Influence of helical blades on the horizontal bearing capacity of spiral piles for offshore wind power

Abstract

Spiral pile foundations, as a promising type of foundation, are of significant importance for the development of offshore wind energy, particularly as it moves toward deeper waters. This study conducted a physical experiment on a three-spiral-pile jacket foundation under deep-buried sandy soil conditions. During the experiment, horizontal displacement was applied to the structure to thoroughly investigate the bearing characteristics of the three-spiral-pile jacket foundation. This study also focused on analyzing the bearing mechanisms of conventional piles compared with spiral piles with different numbers of blades. Three different working conditions were set up and compared, and key data, such as the horizontal bearing capacity, pile shaft axial force, and spiral blade soil pressure, were measured and analyzed. The results show the distinct impacts of the spiral blades on the compressed and tensioned sides of the foundation. Specifically, on the compressed side, the spiral blades effectively enhance the restraint of the soil on the pile foundation, whereas on the tensioned side, an excessive number of spiral blades can negatively affect the structural tensile performance to some extent. This study also emphasizes that the addition of blades to the side of a single pile is the most effective method for increasing the bearing capacity of the foundation. This research aims to provide design insights into improving the bearing capacity of the foundation.

Keywords

offshore wind power / spiral pile / helical blade / bearing capacity

Funding

National Natural Science Foundation of China(52171274)