Abstract
　Recently, beach erosion is one of the most interested problem in coastal engineering. The shore protected with the submerged breakwater has attracted special interest. The effect of wave damping by the construction of submerged breakwater has been fairly clarified experimentaly. However, numerical study with the submerged breakwater has not been performed for the wave transformation and change of beach profile covering the whole beach. The main reason is that it is difficult how to evaluate the beach reflectivity.
　In this paper, a numerical model with beach reflectivity is proposed and numerical simulation is performed for predicting the wave damping rate and the beach erosion by the construction of submerged breakwater at a prototype.
　The numerical results agree with the experimental results obtained by Nagai et al. and Takayama et al. concerning the wave transformation near/behind the submerged breakwater. The erosion near the shoreline is reduced and the construction of submerged breakwater is available to project the shore.

【キーワード】：海岸侵食，潜堤，波浪変形，反射

*愛媛大学工学部海洋工学科
Department of Ocean Engineering, Faculty of Engineering, Ehime University
**愛媛大学大学院工学研究科
Graduate Course of Ocean Engineering, Ehime University