Prediction of the vertical permeability of needle-punched nonwoven geotextiles by fractal geometry theory

摘要

Fractal geometry theory has proved to be a powerful tool for the analysis of porous media with complicated microstructures. With the assumption that needle-punched nonwoven geotextile has the same porosity and pore size distribution in two and three dimensions, a fractal model was used to analyse the vertical permeability of needle-punched nonwoven geotextiles. The pore tortuosity fractal dimension, area fractal dimension and characteristic parameters of nonwoven geotextiles, such as mass per unit area, thickness, pore size, fibre diameter and density, were all represented in the model. The pore tortuosity fractal dimension and area dimension were determined by the box-counting and Sierpinski-type gasket methods, respectively. Four geotextile samples were selected to verify the validity of the fractal model used in present study and the good agreement between the theoretical and experimental results suggests that the fractal model was highly accurate.