Landfill base liners
Geosynthetics fulfill the stringent containment parameters of landfill liner regulations
Landfill base lining systems provide permanent protection of soils and groundwater from the pollutants in a waste mass. Lining system requirements are often specified in national regulations and geosynthetics have become common components of these systems. Geosynthetics fulfill the stringent containment parameters of landfill liner regulations.
Geosynthetics provide an efficient, significantly effective and durable barrier for longterm environmental protection. But achieving this effectiveness requires proper design, specification and installation of the geosynthetic system. To remove waste for repair or remediation of an improperly designed or executed barrier system is technically difficult and expensive. The geosynthetics utilised in a base lining system must be made from highquality raw materials. The geosynthetics must be highly resistant to chemical and biological attack. For side slopes, the polymeric barrier must have the proper frictional characteristics for geosynthetic-geosynthetic and geosynthetic-soil. Understanding how to properly evaluate and select these materials will prevent unacceptable creep or the development of tensile stresses in the system. Creep and unpermitted stresses could lead to slope instability and possible failure.
The thickness of geomembranes in a base lining system is generally established in regulations. In the United States, for example, primary commonly call for 1.5mm HDPE geomembranes. In Germany, 2.5mm is standard, in other European countries such as the UK 2mm thick HDPE geomembranes are used. Compared to general construction solutions like an asphalt layer, both of these geosynthetic thickness ranges are significantly more costeffective and they are far more impermeable and durable in containment.
In many countries, geosynthetic clay liners (GCLs) are also permitted to be used in a landfill lining system as an alternative to clay mineral layers. Systems may also include nonwoven geotextiles to protect impermeable barrier materials from installation damage and ballastrelated overstressing. Protection layers are determined by the height of the landfill and the grain size and configuration of the drainage layer. Nonwoven geotextiles may also act as a sep aration and filtration layer between the mineral drainage layer and the waste.