防潮堤に作用する津波に対する海岸砂丘の効果に関する実験

Abstract

It is necessary to consider coastal dunes in the design of anti-tsunami structures such as seawalls. This experiment has been conducted in Tsunami Generator in DPRI. We have measured the pressure on the seawall induced by 2 types of tsunamis. They were reproduced in different ways, and defined as solitary wave and long wave. The solitary wave has a short duration and steep peak, and the long wave is a current flow accompanied by the long duration. Then, we have investigated the reduction effect of dune topography and the influence of suspended sediment against wave force. Against the wave force by the solitary wave, coastal dune has had the mitigation effect by reducing both of flow velocity and inundation depth. However, costal dune did not affect the force by long wave. Besides, seawall has been received larger pressure and force in the case that the sediment from the dune is concentrated in the tip region of wave.