Numerical analysis of embankment failure due to overflow based on erosion rates of soils

Abstract

Recently, the failure of embankments, such as levees and small embankment dams for irrigation reservoirs, has occurred more frequently because of a greater chance of severe typhoons and localized heavy rains. Overflow is known as a primary cause of embankment breaks. The purpose of this study is to develop a numerical method which can predict the breach process of an embankment caused by overflow. This paper presents two-dimensional and three dimensional numerical simulation of the embankment breaching. The finite volume method with a Riemann solver is applied to numerically solve shallow water equations for computing the overflow on the embankments and the configuration change of the embankment profiles is successively calculated in accordance with the erosion rates of the embankment materials as a function of the bed shear stress exerted onto the embankment surface. In order to achieve the stable computation, the surface gradient method was incorporated into the finite volume discretization. The comparison between the numerical results and experimental investigations has revealed that this numerical method stably computes the embankment profiles subjected to overflow breaching and the time up to embankment breaks can be well predicted.