深埋巷道地应力特征及优化支护设计

In-Situ Stress Characteristics and Optimal Support Design of Deep Roadway

针对深部巷道地质环境复杂及围岩变形剧烈、巷道变形量达数百毫米的现状,提出以地应力测量为前提、测力锚杆全程监测为基础、高预紧力全长锚固技术为核心、通过数值模拟加以修正的动态支护优化设计方案。以淮南潘三煤矿1621(1)工作面运输巷道为例,采用应力解除法对地应力进行实测,在巷道关键位置安装测力锚杆实时监测并记录锚杆轴力,结合数值模拟对优化前后的支护方案进行对比。结果表明,深部巷道以水平应力为主,随着巷道掘进方向与最大水平主应力方向夹角的增大和主应力差的增加,巷道变形迅速增大;采用现有全长锚固支护时施加的预紧力较低,巷道浅部顶板变形剧烈,未能发挥全长锚固的优势;采用高预紧力结合全长锚固优化支护来提高围岩的抗变形能力,改善围岩特性,增加围岩有效应力,可减小巷道变形,优化支护效果比较显著。

In view of the complex geological environment of deep roadways, the intense deformation of surrounding rocks, and the deformation of roadways reaching hundreds of millimeters, a dynamic optimal support design scheme was proposed. It is based on in-situ stress measurement, full-range monitoring of force-measuring bolts, and high pre-tightening force full-length anchoring technology, and modified by numerical simulation. Taking the transportation roadway of 1621(1) working face of Pansan Coal Mine in Huainan as an example, the stress relief method was used to measure the in-situ stress, and the force measuring bolt was installed at the key position of the tunnel to monitor and record the axial force of the bolt in real time. Combined with the numerical simulation, the support schemes before and after optimization were compared. The results show that horizontal stress is the main factor in deep roadway. With the increase of the angle between the direction of roadway driving and the direction of maximum horizontal principal stress and the increase of the principal stress difference, the deformation of roadway increases rapidly. Due to its small pre-tightening force in existing support schemes, the full-length anchorage cannot play its full role, and the shallow roof of roadway shows intense deformation. In the optimized support design scheme, the anti-deformation ability of surrounding rock is improved by high pre-tightening force combined with full-length anchorage support. And the characteristics improvement and the effective stress increase of surrounding rock can reduce the deformation of roadway, thus contributing to a sound support effect.