The Recycling Torque of a Single-Plate Helical Pile for Offshore Wind Turbines in Dense Sand

Abstract

The helical piles have been being treated as a kind of novel foundation for offshore wind turbines recently, due their fast installation, high uplift capacity, convenience for recycling, and other advantages. The recycling of the helical pile especially will reduce the cost significantly and protect the environment as much as possible. However, the research for this area is basically in infancy and there is no reference for predicting the recycling torque of a helical pile in sand. In order to predict the recycling torque of single-plate helical piles in dense sand: a theoretical model, which was inspired by the way to predict the installation torque of single-plate helical pile in sand, was developed, and a series of single gravity model tests were conducted to verify that theoretical model. The theoretical model can predict the recycling torque of single-plate helical pile considering the influences of the size of helix and the vertical force on the shaft. This model fills in the blank of predicting the recycling torque of a single-plate helical pile in sand and it is also useful guidance for the choice of suitable recycling equipment.

Control of screw pile installation to optimise performance for offshore energy applications

“…Secondly, helical piles are "silently" installed, with very low underwater noise, whereas pile driving associated noise is considered harmful for marine life (Bailey et al, 2010). Finally, they could be removed by reverse rotation (Ding et al, 2019) to allow complete decommissioning.…”

Physical and Finite Element Models for Determining the Capacity and Failure Mechanism of Helical Piles Placed in Weak Soil

“…Moreover, theoretical studies related to helical piles focused on determining the net value of the bearing capacity by considering several assumptions while experimental studies generally focused on the parameters that affect the bearing capacity (number of helixes, spacing ratio between helixes, helix diameter, soil density, etc.) [29][30][31][32]. In the experimental studies, where the effect of helix number on the bearing capacity was investigated, the helix diameter was generally kept constant, whereas the number of studies in which the effect of the location of the upper helix plate was investigated was quite limited.…”

The Influence of the Shaft on the Uplift Capacity of Single-Plate Helical Pile in Clay

“…These expressions can be a practicable tool for engineers to improve the accuracy of their estimates in practical design scenarios. The presentation of failure mechanisms and the mutual influence between the plate anchor and the shaft on the uplift capacity of Although the uplift capacity of a helical pile has been investigated with experimental research [8][9][10][11], numerical simulation [12][13][14], theoretical analysis [15][16][17] and machine learning algorithms [18][19][20], the effect of the shaft on the uplift capacity of the helical pile is normally ignored. Due to the neglect of the contribution of the shaft on uplift capacity in previous methods, the design size of helical piles might be excessive, which will cause extra manufacturing expenses and challenges in transportation and installation for helical piles.…”