Characterization of Unsaturated Nonwoven Geotextiles

Abstract

Geotextiles are increasingly being used in a wide variety of applications, such as reinforcement, separation and drainage. These geotextiles are often in contact with unsaturated soils; however the hydrologic behavior of geosynthetic materials in unsaturated environments is most often ignored because the basic characterization of these materials does not exist. Test methods for measuring water retention data and transmissivity under suction have been developed for nonwoven geotextiles. These measurements complement simple contact angle and capillary rise measurements to characterize nonwoven geotextiles under unsaturated conditions. Results indicate that the tested nonwoven geotextiles exhibit properties and behavior similar to coarse, uniform soils. The unsaturated behavior has been found to be hysteretic; that is the behavior depends on whether the geotextile is being dried or wetted. Penetration of adjacent soil into the geotextile has also been found to affect its behavior. Soil column tests that include nonwoven geotextiles confirm that they will significantly affect unsaturated flow in soils.