urja: Bengaluru: TBM Vindhya to achieve breakthrough in 20 days: BMRCL MD | Bengaluru News – Times of India


BENGALURU: Close on the heels of Tunnel Boring Machine (TBM) named Urja completing drilling a distance of 855 metres from Cantonment station towards Shivajinagar underground station, another TBM Vindhya is all set to achieve a breakthrough.
Speaking to reporters after the breakthrough of TBM Urja at Shivajinagar, BMRCL MD Anjum Parwez said: ‘TBM Vindhya which is tunneling in the same direction is expected to achieve breakthrough in 20 days. All nine TBMs have together completed tunnelling of 3.8 km. Every day, up to 40 metres of tunnels are being built by the TBMs. We are taking measures for early completion of tunnel work” he said.
Sources said two more TBMs Varada and Rudra will also achieve breakthrough by year-end. BMRCL officials said both the elevated and underground sections (Kalena Agrahara-Nagawara) will be operational by March 2025.
A BMRCL engineer told TOI “A total of 80 workers per shift (8am-8pm and 8pm-8am) were working for this section between Cantonment and Shivaji Nagar round the clock for more than a year. They all are excited and happy to see the breakthrough after their efforts and hard work. This is one of the most critical sections since it has so many old buildings and densely populated areas. In fact, we identified 14 borewells in the section during tunnelling. We plugged all those and also paid compensation to the respective owners” he added
Journey of TBM Urja
February 2019: Larsen & Toubro received bids for the underground section from Vellara Junction to Shivajinagar (2.7km) and Shivajinagar to Pottery Town (2.8km).
November 2019: TBM manufacturer China Railway Construction Heavy Industry (CRCHI) dispatched the slurry machine after completing factory acceptance tests.
February 2020: TBM parts arrived in the city from China to Chennai port and then by road to Bengaluru.
March 2020: Metro workers began lowering parts of the TBM named Urja at Cantonment station.
June 2020: Tunneling work from Cantonment (Bamboo Bazar) towards Shivajinagar commenced.
September 2021:TBM Urja completed drilling a distance of 855 meters from Cantonment station towards the Shivajinagar station.
Tough geology condition
Bengaluru has a difficult geology condition with a mix of hard granite, large boulders, soft soil and high groundwater level. “The expected geology in this tunnel section is about 250m in hard rock, 350m in mixed-ground conditions and about 255m in soil,” a BMRCL release had said during commencement of tunnelling work last year. In Phase 1, TBMs faced several difficulties due to the tough geology condition. In 2014, cutterhead of TBM Godavari was damaged which delayed the Phase 1 UG work work
Issues
Covid-19 pandemic, lockdown and India-China standoff has also delayed the Phase 2 UG work. In fact, visits of the Chinese team needed for the assembly, deployment and operation of TBMs including Urja were delayed due to the visa restrictions as well as the stand-off between India and China. There was also a shortage of workers due to Covid and lockdown. In 2018, BMRCL cancelled this UG section tenders due to exorbitant prices quoted by construction firms. The firms reportedly quoted around 70% more than the BMRCL estimated for the UG section
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Sagar Biswas

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