Analysis of pore size distributions of nonwoven geotextiles subjected to unequal biaxial tensile strains

Nonwoven geotextiles are highly porous structures consisting complex shapes of pores. The filtration applications of nonwoven geotextiles are typically subjected to unequal biaxial tensile strains, which can cause the changes in pore sizes and result in soil clogging or leaking in the protection of banks or slopes. Some previous studies indicated that the pores decrease with biaxial tensile strains, whereas the other studies showed the opposite trend. Depending on the theoretical model of Rawal, a theoretical solution has been proposed that accounts for the pore size distributions of nonwoven geotextiles subjected to unequal biaxial tensile strains. A comparison has been made between the theoretical and experimental pore size distributions at defined levels of equal biaxial tensile strains. Both the theoretical and experimental pore size distributions increase with the equal biaxial strains. When it comes to the unequal biaxial tensile strains, the theoretical solution indicates that the changes of pores depend on the ratio of strains in two directions and the values of strains. The larger the ratios of strains in two directions are, the more fibers reorient towards the direction of the larger strain, the narrower the pore will be. Nevertheless, under the same ratio of strains in two directions, the larger the stains are, the larger the pore will be stretched. The solution may explain the inconsistencies among the previous results.