Regression analysis of physical and geotechnical properties of surface marine sediments

Abstract

Physical properties, undrained shear strength, and sound velocity of marine sediments (< 5 m below the seafloor) were measured in the laboratory on gravity and box cores taken in Eckernfoerde Bay, Baltic Sea. Shear wave velocity of surface marine sediments was estimated based on in‐situ measured profiles of shear modulus versus depth. Sediments at the study site are mainly soft silty clays, with high water content, high void ratio, high organic content, low bulk density, gas bubbles, low compressional and shear wave velocity, and low shear strength. Based on the sediment properties, regression analyses indicate that sound velocity correlates with sand %, water content, and shear strength for these samples. The results indicate that sound velocity may correlate with shear strength of marine sediments in a relative uniform environment, such as nongassy sediment. No usable relationship between sound velocity and sediment properties was found for gassy sediments. Shear wave velocity correlates with shear strength, bulk density, and effective overburden pressure, the shear strength increases with increasing depth and effective pressure for both gassy and nongassy sediments. Compared to gassy sediments, the shear strength of nongassy sediments increases more rapidly with effective pressure or depth. Higher‐order terms are not necessary in the models for surface sediments.