ABSTRACT
Composite-type breakwaters made of concrete caisson and rubble mound are widely employed in Japan. The powerful tsunami of 2011 severely damaged these breakwaters. Hence, there is an urgent need to reinforce them to prevent such extensive damage in another tsunami. One of the possible reinforcement methods involves piling stones behind the caisson. A stability assessment method has been proposed, but it has not been completely verified. Thus, centrifuge modelling was implemented to examine the stabilities of the rubble mound and piled stones under the condition of a significant tsunami-induced water-level difference. The effect of reinforcement was investigated by altering the sectional shape of the piled stones. Consequently, a bearing capacity failure was observed in the cases with none and insufficient amount of piled stones. The stability observed in the centrifuge was analysed using the proposed stability assessment method with the help of the circular slip analysis. This method was verified to be able to simulate the model tests.
