The coastal structures allow the wave overtopping. However the extreme wave overtopping could cause damages on rear slope. The most of the researches for the armor stability were about on the sea side slope of rubble mound structures. van Gent (2007) performed the experiments about the stability of the rock material on the rear side slope of rubble mound structures with L-shaped crest elements.
In this study, 2-D model tests were performed to investigate the stability of concrete armor units covered on harbor side slope of rubble mound structures. The rectangular shaped crest elements were applied and the tetrapods were placed on harbor and see side of the rubble mound structures. The stability were investigated using the damage level (Nod=0.5) and it could be known that the armor unit weight ratio for the rear slope of rubble mound structures needed 0.8 times of that for sea side slope.
