Investigation And Technical Study On Effect Of Pressure Relief Depth And Detachment Of Long-distance Protective Layer Of Pingdingshan Coal Mine No.6

Coal mine and gas outburst has always been the main outstanding problem in mine disasters.Due to the complexity of coal and gas outburst principles,prevention of coal and gas outbursts has become a major problem at home and abroad.After many years of on-site practice at home and abroad,it shows that the protection Layer mining is currently recognized as a more economical and effective anti-invasion measure.This paper takes Pingdingshan Coal No.6 Mine as the engineering background,inspects and verifies the protective effect of mining under long-distance protective layer,and delimits the scope of pressure relief protection.Using theoretical analysis,numerical simulation,similar simulation,field practices and other technical means to determine the effect of protective layer mining on the coal mining and overlying coal rock strata,and to discuss the stress changes,deformation and destruction of the protected coal rock under the influence of mining,and analysis.The protective layer mining pressure relief effect of the mechanism.Using FLAC3 D Simulation Software to examine the stress changes of surrounding rocks of protected strata and the destruction of coal rocks and the investigation of the movement law of overlying strata.The laboratory similar simulation experiment was used to study the internal mechanical changes of the protected layer coal seam under the influence of the protection layer mining and the evolution of the cracks inside the macro coal seam.A total of 22 boreholes were drilled on the site to inspect the changes of the gas basic parameters of the protected layers before and after the protective layer was mined.It was found that the coal gas pressure before and after mining decreased by 0.52 MPa,the gas content decreased by 45%,and the gas permeability coefficient of the coal seam expanded by 200 times.The maximum deformation rate of the coal seam was 49.05 ‰.After comparative analysis of numerical simulation results and similar simulation results,It is concluded that the protection scope of protective layer mining is to cut in the direction along the protective layer working face along the strike direction,the distance within the stop line is 40.9m,and the fault direction of the lower D 6 coal seam is opposite to that of the WU 8-22250 protected surface 16.4m,the upper part is opposite to the WU8-22250 protected layer in the working surface of the wind lane is wrong 8.7m,the maximum pressure relief angle is 62°,the protection layer working face tends to the lower pressure relief angle is 77°,the tendency of the upper relief angle is 83°...