Abstract
This study focuses on behavior of coral gravels under waves penetrating through coral grave bed around the surf and swash zones. We first carried out laboratory experiments and estimated the fluid velocity and the vertical pressure gradiaent in the gravel layer near the bed surface. Numerical models based on 2D flow model accounting for porous media and DEM were applied to investigate the behavior of coral gravels under such fluid forces. It was found through this study that the magnitude of vertical forces induced by the flow velocity and pressure gradient inside the gravel layer is comparabale to gravitational force and has significant influence on enhancement of the shoreward movement of gravels near the shore and also of the stability of gravels in the swash zone on steeply sloping foreshore bed.
