大直径曲线盾构隧道中，盾构掘进时盾构对其两侧和拱顶上方的土体作用不同，不同位置土体表现出不同的变形规律。为了保证曲线盾构隧道施工安全进行，并针对变形的差异性提出相应的解决方案，采用现场监测和FLAC 3D数值模拟相结合的方法，对超大直径曲线盾构隧道施工中周边土体变形进行分析，监测项目包括地表沉降、分层沉降、土体深层水平位移。研究结果表明：1）随着隧道掘进，地表沉降呈现反“S”形变形趋势，与3个变形阶段对应，即盾构切口到达时缓慢隆沉，盾构通过时沉降较快，盾尾脱出时沉降趋于稳定； 2）横向沉降槽曲线中，掘进时隧道掘进方向曲线内侧沉降量比外侧对称位置沉降更大； 3）土体水平位移在隧道掘进方向曲线内侧变形量小于外侧变形量。

The surrounding ground will be disturbed when a large diameter shield bores in curved section. In the paper, analysis is made on the influence of a superlarge diameter shield tunneling on the surrounding environment by means of site monitoring and FLAC 3D numerical simulation, so as to guarantee the safety of the construction and to provide a solution for the deformation difference. The monitoring items include ground surface settlement, layered settlement and deep horizontal displacement of soil. The study results show that: 1) The ground surface settlement takes place in 3 stages, i.e., when the cutting ring of the shield reaches, the rate of the ground surface settlement is low; when the shield passes, the rate of the ground surface settlement is high; when the shield tail passes, the rate of the ground surface settlement becomes stable; 2) The ground surface settlement on the inner side of the curved tunnel section is larger than that on the outer side of the curved tunnel section; 3) The horizontal displacement of ground on the inner side of the curved tunnel section is smaller than that on the outer side of the curved tunnel section.