25 Years of Experience with a Lysimeter System with Geosynthetic Clay Liners

Since 1999, a lysimeter facility with 6 test areas has been installed in a hillshaped soilbody in northern Germany, in which long-term tests with geosynthetic clay liners are carried out. Inside of the hill is a measuring room which contains the devices for measuring the precipitation, the amount of drainage water above the GCLs and the amount of permeation water passing through the GCLs every 10 minutes since 25 years. Based on this data, the Long-Term behaviour was investigated under various boundary conditions and the efficiency of the Geosynthetic Clay Liners under different boundary conditions was analysed. Different types of geosynthetic clay liners were investigated and it was considered under different overload-situations. The paper provides an overview of the general test set up and the most important findings on long-term permeability, influences from dry-wet and freeze-thaw cycles, and other findings from 25 years of testing the lysimeter system.