An improved rotating cylinder technique for quantitative measurements of the scour resistance of clays

The methods developed to predict the action of eroding fluid on cohesive soils lead to contradictory predictions. Most of them are questionable since they ignore the physicochemical parameters that seem to control the erosion process. In order to study the scour resistance of intact or remolded cohesive soils, a rotating cylinder technique allowing for the control of essential parameters was recently improved by the authors. Intact or remolded samples can be used. The water quality is controlled in order to respect the in situ physicochemical conditions. The shear stress transmitted by water to the clay surface is directly and accurately derived. The dry weight of eroded material per unit time and unit area, for given conditions, is also directly and adequately measured. The influence of water quality, or of any treatment of the clay, may be quantitatively analyzed. Key words: erosion, scour, clay, rotating cylinder, viscometry, physical chemistry, river channels.