Abstract
After the disaster of coastal dikes by the 2011 Tohoku Tsunami, the improvement of coastal dike design in response to external force of the design Tsunami is under progress. In this study, several structure types of coastal dike, which can stand for the more external Tsunami force, such as Nankai Trough Tsunami, without changing the length of dikes are proposed. Besides, scouring suppression effect was verified using a developed numerical model based on CADMAS-SURF/2D considering geomorphological process. As a result, it was confirmed that the structure typeswithstreamline at top of inner and back slope and drainage in landside of dike toe, were more effective than structures with moderating back slope. This new structure types could make similar width of current dikes. Therefore, it was suggested that this new structure types is not only effective to protect inland from Tsunami, but also they will not bring over negative effects to environment.
