【摘要】 研究目的：盾构掘进过程中出现盾体偏转的情况较为普遍，一般以±1°～±3°以内的小角度偏转为主，大角度偏转较为罕见，本文针对特殊火山灰地层盾体超90°侧滚偏转实际案例，基于刀盘扭矩传递路径与盾体抗偏转扭矩组成，从盾体与围岩的接触状态、管片衬砌抗旋转能力等方面对盾体偏转原因进行了详细分析，揭示盾体大角度偏转机理，给出有效的盾体抗偏转控制措施。研究结论：（1）盾体与地层之间的摩擦力可以给盾体偏转（旋转）提供足够的抵抗力矩，盾体侧摩阻力不足是导致盾体大角度侧滚偏转的主要原因；（2）管片衬砌环缝未设置凹凸榫、环缝接触面之间的抗剪能力不足，是引起盾尾内已拼装管片与盾体一同发生偏转的主要原因；（3）应采用中盾注浆及时将盾体周边空隙填满，确保盾体与地层紧密接触，增加盾体摩阻力，减少地层应力释放与沉降变形风险；（4）盾体发生一定角度偏转时，宜优先考虑仿形刀超挖并调整盾尾注浆位置，仿形刀超挖可以给盾体纠偏提供空间条件、盾尾注浆可以将盾体向超挖部位“顶推”；（5）本研究结论可为类似工程提供借鉴与参考。更多还原

【Abstract】 Research purposes: Shield deflection during tunnelling process is a relatively common occurrence, typically manifesting as minor yaw angles within the range of ±1°-±3°. Large-angle deflection of the shield body is relatively rare. This paper addressed an actual case of severe shield deflection exceeding 90° in roll within a specific volcanic ash stratum. Based on the torque transmission path of the cutterhead and the composition of the shield body’s anti-deflection torque, a detailed analysis was conducted on the reasons for the deflection of the shield body from aspects such as the contact state between the shield body and the surrounding rock, and the anti-rotation capacity of the segment lining. And then, the mechanism underlying large-angle shield deflection was elucidated. Furthermore, effective anti-deflection control measures for the shield body were proposed.Research conclusions:(1) Insufficient lateral frictional resistance between the shield and the surrounding ground is the primary cause of large-angle shield roll deflection. The friction generated at the shield-soil interface can provide sufficient resistance torque to counteract shield rotation.(2) The absence of tongue-and-groove joints in segment rings, coupled with inadequate shear resistance at the ring interfaces, is the main reason why already-erected segments within the tail skin rotate together with the shield body.(3) Grouting through the shield body should be promptly implemented to fill the annular void around the shield, ensuring tight contact with the ground. This enhances shield-ground friction and mitigates the risks of ground stress release and settlement deformation.(4) When shield roll deflection occurs, priority should be given to overcutting with profiling cutters combined with adjusting tail void grouting positions. Overcutting creates the spatial conditions necessary for shield rectification, while tail grouting can "push" the shield towards the overcut area.(5) This paper can provide a reference for similar projects in the future.更多还原