Research Engineer, School of Civil and Environmental Engineering, The University of New South Wales, Sydney,
Professor, School of Civil and Environmental Engineering, The University of New South Wales, Sydney,
(Received 25 February 2003; accepted 26 August 2003)
The Slot Erosion Test and the Hole Erosion Test have been developed as fast and simple tests for studying the erosion characteristics of soil in cracks in embankment dams. The erosion characteristics are described by the Erosion Rate Index, which measures the increase of erosion rate with respect to an increase in the hydraulic shear stress; and the Initial Shear Stress, which represents the minimum hydraulic shear stress when erosion starts. Knowledge of these erosion characteristics aids in the prediction of the likelihood of embankment dam failure due to piping erosion in a risk assessment process.
Values of the Erosion Rate Index span from 0 to 6, indicating that the changes in erosion rates in response to changes in hydraulic shear stress can differ by up to 106 times across different soils. The Erosion Rate Index is apparently influenced by the soil fines and clay-sized content, plasticity, dispersivity, water content, dry density, degree of saturation, clay mineralogy, and possibly the presence of cementing materials such as iron oxides. Coarse-grained, noncohesive soils, in general, erode more rapidly and have lower Initial Shear Stresses than fine-grained soils.
Paper ID: GTJ11903