Large monopiles with, for instance, 8 m diameter and total length of 80 m (30-40 m embedded in the ground) are commonly adopted in current offshore wind practice in suitable geotechnical conditions. Piles of such size require large impact hammers to ensure successful pile driving in a variety of soil conditions. Environmental constraints regarding underwater noise during pile installation add to the numerous challenges associated with monopile installation. It is necessary to explore alternative installation approaches, which are of less impact on the sea life (lower noise emissions) and at the same time do not compromise adequate operational performance of the foundation. To address this challenge, the Gentle Driving of Piles (GDP) JIP has been launched in the Netherlands. The experimental scope of the project includes pile installation using impact hammering, axial vibratory driving, and a novel vibratory installation method named Gentle Pile Driving, based on simultaneous application of low-frequency/axial and high-frequency/torsional vibrations. This paper overviews activities and preliminary results after the first year of project, particularly regarding the development of a new GDP vibrohammer and the execution of 1/10-scale field tests.
Andrei V. Metrikine, Apostolos Tsouvalas, Maxim L. A. Segeren, Ahmed S. K. Elkadi, Faraz S. Tehrani, Sergio S. Gómez, Rob Atkinson, Federico Pisanò, Evangelos Kementzetzidis, Athanasios Tsetas, Timo Molenkamp, Kees van Beek and Peter de Vries
Keywords: offshore wind, monopile, pile installation, vibratory driving, field testing, cyclic lateral load testing, sand, underwater noise
Publisher: DFI