Abstract: A simplified 3D finite-element model which can be availably applied to analyzing the dynamic nonlinear effect on pile-supported superstructure system in layered soil-field is presented.The real-time movement of the system is simulated based on the reasonable description about the behavior of contact on interface of pile-soil and the viscous-spring boundary under dynamic condition.It is indicated that the nonlinear characteristic of slide or debonding in pile-soil interface largely influence the structural response,even if subjected to non-strong shock.So the perfect bond hypothesis may not be suitable for estimating the dynamic behaviour of pile-bearing structures effectively.

Key words: SPS system, spring-damping boundary, interface nonlinearity, dynamic response