GCL

GCL (Geosynthetic clay liners) are prefabricated barrier layers with a core of swelling clay held between two geotextiles, bonded together so the panel stays intact during handling and installation. When the clay takes on water it expands into a dense, very low-permeability seal — achieving in a fraction of an inch what would otherwise require several feet of compacted clay placed and tested in lifts.

That efficiency drives the choice on most projects: far less material to import and place, a thinner overall section that preserves airspace or storage volume, and a manufactured product with consistent properties rather than one dependent on field compaction and moisture control. The clay core also reseals itself around small punctures and around penetrations, an advantage on sites where settlement or minor damage during construction is expected. They are used in landfill liners and caps, ponds and lagoons, canals, secondary containment and containment pits, either alone or combined with a geomembrane in a composite barrier.