护盾式TBM穿越断层破碎带岩机相互作用三维数值模拟研究

3D Numerical Simulation of the Interaction between Rock Mass and Shield TBM Passing through the Fault Fracture Zone

  • 摘要: 护盾式TBM掘进穿越断层破碎带时,围岩收敛变形过大易引起TBM卡机。文章以某输水隧洞工程为背景,采用FLAC3D进行数值模拟研究,探究TBM在穿越断层破碎带时机身所受摩阻力的变化特征,分析超前支护强度及超挖间隙等因素对护盾式TBM机身受力及卡机风险的影响规律。研究结果表明,护盾式TBM机身在软弱破碎地层中所受摩阻力是TBM掘进穿过该区域时卡机灾害发生的关键控制因素。机身处于断层破碎带时,护盾处围岩径向相对收敛变形达到0.16 m,超过预留变形,护盾所受的挤压力及前进摩阻力较高,护盾所受最大摩阻力约为108.71 MN。施加锚杆后洞周最大收敛位移减小了17.06%左右,说明锚杆支护作用对断层破碎带处洞周围岩变形影响显著。

     

    Abstract: TBM jamming may occur due to exceeded convergence of surrounding rock when a shield TBM passes through the fault fracture zone. Taking a water conveyance tunnel as the engineering background, the numerical simulation is conducted by FLAC3D to explore the changes of frictional resistance of TBM passing through the fault fracture zone and to analyze the influence of advance support strength and overcut gap on force applied on shield TBM and jamming risk. The simulation results show that the frictional resistance of TBM is the main control factor to cause the jamming of TBM passing through the fault fracture zone, the radial relative convergence of surrounding rock at the TBM shield is 0.16 m which exceeds reserved deformation value, the squeezing force and forward frictional resistance on shield are high with the maximum frictional resistance of 108.71 MN, and the maximum peripheral convergence declines by around 17.06% after supporting with anchor bolts, which means the anchor bolt support can significantly influence the peripheral deformation of surrounding rock in fault fracture zone.

     

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