Abstract
Tsunami breakwaters are required to have the redundancy and ductility, which is the performance to maintain the tsunami prevention effect without being broken immediately, even by the huge tsunami exceeding the design level. Kamaishi baymouth breakwater was destroyed by the tsunami in March 11, 2011. Hydraulic model experiments reproducing the failure had been conducted and proved that the sliding of the submerged breakwater at the opening section caused the failure of the breakwater head. Also, it had proved that the normal caisson structure or the precast concrete blocks could not secure the stability against huge tsunamis as a submerged breakwater.
The steel flame structure filled with rubble stone, which is similar to the huge gabion, have been developed as a submerged breakwater at the opening section of tsunami breakwater to increase the stability against tsunami flow. In this study, hydraulic model experiments were conducted in order to investigate the stability against tsunami. The lift force acting on this permeable structure is much smaller than that on the normal submerged caisson structures.
