The Tiller-Flotten research site: Geotechnical characterization of a very sensitive clay deposit

The Tiller-Flotten research site was developed through the Norwegian GeoTest site (NGTS) project. The site consists of a more than 50 m thick marine clay deposit. The top 7.5 m of the deposit shows a low to medium sensitivity, while sensitivity increases up to approximately 200 from 7.5 to 20 m below the ground surface. A wide variety of in situ and laboratory data have been acquired to investigate the geotechnical, geological and geophysical properties of the material. The sensitive clay shows low to medium plasticity and a liquidity index (IL) above 1.6. It shows some overconsolidation (OCR ≈ 1.5-3.0) linked to the glacial history of the area. Its strength and stiffness properties show good agreement with some well-known correlations for sensitive clays. Anisotropy in undrained shear strength is also similar to other sensitive clays of Norway. It is hoped that the next years will see an increased use of this benchmark test site at Tiller-Flotten. The site can be used as a research tool, as training and teaching facilities and as ground for development of new soil models, testing of new investigation methods and further advance the state-of-the-art in sensitive clay material.