Physical modeling of the dynamics of a revetment breakwater built on reclaimed coral calcareous sand foundation in the South China Sea—tsunami wave

In this study, taking the reclamation engineering in the South China Sea as the background, several wave flume experiments (geometrical similarity scale is set as 1:10) are performed to study the dynamics and the stability of a reclaimed calcareous sand foundation and the breakwater built on it, under the impacting of tsunami wave. Tsunami wave is similarly simulated by N wave in the wave flume. It is shown by the experimental results that the revetment breakwater has no visible displacement, and there is no significant deformation in the reclaimed coral sand foundation, regardless the foundation is in dense or loose state under tsunami wave attacking. Furthermore, there is indeed excess pore pressure generated in the reclaimed coral foundation with a maximum magnitude of 1.5 kPa, caused by the water overtopping or the seepage. It is found that the excess pore pressure has not caused liquefaction in the reclaimed calcareous sand foundation due to the fact that there is only one peak impacting for the tsunami wave-induced load, rather than a cyclic one. Finally, it is concluded that the reclaimed calcareous sand foundation and the breakwater built on it are basically stable under tsunami wave impacting. However, the excessive water overtopping would be a potential threat for the vegetation behind the breakwater, as well as for the underground desalinated water in the reclaimed lands.