An Innovative Composite Liner System for Coal Combustion Residual Containment Projects

摘要

A composite liner refers to a geomembrane that is underlain by a layer of either compacted clay or geosynthetic clay. One or more filters and drainage materials are almost always used in association with liners. These can be of a particulate type (such as sand, gravel, or select waste) or, alternatively, a geosynthetic drainage layer (GDL) is often used. The geosynthetic clay liner (GCL) alternative to clay and the GDL alternative to sand or gravel represent the current state of practice for liner systems in municipal solid waste projects, though this is not yet the case in CCR containment projects. Equivalency beyond doubt and proven performance are often necessary in order for geosynthetic alternatives to become acceptable substitutes for traditional materials. While this is generally accepted to be the case for many types of waste containment projects, CCR projects are relatively new, and performance data is still being generated. It is necessary for the properties of existing geosynthetics to be investigated in terms of the specific environments of CCR projects, and new products are typically developed when existing ones prove to be inadequate. This paper presents data for the GDL, geomembrane, and GCL used in CCR containment composite liner systems.