OPTIMUM CONDITION FOR STABILTY OF AN ARTIFICIAL BEACH WITH A GRAVEL FILTER LAYER UNDER IRREGULAR WAVE ACTION

Gozo Tsujimoto, Tokuzo Hosoyamada, Tetsuya Kakinoki

Abstract


The safety of a fail-safe artificial beach was studied. Beach profile changes and the onshore-offshore distribution of the sand particle size were measured in a water flume. Under the action of erosive waves, sand particles are deposited on the run-up area. Because of the increasing permeability of the filter layer, the beach profile can be in equilibrium. A filter layer promotes the sorting of sand particles, and depositional waves deposit coarse sediments on the onshore side and fine sediments on the offshore side for an erosive-type beach. A filter layer has the potential to change the beach profile without requiring changes in the water level. The permeability of a filter layer has greater effect on the water velocities and water surface in the stage of run- down than in the stage of run-up.

Keywords


sediment transport; numerical simulation; change in water level; digital image

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