...L. Tang; W. Francey; J. Zheng; X. Wang; X. Luo Gradient ratio tests were conducted to investigate the filtration behaviour of staple fibre needle-punched nonwoven geotextiles subjected to unequal biaxial tensile strains. Three groups of biaxial tensile strains were designed, with the ratios...

...E. M. Palmeira; M. G. Gardoni; D. W. Bessa da Luz This paper presents the results of gradient ratio tests on different soil–geotextile systems under normal stresses up to 2000 kPa. Different types of soil and geotextiles were tested, and the soil particles that passed through the geotextile...

... was also observed in field test cells by exhuming geotextile samples from the cells after exposure followed by analysis. The results indicated that the sludges could be filtered with nonwoven geotextiles selected on the basis of geotextile permittivity. The standard gradient ratio test did not always...

.... The results indicate that the sludges can be filtered using woven geotextiles and the selection of a proper filter can be made on the basis of geotextile pore structure parameters, i.e. percent open area and pore opening size distribution. The standard gradient ratio test did not always reflect the filtration...