GEWI®Plus Piles secure Flood Basin for new High-Speed Line
The Ligne à grande vitesse „Sud Europe Atlantique“ (LGV SEA) is a new high-speed line for the TGV in France that will reduce travel time from Paris to Bordeaux from three to two hours. The new, 300km long section, which will be opened in 2017, connects Tours and Bordeaux.
In the municipality Ambarès located 20km from Bordeaux, the section runs through a natural depression. Because rain water accumulates in this dip, a retention basin had to be built in this area.
The 5,000m³ basin was built as a subterranean reinforced concrete retention basin. The floor slab was anchored using Ø 57.5mm GEWI®Plus Micropiles for uplift control.
The walls of the basin were anchored in the surrounding marl. The complete structure is stabilized by the 800m² floor slab and a concrete cover plate. The micropiles were installed from an elevated platform in a 2.5m grid and cut to the level of the excavation floor after filling with soil. In addition, the 10m long GEWI®Plus Micropiles were anchored using a special reinforcement structure mounted on the floor slab.
The general contractor, Solétanche Bachy, installed a total of 111 micropiles supplied by DSI France into cased boreholes. The casing was removed during cement mortar injection. DSI France supplied the GEWI®Plus Micropiles to the jobsite just in time within the limited timeframe so that pile installation was successfully completed within two months.