摘要：The surrounding environment of shield tunnel construction under different geological conditions directly affects the safety of subway construction, so the real-time monitoring of surrounding environment has become a hot issue in subway construction. Among them, the settlement in the process of tunnel construction is the top priority of environmental monitoring. Tunnel long-term settlement monitoring should be conducted continuously from the construction stage to the trial operation stage, as well as to the operation stage. However, for most of the shield- tunnel engineering in practice, it is difficult to ensure the continuous long-term tunnel settlement monitoring due to the influence of various factors. The cumulative settlement data of operating tunnel can only reflect the deformation law of metro shield tunnel at a certain stage. Therefore, it is difficult to evaluate the actual deformation characteristic and the stress state of the shield tunnel. The theoretical calculation and example analysis were performed to verified the above viewpoint. The results show that the continuity and integrity of the measured settlement data should be ensured when they were used for evaluating the structural safety of the operating shield tunnel. However, once the measured settlement data were discontinuous, the deformation law, the longitudinal deformation and the stress characteristic of the operating shield tunnel should be evaluated respectively using the combination of the cumulative settlement data and the elevation data. This study can effectively improve the monitoring effect of shield tunnel settlement environment, and improve the reliable technical support for the safe and efficient construction of the tunnel.
