Research on stress and seepage law of pressure relief and enhanced extraction in coal seam group protection layer
To study the migration law of coal seam gas under the influence of coal seam protection layer mining and gas extraction,a model of coal and rock mass permeability considering the influence of mining disturbance was constructed,and tests were verified.Com-bining the geological conditions of Zhangji Coal Mine,the multiphysics coupling software COMSOL was used to simulate the pressure re-lief and permeability enhancement laws and gas movement law of the stope during the mining of the protective layer,as well as the change of stope gas content under different extraction times under drilling and extraction conditions.The results showed that the No.8 coal seam was mined as a protective layer,with the advancement of the working face,the range of pressure relief and the degree of pres-sure relief of the protective layer gradually increased,the maximum pressure relief degrees of the No.4 and No.6 coal seams were 27.8％and 42.6％,respectively,and the best relief effect was achieved for No.6 coal seam,which had the best pressure relief effect for No.6 coal seam.With the advancement of the working face,the gas seepage field range and seepage velocity in the mining area both in-creased,and the gas gushed out in the direction of the No.8 coal seam goaf.Through the protective layer mining and pressure relief combined with through-layer drilling extraction,the gas extraction efficiency was improved,the coal seam gas content was reduced,and the risk of coal and gas outburst was effectively reduced.
万方数据
维普
