An Efficient Numerical Method For Three-dimensional Foundation-soil-Foundation Dynamic Interaction

The shortage of land resources and the restrictions of city planning have resulted in an increasingamount of high-density structure groups during the process of urbanization.When an earthquakeoccurs, dynamic interaction not only exists between structure and foundation, but also betweenadjacent structures through the foundation and soil. However, the present seismic response analysisand seismic design of structure are both aiming at the analysis and design for single structure, withoutconsidering the interaction between structures. It is of great significance that recognizing the effect ofthe interaction and taking reasonable consideration for the seismic design of structure.Based on the existing research results of soil-structure dynamic interaction, considering thestructure-soil-structure dynamic interaction analysis model, the analysis method of foundationdynamic impedance considering the influence of adjacent foundation dynamic interaction is proposed,and the foundation impedance with consideration of the adjacent foundation is obtained throughprogramming. In addition, analysis of the effect of adjacent foundation spacing, arrangement andfoundation dimension on the foundation impedance is made. In this paper, main work is as follows:(1) A time domain method of foundation dynamic stiffness considering the effects of adjacentfoundation which is realized by programming is proposed. Through imputting pulsedisplacement to the concerned foundation, and applying the concentrated mass explicit finiteelement method combined with the local transmissiom of artificial boundary, the couter-forcetime-history of base to each foundation is obtained, and with application of FFT, the foundationdynamic stiffness is obtained.(2) Two adjacent square bases are chosen to analyze their dynamic flexibility through the proposedmethod, by comparing with the results of Lin-Rosset-Tassoulas, the effectiveness of theproposed method is preliminary verified.(3) Through numerical examples, the influnence of the space between adjacent base, relative size,arrangement and the embeded depth on the foundation impedance is analyzed.(4) Finally, the whole work is summarized and further research suggestions are given.