VISUALIZED EVALUATION OF INTERNAL EROSION PROGRESS UNDER DIFFERENT SEEPAGE FLOW HISTORIES

Abstract

In Japan, the frequency of torrential rain events has increased yearly, and many embankment structures have often failed. With age, many embankment structures have lost their original stability. The seepage history of rain and groundwater has caused the migration of fine particles within the soil, whereby the mechanical properties of the embankment may have changed. Current guidelines for the construction and maintenance of embankment structures often assume that the structures are made of uniform materials and rarely consider the deterioration of the soil materials. Therefore, systematizing our understanding of the effects of embankment inhomogeneity on stability dynamics is essential. In this study, visualization of fine particle migration was performed using transparent soils. The influence of different seepage histories on the process of internal erosion was then evaluated. Once soil particles moved significantly, subsequent movement was small, even when the hydraulic gradient was changed. However, at a certain time, after the water table dropped and then rose again, fine particles would again mobilize significantly. Furthermore, this study suggests that the water table fluctuation may weaken the soil.