Average Wave Overtopping Volume of Rubble-mound Structure Covered by Tetrapods: Effects of the Width of Armour Crest and the Structure Slope

The average wave overtopping volume is used as a design parameter for coastal structures. The crest elevation of a structure should ensure the wave overtopping volume within acceptable limit. In this study, the effects of the width of armour crest in front of the superstructure and the structure slope on the average wave overtopping volume were experimentally examined for a rubble-mound structure covered with tetrapods. Twodimensional physical model tests on a rubble-mound structure were performed for measuring the wave overtopping under various water depth and wave conditions. As the width of the armour crest increased, the average wave overtopping volume decreased, and it also decreased when the structure slope was gentle. An empirical formula from the experimental data was proposed to predict the average wave overtopping volume for a rubble-mound structure.