Abstract:The first time fracturing of the main roof is often analyzed with the fixed boundary conditions at four edges which are difficult to achieve in practice. A mechanical model of elastic thin plate with the elastic boundary foundation condition was established. The influences of the elastic foundation coefficient k,the span L,the main roof thickness h,the elastic modulus E,Poisson?s ratio on the principal moments and initial fracture position of the main roof are calculated with the finite difference method. The first time fracturing of the main roof with the elastic foundation boundary calculated based on the fracture criterion of principal moments occurs in the middle or at the long side ahead of the coal wall. When the ratio of k/E or k/h3 or k/(Eh3) is constant,the fracture position of the main roof is not changed. When the ratio of k/E or k/h3 or k/(Eh3) is small,the middle of the main roof fractures firstly,namely,when the coal seam is soft and the thickness and elastic modulus of the main roof are large,the main roof fractures firstly in the middle. When the ratio of k/E or k/h3 or k/(Eh3) is large,the long side edge ahead of the coal wall fractures firstly,namely,when the coal seam is hard,and the thickness and elastic modulus of the main roof are small,the first fracturing position is at the long side edge ahead of the coal wall. The initial fracturing of the main roof with the elastic foundation boundary is determined by k,L and the stiffness D of the main roof.
何富连,陈冬冬,谢生荣. 弹性基础边界基本顶薄板初次破断的kDL效应[J]. 岩石力学与工程学报, 2017, 36(6): 1384-1399.
HE Fulian,CHEN Dongdong,XIE Shengrong. The kDL effect on the first fracture of main roof with elastic foundation boundary. , 2017, 36(6): 1384-1399.
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