Abstract
Seepage velocities in several breaker zones were measured with dye for visualization. Pressure gauges were also installed to obtain pore water pressure. Three cases of different incident-wave periods were treated in laboratory experiments. The time-averaged pore water pressure was higher near the shoreline, resulting in the seepage flow, the maximum velocity of which was larger as the incident-wave period was longer, generally moving from onshore to offshore. The penetrated water flowed out from the permeable seabed at a bar top or on the rather offshore side of the bar top if a bar was developed remarkably. The pore water pressure in the breaker zone showed time variation depending on the wave phases including wave breaking and bore propagation. There was a phase when the pore water pressure was locally low below the bar.References
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