Response of X shaped pile in clay soil subjected to torsional and inclined compression loads

Many offshore structures with pile foundations have failed due to the inadequate design for torsional loads caused by earthquakes, winds, and storms. To address this, the PLAXIS 3D V20 software was used to conduct a comparative analysis between the innovative XCC pile and the conventional circular CCC pile, both sharing the same cross-sectional area. This analysis assessed the performance of the XCC section pile under pure torsion loads, inclined loads, and a combination of both, along with studying the effect of load direction on the XCC pile. The findings indicated that the XCC shape significantly enhances performance under torsional and inclined loads. Specifically, for an XCC pile with a radius (rxcc) of 0.45 m, open arc spacing (ap) of 0.14 m, open arc degrees (θ) of 90 degrees, and a pile length (Lp) of 10 m, and a CCC pile with an equivalent radius (rccc) of 0.342 m, constructed in clay soil with a cohesion (Cu) of 70 KN/m2, the XCC section pile showed an enhancement ratio of 490% under pure torsion, and up to 39% under inclined loads. Furthermore, torsional loads reduced the inclined load capacity by approximately 6–21% in circular piles and 11–15% in XCC piles, corresponding to a total displacement of 0.05D m. The increased bearing capacity of the XCC pile can be attributed to an increase in total skin resistance, arching effect, and passive resistance, enhanced by the pile’s effective shape.