Embankment Load Of Cfg Pile Composite Foundation Settlement Research And Design Methods Discussed

High-speed railway construction is developing rapidly in our country. CFG pile composite foundation is widely applied in the subgrade project of high-speed railway construction because of its high bearing capacity, small settlement, widespread applicable scope, quick construction speed, easy quality control, low project cost and some other advantages. The theory system and design method of CFG pile composite foundation under the rigid foundation is relative consummate, and direct the project practice effectively. The theory system and design method of CFG pile composite foundation under the flexible foundation(subgrade) are not mature now, and need further research.The paper studies on CFG pile composite foundation under the flexible foundation by means of numerical analysis and theoretical analysis, in order to provided references and help to theoretical analysis and practical use for the future. The research work of the paper involves several aspects as follows:(1)The concept and classification of Composite foundation, the development history of CFG pile composition and the research status of CFG pile composition under embankment load are expatiated. The mechanism and failure mode of CFG pile composite foundation are researched.(2)The settlement property and the bearing capacity property of CFG pile composite foundation under the flexible foundation are analyzed by contrast with CFG pile composite foundation under the rigid foundation. The settlement rule, the shaft resistance distributing, the shaft stress distributing, the develop rule of pile-soil stress ratio are studied.(3)The shaft resistance distributing sketch of CFG pile is educed. Based on this, a settlement formula of CFG pile composite foundation is inferred. Applied to a project, it is provided that the formula is applicable to some extent.(4)Take CFG pile composite foundation under embankment load as object of study, its settlement influencing factor is discussed, such as geogrid, thickness and modulus of cushion, length of pile, modulus of pile, diameter of pile, pile spacing and so on. Based on this, the primary and secondary factor order affects its settlement is obtained through the orthogonal analysis.(5)The design mentality of Composite foundation is summarized. The design method of CFG pile composite foundation under embankment load is summarized and analyzed especially. And the method is applied to a project, hoping to be a reference of similar projects.