特厚煤层强动压巷道围岩控制技术研究

Research on surrounding rock control technology for strong dynamic pressure tunnel in extra thick coal seams

针对特厚煤层强动压巷道难维护问题,以中煤平朔井工一矿19110辅运巷道为研究背景,采用数值模拟、理论分析和现场实测等方法,对巷道围岩的采动应力演化规律、变形破坏特征进行了研究,开展了支护方案优化设计和现场试验。研究结果表明:巷道受回采工作面采动支承压力显著影响位置主要发生在滞后临近回采工作面的采空区后方;根据不等压巷道弹塑性力学分析可知,侧压系数对巷道围岩的变形和破坏具有较大影响,巷道的变形量和塑性区半径均随着侧压系数的增大而增大。依据数值模拟和理论计算确定的侧压系数小于2,巷道塑性区半径按1.90 m设计,巷道支护优化设计方案为:锚杆均采用MSGM-335、Φ22 mm×2400 mm左旋无纵筋螺纹钢,顶锚杆间排距为900 mm×1000 mm,每排布置6根,最外1根距帮350 mm,安设钢带加强支护;帮锚杆间排距为1200 mm×1000 mm,左右帮各布置3根,上面1根距顶300 mm;锚索采用Φ21.8 mm十九芯钢绞线,长度视顶煤厚度采用10300~13300 mm,每排布置2根,间排距为2000 mm×3000 mm。现场试验巷道变形监测结果表明,支护方案对巷道围岩的变形控制效果较好。

Aiming at the problem of difficult maintenance and strong dynamic pressure roadway in extra thick coal seam,taking the 19110 auxiliary transportation roadway in Pingshuo No.1 Coal Mine as the research background,using the methods of numerical simulation,theoretical analysis and field measurement,the evolution law of mining stress and deformation and failure characteristics of roadway surrounding rock are studied,and the optimization design and field test of support scheme are carried out.The results show that the significant influence of the mining support pressure on the roadway mainly occurs behind the goaf that lags behind the adjacent mining face.According to the elastic-plastic mechanical analysis of unequal pressure tunnels,it is known that the lateral pressure coefficient has a significant impact on the deformation and failure of the surrounding rock of the tunnel.The deformation amount and plastic zone radius of the tunnel increase with the increase of the lateral pressure coefficient.The lateral pressure coefficient determined based on numerical simulation and theoretical calculation is less than 2,and the radius of the plastic zone in the tunnel is designed to be 1.90 meters.The optimized design plan for tunnel support is:MSGM-335Φ22 mm×2400 mm left handed threaded steel without longitudinal reinforcement anchor rods is used,with a row&line space of 900 mm×1000 mm between top anchor rods,6 pieces arranged in each row,with the outermost one 350 mm away from the side,and steel strip reinforcement support installed.The row&line space of 1200 mm×1000 mm between sidewall anchor rods,with 3 pieces arranged on the left and right sides,and 1 piece on the top 300 mm away from the top.Anchor cable usedΦ21.8 mm nineteen core steel strands,with a length ranging from 10300 mm to 13300 mm depending on the thickness of the top coal.Two strands are arranged in each row with a row&line space of 2000 mm×3000 mm.The deformation monitoring results of the field test roadway show that the optimized support scheme has a good effect on the deformation control of the surrounding rock of the roadway.