Abstract: Coralline soils are the emerging preferred geomaterial for island-reef engineering and harbor engineering in tropical regions, and wide gradation is the main feature of their structural composition. The liquefaction resistance of coralline soils is gaining attention due to the high seismic risk of related engineering projects. In order to investigate the liquefaction resistance of coralline soils containing fine grains, the saturated undrained dynamic strengths of three groups of representative graded samples with designed relative compaction of 0.4–0.8 and two groups of samples without fine grains were measured by large-scale dynamic triaxial liquefaction test based on an actual site of coralline soils in a tropical harbor engineering in the eastern Pacific Ocean. The test results indicated that the power function could simulate the relationship between the cyclic stress ratio and the number of cycles to cause liquefaction for coralline soils containing fine grains; the presence of fine grains and the increase of relative compaction did not significantly improve the liquefaction resistance of coralline soils; the excess pore water pressure development pattern of liquefaction process of coralline soils was similar to that of sandy soils, and the inverse sine model with two or three parameters could simulate the excess pore water pressure development of liquefaction process of coralline soils containing fine grains. The study revealed that the fine-grained coralline soils still belonged to liquefiable soils. Based on an actual engineering project, the same type of engineering project needed to consider the prevention of seismic liquefaction hazards in the design, construction and use stages, and this study provided technical support for the prevention and control of liquefaction for coralline soils.

Key words: coralline soils, fine-grained soil, liquefaction test technique for coralline soils, excess pore water pressure, hydraulic fill coralline soil engineering