Abstract
The cavity behind bank protection occurs under stormy waves and flooding. In this study, we investigated the flow-out mechanism of back-filling sand under cyclic loading of water pressure experimentally and theoretically. As a result, it is clarified that cyclic seepage force which occurs around revetment under water pressure variation plays an important role to the movement of sand around revetment and also clarified by visualization technique that the sand around revetment moves like a circular arc. Furthermore, the effect of pressure distribution behind revetment and the effect of the porosity of bed on the flow-out phenomena are examined.
