L&T’s Delhi Metro TBM-3 Records Breakthrough at IGNOU Station

Larsen & Toubro (L&T) today celebrated tunnel boring machine (TBM) DZ1125’s breakthrough at IGNOU Station of Delhi Metro’s 23.622 km Golden Line (Line-10) which will connect Aerocity – Tughalakabad via 15 stations.

This was TBM-3 (DZ1125)’s very first breakthrough and overall the sixth breakthrough for Delhi Metro Phase 4 project’s 6.51 km Package DC-09 connecting Kishangarh – Saket G Block.

DZ1125 is a 97m long CRCHI Earth Pressure Balance (EPB) machine and was commissioned in November 2023 to build the 1470m up-line tunnel from Chhattarpur Mandir Station to IGNOU Station. Its sister machine TBM-4 (DZ1124) was commissioned a month later, but passed TBM-3 and arrived at IGNOU Station in February.

DZ1125 built 1048 rings (1 ring = 1.4m) with an inner diameter of 5.8m at an average depth of 27m. Per the Delhi Metro Rail Corporation’s press release, the new tunnel has a minimum depth 15m and maximum depth of 39m. This breakthrough marks the completion of Delhi Metro Phase 4’s deepest twin tunnels.

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 Golden 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.

DZ1125 is one of L&T’s four TBMs working on Package DC-09 between Kishangarh – Saket Ramp. The others are DZ1122, DZ1123 and DZ1124.

This was the 6th of 10 breakthroughs planned in Package DC-09. TBM-3 and TBM-4 will now be dragged through IGNOU Station’s box and recommissioned to build roughly 1.2 km twin tunnels towards Neb Sarai.

L&T’s TBM-1 (DZ1122) and TBM-2 (DZ1123) have each recorded two breakthroughs and were recently recommissioned from Neb Sarai Station to build roughly 730m tunnels towards the City Forest Ramp.

With today’s development, a total of 9 tunnel breakthroughs have been recorded so far for the Golden Line with 6 tunnels (3 twins) continuously connected between Kishangarh – IGNOU.

Here’s the breakthrough count from east to west: 2 by Afcons for Package DC-07, 6 by L&T for Package DC-09, and 1 by J Kumar on Package DC-08. A full list of breakthroughs including contractors for all Golden Line civil & system packages can be viewed here.

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– TMRG