Pressure waves and their influence on fatigue damage of shield tunnel segment structure

Abstract

In this study, a three-dimensional numerical model was used to analyze the transient pressure on a segment structure and the CFD caused to it under pneumatic loading action. The results of two trains meeting in the tunnel show that the tunnel cross-sectional area, train speed, and tunnel location significantly influence the peak pressure wave generated on the segment structure. After the trains completely exit the shield tunnel, the peak values of the aerodynamic load may still be higher than that of the aerodynamic pressure wave caused by the trains running in the tunnel, and may last for approximately 10 cycles. Based on the characteristics of the pressure peak values, the mathematical relationship between the attenuation rate of the peak-to-peak pressure values and the number of periods was fitted; the CFD equation was modified, and the rationality was verified. The CFD of the segment structure was approximately proportional to the square of the number of aerodynamic load periods. Thus, the maximum CFD calculated for 100 years is 0.107 × 10−2. This indicates that fatigue damage does not occur in the segment structure under an aerodynamic load.