Integrated Approach for Structural Stability Evaluation Using Real-Time Monitoring and Statistical Analysis: Underwater Shield Tunnel Case Study

Real-time monitoring of underwater construction is important for structural stability. To prevent tunnel disasters, an integrated analysis framework for tunnel stability evaluation was proposed using real-time monitoring and statistical analysis. A typical underwater shield tunnel, located in the Yangtze River, China, was selected as a case study. A structural health monitoring system (SHMS) was developed to implement real-time monitoring of the water pressure, temperature, and strain during the service period. An analytical model was developed to investigate the mechanical behaviors of the structure based on the monitoring data obtained from the SHMS. To calibrate the model parameters, numerical simulations were carried out using the finite element method with parameters based on the geological conditions for the study site. Consequently, the results indicate that (1) the numerical results agreed well with the analytical results, which showed that the response of the segment strain varied with position and the maximum strain occurred in the arch crown; (2) the segment strain increased with decreasing water pressure, and the maximum value was $4.118\times {10}^{-7}$ when the water pressure changed by 1 kPa; and (3) the strain variation and temperature were proportional, and the maximum value was $13.492\times {10}^{-6}$ when the temperature changed by 1°C. As a potential application, the proposed method was used to predict future behaviors of the structure, which is crucial for preventing disasters, and provides a reference for underwater construction.