Some Experiments on Restrained Shrinkage of Clays Undergoing Drying
This paper describes engineering applications which show the engineering significance of testing the phase composition of soils, including determining the level of water saturation. It further explains why, in order to accurately model in situ conditions in soil deposits, it is necessary to test the phase composition of soil under conditions of horizontal restraint and changing moisture content. The paper reviews the lineal measurement method of Sibley and Williams (1989), which was initially developed to test unrestrained clays. The method has now been adapted for use in characterizing phase relationships in horizontally restrained soil specimens undergoing drying. Results obtained using the new test have drawn attention to the fact that while soils undergoing drying are invariably restrained by naturally occurring mechanisms, the level of this restraint may vary widely. A useful index of the level of restraint applied to a slurried soil specimen undergoing drying is the moisture content at which initially 1-D (vertical) shrinkage behavior becomes isotropic.