Construction Of Similar Simulation Experimental Platform For Stress Characteristics Of Mining Overburden And Discrete Fractures

Nowadays,coal mining conditions are getting more and more difficult,coal and gas outburst accidents occur frequently;protective layer mining is currently the safest gas prevention and control technology,but its influencing factors are numerous.The paper divides the mining horizon from the protective layer mining,ie the layer spacing.Differently,the effect of mining horizon on the effect of pressure relief and permeability is studied.In this paper,after collecting a large amount of data,according to the coal and gas outburst mechanism,the protective layer mining mechanism and the distribution of the three layers after the protective layer is mined,the influence of the mining horizon on the pressure-relieving effect is studied through theoretical analysis and FLAC3 D numerical simulation.Through theoretical analysis,the distribution of the three bands is analyzed under the condition of shielding other factors,and then numerical simulation is carried out.The thickness of the protected layer and the lithology of the overburden are designed first,and the height of the fallen zone and the fracture zone are calculated by the empirical formula.At the same time,according to the condition that the protected layer is in the lower part of the fracture zone,the upper part of the fracture zone and the lower part of the curved subsidence zone,The three protective layers with different spacing between the protected layers are simulated by the FLAC3 D numerical simulation software to simulate the excavation of the protective layer.By using different coal seams as the protective layer,the Tecplot post-processing software processes the data to study the protective layer after the mining layer transformation.The deformation trend of the principal stress and the expansion deformation rate,after the comprehensive analysis,the smaller the layer spacing is,the closer the mining horizon is to the protected layer,and the corresponding pressure relief effect is better.This paper also designs a similar simulation experimental platform,which provides conditions for further study of discrete fracture characteristics.