无砟轨道路基不均匀沉降区高速列车动力特性

为研究路基不均匀沉降对无砟轨道损伤及高速列车动力响应的影响，基于混凝土塑性损伤理论，建立了可考虑无砟道床混凝土损伤行为的车辆-无砟轨道-路基耦合动力学模型，并与线弹性模型计算结果进行对比，分析路基不均匀沉降波长、幅值及行车速度对高速列车动力学特性的影响.结果表明：路基不均匀沉降会造成无砟道床损伤，塑性损伤模型计算结果更能反映轨道服役状态；在各车辆动力学指标中，车体垂向加速度受路基沉降幅值影响最大；车辆动力学响应对波长20 m以下的路基不均匀沉降较为敏感，应对其重点关注；行车速度的增大会增加车辆动力响应，使轮轨作用力明显提升，车辆平稳性指标呈现接近线性的增长趋势.

Dynamic Characteristics of High-Speed Trains in Differential Subgrade Settlement Zone of Ballastless Track

To study the effect of differential subgrade settlement on the potential damage of ballastless track and the dynamic response of high-speed trains, based on the concrete plastic damage theory, a vehicle-ballastless track-subgrade coupling dynamic model that considers the ballastless track bed damage is established. The applicability of the model is demonstrated by comparing with the calculation results of the linear elastic model. The effects of subgrade settlement wavelength, amplitude and the vehicle speed on the dynamic characteristics of high-speed trains are analyzed. The results show that, the differential subgrade settlement could cause the damage to ballatless track bed. The results of the concrete plastic damage model of ballastless track are more in line with actual service status of the track. Among the vehicle dynamics indicators, the vertical acceleration of the vehicle body is most affected by the subgrade settlement amplitude. The vehicle dynamics response is sensitive to the differential subgrade settlement with a wavelength below 20 m, so it should be paid more attention to. The increase of the train speed increases the dynamic response of the vehicle, the wheel-rail force increases significantly, and the vehicle stability index shows a nearly linear growth trend.