Last night, Tunnel Boring Machine S937 made a breakthrough at Delhi Metro’s Nehru Enclave station! Unlike other breakthroughs, a drilling machine was deployed to assist with tearing down the diaphragm “D-wall” of the shaft. The S937 Earth Pressure Balance TBM was commissioned by the Pratibha-FEMC JV (CC-23) from the Greater Kailash station on July 18 2015 and actually reached the Nehru Enclave’s TBM retrieval shaft a week ago on February 16. On its way, it built 782 rings (1095m) for the 38.235 km Magenta line’s up-line tunnel of the Phase 3 project.
Satellite view of Nehru Enclave’s receiving shaft:
A government school with precarious foundations is located to the west of the shaft, so a drilling machine was deployed to slowly drill and cut through the D-wall along the eye of the tunnel.
More images will be added here once they become available, so do come back!
As of last night, the S723 TBM which is working on the parallel down-line tunnel has completed 347/780 rings and is expected to make a breakthrough by the end of April. Fun Fact: S723 was used by the Pratibha-CRFG JV for excavating and building CC-01’s tunnels between Central Secretariat – Janpath – Mandi House! That 3.3 km section opened for commercial operations on 26 June 2014.
With this breakthrough out the way, now 8 more breakthroughs are left to be made on the Magenta line. The next one will soon take place at the Panchsheel Park station by a TBM deployed from Chirag Delhi for the down-line tunnel.
For more updates on the Delhi Metro’s Phase 3, check out the Delhi section of The Metro Rail Guy!