Our large geotechnical investigation led to Eoliennes en Mer Dieppe Le Tréport (EMDT) developing an optimised foundation design for a wind farm project at Le Tréport. This will allow EMDT to address challenging ground conditions at an early stage of the design, mitigating future risk to the structures.
EMDT plans to develop a 62-turbine offshore wind farm off the French coast between Le Tréport and Dieppe. To obtain an optimised foundation design for the wind farm, EMDT commissioned Fugro to deliver a full offshore geotechnical investigation on the proposed site in the English Channel.
We started work in 2018 and completed the geotechnical investigations in under 4 months. We drilled 63 geotechnical boreholes at the turbine locations, offshore voltage station and along the cable routes, to a maximum depth of 80 m below seafloor, to capture the full complexity of the site.
To ensure the project was completed within the required time frame, three vessels and a jack-up barge were deployed in stages, using dynamic location planning between vessels to maximise operational efficiencies.
All geotechnical requirements of the project were met in full, with excellent sample and core recoveries obtained in very difficult ground conditions. We used an automated logging system to guarantee retrieval of the best quality data as we cored through different chalk and rock profiles.
The offshore campaign was followed by a large in-house laboratory programme that included advanced static and dynamic testing to determine soil strength and stiffness parameters, enabling us to characterise the ground conditions.
During our campaign, we recorded nearly 102,000 field exposure hours and carried out an extensive offshore programme that included:
| During our campaign, we recorded nearly 102,000 field exposure hours and carried out an extensive offshore program that included:
down hole cone
penetration testing (CPT) metres
seabed CPT metres
in situ thermal conductivity
Our comprehensive project management, coupled with clear lines of communication with EMDT, resulted in completion of this extensive project safely and on time.
On behalf of EMDT, I would like to congratulate all of Fugro’s offshore team, supported also by onshore teams, for the completion of this project, which was quite challenging. They managed to master the chalk, overcome some technical challenges and, above all, do it in a safe manner.
Benoit Caillet, Soil Assessment Manager, EMDT