Finite element limit analysis of ultimate lateral pressure of XCC pile in undrained clay

X-section Cast in place Concrete (XCC) pile is a non-cylindrical pile that the cross section not obeying plane rotationally symmetric. In this case, the geometry of cross section as well as the lateral load direction may have influence on the ultimate lateral pressure of XCC pile. This paper presents rigorous upper and lower bound solutions for the ultimate lateral pressure of X-section Cast in place Concrete (XCC) pile in clay through two dimensional plane strain finite element limit analysis (FELA). The geometric effect, lateral load direction and the adhesion factor at the pile-soil interface are selected for parametric study. Subsequently, an empirical closed-form equation of the ultimate lateral pressure factor is proposed for predicting the lateral force acting on a XCC pile in undrained clay. It is found that the XCC pile with relatively small ratio of b/a has larger ultimate lateral pressure than the conventional circular pile under the condition of the same area of cross section.