2013 – Hydropower canal geomembrane liner analytical techniques

J.P. Giroud, Neil Jacka, Christopher Dann and Jeremy Eldridge

The remediation of a large hydropower canal included the lining of selected reaches of the canal with a geomembrane to extend the life of the canal and enhance seismic resilience. This paper presents a summary of innovative analyses performed to select and design the geomembrane liner system. Two mechanisms that induce tensile stress and strain in the geomembrane following the development of cracks in the supporting subgrade resulting in the deflection of the geomembrane over the cracks under the applied water pressure were analysed. The analysis uses the concept of ‘co-energy’, a geomembrane property that evaluates its ability to withstand stresses and strains together. A range of ballast configurations undertaken to assess the tension, strain and deflection of the geomembrane while evaluating the resistance to hydrodynamic forces and other loads were analysed. Stability analyses showed that geosynthetic reinforcement of the ballast over the upper canal slopes was required.

Keywords: Canal, Lining, Geomembrane, Design, Seismic resilience.