Quick Clay

Synonyms

Glaciomarine sediment; Leda clay; Sensitive clay

Definition

Quick clay is a special type of clay prone to sudden strength loss upon disturbance. From a relatively stiff material in the undisturbed condition, an imposed stress can turn such clay into a liquid slurry.

Discussion

Quick clay is defined as a clay where the undisturbed shear strength of the soil is at least 30 times greater than the remoulded (or disturbed) shear strength (Torrance 1983). The ratio of undisturbed to disturbed strength is termed sensitivity. Thus a quick clay is very sensitive.

Quick clay is common along previously glaciated coastlines in parts of Canada and Scandinavia, and has also been found in Japan and in Alaska. Coastlines in these areas were submerged by the weight of glaciers during glaciation. As glaciers retreated, seas migrated inland with retreating icefronts. Glacially ground sediments, transported in plumes of glacial meltwater were deposited in the salt water of these ice marginal seas.