Bangalore Metro’s TBM Tunga Records Final Breakthrough at Nagawara
ITD Cementation India today celebrated tunnel boring machine (TBM) S-839B’s final breakthrough at Nagawara Station’s South Shaft on the 21.386 km Bangalore Metro Pink Line (Reach 6) project.
Nicknamed Tunga, this was TBM S-839B’s 4th of 4 planned breakthroughs and ITD Cem’s 7th of 8 breakthroughs planned for the 73.92 km Bangalore Metro Phase 2 project’s 4.591 km Package RT-04 (Tannery Road – North Ramp).
This Herrenknecht mixed-shield EPB machine was first commissioned in June 2021. For its final assignment, it built a 938m tunnel from Kadugondanahalli Station’s north shaft to a cut & cover shaft located south of Nagawara Station across the Outer Ring Road (ORR) – view on Google Maps.
TBM Tunga had started its final drive on February 1, 2024 through mixed face hard rock conditions which is typical for Bengaluru. By June-end it had completed tunneling 469 meters and opened up at least two major sinkholes. After passing through that zone, it bored 308 meters in the month of July setting a new local monthly record thanks to favorable soil conditions along the rest of its path.
Here’s a summary of all completed drives – click on the links to see details and images:
- Venkateshpura to Tannery Road (822m): June 2021 – June 2022
- Tannery Road to Shadi Mahal TBM Retrieval Shaft (209m): June 2022 – August 2022
- Venkateshpura to Kadugondanahalli (1184m): October 2022 – December 2023
- Kadugondanahalli to Nagawara South Shaft (938m): February 2024 – September 2024
ITD Cem’s scope of work involves building a combined total of 6.34 km twin tunnels, roughly 360 meter ramp at Nagawara, and four underground stations at Tannery Road, Venkateshpura, Kadugundanahalli (formerly Arabic College) and Nagawara.
A cool video of the entire event can be viewed here.
With this development, Tunga’s job is now over! It’s become the 8th of 9 machines after Varada, Avni, Urja, Lavi, Vindhya, Vamika & Rudra to finish all of its tunneling assignments.
Tunneling works for the entire up-line tunnel is now 100% complete. Per BMRCL’s press release, overall tunneling progress for Phase 2 now stands at 20,582/20,992m.
A total of 25/26 tunnel breakthroughs have recorded so far: 8/8 on Package RT-01 by Afcons, 4/4 on RT-02 by L&T, 6/6 on RT-03 by L&T, and 7/8 on RT-04 by ITD Cementation.
Today’s milestone was the penultimate breakthrough and now only one more is left by TBM Bhadra (S-840B) working on the parallel down-line tunnel. That machine has roughly 409m to go, and I hear ITD Cem is currently targeting an October 26 breakthrough. The exact date of course depends on how things progress in the coming weeks, and as shared in the past – importantly the availability of state ministers who’d want to be present for the final event. Stay tuned!
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– TMRG
Good going, I can’t wait for the last one. BMRCL applied so many learnings from disastrous Phase 1. Hope they continue the momentum for subsequent phases.
Congratulations to entire ITD & Herrenknecht community
Awasome work. Congratulations to all team.
Great relief for common man.
Great coverage. Good work ITD
Awasome work. Congratulations to all team.
This is wonderful! Congrats and best wishes everyone on the continued success and progress. Cheers!
Congratulations whole Metro team for your hard work and commitment.
Good news, tunnel boring is in the final phase & likely to be completed in few days. BMRCL must ensure fast completion of the stretch to add to existing network.
Completion of a Project gives the Engineers especially , a huge sigh of relief and satisfaction. It is the result of tremendous efforts, applying Enginnering knowledge and skills combined with technical acumen. Challenges are plenty when doing underground work- some expected and many unexpected. Making a project successful needs high Project Management skills along with tireless efforts of the workers and Engineers whose sweat and blood(occasional injuries and fatalities too) .
Kudos to the entire team of Engineers, keep it going, so that Bengalureans can travel in peace and reduce stress on the overloaded traffic on road.