BENGALURU: After tunneling for 401 days from the Venkateshpura Metro station, Bengaluru Metro’s Tunnel Boring Machine (TBM) ‘Tunga’ had its breakthrough on Wednesday at Kadugondanahalli (KG Halli) Metro station on Wednesday around 11.15 am. It completed tunneling a distance of 1,184.4 meters. With just two out of the nine TBMs yet to be completed, tunneling for the entire underground network is likely to be concluded by June 2024.
An official release said, “With this breakthrough, a total of 89.7% of the underground corridor has been completed- 18,832.3 meters out of 20,992 meters.”
The TBMs are building the 13.76-km underground corridor from Diary Circle to Nagawara, which is part of the Reach-6 line from Kalena Agrahara to Nagawara.
Giving details, a senior BMRCL official told TNIE, “This is the second drive of Tunga. In its first drive, it had tunneled 1,066.88 meters from Venkateshpura station (South) to Shaadi Mahal. It was lifted from the shaft and brought to the North end. For its third drive, it will tunnel 939 meters from KG Halli to Nagawara. The tunneling is expected to be completed by the end of May.”
When asked about the challenges faced, the official said the twin challenges included, the mixed ground and the tunneling below the railway line near KG Halli.
The last TBM on its journey, ‘Bhadra’ is tunneling parallel to it. “It has completed its first leg and is drilling its second leg on the same stretch just completed by Tunga. It will complete its third leg by June next year. The geology of Bengaluru is making it tough too.”