The influence of different geothermal distributions on the pressure transients of high-speed trains passing through tunnels

Abstract

In this paper, experiments and numerical simulations are used to study the pressure wave transient laws, propagation characteristics and dynamic temperature field changes in tunnels located near geothermal hot springs. To simulate different temperature distributions, areas of 0–80 m, 80–160 m, 160–240 m and 270–350 m are heated, and the tunnel pressure wave peak value and train surface pressure wave peak value are studied accordingly. The research shows that when the heating zone is 0–80 m, the influence on the initial pressure wave is the greatest, the change rate is 8–10 %, and the initial expansion wave change rate is 5–10 %. When the heating zone is 80–160 m, there is little change in the pressure wave peak value in the first and second stages, and the expansion wave peak value is larger than the normal temperature in the third stage. When the heating zone is 160–240 m, the change rate of the pressure wave peak is small. When the heating zone is 270–350 m, there is a negligible change in the initial compression wave and expansion wave peaks in the first and second stages, and the change rate in the third stage is 2–4 %. Moreover, the heating zone located in front of the tunnel has a greater impact on the pressure at the tip of the train's nose, and the heating zones located in the middle and end of the tunnel have little effect on the initial positive peak value of the train pressure wave but a greater effect on the negative peak value. This study explores the influence mechanism of different geothermal distributions on pressure waves, which can provide more accurate boundary data for improving passenger comfort and the train thermal structural performance in high-temperature tunnels.