采场顶板X-O型断裂形态力学分析

Mechanical analysis for X-O type fracture morphology of stope roof

采场顶板的破断形态与采场来压、瓦斯抽放、地下水运移、地表沉陷等有密切关系.建立四边固支顶板的弹性薄板力学模型,利用里茨法理论分析顶板断裂形态的产生机理,得出顶板发生破坏以及破坏延伸、转移的规律.在有限元分析软件ANSYS中,依据材料的最大拉应力准则,利用生死单元技术对顶板的空间断裂形态进行三维数值模拟.结果表明,顶板沿长短边的破坏与理论分析相符,得到顶板沿厚度方向的破坏规律,形成空间"O"型裂纹形态,顶板下底面中心的破坏呈层层剥离现象,确定了裂纹出现分叉的具体位置,形成了空间"X"型裂纹形态,综合得到顶板的空间"X-O"型断裂形态.

The fracturing morphology of stope roof is closely related to the weight of stope,gas drainage,groundwater migration,surface subsidence and so on.A mechanical model of elastic plate for the four edge clamped roof was established and the fracture mechanism of the roof was analyzed using Ritz method.The laws of the breakage and breaking elongation and transfer of stope roof were obtained.Based on the maximum tensile stress criterion of materials,a three-dimensional numerical simulation for the space breaking morphology of roof was carried out using the life and death element technology in the finite element software ANSYS.The results show that the destruction of the roof along the length and short side is in line with theoretical analysis.The failure law along thickness direction of roof was obtained and a space ＂O＂ shape crack was formed.The destruction strips layer upon layer under the center of roof bottom.The specific location of cracks branching was identified and a space ＂X＂ crack morphology was formed.Finally the space ＂X-O＂ type fracture morphology was obtained.