Abstract: Some results of static analysis considering the interaction between superstructure and composite foundation are obtained. However, the research on the response under dynamic loading, especially under earthquake loading, is very inadequate. Via relevant tests, ABAQUS are verified by comparison with EERA. The results show that the elastoplastic constitutive model based on Drucker-Prager yield criterion and the method of finite element and infinite element coupling can adequately simulate the nonlinear dynamic characteristics of soil and the infinite boundary. To the actual problem，the whole finite element model of rigid pile composite foundation-raft-superstructure system is established. And dynamic elastoplastic time-history analysis is made; the differences between rigid pile composite foundation and pile foundation in seismic response are analyzed. The seismic mechanism of rigid pile composite foundation, including the dynamic responses of piles, cushion and raft, is studied under different earthquake intensities; and the earthquake response and seismic performance of superstructure are analyzed deeply. It is shown that cushion has no damping effect almost under minor earthquake; rigid pile composite foundation is superior in seismic performance to pile foundation under major earthquake. The stronger earthquake is, the better damping effect is. But it is limited, the damping coefficient is over 0.8 generally. The results can provide references to engineering practice.

Key words: rigid pile composite foundation, elastoplastic constitutive model, infinite elements, earthquake intensity, seismic performance