Retention performance of woven geotextiles subjected to cyclic-flow conditions

Woven geotextiles are widely used as filters in geotechnical, hydraulic, and environmental applications. Depending on the application, geotextile filters can be subjected to uni- directional, bi-directional, or cyclic-flow conditions, with cyclic flow occurring in two directions repeatedly over time. The selection of a suitable geotextile filter is of critical importance, particularly for cyclic-flow conditions. Cyclic-flow conditions can rapidly lead to an excessive loss of fine soil particles and failure of a soil-geotextile system. Although these conditions are frequently encountered, limited work has been done to evaluate the retention behavior of geotextiles under cyclic-flow conditions. In this study, the retention performance of nine different woven geotextiles with five different soils under cyclic-flow conditions was modeled using a bi-directional hydrodynamic filtration test (BHFT). Based on the results of this research, a retention criterion of AOS/d₈₅ of 1.62 is proposed for woven geotextiles subjected to cyclic-flow conditions, where AOS is the apparent opening size of the geotextile or O₉₅ as determined by dry sieving (ASTM D4751) and d₈₅ is the soil particle diameter corresponding to 85% by weight of finer soil particles. Additionally, an allowable soil-loss limit less than 5000 g/m² is proposed.