Review Of A Dam Constructed Using A Bgm After 15 Years Of Service
Annual Conference
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A bituminous geomembrane (BGM) was used in 2000 for the construction of the upstream waterproofing face of La Galaube dam in the south of France. The BGM was selected for this application after a technical comparison with other options including an impervious clay core, asphalt concrete and a PVC solution. This paper will describe the different phases of the project, the specific techniques and equipment that were required to carry out the rapid construction (in 4 months) of 23,000 square meters of impervious structure, and will detail the quality management. Storage capacity of this dam is more than 35 million cubic meters, in order to supply potable and irrigation water (BGM has NSF 61 Certificate for potable water).
The stability of the dam is ensured by the weight of the rocks, which consist in about 800,000 cubic meters of mica-schist excavated on the site. The embankment is based upstream on a reinforced concrete plinth, founded on fresh or slightly weathered granite. The dam is 380 meter long on the crest and the slope is 2 H to 1 V. The maximum height above the foundations is 43 meters. The dam has been in service for 15 years and the watertightness has been carefully monitored by the asset owner EDF (French Electricity Corporation). We will also refer to some other dams waterproofed with a bituminous geomembrane: In France, Ortolo (37m high) in Corsica waterproofed with a bituminous geomembrane. We will discuss the practical challenges on site with strong winds and flooding during construction and how these were overcome. Ospédale (25m high) a 37 years old ICOLD dam which was the first high dam waterproofed with a geomembrane. We will discuss the Ministry of Agriculture’s complete survey of this dam. In Chile, El Mauro dam in 2006, a RCC dam with an upstream face using a BGM on a slope of 0.7 H to 1 V. In Peru, Cerro Lindo, which was subjected to and survived an earthquake of 8.1 magnitude. We will give the results of the audit done by Golder Associates on Cerro Lindo after the earthquake.