Historic day for Bengaluru! Moments ago, Larsen & Toubro commissioned tunnel boring machine (TBM) Urja – their first of four machines – at Cantonment Station in the presence of Karnataka’s Chief Minister for building tunnels on the 21.386 km Line-4 (Reach 6 / Pink Line) of the 73.92 km Bangalore Metro Phase 2 project.
This machine is one of 9 TBMs which will be deployed by Larsen & Toubro (Packages RT-02 & 03), Afcons Infrastructure (RT-01) and ITD Cementation (RT-04) for building the Pink Line’s 13.885 km underground section between Dairy Circle and Nagawara consisting of 12 stations.
As explained earlier, this Ø6.67m slurry machine (DZ670) was dispatched from TBM manufacturer China Railway Construction Heavy Industry Co., Ltd. (CRCHI)’s plant in Changsha after completing factory acceptance tests (FAT) in November 2019. The machine’s parts arrived in the city in February and workers began lowering them into the station’s southern-end in March.
Per the tunneling plan, this TBM along with TBM Vindhya, will exclusively build tunnels on the 2.884 km package RT-03 (Shivajinagar – Tannery Road) which was awarded by the Bangalore Metro Rail Corporation Ltd (BMRCL) in February 2019.
The machines will first travel roughly 860 meters to Shivajinagar, and then be brought back to the Cantonment Station for building tunnels towards Pottery Town and Tannery Road stations. Per BMRCL’s press release, the “expected geology in this tunnel section is about 250m in Hard Rock, 350m in mixed-ground conditions and about 255m in soil.“
Within the station’s shaft, TBM Urja will today build only 1 temporary ring which is equivalent to 1.4 meters. Some amazing images of the ring segments stacked at L&T’s yard can be viewed here.
Back in 2017, a day prior to the inauguration of Phase 1’s final section, I wrote a post with supporting images on the history of the Phase 1 project’s tunneling, specifically the Green Line’s 4 km underground section, which took over 4 years to complete. Check it out here for a refresher on the geology challenge that awaits – History of Bangalore Metro Green Line’s Underground Section
For more updates, check out the Bangalore section of The Metro Rail Guy!