Abstract
The performance of the seawall on Urayasu coast have decreased under the presentcondition such as the seawall's body subsidence, design wave alteration, and incidence wave height increment caused by dredging. In this study, we research the performance of the seawall and several countermeasures through hydraulic model experiments, and clarified the following points. Seabed gradient and design wave increment, the body subsidence let the external force that affects to the body increase. Consequently, the force particularly brings about wave setup on outer waterside catwalk, it is difficult to prevent the overtopping by restoring only the catwalk. Considering effect against wave over topping, cost, and stability ofthe body, the effective countermeasure is chosen increasing height of the seawall normal line. We reconfirmed the importance of the experiments for understanding the hydraulic phenomenon.
