深部过断层巷道围岩稳定性及控制技术研究

Study on the Stability and Control Technology of Surrounding Rock of Deep Tunnel Through Fault

  • 摘要: 顾北煤矿14321工作面埋深大、地应力高,断层发育,巷道围岩难以控制。针对14321风巷穿越断层破碎带的支护问题,本研究通过顶板弯曲变形力学分析,计算得到顶板最大挠度和破裂区宽度,和数值模拟结果相互印证;采用FLAC3D数值模拟方法,全过程模拟了煤巷过断层的围岩响应。重点分析了F14321−1断层前后10 m范围内围岩的超前支承应力、塑性区及位移场的动态演化规律。结果表明:(1)工作面超前支承应力峰值呈先增后降趋势;(2)距断层10~5 m区段,巷道两帮塑性区范围大于顶底板;(3)掘进至距断层5 m处,顶底板塑性破坏程度显著加剧;(4)过断层期间两帮移近量始终高于顶底板,且断层处围岩移近量出现突变,顶板位移增幅最为突出。实施锚−网−索−喷支护后,巷道顶板下沉量减少34 mm,两帮移近量减少21 mm,底部鼓起量减少44 mm,证实该支护体系可有效抑制围岩变形,保障过断层巷道的稳定性控制。

     

    Abstract: The 14321 working face of Gubei Coal Mine has a large burial depth, high ground stress, well−developed faults, and the surrounding rock of the roadway is difficult to control. To address the support challenges of the 14321 ventilation roadway passing through a fault fracture zone, this study conducted a mechanical analysis of roof bending deformation. The maximum roof deflection and fracture zone width were calculated, with results corroborated by numerical simulations. Using the FLAC3D numerical simulation method, the entire process of the roadway traversing the fault and the surrounding rock response was simulated. The analysis focused on the dynamic evolution of the advanced abutment stress, plastic zone, and displacement field within 10 meters ahead of and behind the F14321−1 fault. The results indicate that: (1) The peak value of the working face's advanced abutment stress initially increases and then decreases; (2) In the section 10 to 5 meters from the fault, the plastic zone range in the roadway ribs is larger than that in the roof and floor; (3) When excavation reaches 5 meters from the fault, the degree of plastic failure in the roof and floor significantly intensifies; (4) During fault crossing, the convergence of the ribs consistently exceeds that of the roof and floor, with a sudden change in surrounding rock convergence occurring at the fault, where the increase in roof displacement is most pronounced. Following the implementation of combined bolt−mesh−cable−shotcrete support, roadway roof subsidence decreased by 34 mm, rib convergence reduced by 21 mm, and floor heave decreased by 44 mm. This confirms the effectiveness of this support system in controlling surrounding rock deformation and ensuring the stability control of the roadway traversing the fault.

     

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