【作者】 高平；

【导师】 魏德敏；

【作者基本信息】 华南理工大学 ， 防灾减灾工程及防护工程， 2014， 博士

【摘要】 本文针对现有各类模型的局限性及存在的问题，提出了大型渡槽的二维半流固耦合模型。以简支U型渡槽为研究对象，采用二维半流固耦合模型进行了静力和动力数值计算分析，通过与三维模型计算结果进行对比分析，证明了该二维半流固耦合模型在渡槽的动、静力分析中均可获得较好的计算结果。通过对受到横向地震荷载的多跨联合大型渡槽进行流固耦合分析，研究了梁式渡槽槽身在横向地震荷载下的扭转效应。以支撑不等高的三跨大型梁式渡槽作为研究对象，研究了其在水平正交双向地震作用下的结构响应分析。本文进行了以下研究工作，并得到了一些有意义的结论：（1）提出大型渡槽的二维半流固耦合模型。大型渡槽的二维半流固耦合模型是在已有的大型渡槽的流固耦合建模方法的基础上，针对目前不同计算模型存在的缺陷，在流固耦合理论以及结构动力学理论的基础上，按照平面问题与空间问题相结合的方法，提出的一种更好的流固耦合模型。本模型可有效降低非线性流固耦合求解的方程自由度，使得运算效率极大地提高，适用于实际工程应用中的多跨联合渡槽大规模求解。（2）采用二维半流固耦合模型对大型渡槽进行了静力计算分析。以简支U型渡槽为研究对象，采用二维半流固耦合模型进行了静力数值计算分析。本文提出的二维半流固耦合模型，在静力作用下，可很好地模拟三维渡槽结构的槽身以及支撑的位移以及内力，也可以很好地模拟三维渡槽结构的壳槽内内水压力，并可以很好地反映耦合作用的三维效应。因此，本文模型可以满足工程实践中渡槽静力计算的精度要求。合理地设置二维流固耦合片的数目可以达到良好的静力模拟效果。（3）采用二维半流固耦合模型对大型渡槽进行了动力计算分析。以简支U型渡槽为研究对象，在静力分析基础上，采用二维半流固耦合模型进行了动力数值计算分析。本文提出的二维半流固耦合模型，在动力作用下，可较好地模拟三维渡槽结构的槽身以及支撑的位移以及内力变化规律，也可以较好地模拟三维渡槽结构的壳槽内内水压力变化规律，并可以较好地反映耦合作用的三维效应。因此，本文模型可以满足工程实践中渡槽动力计算的精度要求；而且，本文提出的二维半流固耦合模型保持了较高的计算效率，便于工程利用。（4）对大型渡槽的槽身地震扭转效应进行了研究。针对渡槽两端支撑刚度的不同、支撑条件的差异是否会导致渡槽的槽身结构发生不利的扭转问题进行研究。在不同地震波激励作用下，支撑刚度差异对槽身跨端扭矩的影响程度不同，在工程分析中，需要考虑不同地震激励荷载的周期特性差异。在渡槽的设计中，对于简支梁式渡槽，用来设计整个槽身的控制条件一般可以采用跨中截面的内力。在地震过程中，由于跨中截面的应力最大，以跨中截面的内力作为控制条件来设计整个槽身是可以满足抗震要求的。（5）对大型渡槽槽身的水平双向地震响应进行了研究。以支撑不等高的三跨大型梁式渡槽作为研究对象，利用有限元分析软件ADINA，采用时程分析方法和流固耦合有限元计算方法，研究了其在水平正交双向地震作用下的结构响应。水平双向地震作用下，渡槽槽身的竖向位移和变形、竖向弯矩与横向地震动单独作用下的差别不大，受纵向地震动的影响较小。相比较纵向或横向地震动单独作用，在水平双向地震同时作用下，槽身截面最大主应力的增大较明显，因此，在进行槽身局部设计时，应该将水平双向地震作用纳入考虑。更多还原

【Abstract】 This paper presents the2.5D fluid-structure interaction (FSI) model of aqueduct, due tothe limitations and problems of existing models. A simply supported U-shaped aqueduct isintroduced in the numerical analyses to study the2.5D FSI model and compare it with typical3D FSI models in the dynamic and static analysis of aqueduct. The results show that thismodel has good simulation results for dynamic and static analysis of aqueduct-water couplingsystem. And the torsion effect of a multi-span aqueduct body under the lateral seismicexcitation is studied by the numerical analysis of fluid-structure interaction. Finally, athree-span aqueduct with unequal height piers is introduced to study its structural responseunder the horizontal, orthogonal and bidirectional seismic action. The main work andconclusions in this paper are shown as follows:（1）The2.5D fluid-structure interaction model of aqueduct is established. This model isbased on the existing modeling methods of aqueduct, structural dynamic analysis theory andfluid-structure interaction theory, combing plane problem with space problem. Comparedwith existing models, the2.5D FSI model of aqueduct can effectively reduce the orders ofnon-linear fluid-structure interaction equations to improve its computational efficiency, whichis practical in the large-scale calculation of multi-span aqueduct.（2）The static structural response of large-scale aqueduct is analyzed with2.5D FSImodel. A simply supported U-shaped aqueduct is introduced in the static structural analysis.The numerical results show that under static loading, the2.5D FSI model presented in thispaper not only can well simulate the displacement and internal force of aqueduct body, butalso can well simulate the water pressure acting on the aqueduct interface wall and reflect the3D coupling effect. Therefore, the2.5D FSI model can meet the requirement of precision inthe static analysis of aqueduct, and can obtain good simulation results with appropriateselection of the amount of coupling planes.（3）The dynamic structural response of large-scale aqueduct is analyzed with2.5D FSImodel. A simply supported U-shaped aqueduct is introduced in the dynamic structuralanalysis based on the above static analysis. The numerical results show that under dynamicloading, the2.5D FSI model presented in this paper not only can well simulate thedisplacement and internal force variation of aqueduct body, but also can well simulate thewater pressure variation acting on the aqueduct interface wall and reflect the3D couplingeffect. Therefore, the2.5D FSI model can meet the requirement of precision in the dynamic analysis of aqueduct, and it is time saving and practical in engineering applications.（4）The torsion effect of large-scale aqueduct is studied. The study is focused onwhether the difference in the stiffness of piers and the support conditions of each span ofaqueduct causes bad torsion effect of aqueduct body. Though there is difference between theend supports’ stiffness of each span of aqueduct, the torques have little difference, whichmeans that the difference of supports’ stiffness has little influence on the torque internal forceof aqueduct body. In the design of a simply supported aqueduct, the mid-span section internalforce is usually adopted as the design threshold of the aqueduct body. During the earthquake,the mid-span section internal force is the maximum of internal force. Therefore therequirements of seismic safety for entire aqueduct body can be met if the mid-span sectioninternal force is adopted as the design threshold.（5）The horizontal and bidirectional seismic response of large-scale aqueduct is studied.A three-span aqueduct with unequal height piers is introduced to study its structural responseunder the horizontal, orthogonal and bidirectional earthquake action in the general finiteelement program ADINA, adopting the dynamic time-history method and fluid-structureinteraction numerical method. The results show that the vertical displacements, verticaldeformation and vertical moments of aqueduct body under the bidirectional seismic action arevery similar to those under the lateral seismic action alone, and are little influenced by thelongitudinal seismic action. Compared with longitudinal or lateral seismic action alone, underthe horizontal and bidirectional seismic action, the increase of the maximum values of sectionprincipal stress is obvious. Therefore, horizontal, orthogonal and bidirectional seismic actionshould be considered in the design of aqueduct.更多还原