Three-Dimensional Numerical Simulation Of Pile-Soil-Structure Interaction

The research of pile-soil-structure dynamic interaction is very important to improve the reliability and safety of pile foundation under dynamic loads. Many researchers have done lots of works in this field and obtained a large number of valued results. However the dynamic interaction of pile-soil-superstructure system is so complicated that there are still many key issues to be required for further researches.Several main models and methods of pile-soil-structure dynamic interaction are commented in detail, and their advantages, disadvantages and application are stated.In the dissertation, an analysis model of 3×3 group pile foundations with different pile spacing and pile diameter is built up. The pile-soil-structure dynamic interaction under horizontal seismic excitations is analyzed by using three-dimensional elastic-plastic finite element method in the develop platform of ANSYS. Drucker-Prager model is chosen to simulate the non-linear characteristics of soil. The computational region of the soil is 20 times of pile diameter. The seismic load is input at the tip of the pile. The bottom of the model is constrained in three directions. 3-D viscous-elastic artificial boundary is adopted to simulate the boundary condition. The pile ,soil and pile foundation mat are simulated by solid45 element .The superstructure was modeled as single degree freedom system. The rigid connect between superstructure and pile foundation mat was carried out by constraint condition. After calculation, the distribution of the shear stress amplitude along the pile was obtained and some valuable conclusions are drawn. In general, the distribution of shear stress amplitude along the pile is inverse-triangle; the corner-pile has the maximum shear stress; the difference that different piles endure the shear stress will reduce as the space among piles increases.The characteristics of non-linear of surface-to- surface contact element between soil-pile are studied by use of 3-D elastic-plastic finite element methods. The results show that characteristics of contact-element have a big effect on the dynamic response of structure and pile foundation. In general, the shear force and...