Characterization by Sampling and in Situ Testing – Connecticut Valley Varved Clay

Varved clays, which consist of alternating layers of silt and clay, are common in glaciated regions of North America and Northern Europe. This layering results in several unique engineering properties making varved clays a challenging soil for engineering design. Varved clays have hydraulic conductivity and undrained shear strength anisotropy that far exceeds that of most other soils. The strength of the soil for shearing along the horizontal varves is much less than that for shearing across the varves. This paper summarizes the geotechnical engineering properties of Connecticut Valley Varved Clay (CVVC). CVVC is a lacustrine soil deposited approximately 15,000 years ago during retreat of the Laurentide Ice Sheet. Results from soil sampling, in situ testing, and laboratory testing conducted during the past 15 years for a deposit of CVVC at the National Geotechnical Experimentation Site in Amherst, Massachusetts, USA, are presented.