盾构隧道管片上浮的机制研究

盾构法施工时难以避免地会对隧道周围地层造成扰动,引起地表位移,对盾尾间隙的充填可以有效地控制盾尾地表沉降。但在盾构掘进、盾尾间隙注浆施工中,隧道管片局部或整体上浮现象也时有发生。对管片结构在施工过程中受力状态进行分析,将管片的上浮归为四大类,即管片封闭成环的上浮、盾构掘进顶推时的上浮、脱出盾尾后管片的上浮、浆液初凝后管片的上浮。并提出管片脱出盾尾后至浆液初凝前的上浮计算方法,此外针对盾构施工期间管片的上浮,提出了管片上浮的控制措施。研究成果可为盾构隧道管片抗浮设计及施工提供一定的技术依据。

Research on Upward Moving Mechanism for Segment of Shield Tunnel

During the process of shield tunneling,it is inevitable to disturb the surrounding stratum and cause surface displacement. The key to control surface subsidence is to effectively fill the gap of the shield tail. But the lining segment is prone to partial or wholly upward moving in shield driving and shield tail gap grouting. In this paper,the upward moving of segment structure is classified into four categories in terms of stress state in the construction process,including the upward moving when the segment is closed to form a ring,the upward moving when shield is advancing,the upward when segment is off the shield tail and the upward moving after grout is initially set. And the calculation method for segment upward moving is proposed from the time when segment is off the shield tail to the time when grout is initially set. In addition,measures to control upward moving of segment are put forward. The research results may provide technical references against segment upward moving in design and construction of shield tunnel.