Abstract: The dynamic field response to earthquake in the coral sand is affected by its special engineering properties. In order to reveal the seismic response characteristics of the pile-soil-superstructure in the coral sand site, the shaking table tests of pile groups with three-storey frame structure in coral sand under different earthquake intensities are carried out. The dynamic responses to soil and structure are analyzed and compared with those in the liquefied quartz sand of Fujian. The results show that the excess pore water pressure ratios in both coral and quartz sands are far less than 1 under 0.1g seismic intensity, demonstrating that no liquefaction occurs in both sites. However, both coral and quartz sands are liquefied under 0.2g seismic intensity, and the liquefaction degree of coral sand is less than that of quartz sand. Compared with the quartz sand site, the coral sand site still has some shear strength and stiffness after the liquefaction. The settlement, horizontal displacement and column bending moment of coral sand site under 0.1g and 0.2g seismic intensities are smaller than those of quartz sand site. The position of peak bending moment of pile foundation under different seismic intensities is not the same.

Key words: coral sand, shaking table test, pile group, dynamic response, excess pore water pressure