Prediction of Settlement Induced by Tidal Fluctuation for Underwater Shield Tunnel During Service Based on Historical Monitoring Data

Underwater shield tunnels take significant parts in urbanization, such as metro tunnels and utility tunnels. It is important to determine the structural performance and safety during service under complex changes in structure and surrounding ground. One of the influencing factors for underwater shield tunnels is tidal fluctuation. To study the effect of tidal fluctuation on the settlement of underwater shield tunnels, field monitoring, theoretical calculation and statistical analysis are carried out for an underwater shield tunnel crossing the Huangpu River in Shanghai. Based on the historical monitoring data of tunnel settlement and tidal level, the analysis and prediction of tunnel settlement are carried out. The large positive linear association between variables during the service are revealed and verified. It's necessary to consider the effect of tidal fluctuation on tunnel settlement when analyzing the performance and safety of underwater shield tunnels given the unneglectable contribution. Further, the mechanical parameters of the tunnel structure and surrounding ground are determined. A data-driven prediction method of long-term settlement for underwater shield tunnels is proposed and compared. The comparison of different prediction window implies that the mechanical parameters of tunnel structure and surrounding ground only changes slightly in a short period. The results are meaningful for the evaluation and analysis of the performance and safety of underwater shield tunnels.