Experimental Study on Liquefaction Characteristics of Coral Gravelly Soils with Different Particle Size Distributions

Many laboratory studies have shown that particle size distribution (PSD) affects the liquefaction susceptibility of granular materials. However, few studies have focused on the impact of PSD on coral particles. In this study, two different soil families were prepared: one with three levels of mean particle size (D-50) with identical uniformity coefficient (C-u)and the other with four levels of C-u with the same D-50 for coral gravelly soils. In addition, a series of undrained cyclic triaxial tests were conducted on coral gravelly particles with two groups of PSDs at a relative density of 40% and an adequate confining pressure of 100 kPa. The test results indicated that D-50 with identical C-u can affect the undrained cyclic behavior of coral gravelly particles. In contrast, C-u with identical D-50 does not impact the undrained cyclic behavior of coral gravelly particles. The developing pore water pressure was uniform when the sample was subjected to the same cyclic loading. For samples with changing D-50 values of 2.35, 4.70, and 7.05 mm, increasing D-50 improved the cyclic liquefaction resistance. For samples with changing C-u, increasing C-u in the range of 1.06-5.00 first increased and then decreased the liquefaction resistance.