On the Role of Chemistry in the Development and Behavior of the Sensitive Marine Clays of Canada and Scandinavia

The Scandinavian and Canadian experiences are reviewed and analyzed in the light of recent experiments involving the effects of added salts on the remolded shear strength and the liquid limits of two Ottawa area clays, both of which had low porewater salinity in their natural state. The response was similar to that observed in the Scandinavian marine clays where the sensitivity decreases as the salinity increases. It is concluded that the similarities relating to the influence of chemical factors are greater than previous interpretations have indicated. The precise relationship between porewater salinity and sensitivity in Leda clay appears to be unique to each sample and a broad geographic relationship should not be expected. Even short range similarities may be obscured by the generally low salinities of the Canadian marine clays and the great variability in other factors, such as texture and degree of cementation, which also affect the sensitivity.