Since the late 1980s, geosynthetic clay liners (GCLs) have been specified and used by design engineers, agencies and owners as an alternative to soil barriers in various applications. The growing interest in these products stems from the unique properties and advantages they offer. They are very effective as a hydraulic barrier even under high gradient conditions; they are easy to install; show a high robustness against installation stresses and they can withstand elongation as well as settlement stresses without significant impact on their hydraulic performance.
The wide range of GCL use includes landfill caps and base liner applications, environmental protection barriers under roads and railways, within various containment structures such as dams, canals, ponds, rivers and lakes, even for waterproofing of buildings and similar structures. However, their potential in other applications is only limited by convention. Numerous laboratory studies have shown the excellent performance capable with natural sodium bentonite geosynthetic clay liners. In more recent years, field conditions have been replicated in large-scale simulations to study the complex environmental effects such as wet/dry and freeze/thaw cycles.
Geosynthetic clay liners are mostly used to replace a compacted clay liner (CCL) or soil barrier. Natural sodium bentonite typically acts as the primary sealing element. In many applications, GCLs are also used in combination with a geomembrane and replace the CCL, such as landfill base seals or landfill caps, to achieve a composite-lined sealing system with two independent liners which complement each other, i.e., act as barrier against polar and non-polar contaminants. In other applications such as golf course ponds and/or storm water managements ponds, a GCL on its own will suffice. GCLs are widely used around the globe by various landfill owners.
Landfill design engineers should be made aware that a new design book is available to them Barrier Systems for Waste Disposal Facilities by R. Kerry Rowe, Robert M. Quigley, Richard W.I. Brachman & John R. Booker ISBN 0-419-22630-3.
Bruno Herlin, P.Eng. is a project engineer with Terrafix Geosynthetics Inc. in Toronto, Ontario and is responsible in the Canadian market for geosynthetic clay liners from Bentofix Technologies Inc. E-mail Bruno at email@example.com