Dynamic Properties Analysis Of Foundation-Dam Interaction System

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.