The first double geomembrane liner 40 years later

The first double geomembrane liner 40 years later - Part 2

Giroud, J.P. / Gourc, J.P.

The first double liner with two geomembranes was constructed in June 1974 and has been in continuous service since then. The double-lined structure is a water reservoir located in Pont-de-Claix, near Grenoble in southeastern France. The geotechnical study showed that strict leakage control was necessary to avoid a risk of slope instability. A double liner was designed and constructed - a new concept at the time. This article is intended to contribute to the history of the geosynthetics discipline by presenting the development of a concept - the double liner - that is an essential feature of a number of structures containing liquids and waste, and by describing the construction and performance of this landmark reservoir, the first structure constructed using a double liner with two geomembranes. This article will also serve as a reference document for tests performed in the future when the geomembrane is removed. This case history shows that a reinforced butyl rubber geomembrane can last 40 years when it is exposed in a temperate climate with hot summers, which is remarkable. Ironically, butyl rubber geomembranes are much less used today than they were in the 1970s in part because they were thought to have insufficient durability. It should be noted that several types of modern geomembranes would last longer than 40 jears under the same conditions, which is encouraging. This reservoir can be considered a historic landmark of the geosynthetic discipline for the following reasons: (1) it is the first double geomembrane liner; (2) state-of-the-art design and testing were done four decades ago; and (3) the performance of the geomembrane has been remarkable.