Study On Behavior And Design Method Of Pile-raft Foundation With Variable Rigidity

Theory analysis,model and site test on pile-raft foundation with variable rigidity studied by scientific workers started from 50's of last century,and many analysis and design method have been put forward. People have certainly understood the work characters about the foundation at present,but some is also not understood. In order to make the pile-raft foundation with variable rigidity design better,further study on the work characters is significant and practical. There are many limitations on site test, to some extent numerical analysis is an effective way to compensate the deficiency of site test.FLAC3D is a powerful geotechnical anlysis software,many case used the software are successful.The law is found based on model test,it is necessary to study further based on numerical analysis,and the laws are studied again,then the laws used in practical engineering are safe. The settlement calculation method of Pile-raft Foundation is summarized, advantages and disadvantages are pointed out. Based on a certain high-rise frame-shear structure pile-raft foundation,numerical models with 5 different modes of piles are made,and the result presents the model with different distance and length is better than others,increasing the length of central piles can reduce the total and different settlement,so this mode of piles is a better one.5 different raft thickness numerical models are made again,the result presents that there is a better thickness which can make the settlement reduce a lot.All the study results can be used to guide the practical engineering.