Advances and Remaining Challenges for Geosynthetics in Geoenvironmental Engineering Applications

Nine issues of importance to the use of geomembranes (GMs) and geosynthetic clay liners (GCLs) as part of composite liners in geoenvironmental applications are examined. These issues include the effect of: GCL-leachate compatibility on hydraulic conductivity; freeze-thaw on GCL performance; internal erosion on GCL hydraulic conductivity; temperature on advection and diffusion as well as desiccation of GCLs and compacted clay liners (CCLs); the choice of protection layer on the strains developed in GMs; wrinkles on strains developed in GMs and the thinning of GCLs; holes in GMs on leakage through composite liners; winkles in GMs on leakage through composite liners; diffusion through GCLs and GMs; and temperature and leachate exposure on the service life of GMs. It is suggested that GCLs and GMs can play a very beneficial role in providing environmental protection. However, like all engineering materials they must be used appropriately and consideration should be given to factors such as those addressed in this paper. There is a need for site specific design, strict adherence to construction specification, and appropriate protection of the geosynthetics after construction. In particular, given the diversity of available GCLs and their different engineering characteristics, GCLs should be selected based on the required engineering properties, not