The Delhi Metro Rail Corporation (DMRC) on Tuesday completed the tunneling work on the deepest underground stretch on the phase-4 Aerocity – Tughlakabad corridor of Golden Line with the breakthrough of a tunnel boring machine at the IGNOU station site.
On this occasion, Delhi Chief Minister Rekha Gupta and Minister Manjinder Singh Sirsa were also present to extend their congratulations to the Metro officials.
Advertisement
The new tunnel has been built at an average depth of around 27 meters, one of Delhi Metro’s deepest, it said in a statement, adding that as part of the Phase 4 work approved so far, 40.109 kilometers of underground lines are being constructed and the corridor has underground sections totaling to 19.343 kilometers.
Advertisement
The DMRC added that the work on a parallel tunnel between Chhatarpur Mandir (Aerocity) and IGNOU (Tughlakabad) was completed in February and with the latest breakthrough, tunnelling for both up and down lines has now been finished.
Giving details about the previous deepest stretch, Delhi Metro said that a tunnel on the Magenta Line at Hauz Khas in Phase 3 was built at a depth of about 30 meters while another tunnel for the Airport Express Line that passes below the Rajiv Chowk Metro station is about 45 meters.
The tunnel has been built using the proven technology of EPBM (Earth Pressure Balancing Method) with a concrete lining made of precast tunnel rings. These tunnel rings were cast at a fully mechanized casting yard set up at Mundka. The concrete segments were cured with a steam curing system to achieve early strength.
This tunneling drive faced challenges of steep gradient along with varied geology comprising mica and hard rock were encountered due to which the screw auger got damaged and was replaced during the drive.
Advertisement
