Review of engineering behaviour of marine clays in Eastern Canada

Leda clay deposits are thought to belong to a single marine episode that sedimented in the Champlain Sea between 12000 and 9000 years BP. Differential uplift ended the marine episode and subsequent sediments were deposited in estuarine followed by near-freshwater to lacustrine conditions. Rock-forming minerals consisting of feldspars, quartz and amphiboles make up a large part of the clay size fraction. The dominating phyllosilicates are micas and illites, or hydrous micas. The fabric of the deposit consists of an assemblage of silt and clay size rock fragments in which clay minerals are generally randomly oriented.Major engineering problems are reviewed against the background of depositional history, nature of the soil fabric formed during sedimentation, subsequent structural alterations, mineral composition and pore water chemistry, all among the more important factors responsible for the engineering behaviour of these soils.