CONSOLIDATION AND PERMEABILITY BEHAVIOR OF HIGH-POROSITY BALTIC SEABED SEDIMENTS

The consolidation and permeability (hydraulic conductivity) characteri stics of the high-porosity surficial seabed sediments from a test site in the Eckernforde Bay, Baltic Sea, were studied using a constant rat e of strain (CRS) consolidation and hydraulic conductivity testing sys tem employing flow pumps. These silty clay sediments are characterized by high void ratios, high organic content, and variable concentration of methane gas. Results from CRS consolidation tests show appreciable apparent overconsolidation of the sediments at the upper 200 cm with a gradual transition to normally consolidated states below 250 cm in d epth. The highly compressible nature of the material is reflected in t he large values of the compression index. The hydraulic conductivity o f the box core samples ranges from 2.5 X 10(-7) to 3.0 X 10(-6) cm/s f or void ratios ranging from 4.5 to 7.0 with a linear relationship betw een void ratio and log of hydraulic conductivity. The engineering beha vior of these sediments is of practical significance in geoacoustic mo deling of the seafloor for studies related to mine countermeasure prog rams.