Three-dimensional nonlinear finite element modeling of composite foundation formed by CFG–lime piles

Cement–Flyash–Gravel (CFG) pile is a widely used ground improvement technique. A CFG–lime multi-pile composite foundation is a new concept utilizing CFG and lime piles. This study presents the results of finite element analyzes using ANSYS software to investigate the behavior of composite CFG–lime pile foundations under various load distributions. The parameters studied include the length and diameter of piles and the thickness of the cushion. The stress distribution beneath the composite foundation, the influence of the cushion on load-settlement behavior, and the ratio of stresses in the piles to those in the subsoil are also studied. The results show that settlement is much more significantly affected by the length and diameter of the CFG pile rather than that of the lime pile. This suggests that the CFG pile indeed acts as a settlement-reducing pile, which is in accordance with the working principle of such composite foundations. On the other hand, the load distribution between piles and subsoil is significantly affected by the cushion thickness.