采前加固锚索断裂原因分析及防范措施

针对潘三矿1632(3)工作面运输巷发生的一起锚索断裂导致死亡事故,结合工作面开采布局、巷道支护方案和工作面回采前加强支护措施,总结并分析了断锚处巷道矿压显现特征。通过分析相邻工作面回采后侧向支承压力的影响范围,两帮支护对巷道围岩稳定的作用及巷道顶板的运动对锚索的破坏机理,找出了锚索断裂的原因:该工作面运输巷布置位置设计不合理,巷道布置于上一工作面回采引起的侧向应力集中区;两帮未能采取有效的支护措施,尤其是支护刚度严重不足,在工作面超前支承压力的影响下,帮部锚杆未能发挥应有的效能,增加了巷道顶板跨度,加剧了顶板离层;顶板运动形成对锚索的拉力及剪切力共同作用致使其破断。最后,提出了防范回采工作面巷道顶板锚索破断的保障措施:开采布局保障、设计底线保障、技术保障和组织保障,为类似工程条件下回采巷道的开采设计、使用和维护提供了参考。

Cause analysis and preventive measures of reinforced cable fracturing before mining

In view of a fatal accident caused by a broken cable in 1632（3） working face of Pansan Coal Mine，combined with mining layout of working face，the supporting scheme of roadway and measures to strengthen supporting before mining of working face，this paper summarized and analyzed characteristics of mine pressure manifestation of roadway at the broken anchor.Based on analysis of influence range of the lateral supporting pressure after mining of the adjacent working face，the effect of the two sides of supporting on stability of roadway surrounding rock and the damage mechanism of movement of roadway roof on cable，the causes of cable fracture were found out:the layout of transport roadway in the working face was unreasonable，the roadway was arranged in the side stress concentration area caused by mining of previous working face; the two sides failed to take effective supporting.The supporting measures，especially supporting rigidity were seriously insufficient.Under influence of advance supporting pressure of working face，the side bolt failed to play its due role，which increased roof span of roadway，and intensified roof separation; the joint action of roof movement on tensile force and shear force of cable caused its breakage.Finally，the paper put forward safeguard measures to prevent roof cable breaking in the working face:the safeguard of mining layout，the safeguard of design bottom line，the safeguard of technology and organization，which provided a reference for mining design，use and maintenance of the working face under similar engineering conditions.