Author(s): Stella Arnaouti; Panayotis Prinos
Linked Author(s): Panagiotis Prinos
Keywords: Dike; Erosion; Numerical simulation; Overtopping; FLOW-3D
Abstract: Sea-dikes are widely used to protect the inland from sea wave attack. Wave overtopping is one of the most common failure mechanisms that dikes face. Indeed, apart from the inland flooding, wave overtopping can erode the dike’s body, reduce its functional efficiency and - under extreme conditions - jeopardize the safety of the structure as a whole. To enhance the insight of the erosion process, a two dimensional numerical analysis is performed by using the sediment scour model of the commercial code FLOW-3D. The erosion of a dike that consists of uniform sand with initially trapezoidal shape under constant water surcharge is simulated numerically. The sensitivity of the erosion results to the dike material parameters (sand grain size, maximum bed concentration and soil repose angle) is highlighted. Furthermore, the water free surface elevation as well as the continuously changing shape of the eroded dike obtained from the numerical simulation are compared with plane dike laboratory experiments presented in Pontillo et al. (2010). The dike – without a core or a surface layer - had a total length of 1. 9m, height of 0. 2m and width of 0. 2m. The discrepancies observed between the numerical and experimental results are thoroughly discussed. Despite the discrepancies, this work aims at providing a better understanding of the erosion process under the complex bed shear stresses induced by flow overtopping and thus, offer valuable guidance for adequate flood risk assessment and management.
Year: 2013