The Study On Gas Comprehensive Drainage Technology Of "Three-soft" Coal Face

For the change of the thickness of coal seam is big, gas permeability coefficient ofcoal seam is low and have no protective coal seam in mine, the gas drainage is one ofthe main outburst prevention measures. This article takes Xinan coal mine as the testmine, uses the theoretical calculation and analysis、test investigation in the mine andcomputerized numerical simulation so on, and carrys out the technology research on gascomprehensive drainage way of “three-soft” coal face, in order to achieve improve coalseam gas drainage rate and reduce the amount of gas emitted from working face.The main research contents of the article: taking elastic-plastic mechanics theory asfoundation, setting up the simple mechanical model of the stress deformation arounddrilling, getting the analytical solution of drilling discharging pressure radius under thecircumstance of axisymmetric, and using computer to simulate and analysis the spherethat discharging pressure influences around drilling,through the contrast and confirming,and combined with the actual situation in the mine, put forward the coal seam gasdrainage drilling parameters design scheme, results of verifing the field test show thatthe gas content reduce to45.8%, gas drainage rate reach to34.3%; In addition, throughthe research mined-out area on the overlaying strata "three zones" the distribution lawand combining with the analysis of the investigation, to determine the goaf vertical"three zones" height range, optimize the working arrangement of mined-out area highfracture drilling parameters, through the field validation, the parameters of the drainageborehole design is reasonable, gas drainage density improve to38%, effective to solvethe problem that the gas concentrations over the limit in the working face. Finallyanalysis and evaluate the gas drainage effect, put forward some optimization gasdrainage management technology that can provide key technology and support for thecomprehensive control gas extraction.Research shows that, through the gas comprehensive drainage technology researchin the working face, the coal seam gas drainage rate in the working face is obviouslyimproved, the coal and gas outburst threatening is reduced, and achieve the minehigh-efficiency safe production.