Installation Behavior of Open Ended and Closed Ended Piles with Torque Application

Screw piles offer several potential benefits for deployment offshore for renewable energy developments. They are easy to install, have the potential to achieve large capacity and generate low noise and vibration during installation. This latter benefit makes them an attractive alternative to driven piles where there are concerns over the impact of installation on marine mammals. Although screw piles are attractive for offshore deployment, their recent use has been limited to small piles therefore, to allow offshore deployment considerable upscaling of these piles must occur. This increase in size comes with concerns of how they will perform and the requirements for installation. For example, it is well known that the shaft capacity of a driven pile is influenced by plugging or coring behaviour internally. As screw piles are installed by rotation and vertical force, it is necessary to investigate how this installation process effects pile plugging behaviour. As part of a preliminary study, the effect of rotation on plugging and installation capacity behaviour was investigated by 1g small scale model testing in sand. The addition of rotation during installation was seen to give a significant reduction in the pile penetration resistance in both open and closed ended piles.