Tunnel Boring Reaches Key Milestone at Toulouse’s Matabiau Metro Station
Toulouse, France – A tunnel boring machine (TBM) has successfully pierced the Matabiau metro station wall, marking a notable advance in the construction of Toulouse’s Line C extension. The operation, completed using a specialized “bell drill” technique, avoids disruption to nearby infrastructure including Line A, the Marengo station, and SNCF rail works.
The Matabiau station construction employs a unique method to minimize impact on surrounding structures. Unlike previous stations where drilling was visible, here the TBM entered the station within a 10-meter diameter, 15-meter long metallic airlock – a “bell” – to excavate and install the tunnel’s final structure while maintaining the station’s waterproofing and stability. Prior to the TBM’s arrival, the bell was filled wiht soil to maintain pressure until the final tunnel ring was laid, connecting the tunnel to the station walls.
According to Tisséo, the technique is dictated by local geological conditions, including soil characteristics and groundwater presence. It has previously been used at the Colomiers Gare and Bonnefoy stations.
The TBM, named Marie-Thérèse de Villeneuve Arifat, has now traveled 1.2 km, completing 30% of its 4 km route. 42% of the Line C extension’s layout has been excavated. The next phase will take the TBM towards the François-Schovie station, another sensitive area where it will intersect with Line B.