基于频变等效参数的无砟轨道——路基动力响应分析

he subgrade in composite beam model and beam and slab model of the ballastless track-subgrade can be equivalently assumed to be the spring and damping of fixed parameters in dynamic analysis. The research described in this paper is based on the semi-space theory of dynamic foundation and the equivalent conditions of subgrade and semi-space to obtained the frequency-dependent subgrade equivalent parameters, and adopts the finite element method to establish composite beam model and beam and slab model of the ballastless track-subgrade dynamic analysis. Applying the wheel-track force considering unevenness excitations on the different positions of the steel rails, and the similarities and differences of the track structure dynamic response characteristics are analyzed for the different models with different loading cases. The numerical results are compared with the measured ones, and the reliability of this modeling method as well as the calculation method of equivalent parameters of subgrade is verified. It shows that this method can reflect more realistic characteristics of the subgrade structure and even the frequency response in the entire track line system.