Geological, geophysical and mechanical identification of marine deposits from the Gulf of Finland

Abstract

The paper presents experimental results of investigations of offshore deposits from the Gulf of Finland in the Baltic Sea. Firstly, it briefly reviews the sedimentary history of the studied site. Then, it presents results from marine geological investigations, including seismoacoustic reflection sub-bottom profiles and long sediment cores collected by piston coring. Finally, the paper presents the physical and mechanical properties of the intact soil samples through geotechnical laboratory tests. The data show the distribution of water content, bulk density, undrained shear strength, sensitivity, and organic content of the samples at various depths up to approximately 4 meters. The undrained shear strengths, obtained by fall cone tests, are scattered and the variations are ±35% for the studied specimens. A quantitative correlation between geotechnical data and local sedimentary units and depositional history was not possible in this study. Further efforts are needed to reduce the uncertainties and measurement errors in determining the undrained shear strengths in geotechnical laboratory.