Mechanisms affecting long-term filtration behavior of geotextiles

Abstract Geotextiles made from synthetic fibres are used in drainage applications. The textiles must allow the passage of water while retaining soil particles in place. This function can be assumed for many years if no alteration or change of their structure results from chemical attack, mechanical deterioration, mineral and bacterial clogging and accumulation of particles, or organic matter between or upstream of the fibres. In this paper, the mechanisms involved with particle migration, soil stabilization and sediment retention are presented to give an understanding of filter performance. The degradation of fibres from mechanical, biological, chemical and environmental attacks are briefly examined. Mineral, bacterial and organic clogging, blinding and blocking of geotextiles are discussed in detail. From the knowledge of these mechanisms, the critical aspects of geotextile durability on design criteria are presented to take into account hydraulic property changes, allowable clogging level, filter selection and installation procedures.