OasisLMS

The use of helical piles has experienced substantial growth, particularly as a potential offshore foundation system, due to their distinct advantages over alternative systems. Helical piles are often installed in groups to support heavy loads, necessitating an accurate assessment of their behavior for reliable design. In this study, a finite element model was developed to extensively analyze the uplift and lateral behavior of group piles in soft clay soil. In total, three different configurations arranged in rectangular, triangular, and square patterns were used. The pile spacing ratio (S_g/D) was varied as 2, 3, 4, and 5. The problem was simulated using Plaxis 3D software and validated with laboratory-scale model test data. The validated model was then employed to investigate the group effect for three different configurations viz. rectangular, triangular, and square patterns, with varying center-to-center spacing of helical piles. The term "group efficiency" was used to describe the impact of each group on the ultimate capacity. The results indicated that the group efficiency is significantly influenced by the number of piles, center-to-center pile spacing, and the selected failure criteria used to interpret the test data. The measured loads and the displacement contours gave insight that the helical pile spacing ratio greater than or equal to 4 exhibited negligible group effect. The study also examined and reported on the load-transfer mechanism for different group configurations. Lastly, based on the assumed failure criteria, an optimal spacing ratio is suggested for both vertically and laterally loaded group helical piles.

Vignesh Venkatesan, Sanjivani College of Engineering; Muthukumar Mayakrishnan, Vellore Institute of Technology (VIT)

International Conference Proceedings