ABSTRACT
In Composite river banks, fluvial erosion of material from the lower, non-cohesive, bank typically occurs at a much higher rate than erosion of cohesive material from the upper cantilevered part of the bank. Predicting cantilever riverbank collapse due to fluvial erosion or seepage erosion undercutting has not been fully studied or modelled, even though its role in streambank erosion may be important. In this research, we have decided to investigate most probable riverbank erosion mechanism in an experimental model. This paper presents results from a series of large-scale models that were tested on a cubic box and recorded using a high-speed, high-resolution digital camera. The failure pattern and related mechanism of cantilever failure was provided based on continuous images taken from deformations of soil block. It is shown that at least for our laboratory study conditions, beam (toppling) failure is most common than shear type failure in composite riverbanks.
