“三软”煤层回采巷道围岩变形机制与加固技术研究

Research on the Deformation Mechanism and Reinforcement Technology of Surrounding Rocks in the Mining Roadway of"Three Soft"Coal Seam

针对“三软”煤层巷道围岩变形严重等问题,以1307工作面回风巷为工程背景,通过室内试验、数值模拟与工业性试验相结合的方法,掌握了巷道围岩力学特性及变形破坏机制,提出并应用了巷道加固技术。结果表明:巷道围岩矿物成分占比较高,且巷道在原支护方案下围岩裂隙发育范围大、锚杆索受力接近破断载荷,围岩变形严重;揭示了支护方案不合理、围岩力学特性差为巷道围岩变形破坏的机制,明确了巷道两帮、底板为加固控制的关键部位,提出了“全长黏结锚固+帮部加固+底板加固”的控制对策;构建了不同支护方案的数值计算模型,获得了不同加固方案下围岩的位移及塑性区分布特征,最终确定了巷道控制效果好的加固参数;巷道加固技术应用后,巷道围岩的最大变形量为156 mm,相比于原支护方案,巷道顶、底板与两帮位移量分别减小了84%、87%,巷道围岩得到了稳定控制。

Aiming at the serious deformation of roadway surrounding rock in"three soft"coal seam,taking the return airway of 1307 working face as the engineering background,through the combination of indoor tests,numerical simulation and industrial tests,the mechanical properties and deformation failure mechanism of roadway surrounding rocks were researched,and a roadway reinforcement technology was proposed and applied.The results show that the mineral composition of the roadway surrounding rocks is relatively high,and the fracture development range of the roadway surrounding rocks under the original support scheme is large,the stress of the bolt cable is close to the breaking load,and the deformation of the surrounding rocks is serious.It is revealed that the unreasonable support scheme and poor mechanical properties of surrounding rocks are the mechanism of deformation and failure of roadway surrounding rocks.It is clear that the two sides and floor of roadway are the key parts for reinforcement control.The control countermeasures of"full-length bonding anchorage+side reinforcement+floor reinforcement"was put forward.The numerical calculation models of different support schemes were constructed,and the displacement and plastic zone distribution characteristics of surrounding rocks under different reinforcement schemes were obtained.Finally,the reinforcement parameters with good roadway control effect were determined.After the application of roadway reinforcement technology,the maximum deformation of roadway surrounding rocks is 156 mm.Compared with the original support scheme,the displacement of roadway roof-floor and two sides is reduced by 84% and 87%respectively.The roadway surrounding rock has been controlled stably.