Suction Bucket Installation: Risks during the Installation Process-Paper

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The paper examines installation risks for suction bucket jacket (SBJ) foundations, an increasingly attractive option for offshore wind farms in deeper water and where underwater noise restrictions limit impact-driven foundations. Because suction-bucket dimensions and performance can be governed by installation requirements as well as in-place loads, understanding installation behavior and monitoring it effectively are essential.

The authors analyze data from 20 SBJs installed at the Borkum Riffgrund 2 wind farm in the German North Sea in 2018. Each structure was installed successfully in predominantly granular soils, but the measurements revealed several important risks:

- <strong>Changing pore-pressure conditions:</strong> As installation progressed, the pore-pressure factor increased, suggesting that soil permeability within the bucket—and potentially soil-plug loosening—may increase with depth. Monitoring this factor can help assess installation behavior in real time.
- <strong>Variable internal plug heave:</strong> Soil heave generally followed expectations, but some buckets showed abrupt changes near the end of installation. These variations may reflect complex changes in the three-dimensional soil surface or scouring beneath the monitoring equipment. Inadequate allowance for heave could cause installation problems.
- <strong>Misleading inclination readings:</strong> Suction pressure deforms bucket lids, affecting inclinometers mounted on them. Individual bucket readings may therefore suggest changes in tilt that do not represent the overall jacket’s inclination. Independent structural measurements are needed.

The study emphasizes the importance of reliable, real-time monitoring of penetration, pressure, water flow, and inclination. It also highlights the need to interpret measurements in light of sensor limitations and the complex soil response. These lessons can support safer, more efficient SBJ installations on future offshore wind projects.

Keywords

suction bucket jacket

offshore wind foundations

installation risks

pore-pressure conditions

soil permeability

internal plug heave

inclination readings

real-time monitoring

Borkum Riffgrund 2

suction bucket installation