Dynamic Characteristics of Train-ballastless Track under the Conditions of Differential Settlement of Subgrade

Based on Coupling Dynamics Theory, the dynamic analysis model of vehicle-ballastless track-subgrade is built, and the differential settlement of subgrade of high-speed railway is inputted as irregularity with analyzing the relationship among settlement deformation, train and the dynamic response of track system. The calculation results show that tendency of the vertical acceleration of vehicle body increasing with the increase of settlement is obvious, and the settlement also leads to the substantial increase of vertical wheel rail force, wheel unloading rate and the vertical vibration acceleration of rail,but the settlement affects a little to wheel rail lateral force as well as derailment coefficient. Differential settlement of subgrade directly affects the safety of high-speed train operation and passenger comfort, so it should be strictly controlled.