Water Migration Mechanisms and Drainage Performance of Wicking Geotextiles: A Comprehensive Review of Experimental Studies and Field Applications

Wicking geotextiles are specialized geosynthetics designed to regulate soil moisture through a combination of capillary-barrier and lateral-drainage mechanisms. Laboratory and field studies demonstrate their effectiveness in reducing volumetric water content, restricting capillary rise, and maintaining subgrade and base stability under rainfall, dry–wet cycles, freeze–thaw cycles, and traffic loading. Performance is influenced by soil type, fines content, installation depth, edge exposure, and environmental conditions. Field applications show benefits in pavements, expansive soils, pumping-prone sections, cold-region roadbeds, and permeable urban infrastructure. Multi-layer and composite geotextiles further enhance hydraulic and mechanical performance. Despite these advantages, gaps remain in standardized testing, long-term monitoring, design methods, and durability assessments under aggressive conditions. This review synthesizes recent experimental and field evidence, highlighting mechanisms, performance factors, and research needs to guide the optimal design and application of wicking geotextiles in geotechnical engineering.