【作者】 李国华；

【导师】 燕柳斌；

【作者基本信息】 广西大学 ， 结构工程， 2003， 硕士

【摘要】 在常规工程动力设计中，常采用刚性地基模型，分析结构的动力特性和动力响应。然而上部结构和地基基础是一个有机整体，人为地将其分开有时会给地震反应计算结果带来较大失真。值得指出的是，地基—结构动力相互作用广泛存在于海洋平台、高层建筑、大坝等领域中，随着这些重大工程的修建，在这方面的研究就更为迫切。本文从有限元、无限元原理出发，结合弹性半空间理论，以广西源口拱坝为例，研究了地基基础与坝体相互作用对坝体动力特性的影响。 为了对动力相互作用影响有一个直观的认识，作者完成了FORTRAN语言编制的计算大型结构动力特性程序，并采用三维8结点非协调等参单元分析了坝体在刚性地基情况下的动力特性，并在MATLAB、ANSYS中计算了坝体的动位移时程曲线。 对于弹性地基情况下坝体的动力特性，作者采用了能够反映半无限域介质中位移衰减特性的映射无限元，通过MATLAB、ANSYS、FORTRAN三种计算软件之间数据交换得出了弹性地基下坝体的动力特性，并通过自编Newmark-β法程序计算了坝体在地震荷载作用下动位移响应。 论文通过比较两种地基情况下的坝体动力特性及动位移时程曲线，得出结论： 广西大学硕士学位论文·地基基础与坝体相互作用体系动力特性分析1．与刚性地基下坝体计算结果相比，由于地基的弹性约束作用，坝体的自振频率降低，周期延长；且在地震荷载作用下，坝顶最大动位移增大。L 本文的有限元一无限元耦合分析方法，不仅可以较好地反映波在无限域介质中的能量弥散现象，同时大大减小了计算量，与单纯的有限元法相比，具有显著的优越性。更多还原

【Abstract】 In the course of conventional design, rigid foundation model is used usually for analyzing structural properties and dynamic response. But structure and foundation is an organic system, and if separate them artificially, it will lead to considerable torsion to the result of earthquake response. It deserves to be pointed out that interaction of foundation and structure lies extensively in sea-platform, high-building and huge-dam. With construction of these important structures, the research of this field becomes more urgent. The paper research the influence to dynamic property and earthquake response of dam which is situated in YuanKou, GuangXi, brought about by foundation-dam interaction. The study is based on theories of finite and infinite element, at the same time combining the principle of elastic semi-space.For having a directly perception to the influence of interaction, the author completes program of calculating huge structure’s dynamic properties which worked out by FORTRAN language, and employ 3D incompatible isoparametric element figures out the dam properties in thecondition of rigid foundation meantime. Further the author calculates dynamic displacement of dam in software of MATLAB, ANSYS.As for dam’s dynamic properties in condition of elastic foundation, author uses mapping infinite element, which can reflect displacement’s property of diminishing in semi-infinite materials. Through exchanging data between three analytic software-MATLAB, ANSYS, FORTRAN, dynamic properties of dam is computed in condition of elastic foundation. And then the dynamic displacement curve is obtained under the load of earthquake with the method of Newmark- b.Compared properties and dynamic displacement curve of dam in condition of two foundations, the conclusion is reached:1. Contracted with the calculations of dam in rigid foundation, the frequencies are lesson and periods of dam are lengthened because of elastic restraint of foundation. And under earthquake load, the maximum displacement of dam top is larger.2. Finite and infinite element coupling method applied in the paper can not only reflect the scattering phenomenon of waves, but also lessen the amount of calculation. It has significant advantage compared with pure finite element method.更多还原