INFLUENCE OF SUCTION EFFECT CHANGES DUE TO SEEPAGE FLOW ON PREDICTION OF OVERTOPPING EROSION OF LEVEE

Abstract

 In this study, we developed an overtopping erosion analysis model of levees considering a suction effect by a seepage flow and conducted numerical investigations assuming a case of rapid rise of water level such as small to medium rivers to clarify the influence of the suction effect changes on the overtopping erosion. First, comparative numerical simulations with and without the suction effect showed that the amount of bank erosion without the effect was overestimated compared to that with the effect, indicating the importance of considering the shear resistance force due to the effect. In addition, numerical simulations using different permeability coefficients showed that the small differences in permeability coefficients contributed to the suction effect, and that the larger the grain size, the greater the effect on the erosion process and the amount of erosion. This result suggests that the unique permeability coefficient may have a large error in the prediction of overtopping erosion of actual river levees.