Abstract
Many breakwaters were damaged by the 2011 off Pacific Coast of Tohoku Earthquake Tsunami. Especially the breakwater tilted or turned over due to scour at the rubble mound of the breakwater head and a lack of bearing capacity.
In this study, in order to discuss the stability of the breakwater head, centrifuge model tests to simulate tsunami flow and a numerical analysis using CADMAS-SURF/3D were conducted. As a result, the rubble mound was enormously scoured due to tsunami flow. In addition, it was shown that the area of scour was predicted with the flow velocity distribution in the numerical analysis and the estimation formula for the stability of the rubble mound.
Moreover, in this study, some preventions against scouring were suggested and the effect of them was velified by model tests. According to results of model tests, in case of covering over the surface of the rubble mound with the units packed gravels and installing the L-shape block at the corner of mound, it was revealed that the prevention was significantly effective although the rubble mound was partially or locally damaged.
