A Soil-Water Coupled Analysis of the Deformation of an Unsaturated River Embankment due to Seepage Flow and Overflow

In recent years, many disasters due to floods have occurred around the world. In some cases, the level of river water exceeded the estimated high-water level. It is necessary, therefore, to reconsider the evaluation method for river dike embankments during floods for the safety of the embankments. In this study, a deformation analysis is proposed that can simultaneously consider the unsaturated seepage flow and the overflow. This method is quite different from the conventional method, which considers the seepage flow and the stability separately.An air-soil-water coupled elasto-plastic finite element analysis has been developed to analyze the problem by incorporating unsaturated seepage characteristics. The deformation and the stability of river dike embankments during a flood are investigated. When we consider the overflowing of embankments, the deformation of the embankments becomes larger than the case for which only the seepage flow is considered. From the numerical analysis, it is found that the proposed hydro-mechanically coupled analysis method is an effective tool for estimating the stability of river embankments.