CHARACTERIZATION OF THE BOTHKENNAR CLAY - AN OVERVIEW

Following the purchase by the Science and Engineering Research Council of a soft clay test site at Bothkennar in Scotland, work has been carried out to provide data characterizing the clay for the benefit of future research projects. State of the art methods were used to enhance the research value of the characterization project. Fieldwork in 1989 involved high quality sampling using equipment from Laval and Sherbrooke Universities in Canada, and a 100 mm fixed piston sampler operated by the Building Research Establishment. In situ testing to augment earlier work at the site included in situ permeability, hydraulic fracture and field vane tests. Laboratory testing was undertaken by seven institutions in the UK and by Laval University. It involved the measurement of permeability and its variation with void ratio and flow direction, the measurement of yield and compressibility characteristics in oedometer tests, the measurement of stress-strain-strength and yield characteristics using triaxial and simple shear tests and the investigation of progressive destructuring of the clay using triaxial strain path tests. Using the results from this and earlier work, the Paper gives an overview of the ground conditions and the behaviour of the clay. The study also yielded information on the techniques of sampling and testing appropriate to soft naturally structured soils.