| CFG piles composite foundation is a new method that is applied in reinforcing the soft soil foundation in the late 1980s in China. Due to its economic efficiency and good feasibility, it has been widly applicated in architectural engineering. It has been used in railway recently. There are significant differences between them. First of all, the railway roadbed is traditionally considered to be a flexible foundation, but construction foundation is typical of rigid foundation; Secondly, the building load is static load, but high-speed railway foundation is under dynamic load; Thirdly, the post-construction settlement should be controled within 15mm in high-speed railway which applies the technology of ballastless track, which is stricter than that in building foundations. The analysis about the composite foundation under rigid basic has formed relatively complete theory and methods, which has not yet ripe in the composite foundation under flexible basic yet.In this paper, combining field tests of CFG pile composite foundation under the flexible basis used in high-speed railway, a variety of field monitoring data is analysised for studying the settlement deformation laws of roadbed, reinforce area and the below area, to verify and enrich the current theory of CFG pile composite foundation.Numerical simulation experimentations are carried out on the bearing performances of pile-cap-net composite foundation by using the finite element method (FEM) software of PLAXIS. It proves to be correct and rational on the basis of comparing with the The field monitoring data. The rules of the settlement, roadbed lateral displacement, the stress and settlement of the soil between the caps and the soil under the caps and the cap are obtained.For further studying bearing performances rules of pile-net composite foundation influenced by parameters, such as geosynthetics, cushion thickness, pile strength, space between piles, numerical simulation experimentations are carried out again. |
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