PROPOSAL OF DIAGRAMS FOR THE ESTIMATION OF WAVE OVERTOPPING RATE ON GENTLE SLOPE-TYPE SEAWALL AND CONSIDERATION ON TIME-RELATED VARIATION

The purpose of this study is to clarify the characteristics of wave overtopping on gentle slope-type seawall. Therefore, the experiments on wave overtopping by irregular waves were carried out for gentle slope-type seawalls. Using the results, the diagrams for the estimation of wave overtopping rate were proposed for the gentle slope-type seawalls with 1: 3 and 1: 5 slope. And, these diagrams were compared with the diagram for upright seawall by Goda et al. As the result, by comparing for the upright seawall from the viewpoint of the wave overtopping prevention, the gentle slope-type seawall clarified the advantageous range in the relationship between relative water depth and relative crown height of seawall.In addition, the effects of sea level, wave height, crown height of seawall, wind, and etc. on the timerelated variation of wave overtopping rate were examined using the existed experimental results.