Tunnelling under Metro Phase I to get over in a month

All eyes are on Krishna, the tunnel boring machine (TBM) making headway between Chickpet and Majestic Metro stations. The machine is expected to see the light of day in 30 days.

The machine’s breakthrough at the Majestic station side will mark the completion of the entire tunnelling (8.82 km) of Namma Metro’s Phase 1 which is spread over 42.3 km. Besides, it will enable the Bangalore Metro Rail Corporation Limited (BMRCL) to connect the long-pending North-South corridor (Yelachenahalli to Nagasandra).

BMRCL Managing Director Pradeep Singh Kharola said they were expecting the breakthrough in 30 days.

As of Monday, Krishna has tunnelled 657 metres (438 rings) and is just 82.5 metres (55 rings) away from the breakthrough point. Once the breakthrough is achieved, BMRCL can start post-tunneling works such as track-laying, telecommunication and signalling.

Although the boring machine picked up speed in early July, its cutterhead broke down several times in the last two weeks. “Due to geo conditions, the machine had to be repaired by frequently placing new spares. Now, we are expecting loose soil after a few metres. The tunneling speed is always uncertain and there could be a breakthrough soon,” a BMRCL official told Deccan Herald.

On the other side of the tunnel, the BMRCL has almost completed dismantling Kaveri, the German-made tunnel borer which made a breakthrough in June this year.

Once both the tunnels are ready, the BMRCL hopes to push the train to the southern side in order to start the trial run between National College and Yelachenahalli stations, which are ready for use.

Meanwhile, BMRCL has awarded contracts to supply and instal works (including fabrication) of signage and graphics at three underground stations (Chickpet, KR Market and Majestic) and eight elevated stations (National College, Lalbagh, South End Circle, Jayanagar, RV Road, Banashankari, JP Nagar and Yelachenahalli).

Chief Minister Siddaramaiah had promised to throw open the entire 42.3-km Phase I (Baiyappanahalli to Mysuru Road and Yelachenahalli to Nagasandra) by November 1 this year.
D H News Service