Drainage and filtration properties of non-woven geotextiles under confinement using different experimental techniques

This work presents a study on the influence of stress level on some physical and hydraulic properties of non-woven geotextiles relevant to drainage and filtration. Different types of tests were employed for the determination of geotextile thickness, porosity, permittivity, transmissivity and pore sizes under normal stresses ranging from 0 to 2000 kPa, depending on the type of test. Results of these different testing techniques were compared and their accuracy assessed. The increase of geotextile retention capacity caused by increasing stress levels and geotextile partial clogging was also evaluated, as well as the accuracy of equations for the estimate of geotextile permeability. The results obtained showed a marked effect of confinement on geotextile properties, with special reference to pore size diameters, with implications to current filter criteria for non-woven geotextiles. (C) 2002 Elsevier Science Ltd. All rights reserved.