Author(s): A. Samadi; E. Amiri-Tokaldany; M. H. Davoudi
Linked Author(s): Ebrahim Amiri-Tokaldany
Keywords: No Keywords
Abstract: In composite river banks consist of a cohesionless material overlaid by a cohesive layer of material, bank erosion occurs by fluvial entrainment of material from the lower, cohesionless bank at a much higher rate than material from the upper, cohesive bank. This leads to undermining which in turn produces cantilevers of cohesive material. Upper bank retreat takes place predominantly by the failure of these cantilevers. The Kordan River in Iran is one example of a riverbank which is experiencing excessive erosion and bank retreat through cantilever type failure. In this research, to clarify the importance of the various parameters affecting the stability of composite riverbanks, the impacts of independent parameters affecting the stability of cantilever banks are evaluated in a series of model sensitivity analyses using a new model of riverbank stability analysis. Sensitivity analysis of the effective parameters in stability of banks against cantilever type failure, is carried out in this research for the most probable type of cantilever bank failure, i.e. shear-type failure. The results show that care should be taken when estimating the values of cantilever block height, block width, tension crack depth, block material cohesion, and the block material unit weight as the factor of safety is more sensitive to the variation of these factors. Conversely, a cruder estimation of the soil internal friction angle, matric suction angle, flow depth, and ground water level, may still provide a reasonable degree of accuracy in the bank stability analysis.
Year: 2009