The Japanese company Taisei Corporation, main contractor of this megaproject, has entrusted SBF with carrying out the earthworks: backfilling of the lake with sand placed on a geotextile mattress placed at the bottom of the lake (500,000 m3 of sand used, 2,500 m3 / day), installation of 600 km of geodrains to accelerate the settlement to a depth of 13 m on average on a 1mx1.00 mesh plot, construction of the platform of the tracks and ramps access with crushed gravel over an average thickness of 1m60 (286,000 m3), preloading of crushed materials to a height varying from 5 to 8 m (300,000 m3, installed, then removed after stabilization of the structure), construction of the roads structure composed of a layer of gravel in crushed gravel, a foundation layer in reconstituted moistened gravels 0/20, a base layer in Gravel Bitumen and a wearing course in anti rutting Bituminous Concrete.
