Finite Element Analysis For Piled Raft Foundations Considering The Interaction Of Superstructure

Piled raft foundations, which is extensively used, is an important foundation pattern of highrise buildings. The researches on the interaction characteristics of piled raft foundations and the soil have been being paid close attention to by academic and engineering circles. Though a lot of achievements in the field have been obtained in recent years, many problems remain unsolved for their complex nature. Many works in the field are in wait to do. On the basis of related literature at home and abroad, this paper puts emphasis on studying the problem by finite element. The elastic matieral is used to simulate the piles, raft and superstructure, and the nonlinear elasticity Duncan-Chang model is used to simulate soil as well as interface element method is introduced in between piles and soil. The finite element method is used to analyze the superstructure, and the stiffness matrix is condensed from top to bottom. Using 2D 8-node iso-parameter bending element, 3D 20-node iso-parameter and 3D 16-node interface element, a coupled non-linear numerical approach for the piled raft system is set up. The Object-Oriented programming of finite element software OOPFE (Object-Oriented programming of finite element) with VC++ is developed. The character of average settlement, differential settlement, distribution of pile loading, raft moment, percentage of load taken by raft is analyzed. Case study show that the object-oriented model presented in this dissertation is correct and feasible, and the result is also satisfying.