Abstract: Subsurface erosion in river banks and its details, in
spite of its occurrence in various parts of the world has rarely been
paid attention by researchers. In this paper, quantitative concept of
the subsurface bank erosion has been investigated for vertical banks.
Vertical banks were simulated experimentally by considering a sandy
erodible layer overlaid by clayey one under uniformly distributed
constant overhead pressure. Results of the experiments are indicated
that rate of sandy layer erosion is decreased by an increase in
overburden; likewise, substituting 20% of coarse (3.5 mm) sand layer
bed material by fine material (1.4 mm) may lead to a decrease in
erosion rate by one-third. This signifies the importance of the bed
material composition effect on sandy layers erosion due to subsurface
erosion in river banks.