ABSTRACT
To analyse the periodic fracture process during steeply inclined thick coal seam sub-level mining, the bottom three clamped edges simply supported plate model and the two adjacent edges clamped on the edge of a simply supported plate model are introduced to calculate the deflection of immediate roof before the first or the others subsection’s immediate roof periodic fracture. To verify the normal stress distribution of the two models, FLAC3D simulate the mining process in the steeply inclined thick coal seam mining face. By the simulation results, the normal stress distribution of immediate roof is uniform. According to the simulation results, the normal stress distribution of the immediate roof is uniform. The Galerkin method was used to calculate the solution of deflection equation under the effect of normal stress. The Hooke’s law and arc length theorem were used to calculate tensile stress of immediate roof, and obtain the maximum tensile stress and corresponding position of immediate roof before periodic fracture. Taking the maximum tensile stress strength criterion as the suberect immediate roof fracture criterion, the periodic fracture span can be obtained.
