非一致地震激励下列车-轨道-桥梁耦合振动模型

为探讨行波效应对地震作用下高速铁路桥上列车行车安全性的影响,基于列车-轨道-桥梁动力相互作用理论,采用35个自由度的机车车辆模型、板式无砟轨道模型和桥梁有限元模型,通过引入地震多点激励模式,建立了非一致地震激励下的列车-轨道-桥梁耦合振动模型,并编制了相应的仿真分析程序.以跨度32 m的简支梁桥为例,输入El Centro地震波,计算了一致激励和行波激励下车桥系统的动力响应.结果表明:行波效应对耦合系统动力响应幅值的影响很大.当车速为350 km/h、行波速度为300 m/s时的脱轨系数、轮重减载率和轮轨横向力比一致激励分别降低84.1%、19.5%和87.8%.因此,忽略行波效应可能造成对地震时桥上列车行车安全的误判. 

Dynamic Model for Train-Track-Bridge Coupling System Subjected to Non-uniform Seismic Excitation

In order to analyze the effects of traveling wave effect on the running safety of a train running over a high-speed railway bridge subjected to earthquake action, a dynamic model for train-track-bridge system subjected to non-uniform seismic excitation was set up based on the train-track-bridge dynamic interaction theory and by introducing a seismic multi-support excitation mode. This dynamic model consists of a vehicle model with 35 degrees-of-freedom, a slab track model and an FEM (finite element method) bridge model. A simulated analysis program was compiled. As an example, a simply-supported beam bridge with a span of 32 m was modeled, and the dynamic responses of vehicle and bridge system under uniform and non-uniform El Centro seismic excitations were calculated. The analysis results show that the traveling wave effect has a great influence on the dynamic responses' amplitudes of the coupling system. When the train speed is 350 km/h and traveling wave speed is 300 m/s, the derailment coefficient, the wheel unloading rate and the wheel-rail lateral force reduce by 84.1%, 19.5% and 87.8% respectively compared with uniform seismic excitation. So, when the traveling wave effect is ignored, the judgment of the running safety of a train passing a bridge under earthquake action may be wrong.