Due to the fact that ballastless tracks in high-speed railways are not only subjected to repeated train–track dynamic interaction loads, but also suffer from complex environmental loads, the fundamental understanding of mechanical performance of ballastless tracks under sophisticated service conditions is an increasingly demanding and challenging issue in high-speed railway networks. This work aims to reveal the effect of train–track interaction and environment loads on the mechanical characteristic variation of ballastless tracks in high-speed railways, particularly focusing on the typical interface damage evolution between track layers. To this end, a finite element model of a double-block ballastless track involving the cohesive zone model for the track interface is first established to analyze the mechanical properties of the track interface under the loading–unloading processes of the negative temperature gradient load (TGL) followed by the same cycle of the positive TGL. Subsequently, the effect of wheel–rail longitudinal interactions on the nonlinear dynamic characteristics of the track interface is investigated by using a vehicle-slab track vertical-longitudinal coupled dynamics model. Finally, the influence of dynamic water pressure induced by vehicle dynamic load on the mechanical characteristics and damage evolution of the track interface is elucidated using a fluid–solid coupling method. Results show that the loading history of the positive and negative TGLs has a great impact on the nonlinear development and distribution of the track interface stress and damage; the interface damage could be induced by the wheel–rail longitudinal vibrations at a high vehicle running speed owing to the dynamic amplification effect caused by short wave irregularities; the vehicle dynamic load could produce considerable water pressure that presents nonlinear spatial–temporal characteristics at the track interface, which would lead to the interface failure under a certain condition due to the coupled dynamic effect of vehicle load and water pressure.

由于高速铁路中的无ball轨道不仅承受反复的列车－轨道动态相互作用载荷，而且还承受复杂的环境载荷，因此，对复杂服务条件下无ball轨道的机械性能的基本了解日益增长高速铁路网络中充满挑战的问题。这项工作旨在揭示火车—轨道相互作用和环境载荷对高速铁路无track轨道机械特性变化的影响，特别是关注轨道层之间典型的界面损伤演变。为此，首先建立了一个双块无ball轨道的有限元模型，该模型涉及轨道界面的内聚区模型，以分析负温度梯度载荷（TGL）的加载-卸载过程下轨道界面的力学性能，然后进行分析。阳性TGL的周期相同。随后，通过使用车辆-平板轨道垂直-纵向耦合动力学模型，研究了轮轨纵向相互作用对轨道界面非线性动力学特性的影响。最后，使用流固耦合方法阐明了由车辆动态载荷引起的动态水压对轨道界面的机械特性和损伤演化的影响。结果表明，正负TGL的加载历史对轨道界面应力和损伤的非线性发展和分布有很大影响。由于短波不规则性引起的动态放大效应，在高车辆行驶速度下，轮轨纵向振动会引起界面损伤；车辆动载荷可能会产生相当大的水压，从而在履带界面处表现出非线性的时空特性，这在一定条件下会由于车辆载荷和水压的耦合动力效应而导致界面失效。由于短波不规则性引起的动态放大效应，在高车辆行驶速度下，轮轨纵向振动会引起界面损伤；车辆动载荷可能会产生相当大的水压，从而在履带界面处表现出非线性的时空特性，这在一定条件下会由于车辆载荷和水压的耦合动力效应而导致界面失效。由于短波不规则性引起的动态放大效应，在高车辆行驶速度下，轮轨纵向振动会引起界面损伤；车辆动载荷可能会产生相当大的水压，从而在履带界面处表现出非线性的时空特性，这在一定条件下会由于车辆载荷和水压的耦合动力效应而导致界面失效。