BENGALURU: After spending a total of 517 days of drilling for the Bengaluru Metro, Tunnel Boring Machine (TBM) `Varada’ is set to complete its innings on Friday. It is scheduled to complete its second tunnel running to 596 metres and attain breakthrough at the upcoming Langford Metro station. It will be dismantled and taken off duty and only eight TBMs will continue work on the 13.8-km Underground Corridor for the Nagawara-Kalena Agrahara Line.
The drilling of the second leg, parallel to the first leg and in the same direction from Rashtriya Military School (Vellara Junction) to Langford began on January 27, 2022. A top Metro official told TNIE, “After tunnelling 194 days, it is set to emerge at Langford station on Friday. Varada faced the hurdles of very hard rock and mixed face during its journey and emerged successful. It would be the first TBM to wind up its assigned work and leave the underground portion.”
Varada, procured from Herrenknecht in Germany had a rest period of over two months after completing one round and beginning the next. Afcons Infrastructure has been contracted with the job by the Bangalore Metro Rail Corporation Limited (BMRCL).
Fortunately, since the work was completely underground inside a tunnel, the rains that lashed Bengaluru did not impact the work, the official added.
While Urja and Vindhya have completed two tunnels, they are tunnelling a third leg too. Varada has only been planned for two tunnels.
Asked about the future course of action, the official said, “The machine would be dismantled into parts. They would be lifted using a gantry overground and then transported by a trailer to the yard.”
All the other TBMs are presently in different stages of tunnelling across Reach-6.