ON THE RELATIONS OF SUCTION, MOISTURE CONTENT, AND SOIL STRUCTURE IN COMPACTED CLAYS

This paper describes the results of a series of experiments in which the suction properties of compacted sand-clay materials were measured. For the clays tested, variations in the matric suction, which is controlled by the soil microstructures, tended to be more significant than the osmotic suction, and, hence, total suctions could be related to gravimetric moisture, but not to degree of saturation or volumetric moisture content. These findings raise questions regarding the usefulness of volumetric moisture content and degree of saturation as state variables adopted in constitutive and flow models of unsaturated compacted swelling clays. Thus, a possible deficiency in contemporary hypotheses for the behaviour of unsaturated soils is presented. (A) For the covering abstract see IRRD 881647.