Abstract: X-section cast-in-place concrete pile (XCC pile) can save concrete usage under the same pile perimeter. However, there were relative little studies of the lateral bearing capacity affected by X sectional shape. Based on three key control sectional parameters (outsourcing diameter, open space, and open arc angle), the moment of inertia equation under arbitrary direction axis are built. Then, the moment of inertia influenced by sectional parameters are discussed. Finally, optimized X section type is proposed, of which the moment of inertia can be improved with the same areas or perimeter. The results show that, the moment of inertia increased with outsourcing diameter increasing, open arc degree decreasing, and open space decreasing. Hence, appropriate increase outsourcing diameter, and reduce opening angle and arc, can help improving the moment of inertia, thereby improving the overall bearing capacity of X-section cast-in-place concrete pile.

Key words: soft ground, lateral load, section geometric property, X-section cast-in-place concrete pile (XCC pile), moment of inertia