Woven geotextile permeability under uniaxial and laterally constrained conditions

Woven slit-film geotextiles are often subjected to in-plane tensile loads in engineering applications, which may alter relevant permeability properties. The fractal model of the permeability coefficient in woven geotextiles is extended to predict the permeability coefficient of geotextiles subjected to uniaxial and laterally constrained uniaxial tensile strains. Based on the observation and summary of the variation of the pore size distribution pattern with tensile strain, the pore unit model is introduced. The model is expressed as the functions of the fractal dimension, pore size characteristics, physical parameters and weft strain. A clamping device capable of applying uniaxial tension and laterally constrained uniaxial tension to geotextiles is invented. The validation of the model is verified using the vertical permeability coefficient test and the digital image analysis method on two selected woven geotextile samples. It is shown that the permeability coefficient increased with increasing uniaxial tensile strain. Furthermore, the experimental values tended to change more significantly under laterally constrained uniaxial strain conditions for thinner geotextiles approaching breaking strain and thicker geotextiles. The improved model can accurately predict the values and increasing rate of the permeability coefficient of woven geotextiles subjected to uniaxial and laterally constrained uniaxial tensile strains.