Experimental Study of Contact Erosion at a Granular Interface
Contact erosion appears at the interface of two soil layers subject to a groundwater flow. Particles of the finer soil are eroded by the flow and transported through the pores of the coarser layer. Fluvial dykes are often exposed to this phenomenon. Small-scale experiments combining Refractive Index Matching medium, and Particle Image Velocimetry were carried out to measure the flow characteristics close to the interface between a porous medium and a sandy layer. Velocity and shear-stress distributions were obtained. They underline the spatial variability of stress exerted by the flow on the fine soil which is directly related to the variability of the pore geometry. These distributions can be helpful in better modelling contact erosion by going beyond the simple use of global mean values, such as Darcy velocity, as is usually proposed in the literature.
KeywordsInternal erosion Granular interface Particle image velocimetry Refractive index matching Porous medium
Authors acknowledge the financial support provided by EDF-CIH
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