特厚煤层大断面重复采动影响巷道围岩失稳机理及控制技术

Mechanism and control technology of instability of roadway surrounding rock caused by large section repeated mining in extra-thick coal seam

千万吨矿井生产过程中,为了保证采掘接替,经常出现上区段工作面回采时下区段工作面开始掘进的情况,掘进巷道在服务期间受两次采动影响严重。针对重复采动影响巷道围岩控制问题,以斜沟煤矿23108材料巷为研究背景,研究了重复采动围岩变形失稳机理,提出了高强度大延伸率高预应力锚杆支护技术。研究结果表明:巷道在重复采动应力影响下承受非对称性压力作用,呈现明显的偏向实体侧的应力分布特征,煤柱内部和巷道底板集中发生剪切破坏。一次采动影响阶段是采掘交锋巷道围岩稳定的关键控制阶段,巷道尺寸变大会使围岩塑性区范围扩大,从而导致巷道变形更为显著,高预紧力高支护强度能有效减少巷道围岩变形量。工业试验结果表明,优化支护后锚杆受力均匀、破断失效率低,巷道围岩变形量可控,围岩控制技术有效。

In the production process of ten million tons of mines,in order to ensure the replacement of mining,it is common for the upper section of the working face to be mined and the lower section of the working face to start excavation,the excavation roadway is seriously affected by two mining during the service period.Aiming at the problem of surrounding rock control in repeated mining roadway,taking the No.23108 material roadway of Xiegou Coal Mine as the research background,the deformation and instability mechanism of repeated mining surrounding rock was studied,and the high strength,large elongation and high prestress bolt supporting technology was proposed.The results show that the roadway is subjected to asymmetric pressure under the influence of repeated mining stress,showing obvious stress distribution characteristics biased towards the solid side,and shear failure occurs in the coal pillar and the roadway floor.The primary mining influence stage is the key control stage of the stability of the surrounding rock of the mining confrontation roadway.The increase in roadway size will expand the plastic zone of the surrounding rock,leading to more significant deformation of the roadway.High pre tensioning force and high supporting strength can effectively reduce the deformation of the surrounding rock of the roadway.The industrial test results show that after optimizing the supporting,the anchor rod is uniformly stressed,the failure rate is low,the deformation of the roadway surrounding rock is controllable,and the surrounding rock control technology is effective.The industrial test results show that after the optimized support,the bolt is evenly stressed,the failure rate is low,the deformation of the surrounding rock of the roadway is controllable,and the surrounding rock control technology is effective.