风浪共同作用下对跨海大桥桥上列车走行性的影响研究

When a high-speed railway bridge is built up across the straits, the bridge will be under the action of strong wind loads and wave loads including the train loads. The comfort and stability can hardly be satisfied because of the heavy train loads and the strong dynamic impact effect. Especially while the bridges across the straits, the train running on the bridges will be under the action of the strong wind loads and wave loads. Then the responses of the bridge will be induced by the strong wind loads and wave loads. The induced responses of bridge will bring some exciting function for the train. Meanwhile the action of the wind loads and wave loads will be affected by the induced responses of the bridge. Due to wind loads and wave loads contribute to dynamic responses of the bridge dependently, the coupling action of wind wave and bridge must be considered. While the smoothness of rail is influenced by the large dynamic responses of the bridge, the structure will be heavily impacted. And the passengers’ comfort will be greatly reduced. If the performance of flatness and smoothness of track can not be kept, the running safety will be hardly guaranteed. Therefore, the characteristic of coupled vibration of train-bridge system will be changed due to the influence of the wind loads and wave loads. Then numerical technology is used to simulate the coupling action of wind wave and bridge. And ALE(Arbitrary Lagrangian Eulerian) method is adopted to solve fluid structure interaction. The 3D finite element model of wind wave-train-bridge system is simulated. Then the train and bridge responses of the wind wave-train-bridge system are analyzed. In summarization of the literatures and references about evaluation criteria in domestic and abroad, suggestions are given for providing a reference for design and construction of high-speed railway bridge across the straits.

当高速铁路桥梁通过海峡时，桥梁除了受到列车荷载作用以外，还将受到风荷载及强风掀起的巨浪的作用，当风、浪共同作用时，风场会由于浪的存在而产生一定的改变，两者之间在强度、方向以及频谱等方面具有复杂的相关性，对跨海大桥的作用具有强烈的动态特性、随机性和耦合性，必须同时考虑风、浪的共同作用。因此，车桥耦合振动特性必然因风、波浪荷载的参与而发生改变，本项目将考虑风荷载以及强风掀起的巨浪的相关耦合性，用分离涡模拟方法（DES）模拟其对跨海大桥的共同作用，基于ALE（任意拉格朗日-欧拉方法）的网格运动算法对风浪与桥梁的流固耦合进行求解，将时程分析计算结果作为一种随机性虚拟激励输入到车桥系统中，并建立风浪-车-桥系统耦合振动模型，依据风浪-车-桥系统耦合振动的动力响应并综合国内外的评价标准，对高速列车走行性进行分析，为高速铁路跨海大桥的设计或者已建高速铁路跨海大桥的加固（或鉴定）提供一些参考。

本项目以一座跨海大跨度刚构桥作为研究对象，以SMB风浪经验模型、Davenport抖振响应理论、海洋工程波浪理论为基础，对风浪耦合关系进行了说明，同时在风浪耦合关系的基础上对风场和波浪场进行了数值模拟，在抖振力响应的基础上加入了波浪的影响，建立风-浪-桥空间耦合振动分析模型，对跨海大跨度刚构桥在风浪荷载共同作用下的动力响应进行分析，研究结果发现:(1)从风浪荷载共同作用下的横向位移响应时程曲线可以看出，距离桥墩由跨中从远到近的截面，横向位移绝对增大位移分别为0.1mm、0.17mm、0.1mm，相对增大幅度分别为2%、4%、7%，虽然位移增大的绝对值不明显，但相对增大幅度却逐渐增大，说明距离桥墩越远，波浪对结构的横向位移响应影响越小。(2)与单风荷载作用相比，风浪共同作用的位移响应大于分别单独计算结果；风浪荷载作用位移响应整体受到波浪作用的影响，但对横向位移响应主要作用仍为风荷载作用。(3)波浪荷载作用对墩底横向剪力、墩底纵向剪力增幅影响较大，而对横向弯矩和纵向弯矩的增幅影响较小；波浪荷载作用对横向剪力、纵向剪力、横向弯矩与纵向弯矩时程曲线的影响皆很明显，其振动幅度明显增大。本项目解决了跨海大跨度桥梁的流固耦合问题，取得了跨海大跨度桥梁在风浪耦合作用下的冲击影响规律等研究成果，完善了风浪耦合作用理论，补充了跨海大跨度桥梁在风浪耦合作用下相关领域的研究内容，为风浪作用下跨海大跨度桥梁的设计和加固提供了理论依据。研究成果在桥梁振动研究方向具有较好的科学意义，具备较好的应用前景。