Optimization Design on CFG-Pile Foundation with Different Cushion Thickness in Beijing-Shanghai High-Speed Railway

The cushion, as the core technique of CFG pile composite foundation, greatly affects the foundation characteristics of carrying abilities and deformation. A three-dimensional simulation model of CFG multi-pile composite foundation is established via MIDAS/GTS finite element software to investigate the influence of different cushion thicknesses on the deformation and stress characteristics in CFG pile composite foundation. The design of the Beijing-Shanghai high-speed railway is optimized in accordance with the post-construction settlement of subgrade and the utilization requirements of pile caps and soil between piles. The results show that the settlement in composite foundation would be even applying pile caps and that the optimized thickness of cushion is 0.4 m below the piles which also could satisfy the requirements of the Railway Codes.