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采用理论分析、室内试验及现场实测方法分析高强度采场顶板动载冲击效应发生条件、机制及影响因素。采场围岩组成的非理想刚体系统为围岩发生动力破坏提供条件,建立老顶动力断裂失稳的折迭突变模型,老顶岩层峰后软化模量大于弹性模量是导致突发动力性断裂失稳的内在原因;在确定塑性区范围的基础上得到老顶由弹性稳定状态过渡至整体断裂失稳状态过程中塑性耗散功、断裂面表面能及破断岩块初始动能的解析解;建立老顶断裂线处于煤壁上方不同位置的老顶结构模型并得到老顶发生动载冲击现象的结构条件及冲击作用力的表达式;工作面推进速度加快等效于老顶悬臂梁加载速率提高,老顶岩层抗拉强度的伪增强导致老顶断前储存于悬臂梁中的弹性应变能增多、破断岩块初始动能占总应变能的比例升高,增大了高强度开采工作面老顶发生动力破断失稳的概率。研究成果应用于王庄煤矿,可解释8101工作面发生大范围切顶压架事故原因并可指导围岩加固方式的改善工作。
The conditions, mechanism and influencing factors of dynamic impact of high-intensity stope roof are analyzed by theoretical analysis, indoor test and field measurement. The non-ideal rigid body system composed of stope surrounding rock provides the conditions for the dynamic failure of the surrounding rock and establishes the fold catastrophe model of the failure of the old top dynamic fracture. The softening modulus after the peak of the overlying strata is greater than the elastic modulus, which leads to sudden dynamic Based on the determination of the plastic zone, the analytic solution of the plastic dissipation work, the surface energy of the fracture surface and the initial kinetic energy of the broken rock mass during the transition from the elastic stable state to the overall fracture instability state is obtained. The old roof structure model with the old top fault line at different positions above the coal wall is established and the structural conditions and the impact force of the roof are obtained. The acceleration of the working face is equivalent to the loading rate of the cantilever beam And the pseudo-reinforcement of the tensile strength of the old roof causes the elastic strain energy of the old roof stored in the cantilever beam to increase, the ratio of the initial kinetic energy of the broken rock block to the total strain energy increases, and the high-intensity mining face is increased Probability of power failure occurs at the top. The research results are applied to Wangzhuang Coal Mine, which can explain the causes of a wide range of top pressure racking accidents in 8101 working face and guide the improvement work of surrounding rock strengthening methods.