Sainte-Marguerite, Quebec, Canada
Bentofix® NW (B4000)
The following example illustrates a project using a needlepunched geosynthetic clay liner (GCL) as a stand-alone sealing barrier for a retention dam built for Sainte-Marguertie hydroelectric dam. The construction took place during the winter and a GCL was used due to lack of natural sealing material with weak hydraulic conductivity.
The Sainte-Marguerite dam (90 km north of Sept-Iles) is a structure built up to a height of 20 m (from the riverbed) of which the imperviousness is assured by a Bentofix® Geosynthetic Clay Liner (natural sodium bentonite sandwiched between two non-woven geotextiles and needlepunched together).
The cross-section of the dam is: Foundation made of a 20 cm thick layer of coarse sand compacted by means of explosives and dynamic compaction; Water tight trench with a maximum depth of 65 m, built by means of a “jet grout” high energy injection through 20 m compacted sand, 40 m coarse sediments lying underneath and 5 m into the rock; Sealing with Bentofix® and A 1 m protection backfill in two layers, comprising sand, gravel and stones covers the Bentofix®.