Depositional geochemistry and geotechnical properties of marine clays in the Ariake Bay area, Japan

The present paper provides integrated information on the geological setting, the mineralogy, the depositional and post-depositional geochemistry, and the overall geotechnical properties for Ariake Bay sediment based on the data of the borehole samples collected from different sites in Ariake Bay area. The variation of the geotechnical properties of the sediment, including consistency limits, shear strength, sensitivity and compressibility, can be explained in terms of clay mineral composition, pore water chemistry, and chemical changes of soil materials due to weathering. There exist differences in the geotechnical properties between salt-leached and non-salt-leached clay sediment. The low swelling nature of the smectite which is the principle clay mineral of the sediment contributes to the formation of quick clay in salt-leached sediment.