深部托顶煤小煤柱巷道支护技术研究

Research on support technology for small coal pillar roadways with deep top coal

郭屯煤矿2309工作面轨道巷为沿空巷道,净煤柱宽4 m。分析了现有支护方式存在的问题,主要是支护材料匹配性差,粗牙全螺纹锚杆主动支护效果差。锚杆在冲击载荷下破断时,距破断处600 mm的位置,锚杆的塑性变形仅为破断处变形的1/20,在距冲击载荷施加处较远的位置,锚杆的变形能力还未发挥,锚杆就已经破断。在分析现有支护方式存在问题的基础上,结合地应力测试和围岩结构测试结果,提出了支护改进方案,主要包括采用新型可调心锚索托盘、帮部改用细牙全螺纹锚杆、增加W钢带厚度、提高锚索预紧力、优化帮部锚索布置方式等。现场监测结果表明,优化后的支护方案可有效地提高支护强度,降低巷道围岩变形量。

The track along the No.2309 working face of Guotun Coal Mine is a gob-side entry with a clean coal pillar of 4 m.Analyzed the problems of existing support methods,mainly including poor matching of support materials and poor active support effect of coarse tooth fully threaded anchor rods.When the anchor rod breaks under impact load,the plastic deformation of the anchor rod is only 1/20 of the deformation at a distance of 600 mm from the breaking point.At a distance from the impact load application point,the deformation capacity of the anchor rod has not yet been fully exerted,and the anchor rod has already broken.On the basis of analyzing the problems existing in the existing support methods,combined with the results of in-situ stress testing and surrounding rock structure testing,a support improvement plan was proposed,mainly including the use of a new type of adjustable core anchor cable tray,the use of fine tooth full thread anchor rods for the side,increasing the thickness of the W steel strip,increasing the pre tightening force of the anchor cables,and optimizing the layout of the side anchor cables.The on-site monitoring results indicate that the optimized support scheme can effectively improve the support strength and reduce the deformation of the surrounding rock of the roadway.