工作面煤壁片帮是大倾角软煤综放采场"支架-围岩"系统灾变的致灾源之一。通过建立煤壁空间受力模型、数值计算与理论分析相结合的方法对煤壁片帮的力学机理、形态特征、多发区域以及由其引发的"支架-围岩"系统灾变机制进行了研究。结果表明:煤壁的破坏形式以剪切滑移破坏为主,片帮形态为非规则四棱锥体且片帮具有继发性;工作面倾斜中上部是片帮的多发区域;煤壁片帮后形成的"片帮-冒顶"恶性循环导致支护系统失去对顶、底板运动的控制作用,加剧围岩运动变形,形成"煤壁片帮→顶煤冒空→支架倾倒→底板滑移"的围岩灾变机制。基于以上并结合长山子煤矿1123工作面生产实际提出了大倾角软煤综放工作面煤壁片帮防控措施。
The stability system of support and surrounding rock is broken when the rib spalling occurs at a fully-mechanized top coal caving face in soft seam,which further causes a disaster. Comprehensive research methods of model building,numerical simulation and theoretical analysis have been used to study the mechanical mechanism,morphological features and disaster from different regions of a fully-mechanized top coal caving face. Results show that coal wall broken behavior is mainly a shear and slippage style. Rib spalling figurations show as an irregular four pyramid mass,which may occur secondly and even constantly. Rib spalling is easily taken place in the middle and upper sections of working face. After these behaviors occur,the support system is out of control with the roof and floor deformation under the circumstance of worsen repetition process from rib spalling to roof falling,and then secondly to rib spalling. The study concludes that the disaster mechanism of surrounding rock is the failure process from rib spalling to roof falling,to support instability,eventually to floor-support separation. On the basis of safety production demands of No. 1123 working face in Changshanzi Coal Mine,some relative control measures have been taken according to the results in this paper.