A modified theoretical model has been proposed to predict the pore size characteristics of nonwoven geotextiles under certain uniaxial tensile strains, considering the difference between the out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles. The pore size distributions (PSDs) and O₉₅ subjected to different levels of uniaxial tensile strains in two needle-punched nonwoven geotextiles have been investigated by the dry sieving test. The variation of the fibre orientation with tensile strains and the corresponding effect on pore sizes has been evaluated by image analysis. The out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles have been examined. A comparison has been made between the predictions of the original and the modified models. It is shown that the modified model can more accurately predict the decreasing rate of the PSDs, O₉₅, and O₉₈ than the original one. The corrected theoretical O₉₅ and O₉₈ under certain strains can provide a reference for the filtration design under engineering strains. The fibres reorientating to the loading direction result in the increase of the directional parameter with increasing tensile strains, which leads to the decrease of pore sizes. The theoretical PSDs are sensitive to the variation of directional parameter.

中文翻译：

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单轴拉伸应变下针刺非织造土工织物孔隙尺寸特征的预测

考虑到土工织物的面外泊松比和面内泊松比之间的差异，提出了一种改进的理论模型来预测非织造土工布在某些单轴拉伸应变下的孔径特征。孔径分布（PSD）和O ₉₅通过干筛试验研究了在两种针刺非织造土工织物中承受不同水平单轴拉伸应变的情况。纤维取向随拉伸应变的变化以及对孔径的相应影响已通过图像分析进行了评估。检验了土工布的平面外泊松比和平面内泊松比。在原始模型和修改后模型的预测之间进行了比较。结果表明，与原始模型相比，改进后的模型可以更准确地预测PSD的降低率O ₉₅和O ₉₈。校正后的理论O ₉₅和O ₉₈在某些情况下可以为工程设计下的过滤设计提供参考。沿加载方向重新定向的纤维会导致方向参数随拉伸应变的增加而增加，从而导致孔径减小。理论上的PSD对方向参数的变化很敏感。