Abstract
The extremely huge waves higher than the design waves occur frequently due to the sea level rise and due to big typhoons and the sliding disaster of caisson is increase. In this study, Hydraulic experiments were conducted to verify the applicability to breakwaters with the counter-weight block installed at harbor side of breakwaters which proposed by Mase et al. The experiments were carried out in the constant wave hight and three different wave periods. The sliding distance of the caisson which was reinforced by the counter-weight block was small, therefore it was found that the counter-weight block is effective as reinforcement of breakwaters against accidental waves.
