Numerical Simulation for the Erosion and Stability of Riverbanks Subjected to Different Flood Hydrographs

Abstract

Stability of riverbank under the conditions of five different flood hydrographs and of three bed conditions is discussed using the results of numerical simulation. Three models of hydraulic fluvial erosion, seepage flow, and slope stability are coupled to discuss the effect of the seepage flow and river bed deformation on riverbank stability. The fluvial erosion model predicts the distribution of boundary shear stress along the river cross section and then predicts the erosion progress. The seepage model predicts the spatial and temporal variations in the groundwater table and the pore-water pressure inside the riverbank. Stability model calculates the factor of safety of bank material and estimates the possible failure plane. The three models are based on the finite element method with moving boundaries. The response of riverbank to the oscillated water level in the river and the consequent groundwater table is analyzed. The trend of factor of safety through time is presented. The influence of relevant geometrical, internal and external forces are also discussed.