Analysis of the effect and influencing factors of CFG pile composite foundation treatment in west Sichuan high-plateau airport

In this study, the finite element model (FEM) of the CFG pile composite foundation underlayered filling of the high-fill embankments was established by numerical simulation to analyze the treatment effect and influencing factors of CFG pile composite foundation for high-plateau airports in western Sichuan. The analysis results demonstrate that the maximum foundation settlement occurs in the center with values of 179.8 mm at foundation depths of 0 m. The reliability of the FEM is confirmed by the theoretical calculations for settlement of the composite foundation, then compared with the maximum foundation settlement of treated and untreated; the settlement was reduced by approximately 47.6% with composite foundation treatment. Subsequently, by setting 27 working conditions with varying pile length, pile diameter, and pile spacing, the best foundation treatment was achieved when the pile spacing was constant at 2 m, the pile length and diameter were 20 m and 1.5 m, respectively, and the settlement was 123 mm. Finally, this study found that the pile-soil stress ratio has a logarithmic relationship with the ratio of area replacement ratio and pile length, and the maximum negative shaft resistance has a linear relationship with the product of area replacement ratio and pile length.