Author(s): A.J. Raudkm; S.K. Tan
Abstract: Experiments on erosion of cohesive soils using a circular couette flow erosion device and three clays with eight electrolytes (solutions) at approximately constant temperature are described. The analysis of the experimental results using the erosion model based on the rate process concept shows that the erosion rate of a clay by an electrolyte with different pH-values and molar salt concentrations can be explained by the orientation of the clay aggregates in the slurries before consolidation as well as predicted. The features of the eroded clay surfaces depend on the nature of the clay. The eroded surfaces of stiffer clays look in scanning microscope pictures distinctly pitted, whereas surfaces of clays with face to face stacking appear to flake. The eroded surfaces of soft clays show moulded features and undulating surface forms. However, most of the clays are neither stacked face to face nor soft, and they show an intermediate form of eroded surface features. Except for very soft clay, the surface of the eroded clay is distinctly pitted, in keeping with the picture that clay lumps have been lifted out of the surface.