Author(s): Daisuke Kobayashi; Kazuyuki Ota

Linked Author(s):

Keywords: Rockfill; Seepage line; Hydrodynamic force; Unresolved CFD-DEM

Abstract: In 2023, a flood occurred in Libya owing to a Mediterranean tropical-like cyclone, and two rockfill dams collapsed upstream of a valley known as the Wadi Derna, causing extensive flooding damage in the downstream urban area. To prevent such extensive damage from dam disasters, a numerical simulation method that can appropriately predict the temporal variation in the shape of embankment erosion when the dam overflows and the time until collapse is required. In this study, we conducted an overflow erosion experiment using a rockfill dam model and performed 3-D unresolved CFD-DEM simulation. The simulation reproduced the increase in the seepage line as the overflow discharge increased. Furthermore, it was clarified that discontinuous erosion during overflow occurs through a repeated process in which an increase in the overflow discharge enhances the hydrodynamic force at the seepage outflow point, leading to particle transport and upstream migration of the outflow point. However, the reproducibility of the erosion shape is underestimated at the toe of the embankment. This may be because the hydrodynamic force was underestimated due to the diffusion of the volume fraction of the fluid near the water surface.

DOI: https://doi.org/10.64697/978-90-835589-7-4_41WC-P1663-cd

Year: 2025