深部巷道锚索拉剪破断机理及防护技术研究

Research on the Mechanism and Protection Technology of Deep Tunnel Anchor Cable Tensile and Shear Breaking

在深部复杂应力环境巷道支护工程中开始出现了不同程度的锚索破断弹射等问题,给锚索支护巷道可靠性和安全性带来重大系统性风险。采用数值模拟方法研究了巷道顶板围岩大变形特征以及支护体受力状态关系,巷中两侧锚索受拉剪复合应力显著,岩层层间错动是锚索软剪切破断的主要原因。建立了锚索拉剪复合作用下的弹性势能计算模型,计算得出了锚索自由段破断时瞬时弹射速度为296 m/s,且锚索破断载荷仅为391.1 kN,是沿空巷道等复杂应力环境巷道锚索易发生破断的根本原因。通过弹射吸能装置研发,形成了锚索破断弹射被动防护技术,是深部巷道锚索主被动综合防护技术体系的重要组成部分,选择朱集东煤矿1161(1)工作面轨道巷开展了井下工业试验,有效消除了锚索破断致灾威胁,显著提高了巷道支护安全性。

In the deep complex stress environment roadway support engineering,there have been various degrees of anchor cable breakage and ejection issues,which bring significant systemic risks to the reliability and safety of anchor cable support roadway.The numerical simulation method was used to study the large deformation characteristics of the surrounding rock of the roadway roof and the relationship between the stress states of the support body.The stress on the anchor cables in the roadway is a single tensile stress,while the stress on the anchor cables in the remaining parts is a tensile shear composite stress.The interlayer dislocation of the rock stratum is the main reason for the soft shear fracture of the anchor cables.A calculation model for elastic potential energy of the anchor cable under the combined action of tension and shear was established.It was calculated that the instantaneous ejection velocity when the free section of the anchor cable was broken was 296 m/s,and the breaking load of the anchor cable was only 391.1 kN,which was the fundamental reason why the anchor cable was prone to break in complex stress environments such as gob side tunnels.Through the research and development of the ejection energy absorption device,the ejection passive protection technology for anchor cable breakage has been formed,which is an important component of the active and passive comprehensive protection technology system for anchor cables in deep tunnels.Underground industrial tests have been conducted on the track along the 1161(1)working face of Zhujidong Coal Mine,effectively eliminating the threat of disaster caused by anchor cable breakage and significantly improving the safety of roadway support.