Effects of Uneven Subgrade Settlement on the Dynamics of Train-CRTS III Slab Track Nonlinear Coupling System

Abstract

The uneven subgrade settlement affects the running of high-speed trains on slab tracks. However, the dynamics for the coupling system under subgrade settlement lack in-depth research. A nonlinear train-CRTS III slab track coupling dynamic model under uneven subgrade settlement, which considers the interface contact nonlinearity, is developed in ANSYS and validated by a MATLAB program. The initial track statuses and system dynamics under different settlement amplitudes and positions are extensively researched and analyzed using the model. Some conclusions are drawn: (1) Voids occur in slab track with large subgrade settlements, and nonlinear contact elements are needed to model them. (2) The ratios of initial statuses of slab track induced by uneven subgrade settlement are high for most items. (3) The maximum response distributions differ for different items. Some occur around the settlement boundaries. (4) The effect laws of settlement amplitude and position on the system dynamics differ for different items. (5) The tension force of fastener, tension stress of concrete base, and pressure stress on subgrade will exceed the allowable value when the uneven settlement amplitudes exceed 17, 11, and 18[Formula: see text]mm, respectively.