Kaveri tunnel borer breaks through, opens Metro gateway to south

Took 16 months to tunnel 747m from Chickpet to Majestic  

Tunnel boring machine (TBM) Kaveri set the stage for the much awaited phase of Namma Metro as it made a dramatic breakthrough near Majestic on Wednesday.

After burrowing through hard rock and loose soil beneath the most densely populated areas of Bengaluru, Kaveri emerged on Wednesday eve- ning at the Majestic south shaft in Chikkalalbagh area near Kempegowda metro station.

Terming the breakthrough as “an important milestone in the history of Namma Metro”, Pradeep Singh Kharola, managing director of Bangalore Metro Rail Corporation Ltd (BMRCL) said the entire 42-km of Namma Metro Phase 1 would be completed by the targeted five months.

He also mentioned that the eight-km stretch between Puttenahalli and National College would be ready for trials by September this year. However, Kharola did not confirm whether the Metro would be operational on the entire North-South line from Nagasandra to south Bangalore in the same month.

“Kaveri TBM had to pass through the most difficult terrain under densely populated areas with old buildings above. There was an instance where a toilet of Victoria H ospital near City Market disappeared when the land caved in during tunnelling work. Besides, the machine had also tunnelled beneath the Sirsi Circle flyover without causing any damage,” Kharola told reporters.

Kharola said that at least 200 people, including eight foreign personnel, worked everyday on Kaveri TBM, which started tunneling from Chickpet on March 14 last year. “The Earth Pressure Balance (EPB) type TBM, which was made in Germany, took 16 months to cover 747 metres. The machine has tunnelled around 1,571 metres on the North-South corridor in the last three years, a press note stated.

With three of the four tunnel boring machines already making a breakthrough, Krishna, boring from Majestic to Chickpet, is expected to see daylight in two months. Meanwhile, work related to laying of tracks and signalling will begin, Kharola said.

Survey
N M Dhoke, BMRCL director (RSE), said a Singapore-based agency has been entrusted with the task of studying the geological and geotechnical conditions for Phase II of Namma Metro. Based on the survey, BMRCL would invite tenders for the type of tunnel boring machine (TMB) required for 13.79-km underground work.
DH News Service

N M Dhoke, BMRCL director (RSE): A Singapore-based agency has been entrusted with the task of studying the geological and geotechnical conditions for Phase II of Namma Metro. Based on the survey, BMRCL would invite tenders for the type of tunnel boring machine (TMB) required for 13.79-km underground work.

Trial run from September
Bangalore Development Minister KJ George, who witnessed Kaveri breaking through on Wednesday, said the BMRCL would start trial runs from Puttenahalli to National College at  the end of August or early September while the entire North-South corridor (green line) would be ready by November.

“The East-West and North-South corridors are seeing an average ridership of 1 lakh and 40,000 every day respectively. The completion of the entire Phase I would result in greater patronage,” he said, congratulating the BMRCL and the contractors.