Seismic performance of revetment breakwater and nearby frame structure on reclaimed coral sand foundation in the SCS: Centrifuge shaking table test

Abstract

In the past decade, several artificial lands have been constructed on the top of several natural coral reefs by the way of reclamation of coral sand in the South China Sea (SCS). To protect and utilize these reclaimed lands, a few revetment breakwaters, as well as some frame structures had been constructed along the margins of or on these reclaimed lands. Taking the reclamation project on coral reefs as the engineering background, three centrifuge shaking table tests were conducted to explore the seismic responses of these reclaimed coral sand foundation (CSF), and to evaluate the stability of the revetment breakwater, as well as a nearby frame structure. It is indicated by these physical model tests that the reclaimed CSF has a considerable amplification effect on the seismic acceleration, and this amplification effect is positively correlated to the located altitude. No residual liquefaction occurs in the CSF during earthquake excitation. The maximum residual displacement of the breakwater is about 4 mm in horizontal, while the maximum residual settlement of the frame structure is only 1 mm in the scale of centrifuge. It is judged that the breakwater and the frame structure are in a relatively stable state. Based on the results from comparative research, it is observed that pore pressure is more likely to residually build up, and the amplification effect of acceleration is more obvious in less dense CSF, causing the stability of breakwaters or other structures on coral reef to be relatively poor.