CMRL invites bids to construct 21km tunnel for Phase-2

In a way forward, Chennai Metro Rail Limited (CMRL) is set to take up construction of the Phase - 2 work with the bids called for the construction of 21 km long tunnel from Madhavaram to Taramani.

The underground section of the Madhavaram-Taramani which is part of the corridor 3 of the Phase 2 would be implemented in two packages. The bids have been invited separately for 9 km stretch from Venugopal Nagar at Madhavaram to Kellys and 12 km stretch from Kellys to Taramani Road Junction.

For the tunnelling work, seven tunnel boring machines (TBMs) would be deployed in the Madhavaram-Kellys stretch and eight TBMs would be used in the Kellys-Taramani stretch as part of the construction work. As per the bid document, the tunnelling works should be completed in 1460 days or four year from the award of contract.

According to CMRL officials, the contractor for the tunnelling works would be finalised in two months’ time. “The actual tunnelling work will start at various locations only after the contractor completing the preliminary works including site surveys. It will take more than six months to start tunnelling deploying the TBMs,” the official said.

With the experience from the Phase-1, the official said they have decided to deploy more TBMs to complete the tunnelling as per the schedule. “In the Phase-1, we used 12 TBMs for the 24 km underground stretch,” the official noted.

“Going by our experience of Phase I and geo-technical studies of the alignment, a TBM can tunnel up to 5 metres a day. However, this will depend on the geological conditions,” the official added.

In the Phase – 2, the CMRL proposed to construct 118.9 Km network with 128 stations comprising of three corridors – corridor 3 – from Madhavaram to Sipcot (45.8 Km), corridor -4 – from Lighthouse to Poonamalle Bypass (26.1 Km), corridor-5- from Madhavaram to Sholinganallur (47 Km).

About 65 per cent of the corridors in the Phase – 2 will be elevated and the remaining will underground sections. Works are in progress for the priority corridor of 52 Km from Madhavaram to Sholinganallur – Corridor 3 and Madhavaram to CMBT – Corridor 5. The funding arrangement for priority corridor has already been tied up with JICA.