Design of landfill cover lining systems with geosynthetic clay liners (GCLs)

摘要

Geosynthetic clay liners (GCLs) are currently used in different types of landfill cover systems. Generally a complete system includes a cover soil layer of approximately 1 m thickness, a drainage layer such as a geosynthetic drainage system (GDS) and a shear strength transmitting geosynthetic clay liner. In the last years a lot of different research projects have taken place to describe the efficiency of different lining systems based on the use of GCLs. Therefore several test sites have been built and investigated over some years. Test results show a different efficiency varying with the design of the whole system. All research projects published point out that the efficiency of every mineral lining system - especially GCLs with encapsulated high active clay minerals - depends on the water balance between the sealing element and the surrounding soil layers. In this paper the application of the hydrologic evaluation of landfill performance (HELP) model is described under seasonal varying weather and water balance conditions. A special update enables designers to give a more realistic estimation if the influence of drying processes and rehydrating on a GCL permeability is known.