Study On Interaction Mechanism Of Structure-raft Foundationsoil Of High-rise Buildings

Piled raft foundation is widely used in high-rise buildings. The structure, foundation and subsoil can be seen as an organic whole and influencing each other. The researches on the interaction characteristics of piled raft foundation and the soil have been being paid close attention in civil engineering field.In this paper, the researches of piled raft and interaction theory are summarized comprehensively. Accordingly, two kinds of pile soil interaction models are established. And the models are applied to the analysis the interaction and the results are compared with practice. The follows are in details:(1) The working behaviors of a single pile under vertical load are analyzed, the results are compared with the field measurements, and they are identical .That can indicate: the single pile finite element model was simplified by Beam4 element.(2) Two three-dimension analysis models are established and numerical simulation is used to study the interaction among upper structure, piled raft foundation and soil under vertical load. One is an equivalent complex model ,which see the pile-soil system in grouped piles foundation as a composite material in terms of the equivalent continuum method; the other was established by different element united the one node at which different element contact with each other.(3)The settlement of foundation, the internal force of raft and the internal force of upper structure and so on have been discussed systematically, Besides, the effects of different thickness of the raft are analyzed, and the differences of internal force of upper structure are investigated by conventional method and analysis method including interaction. And the means to decide raft's reasonable thickness is obtained.