Behaviour of Screw Pile Under Axial Compressive and Lateral Loading in Sand for Offshore Energy Foundations

Abstract

To encounter the growing energy demand in the offshore environment, there is a necessity of a huge deployment of energy devices like wind turbines. Upscaled screw piles are gaining popularity as an effective alternative for the offshore wind turbine foundations in deeper waters. The foundations of the offshore wind turbines are typically subjected to axial compressive load from the superstructure and lateral load from the wind and waves. Therefore, the combined load-carrying capacity of screw piles needs to be evaluated for their efficient use as a foundation structure for the offshore wind turbines. In the present study, a three-dimensional finite element analysis is carried out using ABAQUS 2018 to determine the combined load-carrying capacity (under axial compression and lateral) of the screw pile installed in sand. The soil is modelled as Mohr–Coulomb material and the shaft and helix as linear elastic materials. The effect of the number of helixes and the placement of helix on the combined compressive and lateral load-carrying capacity of the screw pile is studied. It is found that the screw piles can significantly increase the combined lateral and vertical load-carrying capacity provided the helixes are placed at a suitable location. The present study will be useful in the design of screw pile for offshore application where they undergo combined lateral (from winds and waves) and dead loads (from superstructure).