Geotechnical investigation enables optimised offshore wind farm foundation design at Le Tréport

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 four months. We drilled 63 geotechnical boreholes at the turbine locations, offshore voltage station and along the cable routes, to a maximum depth of 80 metres below the 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.

Our comprehensive project management, coupled with clear lines of communication with EMDT, resulted in completion of this extensive project safely and on time.