Soil improvement to enable offshore wind terminal operations
Type:
Presented during:
CEDA Dredging Days 2026
Authors:
V. Biernaux and M. Wegman
Abstract
As offshore wind continues its rapid expansion, ports face growing pressure to adapt infrastructure for ever-larger installation vessels. At the BUSS Eemshaven Terminal, a spudcan punch-through incident highlighted the need for soil improvement at a berth designated for offshore wind installation vessels. Geotechnical investigations identified a stiff clay layer with variable strength, where the bearing capacity sometimes matched spudcan loads, resulting in either adequate support or sudden punch through. To create a reliable foundation for jack-up vessels, the project required targeted dredging, engineered backfilling and the construction of a new heavy-duty quay capable of accommodating the loads of large offshore wind farm components. This paper presents the soil improvement works carried out at the BUSS Eemshaven Terminal in 2025. The project combined dredging and earthworks under tight schedules and challenging geotechnical conditions. A key challenge arose from time limitations and environmental restrictions, which prevented the underwater storage of unsuitable clay. Unlike previous campaigns, clay material had to be brought onshore rather than stored within the harbour. The original plan, involving pumping the unsuitable clay to a purpose-built containment area, was revised due to schedule pressures, environmental limits, and concerns regarding the clay's slurrification behaviour, or the lack of it. Instead, the contractor opted for mechanical dredging and disposal, an approach that satisfied environmental permit requirements and optimised port land use. This case study demonstrates how proactive contractor involvement, regulatory compliance and technical adaptability enabled the successful delivery of the works. It offers practical lessons for ports and stakeholders navigating the demands of the energy transition, balancing geotechnical complexity, operational deadlines and environmental obligations in the North Sea and beyond.