Effect of Helices on Lateral Performance of Helical Pile

Helical piles (HP) have been employed extensively in North America and other countries to support superstructures, particularly with applications in power transmission towers and residential and commercial buildings. The main benefits of HPs over standard foundation systems are quick installation, cost-effectiveness, low vibration and noise during installation, improved performance and environmental sustainability. HPs are also widely used to support retaining wall, communication towers etc. which experience high lateral load. Though extensive field tests and numerical analyses have been performed to investigate the lateral capacity of HP in the past few decades, the influence of the helix configuration, especially the parameters such as helix diameter, number of helices, and embedment depth, on the lateral load capacity has not yet been sufficiently explored. The primary intent of this research is to establish how helix components such as diameter, quantity, and embedment depth are correlated to HP lateral performance. Moreover, this study will incorporate experimental validation of HP fabricated with a 324 mm shaft, 5.6 m long, and a single 610 mm helix subjected to lateral load in sandy soil through advanced finite element modeling in Abaqus. In addition, the validated numerical model will be used for a parametric study. The matrix will encompass variation in helix diameter (2–3 times the shaft diameter), embedment depth of helix and quantity of helices (2–3) to cover all possible scenarios of helix configuration to study the effect. Furthermore, the influence of helix arrangement will be studied through a comparison of the load-deflection curve and variation of head deflection and maximum moment demand along the length with the validated model. The results show that the influence of helix diameter (D) and numbers on pile head deflection and maximum moment demand are minimal when top helix is placed at 4D. However, noticeable improvement in pile head deflection is seen when helix is placed at shallower depth. The outcomes of this study highlights the potential impact of helix geometry on the lateral capacity of HP, which is expected to promote more viable and robust HP foundation solutions.