Similar Simulation Experiment And Reliability Study On Inclined Protection Scope Of Under-Protective Layer Mining For Xing Long Coal Mine

Based on the theory of overburden breakage and the law of gas flow in the protective layer mining,the 1601 working face of Xinglong coal mine is used as the research background,and the similar simulation experiment is used to define the protective layer And the reliability of the similar range of protection is verified by the combination of numerical simulation and field investigation.The main achievements of this paper are:?The theoretical analysis method is used to analyze the characteristics of overlying strata during the exploitation of the lower protective layer,and the movement rules of the near horizontal,inclined and steep overlying strata are pointed out.The results show that the horizontal,Distribution Characteristics of Gas Migration Channel Formed by Precipitation Overlying Strata.?The physical similarity simulation experiment of the lower protective layer is carried out,and the stress concentration and stress distribution of the overburden are clarified.The experimental results show that the protective layer has a large stress concentration in the roadway and the return airway,The upper part of the mined-out area is larger than the sinking,and the whole stress distribution is "U".?Based on the simulation results of the lower protective layer mining,the upper and lower boundary relief angles of the effective pressure relief range of the protective layer under the model are defined according to the deformation criterion of 3 ‰,which is 91 °,67.4 °.?Using numerical simulation method,and according to the criterion of residual gas pressure ?0.74 Mpa in coal seam,the upper and lower boundary pressure relief angles of 92.7 ° and 70.1 ° are defined respectively.Based on the deformation criterion of 3 ‰,Protection range,the lower boundary pressure relief angle were 90.3 °,68.5 °.?According to the site investigation and analysis of 1601 working face of Xinglong Coal Mine,the upper pressure relief angle of the lower pressure protection zone is 91.4 ° and the lower pressure relief angle is 67.6 °.By comparing the three methods The protection range of the three methods is different,and the results of the similar physical simulation experiments are closer to the results of the field investigation,which shows that the protection range specified by the physical similarity simulation is basically reliable.