Investigation of soil-piled foundation-structure interaction behavior under dynamic conditions

Seismic soil-pile-structure interaction problem has been initially recognised during big earthquakes such as 1964 Niigata earthquake until which it has been thought that pile foundations working well under static loading conditions would also perform well under seismic loading conditions as well. Such big earthquakes motivated researchers to study in the area of seismic soil-pile-structure interaction. In literature, this problem has been analysed by direct method and substructure method, however substructure method is widely preferred instead of direct method due to its convenience in terms of computer memory and speed. In the substructure method, kinematic and inertial interaction analysis are performed sequentially. In the kinematic interaction stage, variation of free field behaviour due to presence of pile foundation has been investigated first without considering the mass of the superstructure. In the inertial interaction stage, variation in seismic behaviour of foundation and the underlying soils is investigated under the effect of superstructure mass. In the context of this thesis, kinematic and kinematic + inertial interaction analysis of a single pile in a liquefiable soil profile is investigated by using dynamic nonlinear finite element analysis. Multiyield surface Plasticity model (PDMY model) has been used for representing effective stress based behaviour of the soil during seismic loading. Results are interpreted in terms of nonlinear soil properties and pile displacement, moment and shear behaviour. Keywords: Interaction, Kinematic, Inertial, Liquefaction, Pile, Shear behavior.