Geotechnical Soil Data for Floating Offshore Wind Applications: Scottish, Baltic and Adriatic Seas

The design of resilient offshore structures requires knowledge of the geotechnical characteristics of soils present at a given location. In particular, seabed liquefaction, as one of the most severe forms of soil dynamics, must be well understood in order to prevent structural failure. Striving to gain such knowledge and insights, this dataset comprises the results of a unique, experimental campaign involving geotechnical characterisation of site-specific conditions for three selected locations (the Baltic Sea, the Scottish Sea, and the Adriatic Sea). For each of the above-mentioned regions, samples were collected from two locations. In total, preliminary tests were carried out for six types of soil. The geotechnical characterisation focused on determining soil susceptibility to liquefaction together with the mechanical properties of the tested sands, as well as supplementary key model parameters required for both experimental and numerical modelling. The experimental campaign began with a detailed microscopic examination and grain size distribution analysis to classify the soils. Based on the results, five of them were found to meet the initially adopted criteria (these are non-cohesive soils) and were subjected to a detailed testing procedure (a full set of monotonic and cyclic triaxial tests was performed). Soil samples marked with the symbol Adriatic 1 were identified as cohesive and therefore not suitable for liquefaction-related testing.The basic soil index properties were determined, such as grain size distribution, mean grain size d50, maximum and minimum void ratios, and hydraulic permeability. A series of advanced monotonic and cyclic triaxial tests was carried out using cyclic triaxial apparatus available at IBW PAN. Based on the results, the values of mechanical parameters (angle of internal friction, cohesion, elasticity constants) were determined. From the extensive series of monotonic and cyclic triaxial tests, the undrained and drained soil response was identified in order to define contractive and dilative regions. The liquefaction susceptibility of soils was also determined. A database of soil characteristics was compiled to support the development of surrogate soils with scaled properties for further use in physical and numerical modelling. Detailed results of the most significant tests performed are included in the appendixes attached to the report.