Experimental and numerical investigation of the stability of overhanging riverbanks

Although different types of riverbank mass failure have been studied by many researchers, many uncertainties remain in predicting cantilever failures, in part because of a lack of detailed observations of this type of bank collapse. In this study, a laboratory study of cantilever failure was carried out using two types of materials to form overhanging banks with three different densities. The laboratory results show that the occurrence of toppling failures is more probable than the simple shear-type mechanism that has been analyzed most frequently by prior researchers. We go on to model these toppling failures numerically. Specifically, a Mohr-Coulomb model, within the framework of SIGMA/W software (ver. 7.17), was used to simulate the stress–strain behavior of the experimental banks. The numerical results for loess materials are in good agreement with the laboratory observations, but the simulations do not replicate experimental failures observed in higher density, more cohesive soils.