Deep foundations for an Offshore Windfarm – A challenge not only to dive-drill from seabed-PPT Presentation

PPT Presentation

Pdf Summary

The Saint-Brieuc Offshore Wind Farm, developed by Ailes Marines off the coast of France, comprises 62 wind turbines rated at 8 MW each and one offshore substation. Van Oord was the main contractor for the jacket structures, while BAUER Spezialtiefbau carried out the piled-foundation drilling.<br /><br />Between 2021 and 2023, Bauer completed subsea drilling for 190 piles. Drilling points were 29–42 metres below Lowest Astronomical Tide, with drilling depths of 18–46 metres and approximately 10 kilometres of total drilling. The work required precise control of pile height, inclination and grout levels, alongside challenging installation conditions at sea.<br /><br />Key challenges included variable ground conditions and the setup of drilling equipment, including the drilling template, temporary casing, dive-drill tower and dive-drill adapters. Bauer used different drilling tools, such as a rock-auger starter and a full-face cutter. Surveying combined above-water systems, including GNSS and a tachymeter, with underwater acoustic and differential-depth measurements. Cross-checks included manual laser readings. Pressure sensors and inclinometers monitored pile height and alignment, while a fibre-optic thermal system measured grout levels.<br /><br />The presentation describes the project as the world’s first offshore wind farm founded on drilled and grouted steel piles.

Keywords

Saint-Brieuc Offshore Wind Farm

offshore wind

drilled and grouted steel piles

subsea drilling

BAUER Spezialtiefbau

Van Oord

pile foundation

jacket structures

France

marine construction