Pressure-releasing mechanism of local protective layer in coal seam with rock burst

The exploitation of protective layer is a regional effective method for prevention of rock burst. However, when the exploitation of protective layer has little economic value and the safety of main coal seam cannot be guaranteed without it, a new method called local protective layer is proposed, and the mechanism of prevention of rock burst and large deformation is studied. In order to prove the security of the proposed method, a formula for calculating the stress of rock mass under the action of local protective layer is derived by establishing the mechanical relationship model for the local protective layer and the protected layer. The distribution of the main stress and shear stress under different widths of local protection layer is plotted. The stress criterion for the occurrence of shock and large deformation boundary is given. Based on the actual situation of a coal mine in Henan, the calculation method for the effects of the local protection layer is given. The calculated results are applied in the design of a dangerous rock burst face in the coal mine.