Cho, Y.H.; Zhang, C.; Nakamura, T., and Mizutani, N., 2018. Failure mechanism of armor blocks of submerged breakwater. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1166–1170. Coconut Creek (Florida), ISSN 0749-0208.

This paper describes the failure mechanism of armor blocks of a submerged breakwater under regular and long period waves. Laboratory experiments with the scale of 1/50 were conducted in a wave flume. The measured normal and tangential wave forces on the damaged armor blocks were compared with 31 tests for a submerged breakwater with 3 submerged depths and 3 respective wave periods of regular and long period waves. The experimental results described the failure of armor blocks in the threshold conditions occurred mainly at the seaward edge of the crown by normal wave forces under regular waves, and the landward edge of the crown by normal and tangential wave forces under long period waves. Two-dimensional numerical analysis was carried out to investigate the effect of temporal and spatial variation of wave fields around the submerged breakwater on wave force acting on armor blocks. The results demonstrated that the dominant wave forces on armor blocks were induced by the decrease of the pressure near the damaged blocks resulting from the wave breaking for regular waves and the increase in the flow velocity for long period waves. It was confirmed the other blocks on the crown tends to be stable under long period waves.