Desorption and consolidation behaviour of initially saturated clays

TLDR: In this article, the volume change and water retention behavior of highly plastic clays (MX 80 bentonite and Speswhite kaolin) were experimentally determined in one-dimensional consolidation and desorption behavior.

Abstract: One-dimensional consolidation and desorption behaviour of highly plastic clays (MX 80 bentonite and Speswhite kaolin) were experimentally determined in this study. Initially saturated clay specimens were subjected to an increase in suction employing axis-translation technique and salt-solution technique to cover a suction range of 10 kPa to 300 MPa. Consolidation tests were carried out with a maximum applied vertical pressure of 3.2 MPa. The water content and the volume of the clay specimens at each applied suctions were measured. The study revealed that a vertical pressure increase was more effective in reducing the water content and the void ratio for the bentonite studied, whereas a suction increase was more effective in removing water from the kaolinite. The possible structure and fabric of the clays at saturation, at commencement of desaturation, and at residual shrinkage stage are discussed. The observed differences in the volume change and water retention behaviour were attributed to the differences in the mineralogical properties of the clays. vertical pressure, and isotropic loading conditions. Marcial et al. (2002) compared the volume change behaviour of bentonites due to an increase in the vertical pressure and suction. Fredlund (1964) and Flereau et al. (1993) noted that an increase in the vertical pressure and suction have similar influence on the volume change behaviour of expansive clays for a large range of applied suction. Marcial et al. (2002) stated that due to isotropic loading conditions, the void ratio decrease due to a suction increase was greater than that obtained due to a vertical pressure increase. Fredlund and Rahardjo (1993)’s results on silty clay (Fig. 1) showed that the volume change behaviour