Seismic dynamics of revetment breakwater built on reclaimed coral sand foundation in the SCS: insight from 1 g shaking table tests

China has successfully constructed or enlarged a series of artificial lands on the top of some natural coral reefs in the South China Sea (SCS) by the way of reclamation. Many revetment breakwaters have been built around these reclaimed lands to resist the wave impact and scour. Currently, the research on the dynamics of offshore structures under the attack of strong earthquakes is very limited. In this study, taking the reclamation project of the coral reef islands in the SCS as the engineering background, the seismic dynamic response characteristics of a revetment breakwater and its coral sand foundation are studied by 1 g shaking table test. The test results show that the acceleration has a significant amplification effect from the bottom of the foundation to the overlying structure. Under the attack of seismic waves, the response of pore pressure inside the coral sand foundation is strong, and the magnitude of pore pressure increases greatly. Furthermore, the settlement and displacement of the revetment breakwater are not significant, satisfying the seismic fortified standard in China (noted: structures are repairable after attacked by moderate earthquakes). It is indicated that the stability and long-term service performance of the revetment breakwater could be guaranteed. The test results also show that under the attack of highly extreme seismic waves, the revetment breakwater could be seriously destroyed. The failure mode is the significant softening and instability of the coral sand foundation, as well as the excessive sinking of structures on it, caused by the considerable pore pressure built up.