Study on Load Transfer Mechanism of Cast-in-Place X-Shaped Piles

The technology of cast-in-place X-shaped piles is an innovation developed by Hohai University for strengthening soils.Based on the full scale test,the load transfer mechanism of the X-shaped pile was studied by 3D nonlinear finite element analyses.In the analyses the interface elements were used to represent slippage and separation between the soil and the pile.The numerical results were compared with the results of the chamber tests.The difference of bearing behavior between an X-shaped pile and a round pile and the effect of the partial soil plug on shaft resistance and end resistance were studied.The results show that the skin friction varies along the perimeter of the pile's section due to the effect of Poisson's ratio.Similar to the H-shaped pile,there is also a partial soil plug in the X-shaped pile,and the skin friction near the pile base is larger than that of the round pile.The end bearing capacity factor of the Xshaped pile is found to be smaller than that of the round pile,which also reflects the effect of X-shaped section.