Experimental and numerical investigation of the unsaturated behavior of conventional and wicking non-woven geotextiles

Non-woven geotextiles play a crucial role in transportation embankments, including roadways and railways, by providing separation, filtration, and drainage. These embankments typically remain unsaturated, with soil voids containing both air and water. Understanding their behavior in unsaturated conditions requires analyzing water retention curves. Conventional non-woven geotextiles effectively drain gravitational water but struggle in unsaturated conditions, leading to moisture accumulation and potential distress. To address this limitation, a novel wicking non-woven geotextile has been developed, featuring hydrophilic and hygroscopic properties achieved through chemical treatment. This study investigates the unsaturated behavior of this wicking non-woven geotextile compared to conventional non-wicking geotextiles using laboratory experiments, including capillary rise, hanging column, and pressure plate tests, to determine geotextile water retention curves (GWRC) across a suction range of 0–1000 kPa. Numerical studies further explore its working mechanism and drainage performance under varying conditions, such as rainfall and groundwater fluctuations. A validated numerical model, based on wetting front propagation tests, simulates the wicking geotextile's behavior in soil. Results confirm its higher drainage capacity under unsaturated conditions, mitigating moisture-induced distress. These findings highlight the potential of wicking geotextiles in mitigating moisture-induced distress in transportation embankments and enhancing geotechnical performance. • Laboratory tests compare the unsaturated properties of wicking and conventional non-woven geotextiles. • Geotextile water retention curves are analyzed in two orientations. • Wicking geotextiles exhibit superior in-plane drainage under unsaturated conditions. • A validated numerical model captures in-plane wicking behavior. • Numerical modeling confirms superior drainage of wicking geotextile under simulated rainfall and groundwater conditions.