深部厚煤层回采巷道围岩破坏机制及支护优化

为了研究深部厚煤层回采巷道围岩破坏机制及支护对策,基于地质条件分析,采用钻孔窥视仪和地质雷达探测了巷道围岩的破坏模式及规律,通过模拟研究得到围岩的破坏机制,针对性的提出了锚网带与预应力锚索梁耦合让均压的优化支护方案和参数。结果表明:围岩由表面向内部破坏程度依次减弱,形成3~4个破裂区,前2个破裂区为松动圈。松动圈分布在煤层和底板泥岩中,其中顶部围岩松动圈平均深度3 m,易产生离层。煤层越厚巷道越易失稳,其破坏机制是顶板锚杆处在破碎区,产生锚固端滑脱或整体冒落。通过现场支护试验,验证了优化支护方案和参数,有效地控制了厚煤层回采巷道稳定性。

Failure Mechanism of Roadway Surrounding Rock in Deep Thick Coal Seam and Its Support Optimization

To study the failure mechanism and support measures of roadway surrounding rock in deep thick coal seam,based on geological conditions analysis,the borehole TV and geological radar were used to survey the failure modes and rules of roadway surrounding rock in this paper,and the failure mechanism of surrounding rock was obtained through numerical simulation.On this basis,the targeted optimization support program and specific parameters of pretension bolt network coupled with yieldable cable beams were proposed.The results show that the failure degree decreases successively from the surface of surrounding rock to the interior,and forms 3 to 4 failure zones,while the external two failure zones are the traditional relaxation zones.The relaxation zone distributes in coal seam and bottom mud,while the average thickness of relaxation zone in the top is 3m,and is easy to cause separation.The roadway is more unstable in thick coal seam,while the failure mechanism is that the roof bolts locates in the relaxation zone of thick seam,and easily produces slippage of anchor end and overall falling.In-site support test shows that the proposed optimization support program is effective to control the stability of thick coal seam roadway.