For tunnels with large cross-sections, demolition of the temporary shoring of the tunnel can pose a very serious threat to the safety of the structure; Therefore it is very important to ascertain the deformation behavior of the tunnel in this stage. In this study, a tunnel settlement inversion model, based on the strain measurements of distributed optical fiber, has been proposed and the feasibility of the model has been verified by laboratory tests. Based on field observations, the strain distribution characteristics of the optical fibers and the variations in the mechanical properties of the tunnel were analyzed, taking the demolition process into consideration. The results of the monitoring indicated that demolition of the bottom shoring will cause large and uneven crown settlements; this is because this step will weaken the vertical supporting force at the bottom of the arch. Besides, continuous removal of the bottom shoring of the tunnel can result in large settlement and deformation of the crown, which should be pay attention in this stage. The settlement curve of the tunnel has also shown that the strain distribution of the optical fibers was able to reflect the performance of the tunnel in the demolition process of its temporary shorings.

对于大横截面的隧道，拆除隧道的临时支护会对结构的安全性造成严重威胁。因此，在此阶段确定隧道的变形行为非常重要。本研究提出了一种基于分布式光纤应变测量的隧道沉降反演模型，并通过实验室测试验证了该模型的可行性。在现场观察的基础上，考虑了拆除过程，分析了光纤的应变分布特性和隧道力学性能的变化。监测结果表明，底部支护的拆除将导致大而不均匀的树冠沉降。这是因为此步骤会削弱拱形底部的垂直支撑力。此外，连续拆除隧道的底部支护会导致拱顶大沉降和变形，在此阶段应引起注意。隧道的沉降曲线还表明，光纤的应变分布能够反映隧道在临时支护拆除过程中的性能。