Study on the influence of the unreasonable layout of upper protective layer on stress superposition of the protected layer

In order to study the problem of serious deformation and failure of roadway surrounding rocks in the mining process caused by the unreasonable layout of the upper protective layer, by means of field investigation, theoretical analysis, numerical simulation and mine pressure observation, the effect of protective layer in 3203 working face of Zhongxing Coal Mine was studied. The results show that when the width of the coal pillar remaining in the upper protection layer is from 10 m to 70 m, the superposition stress on the protected coal seam is from 13.7 MPa to 18.1 MPa; when the working face width of the upper protection layer is from 75 m to 125 m, the corresponding theoretical vertical effective distance is from 30 m to 52 m; the unreasonable layout of the upper protection layer leads to the poor stability of the surrounding rock in the excavation space of the working face of the protected layer under the influence of stress superposition, and the rational layout of the upper protection layer can effectively improve the stress environment of surrounding rock in the excavation space of the protected layer and ensure the safe and efficient production of the mine.