Stability of Gravel on Mild Slopes in Breaking Waves

Abstract

A recurrent challenge in the hydraulic engineering is to establish the required stone diameter for a stone protection on mild slopes, since the stability of gravel on a mild slope is not yet sufficiently covered by existing design methods. The objective of this study is to investigate the relation between the loads and the stability of stones on a mild slope in order to be able to design a protection with more accuracy, both statically and dynamically stable. It was found that for statically stable structures the required stone diameter can become significantly smaller than the Van der Meer formula suggests. For dynamically stable structures, even smaller stone sizes are found to be stable. This study showed that XBeach-G provides an accurate way of determining the required stone size for gravel protections on mild slopes in breaking waves.