subject: Geosynthetic Clay Liner [print this page] A geosynthetic clay liner (GCL) is a woven fabric like material primarily used for the lining of landfills. It is a kind of geomembrane and geosynthetic which incorporates a bentonite or other clay, which has a very low hydraulic conductivity. The resulting lower permeability slows the rate of seepage out of the landfill. Due to environmental laws, any seepage from landfills must be collected and properly disposed of, otherwise contamination of the surrounding ground water could cause major environmental and/or ecological problems. The lower the hydraulic conductivity the more effective the GCL will be at retaining seepage inside of the landfill. Bentonite composed predominantly (>70%) of Montmorillonite or other expansive clays, are preferred and most commonly used in GCLs. A general GCL construction would consist of two layers of geosynthetics stitched together enclosing a layer of processed sodium bentonite. Typically woven and/or non-woven textile geosynthetics are used, however polyethylene or geomembrane layers or geogrid geotextiles materials have also been incorporated into the design or in place of a textile layer to increase strength.GCLs are produced by several large companies in North America, Europe and Asia. The United States Environmental Protection Agency currently regulates landfill construction and design in the US through several legislations.
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Topics in geotechnical engineering
Soils
Clay Silt Sand Gravel Peat Loam
Soil properties
Hydraulic conductivity Water content Void ratio Bulk density Thixotropy Reynolds' dilatancy Angle of repose Cohesion Porosity Permeability Specific storage
Cone penetration test Standard penetration test Exploration geophysics Monitoring well Borehole
Laboratory tests
Atterberg limits California bearing ratio Direct shear test Hydrometer Proctor compaction test R-value Sieve analysis Triaxial shear test Hydraulic conductivity tests Water content tests
Field tests
Crosshole sonic logging Nuclear Densometer Test
Foundations
Bearing capacity Shallow foundation Deep foundation Dynamic load testing Wave equation analysis
