Study on seismic stability of seawall in man-made island. Pt. 2. Experimental study of seismic performance of seawall using a centrifuge

In the development of the man-made island siting technology of nuclear power plants, one of the most important factors to be verified in design is the seismic performance of the seawalls bounding the island. The overall stability of the seawalls, expected residual deformations of the caisson and of the armored embankment are important factors that must be evaluated. For this purpose, a detailed experimental study examining the performance of a seawall with an armored embankment has been conducted using centrifuge testing method. The effects of existence of an armored embankment, substratum density, substratum thickness, and the extent of ground improvement beneath the structure on the residual deformations of the seawall were closely examined. From the experiment results, it is indicated that displacements of a seawall placed on a thin and dense seabed are small and that the density of the seabed directly beneath the crushed stone mound on which the caisson is placed mainly influences the caisson movements. Moreover it is indicated that the residual displacements of the prototype expected from the results of these tests were small enough to preserve the functions of the seawall in protecting an island against ocean waves overtopping. (author)