Delhi Metro Silver Line: L&T Lowers DC-09’s 3rd TBM DZ1125

Larsen & Toubro last night completed lowering tunnel boring machine (TBM) DZ1125 at Chhatarpur Mandir Station of Delhi Metro’s 23.622 km Silver Line which will connect Aerocity – Tughalakabad via 16 stations.

This is L&T’s third TBM to be deployed for Delhi Metro Phase 4 project’s 6.51 km Package DC-09 connecting Kishangarh – Saket G Block stations. For its first assignment, DZ1125 will excavate and build a 1477m tunnel eastward towards IGNOU Station.

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

On Tuesday morning, work began to carefully lift and move it 26m horizontally, and then lower it 22m vertically into the Chattarpur Mandir Station’s shaft using a strand jack mega lift system specially designed for this package.

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.

Delhi Metro Rail Corporation (DMRC) had awarded L&T with Package DC-09’s Rs. 1428 crore contract in March 2022 with a 42 month deadline.

Their 6.51 km section, with twin-tunnels 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.

I hear L&T’s first TBM, DZ1122, will record its first breakthrough on Thursday at Kishangarh Station after a 1267m journey from Chhatarpur which started in March 2023. As of last Friday, their second TBM DZ1123 working on the parallel tunnel on the same stretch had completed tunneling 1067/1274m.

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– TMRG