Abstract
In the aftermath of the 2011 Tohoku earthquake and tsunami, there has been a growing recognition of the need to reinforce caisson-type breakwaters against tsunamis. To enhance the strength of breakwaters, the method of putting rubble stone or concrete blocks behind caissons has been proposed. However, the resistance mechanisms and reinforcement properties of breakwaters have not yet been identified. Therefore, in this study, these mechanisms and properties were investigated by performing horizontal-loading tests using a breakwater model, and by observing rubble stone or concrete blocks subjected to centrifugal acceleration. Test results showed that large reinforcements could increase the resistance and bearing capacity of breakwaters. Furthermore, it was found that the mound did not reach the critical-limit state although the allowable structural-displacement magnitude would have been exceeded; such mound behaviour should be considered while assessing structural resistance.
