跨海大桥群桩-承台-桥墩整体结构波流力计算方法研究

With the development of China's economy, many cross-sea bridges are going to be built in this century. The environment surrounding cross-sea bridges is extremely harsh, and calculation methods of wave-current force in related codes are not perfect. Also the research methods regarding to wave-current force such as theoretical derivation, numerical calculation and model test are in need of improvement. Study on calculation method of wave-current force acting on the composite structure of cross-sea bridge substructure comprising pile group, pile cap and pier is extremely necessary, the research content includes: wave current interaction; the influence of the substructure on wave-current filed; wave-current force calculation methods of pile group, pile cap and pier considering disturbed wave-current filed; wave-current force calculation methods of the substructure of cross-sea bridge; model test. The scheduled research method is detailed as: firstly analytical or semi-analytical calculation methods of wave-current force are deduced based on wave theory; then if analytical method is too difficult to achieve, numerical calculation and three-dimensional numerical wave tank simulation test methods will be employed to obtain numerical solution; then semi-analytical and semi-numerical solution can be achieved by combining above two parts; finally model test will be used to confirm the semi-analytical and semi-numerical method proposed in this study. The project aims to put forward a wave-current force calculation method, which could not only consider the influence of cross-sea bridge substructure on wave-current filed, but also be precise and accurate. This calculation method would be beneficial to the design of cross-sea bridge and also could provide some theoretical supports to modification of the related codes.

本世纪我国需要建设大量跨海大桥，跨海大桥所处环境恶劣，国内外规范中波流力计算条文还不完善，目前研究中所用的理论推导、数值计算和模型试验方法还存在不少问题。本项目拟对跨海大桥下部结构整体承受的波流力进行研究，内容包括：波浪与海流相互作用；群桩-承台-桥墩整体结构对波流场的影响；扰动波流场下群桩、承台、桥墩波流力计算方法；跨海大桥下部结构整体波流力计算方法；模型试验验证。拟采用的研究方式为：基于波浪理论，推导波流力的解析或半解析解；无法获得解析解时，应用数值分析、三维数值波浪槽模拟试验求得部分数值解；两者结合形成波流力的半解析半数值解；并使用模型试验对半解析半数值方法进行验证。通过本项目的研究，拟提出能够考虑跨海大桥下部结构整体对波流场影响的、简洁、准确的波流力计算表达式，为跨海大桥的设计和相关规范的修订提供理论支持。

本世纪我国需要建设大量跨海大桥，跨海大桥所处环境恶劣，国内外规范中波流力计算条文还不完善，目前研究中所用的理论推导、数值计算和模型试验方法还存在不少问题。本项目对跨海大桥下部结构整体承受的波流力进行研究，内容包括：波浪与海流相互作用；群桩-承台-桥墩整体结构对波流场的影响；扰动波流场下群桩、承台、桥墩波流力计算方法；跨海大桥下部结构整体波流力计算方法以及模型试验验证。主要结论如下：（1）波流相互作用特性；（2）群桩对承台波浪力几乎没有影响；（3）承台水流力阻力系数由于自由端的影响，随着承台淹没深度的减小而减小，得到了承台水流力阻力系数与承台入水深度AR的关系；（4）建立了造波效果、消波效果良好的数值波浪水槽，该数值水槽计算出的结构物波浪力与模型试验吻合很好，该数值水槽建立技术可为其他类似项目提供借鉴；（5）提出了方形、圆形承台孤立波作用下的波浪力计算方法，可被实际工程中波浪力时计算选用；（6）提出了方形承台周期波作用下波浪力计算的三种方式，对比了他们的优缺点以及适用范围，可为实际工程中波浪力计算提供选择；（7）提出了承台对群桩波浪力影响的计算方法，即承台效应系数；（8）提出了群桩-承台波流力计算方法，可为实际工程桥梁下部结构波流力的计算选用。本项目得到的研究成果，可为跨海桥梁下部结构波流荷载的计算、桥梁设计规范相关条文的补充和完善，以及类似海洋结构，如海上风机基础、浮式船坞、海上石油平台等波流力的计算提供参考。该项目研究内容属于流固耦合的范畴，也可为流固耦合基础研究提供参考。