Undrained dynamic behavior of geogrid-reinforced coral sand

In this research, the reactions of geogrid reinforcement on the dynamic performance of medium-dense coral sand with various cyclic stress ratios were investigated using stress-controlled undrained dynamic triaxial tests. The results indicate that the insertion of geogrid decreases the dynamic deformations, and pore pressure build-up rate, and impeded the liquefaction of coral sand. The liquefaction resistance of coral sand increases with the increase in the number of reinforcement layers. The liquefaction resistance of coral sand reinforced with three-layer and two-layer geogrid increases by 333% and 6% compared to unreinforced ones. The geogrid reinforcement layers can effectively resist the complete stiffness degradation of coral sand under cyclic loading. The coral sand stiffness decays at an accelerated rate as the cyclic stress ratio increases, whereas increasing the number of reinforcement layers reduces the coral sand stiffness degradation rate, especially for three-layer geogrid reinforced coral sand at low cyclic stress ratios. Generally, the geogrid as a reinforcement material to coral sand is considered a better alternative to enhance the engineering properties of coral sand and offers significant prospects in coastal and marine engineering construction with coral sand.