X-section cast-in-place concrete (XCC) piles have been studied and implemented since 2008. To advance this technique, primarily for the design of XCC piles, it is important to describe the load transfer mechanism of XCC pile foundations precluding any straightforward constitutive model. In this work, an analytical solution dependent on the cross-sectional geometry and the vertical shearing mechanism is derived by means of equilibrium analysis to calculate the effective vertical stress in the surrounding soil, the positive/negative skin friction, and the axial force/dragload of an XCC pile. Additionally, the soil stress distribution due to the skin friction and the end bearing of the XCC piles is proposed. These stresses are calibrated using a previously reported large-scale model test and the original Geddes solution, which validates the derivation procedures and formulae obtained.
Zhang, D., Lv, Y., Liu, H., & Wang, M. (2015). An analytical solution for load transfer mechanism of XCC pile foundations. Computers and Geotechnics, 67, 223–228. https://doi.org/10.1016/j.compgeo.2015.03.006