Dynamic characteristics of the railway ballast bed under water-rich and low-temperature environments

Abstract

Studying the dynamic characteristics and evolution laws of the ballast bed under low-temperature, rain and snow environments has practical significance for the driving stability of railways in alpine. In this paper, a full-scale ballasted track model was constructed in a programmable temperature control laboratory, and the frequency response function (FRF) curves of the ballast bed under different temperature and humidity conditions were measured. Then the vibration characteristics and the evolution laws of the ballast bed under different conditions were analyzed. The longitudinal transfer behavior and the dissipation of the vibration energy in the ballast bed under different humidity and temperature environments were discussed combined with the finite element method. The results show that the influence of temperature on the vibration characteristics of the ballast bed is not significant in the dry and water-rich environments, but the vibration characteristics of the ballast bed in the frozen environment change dramatically with the decrease of temperature. The vibration energy is harder to dissipate in the frozen ballast bed than in the dry and water-rich ballast beds, and the frozen ballast bed is more prone to be sudden damaged when a train passes due to the significant increase in its stiffness. Thus, the performance monitoring and emergency maintenance of the ballast bed in those environments should be strengthened.