列车移动荷载与非一致地震动作用下轨道-路基系统动力响应

Dynamic response of a track-subgrade system under moving train loads and non-uniform ground motions

为研究列车移动荷载与非一致地震动耦合作用下轨道-路基系统动力响应规律,以京沪高铁和CRH3型列车为研究对象,建立了三维精细化有限元模型,进行了耦合荷载作用下轨道-路基系统动力响应分析。通过平稳地震动时程乘以包络函数合成了非一致地震动,参数化分析了列车运营时速、轴质量及非一致地震动震级对轨道-路基系统动力响应影响规律。结果表明:轨道-路基系统响应幅值并非随列车运行速度提升而增大,存在一个包括临界速度的范围,在此范围内列车移动荷载与非一致地震动耦合作用下轨道-路基系统将会出现强烈振动;随着列车轴质量或地震动PGA(peak ground acceleration)增大,轨道-路基系统出现更显著的震动响应。与一致激励相比,非一致激励下轨道板竖向位移峰值和竖向加速度峰值的出现时间更早。

In order to study the dynamic response of a track-subgrade system under the coupling effect of moving train loads and non-uniform ground motions,a three-dimensional refined finite element model was established,taking Beijing-Shanghai high-speed railway and CRH3 train as the research objects,and the dynamic response analysis of the track-subgrade system under earthquakes combined with moving loads was carried out.The non-stationary ground motion was synthesized by multiplying the stationary ground motion time history by the envelope function.The effects of train operating speed,axle weight and magnitude of non-uniform ground shaking on the dynamic response of the track-subgrade system were analysed parametrically.The results show that the response magnitude of the track-subgrade system does not increase with the increase of train speed,and there is a range including the critical speed in which the stronger vibration of the track-subgrade system will occur under the coupling of moving train loads and non-uniform ground motions.With the increase of train axle load or the PGA of ground motion,the track-subgrade system shows a more significant vibration response.Compared with uniform excitation,the maximum vertical displacement and the maximum vertical acceleration of the track slab appear earlier under non-uniform excitation.