高应力软岩轨道下山失稳机理与支护技术研究

Instability mechanism and the support technology of rail dip entry in high-stress soft rock

针对高应力软岩巷道的大量变形和破坏问题,以河南红岭煤矿14采区轨道下山巷道为例,研究和分析了变形机理和返修控制技术。该下山出现了顶板下沉、两帮内挤、拱肩和两帮砌碹开裂、底板鼓起等变形破坏形式;通过巷道围岩物理力学实验和松动圈测定,表明该巷道围岩含泥岩和砂质泥岩较多,整体强度低,松动圈范围较大。依据松动圈围岩分类以及耦合支护原理,提出"锚杆(锚索)+U型钢可缩性支架+锚注"耦合支护方式。通过数值模拟实验分析了该支护方式下围岩的力学特征、位移特征和破坏特征。并对其进行现场试验,返修现场应用效果:经过100d观测,巷道顶底板移近量最大值为121mm,两帮收敛量最大值为82mm,监测后期的收敛速率均小于1mm/d,处于稳定状态。

Aiming at the serious deformation and failure in high stress soft rock roadway, we took the rail dip entry in No. 14 mining area of Hongling Coal Mine as an example to study and analyze the deformation mechanism and rework control technology. According to the forms of deformation and failure in the dip entry, including roof subsidence （roof caving）, two sides extrusion, spandrel, fracture of side wall brickwork and floor heave, physical mechanics experiment of surrounding rock and loose circles tests were carried out. The results show that, the surrounding rock contains many mudstone and sandy mudstone with low integral strength, which leads to large loose circles. Based on classification method of surrounding rock loose circle and analysis of roadway＇ s supporting theory, the coupling support method with ＂anchor bolt（anchor cable） ＋ U steel retractable support ＋ anchor ＋ grouting＂ was put forward to rework the rail dip entry. We analyzed the stress distribution, displacement distribution and plastic zone distribution of surrounding rock under the proposed support scheme using numerical simulation. Filed test was also carried out, and the application shows that roof - to -floor convergence of roadway was less than 121mm after 100 days, two -rib convergence was less than 82mm, and the average convergence rate was less than 1.0mm/d in the late monitoring, the rail dip entry was stabilized.