General Analytical Method to Predict the Spatial-Temporal Distribution of Extreme Pressure in High-Speed Railway Tunnels in the Post-Train Stage

Long-duration aerodynamic pressure fluctuation in high-speed railway tunnels in the post-train stage causes fatigue damage to tunnel structures and facilities. It increases the risk of accidents and requires in-depth research. This complex phenomenon is caused by the superposition of multiple pressure waves generated successively when a train enters/leaves a tunnel. In this study, the spatial-temporal distribution of the pressure state (SDPS) model was developed, and general equations describing the transient pressure state distribution were given. Furthermore, a prediction method for extreme pressures in tunnels and a fast calculation program were proposed based on the SDPS model. The proposed model was verified using field measurements. Using the SDPS model, the worst conditions of pressure fluctuations in tunnels were analyzed. The results show that most of the maximum positive and negative pressures are symmetrical around the midpoint of the tunnel axis and appear alternately around it. When the train/wave velocity ratio M <= 0.8 and the train/tunnel length ratio epsilon <= 0.8, the dimensionless position of the maximum peak-to-peak pressure region was concentrated in the region of [0.33,0.67] in the tunnel, indicating the location of potential fatigue damage. The proposed model is helpful in building safe and sustainable transportation systems.