Abstract
Traffic hindrances were often caused by driftwood run-up due to wave overtopping under storm wave conditions on coastal roads behind gently sloping seawalls. In this study, the driftwood patterns around a gently sloping seawall were revealed by the field observation data. Hydraulic model tests with irregular waves of 1/40 scale were carried out in order to disclose the relationship between driftwood run-up ratio and wave overtopping rate for three wave period conditions. The characteristics of driftwood run-up were also shown for different driftwood thicknesses, lengths and densities for the longest wave period condition. The effect of increasing the crest height of wave-dissipating blocks was clarified as for countermeasures of driftwood run-up on gently sloping seawalls. In addition, tests of 1/5 scale were conducted to confirm the stability of a transmissive fence. Based on the test results, the hydrodynamic force when driftwood collided with the transmissive fence can be estimated for design wave conditions.
