Gentle Driving of Piles: Proof of concept laboratory scale tests

The global market for offshore wind energy is currently experiencing tremendous growth, which is expected to continue in the coming decades. Monopiles are one of the most frequently used foundations for Offshore Wind Turbines (OWTs) and are commonly driven into the seabed using impact hammering. The demand for higher capacity OWTs requires the installation of larger monopiles. As monopiles, however, become bigger their installation with hammering and mitigation of generated noise becomes challenging and costly. To optimize installation and to limit noise emissions, an innovative installation technique known as the Gentle Driving of Piles, GDP, has been developed. This technique combines vertical and torsional vibrations under different frequencies with the main driving assistance coming from the torsional force. This paper presents and discusses the results from a series of lab-scale pile driving tests performed in dense sand using the GDP method. For these tests, a lab-scale GDP shaker has been mobilized. During installation of the scaled piles, the frequencies and amplitudes of the vertical and torsional excitation were varied independently with the objective to increase the penetration speed. The results show improved pile driveability with high-frequency, low-amplitude torsional vibrations and showcase the potential of the GDP method in improving installation performance.