双护盾TBM掘进数值仿真及护盾卡机控制因素影响分析

Numerical simulations of double-shield TBM tunneling for analyzing shield jamming control factors

卡机是制约双护盾全断面隧道掘进机(tunnel broing machine, TBM)安全、高效施工的重要工程地质问题。卡机涉及影响因素较多,数值仿真是对各种因素的影响程度进行定量化分析的有效手段。该文提出了考虑双护盾TBM掘进施工过程的数值仿真方法,通过基于内变量热力学的蠕变模型模拟围岩的时效变形特性,并实现围岩与护盾的相互作用的模拟。以某公路隧洞为研究对象,对TBM推进速度和超挖量2个卡机控制因素的影响进行了研究。分析结果表明:增大TBM推进速度,能在一定程度减小接触压力和卡机风险;而超挖量对减小接触压力的作用更为显著,且对于高地应力、软岩条件下的隧洞施工,2种卡机控制措施的收益将更加明显。研究结果可为类似工程的卡机风险分析及TBM推进速度和超挖量等参数的优化设计提供一定的借鉴。

Shield jamming is an important engineering geological problem that restricts safe, efficient construction of double-shield tunnels by tunnel boring machines(TBMs). Many factors influence shield jamming with numerical simulations needed to analyze the influences of these many factors. This study used numerical simulations of the tunneling process of a double shield TBM. The simulations use the creep model based on internal variable thermodynamics theory to simulate the time-dependent deformation of the surrounding rock and the interactions between the surrounding rock and the shield. The simulations were used to analyze the influence of two shield jamming control factors, the TBM advance rate and the overcut, for a highway tunnel. The results show that increasing the advance rate somewhat reduces the contact force and the shield jamming risk. The overcut has a larger effect on the contact force. Careful use of these two shield jamming control measures is more important for tunnel construction with high ground stresses and soft rock conditions. These results provide a reference for shield jamming risk analyses and optimizing the TBM parameters such as the advance rate and the overcut.