Geotextile's Permeability Performance Measurements in Drainage Systems Under Pressure

One of the most important applications of geotextiles is as drainage and filtration adjacent soil in civil engineering projects. The using of this material has several benefits such as such as permeability and filtration that effect of these benefits, theoretical or experimental, have been evaluated by researchers. One of the important issues is the effect of contact pressure on permeability of geotextile-soil systems which has been less investigated. In this paper, the impact of overhead pressure on permeability of the soil in the vicinity of nonwoven geotextiles in a drainage system has been investigated by experimental tests. For this purpose, a special measuring cell was designed and built in soil and geotextile system which the hydraulic properties were evaluated in variation of pressure. The results showed that the variation of system permeability is non-linear in variation of overhead pressure. Also the thickness of geotextile has important effect on the permeability in a soil-geotextile system.