Daniele Cazzuffi
ABSTRACT: The lecture will review the use of geosynthetics in dams, in particular dealing with the barrier function. More specifically, the first case history for this function will be illustrated, i.e. the Contrada Sabetta dam in Italy being the first application of a geomembrane as barrier in 1959, as well as the recent applications in all the five continents.
Presently, in more than 300 dams worldwide, geomembranes are the main waterproofing component.
The geomembrane is generally associated with other types of geosynthetics performing different functions, as nonwoven geotextiles for mechanical protection and drainage, as well as geonets mainly for drainage, thereby forming a geosynthetic barrier system.
In the lecture, uses of geosynthetic barrier systems in the different types of dams will be illustrated. The types of dams reviewed will include: embankment dams (earthfill and rockfill dams), concrete and masonry dams, and roller compacted concrete (RCC) dams. Design and construction aspects will be considered, as well as the selection of geosynthetic materials and the long-time performance.
In particular, the results of an extensive monitoring program of the long-time behavior of PVC geomembranes directly exposed to atmospheric agents on the upstream facing of dams on the Alps (Italy and France) will be described, together with a proposal for the evaluation of their residual life in service.