Effects of ambient pressure on aerodynamic pressures induced by passing metro trains in tunnels: Fid-Bau Portal

Effects of ambient pressure on aerodynamic pressures induced by passing metro trains in tunnels

Liu, Fang / Wang, Fei / Han, Jiaqiang / Zhao, Shengzhong / Weng, Miaocheng

Highlights • The tunnel pressure wave caused by metro trains in high-altitude areas was analyzed. • The ambient pressure has little effect on the waveform of the pressure wave. • The ambient pressure has a significant impact on the peak pressure wave.

Abstract Transient pressure induced by the trains passing through tunnels has a significant influence on tunnel structural safety. When tunnels are constructed at somewhere with high altitude and low atmospheric pressure the impact of ambient pressure cannot be ignored. In the current study, a three-dimensional, unsteady, compressible, RNG ᴋ–ε turbulence model, and the dynamic mesh was employed to explore the effect of ambient pressure on the propagation characteristics of pressure waves inside the tunnel when the train passes through the tunnel at the same speed (100 km/h). Results show that (1) The ambient pressure has limited influence on the waveform of the pressure but strongly affects the peak value of pressure wave, where positive peak value P-max and peak-to-peak pressure difference ΔP linearly increase and negative peak value P-min proportionally decreases with the increase of ambient pressures; (2) The initial compression wave ${Δ P}_{N}$ and pressure increase caused by the friction effect ${Δ P}_{fr}$ linearly increase as ambient pressures increases. However, the ratio of ${Δ P}_{N}$ to P-max is not sensitive to the ambient pressure and values of $\frac{{Δ P}_{N}}{P - m a x}$ remains to be constant.