Fatigue damage and residual life of secondary lining of high-speed railway tunnel under aerodynamic pressure wave

To investigate the fatigue behaviours of tunnel secondary lining under the aerodynamic effects produced by the running high-speed railway (HSR) trains, we proposed a dual fatigue damage accumulation model (DFDAM). In our model, a nonlinear variable load model was nested inside an equal-damage nonlinear model. The nonlinear variable load model was used to calculate the fatigue damage of a tunnel secondary lining after a single HSR train travelled through the tunnel, and the equal-damage nonlinear model was adopted to calculate the fatigue damage after multiple HSR trains travelled through the tunnel. Our proposed model was verified by comparison with laboratory fatigue testing results obtained by other researchers. The proposed model was also used to study the aerodynamic fatigue behaviours of a practical HSR tunnel project. The results show that the damage accu-mulation produced during the train running inside the tunnel is approximately the same as that of after an HSR train tail leaves the tunnel exit. Thus, after an HSR train leaves the tunnel exit, the influences of the aerodynamic pressure on the tunnel secondary lining cannot be ignored. The damage accumulation of a tunnel secondary lining associated with multiple HSR trains passing increases monotonically with the increase of the consumed life fraction. In contrast, the residual life of the fatigue damage decreases monotonically. This study can serve as a reference for studying the operational safety of HSR tunnels.