L&T Lowers Delhi Metro Silver Line’s 1st Tunnel Boring Machine DZ1122

Larsen & Toubro on Thursday & Friday lowered TBM DZ1122 – the first ever tunnel boring machine at Chhatarpur Station of Delhi Metro’s 23.622 km Silver Line which will connect Aerocity – Tughalakabad via 16 stations.

L&T’s team had assembled this CRCHI earth pressure balance (EPB) machine’s cutterhead and shields, weighing 470 tonnes, adjacent to the TBM launch shaft.

It was carefully lifted and moved 26m horizontally, and then lowered 22m vertically into the shaft using a strand jack “mega lift” system specially designed for Delhi Metro Phase 4 project’s 6.51 km Package DC-09 (Kishangarh – Saket G Block).

A similar strand jack system was deployed by L&T and Freight Wings in 2020 to lower TBM Mavala – the largest tunnel boring machine (TBM) to ever be deployed in India – for Mumbai’s Coastal Road (Western Freeway) project.

Another smaller system was also seen in action at Worli & Science Center stations on Mumbai Metro’s Line-3 by Doğuş-Soma JV.

L&T was awarded 65.1 km Delhi Metro Phase 4 project’s Package DC-09’s contract in March 2022 valued at Rs. 1428 crore with a 42 month deadline.

The team launched construction work at Chhatarpur Station’s site in August 2022 and cast its base slab in early January 2023.

Their 6.51 km section, with twin-tunnels smack-dab in the middle of the Silver Line, will connect Kishangarh Station (chainage 5356.285) with a cut and cover ramp (chainage 11867.000) west of Saket G Block Station. It includes 4 stations at Chhattarpur (interchange with Yellow Line), Chhattarpur Mandir, IGNOU and Neb Sarai.

DC-09’s design details such as crossover and ramp locations can be viewed here.

Besides DZ1122, Larsen & Toubro will be deploying another 3 CRCHI machines. Their serial numbers and tunneling assignments remain unknown to me at this time. If someone reading this is aware, then leave a comment below or shoot me a message via the Contact page.

With this development, DZ1122 has become the 1st of 11 TBMs to be lowered for the Silver Line’s twin tunnel excavation work. Afcons on DC-07 (Sangam Vihar – Sarita Vihar Depot) will deploy 4 machines while J Kumar Infraprojects on DC-08 (Aerocity – Kishangarh) will deploy 3 machines.

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– TMRG