Effect of Differential Subgrade Settlement on Dynamic Performance of High-Speed Vehicle and Double-Block Ballastless Track Coupled System

摘要

Due to the superior integrity and stability, the double-block ballastless track is extremely sensitive to the deterioration of substructure. A detailed model that takes the nonlinear subgrade support into account is proposed based on the theory of vehicle-track coupled dynamics. Effects of differential subgrade settlement on the dynamic performance in terms of the wheel-rail force, vibration accelerations, and the track-subgrade contact force are carried out. Results indicate that the settlement-induced degradation of track geometry and the unevenness of track support significantly exacerbate the wheel-rail interaction. The magnitude of the settlement primarily dictates the impact load which eventually aggravates the dynamic responses. There exists a particular range of settlement wavelength related to the distance between bogie centers of the vehicle, resulting in severe vibration of the system. With respect to the operation quality of the high-speed vehicle, the ride comfort bears the brunt of the differential settlement. Moreover, the contact between the concrete track and the soil subgrade is prone to failure as a result of the inconsistent deformations. During the dynamic load, the unsupported area will be slapped continually, leading to abnormal dynamic response. It may not only impair the instantaneous stability of the system, but also impose risks to the long-term behavior of track components.