Abstract
The reduction of tsunami inundation flow and tsunami force by a porous vertical barrier installed on a seawall was investigated to give a better understanding of effects of coastal structures on tsunami hazard mitigation. Laboratory experiments of permeable and impermeable wave barriers exposed to breaking bore were carried out to examine variations in wave height amplifications, inundation flows and wave forces acting on barriers. It turns out that the porous barrier can reduce the inundation depth and discharge effectively. The reduction effects on the inundation depth and discharge are mainly governed by the porosity of barrier and the relative tsunami height to barrier height. The reduction of inundation velocity is less than that of inundation depth. When tsunami height in front of a porous barrier is between 0.5 and 1.0 with respect to barrier height, the wave force acting on the barrier can be significantly reduced in comparison with that of the impermeable barrier. This is because that the reduction of wave force is influenced by variations in tsunami height in front of the porous barrier.
