Dynamic Assessment of Ballastless Track Stiffness and Settlement in High-Speed Railway

Although ballastless track has such advantages as less maintenance and high stability, its big rigidity results in a strong wheel/rail dynamic interaction. In order to study a reasonable stiffness and uneven settlement limit for ballastless track and to optimize the dynamic performance of ballastless track under condition of high-speed running, vehicle together with ballastless track was viewed as an entire coupling system in this study. By adopting numerical simulation, we studied how the stiffness of foundation under rail and uneven settlement of subgrade influence the wheel/rail dynamic interaction. The results show that the reasonable stiffness of foundation under rail is within a range of 20∼30kN/mm, accordingly with a rail deformation within 1.3 ∼ 1.7mm. Through its dynamic analysis under different wavelengths and amplitudes, the uneven settlement of subgrade should be ≤L/1000.