急倾斜煤层放顶煤开采顶煤破碎的Griffith理论分析

Griffith Theory Analyses of Top Coal in Steep Seam

根据急倾斜煤层巷道放顶煤开采工艺特点,运用Griffith强度理论分析了顶煤破碎机理.通过建立Griffith裂纹受力模型,确定了顶煤断裂准则,得出了断裂拉应力与煤层的倾角、开采深度、顶煤的受力状态、裂纹的分布及发育程度等因素有关.煤层裂纹发育、倾角大于45°角,开采深度大于临界开采深度,裂隙或软弱结构面摩擦系数小是放顶煤开采的最有利条件.该结论有利于指导急倾斜煤层放顶煤开采实践.图2,表2,参6.

According to the characters of mining technology in steep seam, the breaking mechanism of top coal analyzed by applying Griffith intension theory. Through constructing Griffith fracture mechanics model, the fracture rule of top coal was established, in which fracture tension stress is demonstrated to be relative to angle of coal seam, mining depth, forced state of top coal, distribution and develop of cracks. The ideal mining coal conditions are to exceed an angle of 45°, the thickness threshold and developed crack. The conclusion provides theoretic basis for generalizing the mining method.2figs., 2tebs., 6refs.