Abstract
Pile foundation responses during strong earthquakes are greatly affected by nonlinear soil-pile foundation interaction. Centrifuge test results indicated that pile responses in liquefied sand change due to large ground displacement and excess pore water pressure buildup. In this paper a practical numerical model is proposed which consists of lumped masses and nonlinear soil springs taking into account pile group effects. The soil springs modified at each step according to the relation of lateral load-displacement of the pile and the changing effective stress in the free ground. Earthquake responses of a structure on pile foundation in liquefiable soil deposits are analyzed using the numerical model. The effects of the inertial and kinematic interactions on pile responses are investigated. Analytical method to evaluate pile stresses induced by earthquake is also discussed.
