收缩徐变对高速列车-轨道-桥梁系统动态特性的影响

收缩徐变效应在高速铁路混凝土桥梁的施工和建造过程中是不可避免的,其会引起桥梁的变形,诱发高速列车运行安全平稳性受到影响。针对该问题,首先选取中国高速铁路中大量采用的32 m简支箱梁桥结构,考虑结构配筋及施工步骤,建立有限元模型,采用JTG2012标准中的收缩徐变模型,分析收缩徐变引起的桥面变形。在此基础上,基于列车-轨道-桥梁动力相互作用理论,将收缩徐变导致的桥面变形视为边界条件,建立考虑收缩徐变的高速列车-轨道-桥梁耦合动力学模型。最后,借助该模型,研究收缩徐变效应对高速列车乘坐舒适性和运行安全性的影响规律。研究结果表明:收缩徐变效应主要影响高速列车的动态特性,而对轨道和桥梁结构的动力学行为影响较小;在收缩徐变效应下,高速列车运行安全性和乘坐舒适性可以得到保证。

Dynamic Analysis of High-speed Train-track-bridge Coupled System Considering Concrete Shrinkage and Creep

Shrinkage and creep effect (SCE) is unavoidable in construction and operation of concrete bridges, which causes bridges deformed and further affects the running safety and ride comfort of high-speed running trains. This paper presents a framework to establish a high-speed train-track-bridge dynamic model considering concrete SCE, and analyzes influences of SCE on dynamic responses of the coupled system. Firstly, aiming at the 32m-long simply supported box girder bridges, which are most widely used in Chinese high-speed railways, a high-speed train-track-bridge coupled dynamic model is established based on the train-track-bridge dynamic interaction theory, including three submodels of the train, the track and the bridge. Then, adopting the JTG 2012 shrinkage and creep model, the bridge deformation and the corresponding rail deformation are calculated based on finite element method. And finally, regarding the rail deformation caused by SCE as the additional track irregularity, the influences of SCE on the dynamic responses of the train-track-bridge coupled system are investigated. Results show that SCE mainly affects the dynamic responses of the train system, while almost has no effect on other structures. Running safety and ride comfort of the high-speed trains can be guaranteed under the influence of SCE.