Introduction to Geomembranes

This introductory article on geomembranes is intended to familiarize the reader with this relatively new material. Geomembranes are flexible, watertight materials used in civil engineering structures such as reservoirs, dams, canals, waste storage facilities, mine tailings repositories and many other types of structure.

This article provides definitions of geomembranes and related materials which, like geomembranes, are part of the geosynthetic family. Geomembranes are described in the article, where it is noted that they are thin (1 to 6 mm thick) and flexible. As geomembranes are waterproof, this article compares them to other waterproof materials used in civil engineering (clay, concrete, bituminous concrete).

This article explains the wide variety of geomembranes available. Some geomembranes - bituminous geomembranes - are made from textile products impregnated with bitumen. However, most geomembranes in use today are polymeric geomembranes, i.e. geomembranes whose waterproof component is based on a synthetic polymer. Several types of synthetic polymer are used to produce polymeric geomembranes. There are geomembranes reinforced with woven or non-woven fabric, and non-reinforced geomembranes.

Geomembranes are produced in the factory in roll form, then transported to the site where they are unrolled and assembled. Alternatively, several rolls of geomembrane are assembled in the workshop to form large sheets. These prefabricated sheets are then transported to the site, where they are deployed and assembled. Depending on the type of geomembrane, these are assembled in the factory or in the field using welding or adhesive products. In this way, waterproofing of large surfaces can be achieved in a relatively short time and without the need for heavy equipment.

As this article shows, the waterproofing function of geomembranes in civil engineering structures can be performed in a variety of ways. In the simplest structures, the geomembrane is used on its own or protected by a layer of earth, gravel or concrete. In more complex structures, particularly those where special performance is required, the geomembrane is used in conjunction with other materials that complement its function in a synergistic way. In waste storage facilities, for example, a geomembrane is often used in conjunction with another waterproofing material (clay or bentonitic geosynthetic) to form a composite seal, which is a high-performance seal combining the properties of the two associated materials. In some reservoirs and waste storage facilities, a double seal is used, consisting of two geomembranes combined with a drainage layer located between the two geomembranes, which collects any liquid that may have leaked through defects in the upper geomembrane,...