Analytical prediction and experimental research on pore size of nonwoven geotextiles under unconfined uniaxial tensile strain

The filtration applications of nonwoven geotextiles are usually subjected to uniaxial tensile strain, resulting in the variation of pore sizes and failure of filtration engineering. The pore-size distributions of two needle-punched nonwoven geotextiles subjected to unconfined uniaxial tensile strains are measured by using the strain-controlled dry sieving tests. The experimental results of the dry sieving tests are compared with the predictions of two analytical solutions. One is the analytical solution of equivalent opening size O₉₅ proposed by She Wei. The other is the analytical solution of pore-size distribution proposed by Rawal et al. The experimental values of O₉₅ of two thermally bonded nonwoven geotextiles tested by previous studies are used to confirm the validity of the two analytical solutions. By comparing the predictions of O₉₅, the accuracy and the error of two analytical solutions are analyzed. O₉₅ decreases approximately linearly with unconfined uniaxial tensile strains. The prediction of the variation rate by She Wei is accurate, while that by Rawal et al. is larger than the experimental rate. The prediction of the value of O₉₅ should be done considering the results of She Wei solution and Rawal solution.