Numerical Analysis Of Aseismatic Capability Of Rigid Pile Composite Foundation

Rigid pile composite foundation can fully use the supporting capacity of natural foundation, the ground bearing capacity obtains a larger enhancement. Rigid pile composite foundation now is applied to many projects such as high buildings and the extra-high buildings. But at present the computation analysis, especially its aseismatic capability, can not be able to meet the project actual needs on rigid pile composite foundation. Rigid pile composite foundation numerical analysis now is mainly focused on plane strain two-dimension numerical analysis or simple three-dimensioned numerical analysis. Because of the troublesome modeling, long computing time or not easy to converge, the research materials are few about three dimensional group pile research.This article establishes a three-dimensioned numerical modal of rigid pile composite foundation, and does a deeper research on the influencing factors such as model size and the soil's elastic modulus arround the piles. The results show that when the model horizontal dimension from the outside edge of foundation is 2 times of the foundation size, and the model vertical dimension down from the pile tip is 2 times of the piles'length, the vertical displacement of the pile will not significantly change. And the change of the soil elastic modulus arround the piles can make little influence.This article also studies the aseismatic capability of three-dimensioned numerical modal of rigid pile composite foundation. Using the response spectrum method and time history analysis method, considering the the feedback of upper structure, this study analysises the structure free vibration characteristics, horizontal displacement and inner force. This paper also compares the results between the two reference for seismic design methods . At last, the studies discuss more variable modulus of cushion effects on the rigid pile composite foundation and find that the modulus of cushion's effects on the seismic behavior of rigid pile composite foundation are not obvious.