Freezing operation for underground metro stations

1 May 2017 - Projects update and handover - France

To the north of Paris, on the project to extend the metro’s Line 12, teams from Chantiers Modernes Construction, Botte Fondations, Sogea TPI (all VINCI Construction France) and Dodin Campenon Bernard are building two new underground stations: Aimé Césaire and Mairie d’Aubervilliers.

An innovative phase during these works: the tympana of the stations are currently being frozen, an operation that will ensure the watertightness and stability of the ground between the tunnel tube and the adjacent diaphragm walls during the earthworks phases. The ground becomes frozen thanks to the circulation, in a closed circuit, of a cooled heat-transfer fluid in the 96 drilling holes radiating out around the tunnel tube, at the level of each tympanum. The entire set-up is monitored by sensors linking the cooling units and the monitoring boreholes to online platforms. The deployment of this technique is a demonstration of VINCI Construction’s expertise in the field of hydrogeology.