The role of geotextiles in geosynthetic applications

Abstract

Nonwoven geotextiles are complex three-dimensional structures formed by the random arrangement of fibres. They are permeable and compressive textile materials and belong to the geosynthetic group, which also includes geogrids, geonets, geomembranes, and geocomposites. The design of appropriate geosynthetics involves careful consideration of the functions of the various constituent materials in terms of the intended end-use. A rational design, which effectively combines geotextiles with other geosynthetics, is required. Needlepunched nonwoven geotextiles are extensively used in civil engineering applications, including road and railway construction, landfills, land reclamation, sea defence, and reinforcement of clay slopes. Such applications require geotextiles to perform more than one function, including filtration, drainage, and separation. The filtration function of geotextiles is to retain the soil, while allowing the passage of the liquid. The drainage function of geotextiles is to transmit the liquid in the plane of the fabric without the loss of soil particles. Therefore, the filtration and drainage functions differ mainly in terms of direction of liquid flow. The separation function of geotextiles involves segregation, followed by retention of soil particles. Thus, the geotextile structure should be designed to fulfil the criteria demanded by the specific end-use.