A Flaring Shaped Seawall (FSS) can drastically reduce a crest height and wave overtopping quantity in comparison with a conventional upright one. In this study, a series of hydraulic experiments were carried out using a two-dimensional flume to apply the FSS to practical use. As a result, armor stones on the rubble mound foundation were stabilized for a series of irregular waves. Flow velocities of wave in front of the FSS were measured to investigate scour. These were almost same as those of the upright seawall, and an average value of flow velocity indicated in the direction of onshore. Furthermore an impulsive breaking wave pressure by regular wave was measured and was about 4.5 times larger than one by Goda's formula. Finally, a diagram to estimate the crest height and wave overtopping rate of the FSS was made.

A Flaring Shaped Seawall (FSS) can drastically reduce a crest height and waveovertopping quantity in comparison with a conventional upright one. In this study, systematic hydraulicexperiments by irregular waves were carried out using a two-dimensional flume. As a result, a diagram to estimatethe crest height and overtopping rate of the FSS was made, and it is found that the overtopping rate and reflectioncoefficient of the FSS are almost similar to those of an upright seawall covered with wave-dissipating blocks.Furthermore pressures by regular waves were compared with ones by irregular waves, and a wave force formula for theFSS in an extreme shallow sea was investigated.