On the erosion of consolidated clay material by a fluid containing sand

Abstract

Erosion of a consolidated clay material by fluid containing sand was tested in a laboratory facility. Two modes of erosion were distinguished: "sand blasting" or impact of individual sand particles moving by saltation and "milling" by sand particles forming part of a moving bed layer of discontinuous dunes. Sand blasting resulted in the more severe erosion and this process was adjusted during the experiments to yield maximum erosion rates. It was found that the overall bed degradation rate was a result of many local, shallow erosional features which coalesced. The maximum overall rate of bed degradation was found to be of the order of 0.2 mm/h or 1.75 m/year for a clay material consolidated to 345 kPa.