高应力大断面巷道围岩注浆加固机理及其应用

    Mechanism and application of grouting reinforcement on surrounding rock of roadway with high stress and large section

    • 摘要: 为解决高应力大断面巷道服务期间变形严重的问题,利用莫尔-库仑准则和力学平衡原理,开展巷道松动圈注浆加固机理和力学模型分析,采用FLAC3D仿真计算软件对4种不同支护形式进行数值模拟,研究不同支护状态下巷道变形演化规律,并开展现场工程实践。研究结果表明:增加承载层的长度可以有效提高巷道围岩的稳定性,注浆加固可黏合破碎岩体,形成骨架结构;分层掘进可减小巷道围岩自由面,从而减缓应力释放速度;滞后注浆可在应力基本释放后对破碎岩体进行最大程度的黏合加固,加固后的松动圈形成整体结构后配合锚杆索支护,能够有效减少围岩破坏以及塑性区发育。实践证明:采用“分层掘进+滞后注浆+锚索补强”支护方案后,掘进期间,顶底板最大移近量约为50 mm,两帮最大移近量约为140 mm,底鼓量约为75 mm;5303工作面回采期间,顶底板最大移近量约为125 mm,两帮最大移近量约为350 mm,底鼓量约为173 mm,虽然回采期间巷道变形量较大,但整体变形可控,能满足深部大断面巷道支护要求。“分层掘进+滞后注浆+锚索补强”支护方案能够有效解决高应力大断面巷道严重变形问题,可在类似地质条件的矿井推广。

       

      Abstract: In order to solve the problem of serious deformation of roadway with high stress and large section during service period, Mohr-Coulomb criterion and mechanical balance principle are used to analyze the mechanism and mechanical model of grouting reinforcement of roadway loose ring. FLAC3D simulation software is used to conduct numerical simulation of four different support forms, study the evolution laws of roadway deformation under different support states, and carry out field engineering practice. The results show that increasing the length of the bearing layer can effectively improve the stability of the surrounding rock of roadway, and grouting reinforcement can strengthen the cohesive broken rock mass to form the skeleton structure. Stratification excavation can reduce the free surface of surrounding rock and slow down the stress release speed. Delayed grouting can strengthen the fractured rock mass to the maximum extent after the basic stress release, and the reinforced loose ring forms a whole structure and is supported with anchor cable, which can effectively reduce the damage of surrounding rock and the development of plastic zone. The practice has proved that after the support scheme of “stratification excavation + delayed grouting + anchor cable reinforcement” is adopted, during excavation, the maximum displacement of the top and floor is about 50 mm, the maximum displacement of the two walls is about 140 mm, and the floor heave is about 75 mm. During the mining period of 5303 working face, the maximum displacement of the top and floor is about 125 mm, the maximum displacement of the two walls is about 350 mm, and the floor heave is about 173 mm. Although the deformation of the roadway is large during mining, the overall deformation is controllable, it can meet the support requirements of deep roadway with large section. The support scheme of “stratification excavation + delayed grouting + anchor cable reinforcement” can effectively solve the serious deformation problem of high stress and large cross-section tunnels, and can be promoted in mines with similar geological conditions.

       

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