abstract：In order to give full play to the role of strike long boreholes in gas control,the principle of gas extraction and relief by strike long boreholes is analyzed and summarized.By means of theoretical analysis,numerical simulation and physical simulation,the key spatial parameters of strike long borehole group are summarized and studied,and according to the working face before the initial pressure and normal production period of gas gush,roof overburden and engineering construction quality and other actual conditions,the theoretical spatial distribution range of strike long borehole group was obtained as follows:9～50 m above the roof,10～60 m in the return air lane,spacing between drilling fields shall not be greater than 500 m,and the lap distance between drilling holes in adjacent drilling fields shall not be less than 80 m.On the basis of the research,the engineering practice and the effect of gas control in working face are investigated.The results showed that:The net gas extraction amount of 1#drilling field is 0.29～0.75 m3/min.The net gas extraction amount of the 2#drilling field is 0.38～1.42 m3/min;The maximum gas concentration in the upper corner is 0.7%,and the maximum gas concentration in the return air flow is 0.56%.The reasonable arrangement of the strike long borehole group in the three-dimensional space,ensures the safety of the coal face before the initial pressure and the normal production period.At the same time,the purpose of full drainage of pressure relief gas is realized.