18 metres below the surface, 31,000 cubic metres excavated in 125 working days

The tunnel boring machine that was lowered at the Chelmsford Club shaft late in January this year as part of Delhi Metro’s Phase III construction emerged at the Janpath metro station site on Thursday after making a 909.3-metre-long tunnel.

The TBM broke through from the South shaft of the Janpath metro station close to the Chandralok building completing the tunnelling work of the Central Secretariat-Janpath stretch in the “Down Line” of this corridor. Tunnelling was carried out almost 18 metres below the earth’s surface and 31,000 cubic metres was excavated in 125 working days and a total of 648 rings were inserted simultaneously during the tunnelling process. The internal diameter of the tunnel is 5.8 metres.

Manufacturing TBMs

The machines were in good hands with the country’s first TBM operators, Lakhwinder Singh and Mohd. Ali Ansari, operating it with assistance from Ram Avtar Singh Rana.

Delhi Metro Rail Corporation’s chairman Sudhir Krishna, who was present at the site, congratulated the entire DMRC team and praised the work culture. He also said that the country will soon start manufacturing its own TBMs. DMRC Managing Director Mangu Singh said the first breakthrough is always special and significant.

He expressed satisfaction that the breakthrough was achieved as per schedule without any delays.

The 3-km stretch is an extension of the Central Secretariat-Badarpur corridor and is scheduled to become operational in July 2014.

This corridor will further extend to Kashmere Gate and will have two interchange stations at Mandi House and Kashmere Gate.

Another TBM is working on the “Up Line” which is 898 metres long and is expected to breakthrough in another two months.

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