Delhi Metro Rail Corporation (DMRC) on Tuesday completed tunnelling work on one of the deepest underground stretches of Phase IV marked by the breakthrough of a tunnel boring machine at the IGNOU station site (from Chhatarpur Mandir) on the Aerocity-Tughlaqabad corridor, part of the upcoming Golden Line.
This new tunnel was constructed at an average depth of around 27 metres, with a minimum depth of 15 metres and a maximum depth of 39 metres, making it one of Delhi Metro’s deepest tunnels. The tunnel boring machine broke through on Tuesday at IGNOU station after boring a 1,460-metre-long tunnel in the presence of chief minister Rekha Gupta and environment minister Manjinder Singh Sirsa.Addressing the media, CM Rekha Gupta said this is a proud moment not only for Delhi Metro but for all residents of Delhi. She said this marks a crucial step toward making public transport in Delhi more efficient, accessible, and environmentally sustainable. Gupta reiterated that providing Delhi with world-class infrastructure remains a top priority of the govt.
‘The work on another parallel tunnel between Chhatarpur Mandir and IGNOU was completed on Feb 25 this year. Therefore, tunnelling work on both the up and down lines has now been completed on this challenging stretch,’ said Anuj Dayal, Principal Executive Director, Corporate Communications, DMRC.
In the current tunnel, around 1,048 rings have been installed with an inner diameter of 5.8 metres. The tunnel was 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 mechanised casting yard set up at Mundka.
‘This tunnelling drive faced challenges of steep gradient along with varied geology comprising mica and hard rock, these conditions caused damage to the screw auger, which had to be replaced during the drive. All necessary safety precautions were implemented during construction beneath existing viaducts and structures,’ said Dayal.
He added that ground movements were monitored with highly sensitive instruments fixed on nearby structures to ensure there was no settlement.As part of the Phase IV work approved so far, 40.109 kilometres of underground lines are being constructed. The Aerocity-Tughlakabad corridor includes underground sections totalling 19.343 kilometres. ‘DMRC has achieved three TBM breakthroughs in the last four weeks, reflecting rapid progress in Phase IV underground work,’ said Dayal.
