The paper mainly studies the geogrid's application and finite element analysis on CFG pile composite foundation.
The finite element model to analyze the relative displacement between the top of pile and soil，and force status of the geogrid
in the situation of CFG pile composite foundation with cushion overlaying geogrid. The result shows that CFG pile composite
foundation with cushion overlaying geogrid has no significant effect on the CFG pile composite foundation's deformation and
subgrade settlement，and the geogrid only work as the safety reserve of CFG pile composite foundation. In addition，through
monitor and analysis of the settlement and deformation test section found that CFG pile composite foundation with cushion
overlaying geogrid has larger settlement，and geogrid has little effect on the settlement of foundation and compression defor原
mation of the soil between piles and only work as the safety reserve，it is consistent with the result of finite element analysis.