Numerical calculation for bearing performances of composite foundation improved by flexible piles

The bearing performances of the composite foundation improved by single-flexible-pile or multi-flexible-pile are calculated by using the FEM software ANSYS. Factors such as load, pile area replacement ratio, pile's length-diameter ratio and pile's distance-diameter ratio, have been taken into the consideration. Results show that in the composite foundation improved by single-flexible-pile, the distance of pile's axial stress peak point to the pile's top is about 0.1 time of pile's length with the increasing of load and pile's length-diameter ratio, while, the settlement tendency both pile and soil are similar. The pile's bearing performance is increased with the increasing of pile area replacement ratio; but the settlement tendency both pile and soil are opposite, which affects the composite foundation's settlement. In the composite foundation improved by multi-flexible-pile, the changes of load and pile's distance-diameter ratio have no influence on loads shared by piles and result in the same tendency for the pile and soil's settlement. The change of pile's distance-diameter ratio has more influence on loads shared by piles and results in the soil's settlement more than the piles' one, which has the obvious influence on the composite foundation's bearing performances.