BASIC STUDY ON THE DAMAGE PROCESS IN THE MIDDLE OF THE CONSTRUCTION OF RUBBLE MOUND BY WAVES

Abstract

 It is a problem that the rubble mound is damaged if high waves strikes during construction of the rubble mound seawall. However, there is little knowledge about the damage process of rubble mound against wave conditions. In this study, we focused on the construction process and examined the damage process of the rubble under high wave conditions by hydraulic model test.

 In all the experimental cases, the crest dropped rapidly from 1 hour to 3 hours later at the local scale. As for the damaged cross-sectional shape, the change on the offshore side was small, and the shoreside edge extended with time. The crest elevation dropped to about 40% of the initial crest elevation at relative wave height H_1/3 / B = 1.17. The damage rate was found to be around 40% at H_1/3 / h = 0.36 and 20-30% at H1/3 / h = 0.5. In addition, it was found that the damage speed is slow in the experiment case with a wide crest width, which is important for considering the damage control of the rubble mound.