Estimation of the installation torque–capacity correlation of helical pile considering spatially variable clays

Abstract

In the offshore fields, helical piles are increasingly deemed to constitute suitable tools for anchoring floating structures and wind turbines. A large number of studies have been published to explore the installation torque–capacity correlation, and most of them are conducted in a deterministic manner. However, natural soils are inherently spatially varying, and analyses taking such variation into account might be closer to the reality. To address this issue, this paper examines the installation and uplift process of helical piles considering spatially varying soils via three-dimensional large deformation random finite element analyses within a Monte Carlo framework. Computed values of the installation torques and the uplift capacities compare well with the results in existing publications, therefore verifying the applicability of the numerical model. Spatially varying soil strength is mapped through the random field, followed by Monte Carlo simulations conducted to determine the torque–capacity correlation in random soils. The results suggest that the torque–capacity correlation might be misestimated once the spatially random soil properties are overlooked. Besides, probabilistic assessments of the pile torque–capacity correlation are performed, which may be of great interest to engineering practitioners in the design method of the helical pile.