| A large amount of theoretical analysis and test researches demonstrate that, the dynamic interaction of soil-foundation-structure system has a great influence on the dynamic characteristics of superstructure, and its seismic response may be remarkably changed. Moreover, for different soil composition and different types of superstructure, to some extent, the force and deformation characteristics of the interaction system are different.The interaction of some buildings is prescribed in code for seismic resistance by decreasing the shear force and the story displacement, while the decreasing method is based on the elastic conditions. In the mean time, the calculation of elasto-plastic deformation must be conducted on the buildings which simultaneously consider code for seismic resistance and severe earthquake action. However, the simplified method of deformation calculation is based on the assumption of rigid foundation.Considering elastic-plastic characteristics of the interaction system, in respect to various structure types and construction ground, whether the decreasing method is reasonable and whether the calculation of elasto-plastic deformation is appropriate are still expected to be investigated. Moreover, at present, the researches on the soil-structure interaction under severe earthquake are little, and the research achievements on the calculation of the elastic-plastic deformation considering the soil-structure interaction are also little. And the piles are one of the widely applied deep foundations, which play an important role in the foundation engineering. Accordingly, the study on pile-soil-structure elastic-plastic dynamic interaction is very important.Based on previous researches, the finite element numerical simulation analysis of the seismic response for the pile-soil and pile-soil-structure interaction system was carried out using the ANSYS software. And the methods and laws of the seismic response were studied. The main achievements are as follows:(1) With the summarization of lots of interrelated references, a state of the art survey of soil-structure interaction is presented, and the analytical methods of dynamic pile-soil-superstructure interaction are summarized.(2) The elastic-plastic constitutive relationship suitable for the pile-soil- structure system was established, and the finite element solution for pile-soil- structure dynamic interaction was built, including solving methods of the nonlinear dynamic equation, simulation of soil border, division of mesh size, and consideration of the damping.(3) A 3-D nonlinear finite element model of pile-soil interaction was established, fully taking into account the nonlinear materials and nonlinear contact. Furthermore the viscoelastic border was realized by the APDL language in the program ANSYS, the time-viscoelastic artificial boundary was amended in the elastic-plastic analysis, and the variation law of the dynamic characteristics of the pile-soil system in the sitesâ…¡andâ…¢was studied.(4) The seismic responses of the pile-soil-structure interaction system underâ…¡andâ…¢sites were analyzed, when the superstructure, which was 5 stories and 10 stories or 20 stories, was frame structure, shear-wall structure, and frame-shear wall structure. By summarizing the reaction characteristics of its internal forces and deformation, some useful conclusions were derived.
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