Liquefaction behavior of fiber-reinforced sand based on cyclic triaxial tests

In this study, the liquefaction behavior and development laws of pore water pressure in fiber-reinforced sand were studied using cyclic triaxial tests, and the effects of cyclic stress ratio, fiber content, and fiber length were investigated. The test results showed that the cycle number leading to liquefaction and liquefaction resistance increased with fiber content and fiber length, whereas the cycle number leading to liquefaction decreased as the cyclic stress ratio increased. The pore water pressure accumulated more slowly in the fiber-reinforced sand than in the unreinforced sand, and the curves of pore water pressure at low cyclic stress ratio (0.195, 0.203, and 0.230) exhibit three stages, namely a rapidly increasing stage, a slowly increasing stage and a sharply increasing stage. The curves of pore water pressure at high cyclic stress ratio (0.258 and 0.282) exhibited a more varied pattern than those at a low cyclic stress ratio. Based on the test results, a three-parameter pore water pressure model was established considering the effect of cyclic stress ratio, fiber content, fiber length, and sand particle diameter. The predictions agreed relatively well with experimental results, demonstrating that the model can be used to predict pore water pressure in fiber-reinforced sands.