On Delhi metro phase III – Janakpuri-Botanical Garden corridor, a tunnel is being built between two pillars of the Violet line. Only a single tube tunnel OF 176 M through which both the tracks will pass.
The average depth of the tunnel is 20.5m below the ground level with 10.7m diameter. “The tunnel crown is about 9.4m below the base of the piers.
The construction of 158m of the 176m has been completed, which started in September, 2013 and is due for completion by June 2015.