Three-dimensional characteristics of pressure waves induced by high-speed trains passing through tunnels.

In this study, the sliding grid method is used to simulate a 350 km/h high-speed train passing through a 350 m standard single-line tunnel. The cross-sectional pressure distribution ahead of the train is investigated, the three-dimensional characteristics and propagation mechanism of pressure waves are described based on iso-pressure surfaces, and a newly accurate pressure sensor layout is proposed. The results show that the farther the cross-section is from the train, the smaller the cross-sectional pressure difference is. Influenced by the shape of the train nose and tunnel cross-section, the pressure waves are not simple planar waves, but spherical waves that vary in complexity over the propagation process. As the pressure difference of the 16.6 m cross-section before the train is within 1 Pa, the pressure waves behind this cross-section are defined as planar waves. Besides, the pressure peak-to-peak value difference between the wall and construction clearance reaches 13% at 70–90 m cross-sections, so the pressure sensors should be placed on the surface of the appurtenances rather than on the tunnel wall. In summary, this study is significant for understanding the formation and transmission mechanisms of pressure waves and guiding the scientific layout of pressure sensors in tunnels. [ABSTRACT FROM AUTHOR]