Impact of Water Level Rise on the Behaviors of Railway Track Structure and Substructure

Extreme weather events, such as floods and heavy rainfall, have become increasingly severe worldwide. Railways can be exposed to high water levels, which may decrease their performance and jeopardize the safety of running trains. This paper evaluates the performance of high-speed railways under various water levels. A full-scale physical model of a ballastless railway was constructed in a test box measuring 15 m wide, 5 m long, and 6 m deep. Water levels in the physical model were raised and lowered with a water level control system. Stationary cyclic loading and train moving loading tests were carried out at four typical water levels: at the subsoil bottom, at the subsoil surface, at the subgrade surface, and falling back to the subsoil surface. Variations in the water level of the subsoil had a minor influence on the dynamic performance of the railway infrastructure. When the water level rose in the subgrade, the track modulus degraded significantly. Both displacement and tensile strain of the track structure increased rapidly with the submerged sub-grade. The transverse distribution of the contact pressure under the track structure changed significantly with variations in the water level. Fine particles were observed to migrate out from the subgrade; this condition became more serious when traffic loading was applied. Appropriate measures should be taken to prevent water level rise in the subgrade.