ABSTRACT
In this study, tsunami overflow experiments of composite breakwaters with different types of surcharge embankments behind the caisson were conducted with a drum centrifuge. In order to stabilise the foundation rubble mound against seepage flow generated by tsunami, it is important to keep pressing the mound just under the caisson toe with an embankment. The embankment by gravel gradually becomes ineffective due to continuation of the scouring. On the other hand, the embankment using the mesh bag units can resiliently hold down the mound just under the caisson toe, so it was confirmed effective even with a small amounts of mesh bag units against scouring and seepage flow in the mound.
