大直径盾构隧道管片错台和姿态线形控制技术研究与探讨

Control Technology for Segment Dislocation and Attitude of Large-Diameter Shield Tunnels

为解决大直径盾构隧道掘进施工中经常出现的管片上浮、错台和线形偏差等难题,对多个大直径盾构工程设备和施工过程进行姿态模拟和现场测试,发现盾构主机经常采用低头或与隧道线形不一致的姿态掘进,管片脱出盾尾后会产生较大的上浮力或水平错动力,造成规律性错台或隧道线形偏差,还会造成管片开裂、破损和渗漏等问题。探究发现:盾构主机重心偏移、盾尾及后方管片上浮或姿态调整过度是造成管片规律性错台和隧道线形偏差的主要原因。分析认为:盾构姿态和隧道线形控制除了受地层性状和浮力等客观条件影响外,还主要受盾构设备、管片结构和施工控制3方面影响。在合理优化盾构设备主机自重、重心和注浆系统,强化管片环缝端面结构和抗剪设计的基础上,通过加强盾构姿态拟合、掘进参数管控和注浆工艺创新等措施,可实现大直径盾构隧道管片错台消减或规避、姿态和线形可控。

During the tunneling process,segments of large-diameter shield tunnels often experience uplift,dislocation,and linear deviation.To address these issues,attitude simulations and field tests are conducted on multiple large-diameter shield engineering projects and construction processes.When the shield main machine operates with a lower head or an attitude misaligned with the tunnel,significant upward buoyancy or horizontal misalignment forces occur at the segments after they exit the shield tail.This force can cause regular dislocation,tunnel alignment deviation,segment cracking,segment breakage,or even leakage.The results reveal that the primary causes of regular segment dislocation and tunnel alignment deviation are the barycenter shift of the shield main machine,the floating of the shield tail and rear segments,and excessive attitude adjustments.Analytical results show that shield attitude and tunnel alignment control are primarily influenced by formation properties,buoyancy,shield equipment,segment structure,and construction control.The phenomenon of segment dislocation can be avoided,and segment attitude and alignment can be effectively controlled by rationally optimizing the weight,barycenter,and grouting system of the shield main machine,strengthening the design of the end structure of the segment ring joint and shear,enhancing shield attitude fitting,controlling tunneling parameters,and innovating grouting technology.