Integrated Geomodel – Horns Rev 3 Case Study

Abstract

Summary Energinet.dk is developing the Horns Rev 3 Offshore Wind Farm. In order to allow developers to evaluate the limitations and opportunities for foundation of turbines geophysical and geotechnical data were collected providing a basis for assessment of soil conditions. Geophysical data were collected in 2012 and the first interpretation was carried out without any boreholes or CPTs available. The conceptual geological model was consequently constructed from available literature. The resulting model presented Holocene units generally less than 10–15 m thick, but locally as deep as 20–25 m. In 2013 geological and geotechnical information was collected. The borehole and CPT data showed poor correlation to the existing geological model. The acquired data indicated Holocene sediments to much greater depths. Age determination (C14) performed on a single sample emphasized this geotechnical observation. Integrated interpretation of geophysical data, borehole and CPT data revealed a complicated Holocene setting down to 40 m in large part of the area with significant regional variation in clay thicknesses. This integrated model is presented in this study.