State of the Art Lecture on Environmental Geotechnics. Protecting the environment from contamination with barrier systems: advances and challenges

The state-of-the-art for barriers systems control of pollution migration and hydraulic structures including liner systems for landfills, mine waste, and dams/lagoons are discussed along with some comments on current significant environmental issues. Recent research on geomembranes, geosynthetic clay liners, and composite liners and the practical implications are discussed. The need to design taking account of the interactions between the liner system components is highlighted. Regional differences relating to environmental geotechnics of municipal solid waste and mining waste and the implications of differences in regulations and climate are discussed. Vertical barrier systems may be regarded as mature technologies and research funding is much more limited. A bibliography of key papers on cut-off walls has been compiled. It is recognized that major changes to cement-bentonite formulations will be necessitated by the drive to reduce carbon footprints together with the dwindling availability of pulverised fuel ash and blastfurnace slag. The implications for environmental geotechnics associated with recycled materials, waste minimization, and some overarching issues are discussed. The paper finishes with some thoughts about the future of environmental geotechnics and some concluding comments.