A Comparison of Marine Clays from Ariake Bay, Japan and the South Nation River Landslide Site, Canada

Abstract

The smectite-dominated Ariake Bay marine clay, the sensitivity of which can increase upon leaching to yield quick clay, is found to conform to the general model for quick clay development that has been proposed on the basis of the properties and behaviour of the Canadian and Scandinavian quick clays. While the Ariake Bay soil is more plastic than the Leda clay from the South Nation site, its plasticity and its yield stress at constant water content, as determined using a coaxial viscometer, decrease with salinity in the same manner. The removal of citrate-dithionite soluble materials decreases the yield stress in both soils although the Ariake Bay soil, from which more is removed, is more dramatically affected. Dispersants decrease the yield stress of both soils. Why, in contrast to most smectites, the smectites in the Ariake Bay marine clay are of low activity and have their activity decrease upon leaching, thereby allowing the development of quick clay behaviour, remains uncertain but it may be related to dominance by high-iron smectites.