By rosebell
Tunnelling on the South Section of Bucharest Metro Line 6 is nearing the halfway point, with TERRATEC’s refurbished 6.39m-diameter EPB TBM advancing beyond the future Gara Băneasa station on the 6.6km twin-tunnel alignment.
The section, extending from 1 Mai to Tokyo, is being delivered for metro operator Metrorex by the Alsim Alarko–Makyol Joint Venture, which secured the contract in March 2022.
Metro Line 6 will comprise 14.2km of twin tunnels and 12 new stations, connecting Gara de Nord in central Bucharest with Henri Coandă International Airport. The South Section includes six stations: 1 Mai, Pajura, Expoziției, Băneasa, Washington and Tokyo.
Since its launch in April 2025, the TBM has encountered varying ground conditions, including sand, clay, silt and gravel, as well as a shallow groundwater table and overburden of as little as 10m in some areas.
A particularly challenging section took the machine beneath Herăstrău Lake, where it passed within 2.5m of an existing tunnel and close to the foundations of a bridge dating from the 1930s. Carefully controlled face pressure enabled the TBM to complete the crossing without disturbing either structure.
TERRATEC field engineers have provided ongoing technical support, including a cutterhead inspection and tool change near the Tokyo station launch area. To accommodate changing ground conditions, the team replaced the disc cutters with rippers.
The TBM’s pre-project refurbishment, informed by its previous operating history, has also supported its performance along the constrained urban alignment.
For the remaining drive, the joint venture is preparing for increased groundwater inflows. In coordination with TERRATEC, additional pressurised air has been introduced at the cutterhead to help control water ingress.
As tunnelling approaches 1 Mai station, the TBM will pass within approximately 3.5m of the existing M4 tunnels. Ground improvement works are planned to manage the risks associated with this close-proximity crossing.
Civil works on the South Section are scheduled for completion in 2027, while the full Metro Line 6 route to Henri Coandă International Airport is targeted to open in 2028.
