EXPERIMENTAL ASSESSMENT ON EVALUATION OF IMPACT FORCE OF TSUNAMI-DRIFTING VESSEL ON SEAWALL BEHIND DUNE

Abstract

 This study examines the behavior of small vessels drifting in a tsunami and the impact force of the drifting vessels on a seawall built behind a sand dune by means of a 1/100-scale hydraulic experiment. As a result, it was determined that the likelihood of a ship colliding with the seawall increases when the non-dimensional initial location (distance from the shoreline) becomes less than 0.6. The bouncing water mass of a tsunami generated in front of the seawall tends to reduce the impact power of a ship on a seawall. When there is a structure in front of the seawall, the influence of the bouncing water mass on the impact force can be estimated by considering the ship's drifting speed and the time lag between the tsunami and the ship reaching the seawall.