Krishna TBM picks pace on North-South corridor

 The Krishna tunnel boring machine (TBM), which was making a slow progress from Chickpet towards Majestic interchange metro station on the North-South corridor, has finally picked up speed this week.

In the last six days from June 28, Krishna TBM has drilled through as many as 18 metres beneath the tough terrain, the highest progress in the last one month. The machine, which was progressing very slow with not more than two meters a day in the previous four weeks, has burrowed three metres a day at present.

June was a  tough month for the machine, which was able to drill not more than 25 metres. This was similar to the progress made by the Kaveri TBM that was launched in March 2015. Kaveri made its way through the difficult 750 metres in the previous month. Its sister machine Krishna, launched in December last year, is expected to breakthrough in approximately two months, sources in BMRCL said.

The fast progress made by the lone TBM Krishna, among the five TBMs being used to tunnel the 8.80-km underground stretch of Phase I of the Namma Metro, is crucial for the Bengaluru Metro Rail Corporation Limited (BMRCL), to start the remaining works.

Chief Minister Siddaramaiah has promised to inaugurate the entire 42.30 km stretch of Phase I network from November 1, this year.

Under tough terrain

Speaking to Deccan Herald, Pradeep Singh Kharola said: Krishna tunnel boring machine is progressing well. But the speed of drilling underground is always uncertain. We cannot guess the timeline of breakthrough as Krishna is still under the tough terrain and loose soil is still a few meters away, he added.

Meanwhile, the BMRCL has taken up the work of dismantling the Kaveri TBM, the German-manufactured tunnel borer, where it was commissioned from the Chickpet station.

The process normally takes more than a month’s time, after which the BMRCL can start track laying, telecommunication and signalling work. The commuters of Bengaluru south are eager to take a metro ride as work between Puttenahalli metro station and city market metro station is almost complete.

Metro stations get KSISF protection

Stepping up security at Metro stations, the Bengaluru Metro Rail Corporation Ltd (BMRCL) has deployed the first batch of police personnel attached to the Karnataka State Industrial Security Force (KSISF). The personnel were trained at the Bangalore Metro Rail Training Institute (BMRTI) in Baiyappanahalli.

BMRCL managing director Pradeep Singh Kharola told Deccan Herald that upgrading the security apparatus was part of the regular process. “We will deploy them at different Metro stations and the first batch is already at work,” he said. At present, home guards and private agencies man the security systems at Metro stations, which are under round-the-clock camera surveillance. Kharola said BMRCL would minimise the number of personnel from the private agency in a phased manner.


Tunnelling so far

Date    Completed    Balance     Progress
May 22    562.5 m (375 rings)    181.5 m (121 rings)    24 m
May 30    575.5 m (381 rings)    168 m (112 rings)    13.5 m
June 06    573 m (382 rings)    166.5 m (111 rings)    1.5 m
June 13    579 m (386 rings)    160.5 m (107 rings)    6 m
June 20    588 m (392 rings)    151.5 m (101 rings)    9 m
June 28    595.5 m (397 rings)    144 m (96 rings)     07 m
July 04    613.5 m (409 rings)    126 m (84 rings)     18 m