Robbins TBM Makes a Breakthrough at Chennai’s Theagaraya Station

Yesterday, TBM 219-364 – a Robbins Tunnel Boring Machine operated by Afcons Infrastructure made a 2nd ‘hidden’ breakthrough at Chennai Metro’s upcoming Sir Theagaraya College Station. After building both tunnels of package UAA-01 between the May Day Park shaft and Central Station, this Earth Pressure Balance TBM was commissioned on March 27, 2017 from the Washermenpet Station to build the up-line tunnel of Chennai Metro’s 2.4 km UAA-08 project from Washermenpet to Korukkupet as part of a 9.1 km northern extension of the 23.10 km Chennai Airport – Washermenpet line to Wimco Nagar.

The Robbins TBM’s 863 meter journey to Sir Theagaraya College was aided by north Chennai’s favorable soil profile which comprises of silty sand, fine sand and clay, and took a little more than 3 months. Part of this time frame includes down-time 8.4m (6 rings) behind the station’s diaphragm wall waiting for it to be completed.

To rehash from the post on TBM S711 which arrived here in late-June, excavation is still underway at the Sir Theagaraya College Station, so this TBM isn’t visible either. Afcons plans to continue building temporary rings within the station box towards Korukkupet and will later dismantle them during excavation works. A similar ‘hidden’ breakthrough, not visible to workers, was performed by the same machine at the Central Station in January 2016 and more recently in Kolkata at Line-2’s Howrah Station.

For images of the TBM shot at Washermenpet, see this post.

Package UAA08: Washermenpet – Korrukupet – view Chennai Metro map & information

Meanwhile, Afcons Infra continues to make good progress on package UAA-02’s tunnels (May Day Park – AG-DMS) since July 2016 when it picked up pending work abandoned by the Gammon-Mosmetrostroy JV in May 2015. Here’s the progress made by the two Herrenknecht EPB TBMs as of July 11 (1 ring = 1.4m) –

TBM Origin Destination Rings Built/Total
S703 Thousand Lights AG-DMS 808/1248
S704 Thousand Lights AG-DMS 626/1246

For more updates, check out the Chennai section of The Metro Rail Guy!


written by

Global traveler who prefers mass rapid transit

6 Responses to "Robbins TBM Makes a Breakthrough at Chennai’s Theagaraya Station"

  1. Navnit S says:

    What is the programa on the elevated section beyond korukkupet till wimco nagar ?

    • TMRG says:

      Piling work for its substructure (foundation) has apparently started. Bidding for its superstructure (viaduct & stations) is ongoing.

    • TMRG says:

      I saw this, but thanks for sharing! The govt’s announcement throws more questions than answers. Wish they’d release more details. I’m trying to gather whatever I can on it and will write about it.

      • Anand says:

        sure we all r waiting fr ur detailed insights and views!
        Also wen likely CG will approve and release the funds for Ph II?
        Also I believe Govt was proposing monorail in Vadapalani- Porur – Poonamallee belt?

        • TMRG says:

          Hi, I’ve updated the Phase 2 info & map page with everything I know on the latest development.

          CG’s approval is dependent on the SG’s approval. Funds will be disbursed over time after construction begins. For that to happen, they first need to secure a loan.


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