New Delhi: The Delhi Metro on Thursday achieved another feat by completing the construction work of its longest ever underground tunnel at Khan Market.
The tunnel, with a length of 1.775 kilometres, is part of the under construction corridor between Central Secretariat and Badarpur and is the longest ever constructed by single tunnel boring machine (TBM) in Delhi Metro, DMRC spokesman Anuj Dayal said.
Till now, two 1.45 kilometre long tunnels constructed between Malviya Nagar and Hauz Khas were the longest tunnels.
Another major achievement is that the construction was completed in just 152 days.
Dayal said of the 1.775 kms, 37.5 metres of tunneling was completed in a day with the installation of 25 rings which is an Asian record.
The tunneling work for this stretch was started on November 21st, 2008. The Central Secretariat Khan Market stretch of 2.53 kilometres is actually the longest distance between any two Metro stations under Delhi Metro.
As this is the longest underground stretch of Delhi Metro without a station, a ventilation shaft is being constructed at Motilal Nehru Marg, Dayal said.
He said the main function of this shaft will be to provide ventilation and fire escape facilities.
Two shafts will be constructed. While one will be used for fire escape, the other will be used for ventilation purposes.
All the tunneling activities on the corridor are expected to be completed by August 2009, Dayal added.
The second phase of Delhi Metro comprises of about 30 kilometres of underground section of which about 18 kilometres are being built using TBMs.