Pore water pressure model for sands reinforced with randomly distributed fibers based on cyclic triaxial tests

Abstract

In this study, the pore water pressure accumulation laws in sand reinforced with randomly distributed fibers was investigated through cyclic triaxial compression tests. The effects of relative density, cyclic stress ratio, fiber content, and fiber length were examined. The test results showed that reinforcing the sand with randomly distributed fibers effectively delayed the pore water pressure accumulation and significantly increased liquefaction resistance. When the test conditions remained unchanged, the pore water pressure accumulation rate of the fiber-reinforced sand decreased as the fiber length and fiber content increased, and reached the lowest when fiber content reached 0.6% and fiber length attained 12 mm. Whereas, the accumulation rate of fiber-reinforced sand increased as the cyclic stress ratio increased, and reached the highest when relative density reached 30%, followed by 50% and 70%. Based on the test results, a three-parameter pore water pressure model that accounts for the effects of fiber content, fiber length, relative density, cyclic stress ratio, and sand particle diameter was established, and a method for estimating the parameters a and b was recommended. The predictions agreed relatively well with the test results, suggesting that the model is applicable to analysis the pore water pressure development laws in fiber-reinforced sands.