Centrifugal model tests on clogging performance of stone columns in coral sand site

Change of clogging and drainage performances of stone columns under many earthquakes is one of the focus issues in construction of artificial dredging island reef and port engineering. The dynamic centrifugal model tests on the composite foundation with stone columns in coral sand are carried out, and the change of clogging and drainage performances of stone columns is discussed through the image observation of the excavation profile of the stone columns, the grain-size distribution tests on the stone columns before and after earthquakes, and the change analysis of the dissipation rate of pore water pressure. The results show that liquefaction occurs at the buried point of 1.25 m, the pore pressure ratio reaches 1.0, and no liquefaction occurs at the buried point of 7.5 m under the seven times of intense dynamic loading. After the tests, no obvious fine particle infiltration is found in the sections of the 9 stone columns excavated from top to bottom, and the grain-size distribution curves of the stone columns tested before and after earthquakes are basically consistent, indicating that clogging pores do not appear in the stone columns. At the buried point of 1.25 m, the pore pressure dissipation rates are respectively 0.027 s^-1 and 0.029 s^-1 under the first and sixth times of intense dynamic loading, which proves that the drainage performance of the stone columns has not changed significantly.