Mumbai: National High-Speed Rail Corporation Limited (NHSRCL) signed a contract with Afcons Infrastructure Limited, on Thursday for the construction of a 21 km long tunnel including India’s first 7 km long undersea rail tunnel in the state of Maharashtra for Mumbai-Ahmedabad High-Speed Rail Corridor under MAHSR C-2 package.
The technical bids of this tender were opened on February 9, and financial bids were opened on April 6.
Speaking on this, NHSRCL’s Managing Director Rajendra Prasad said, “Construction of 21 km of the tunnel is one of the most challenging contracts of the Mumbai- Ahmedabad HSR corridor, which includes the construction of the country’s first twin-track undersea rail tunnel of 7 km at Thane Creek. The three tunnel boring machines and new Austrian tunneling method will be used for the construction of this tunnel.”
India’s first 7 Km long undersea rail tunnel
According to NHSRCL, the 21 km long tunnel will be between the underground station at Bandra-Kurla Complex and Shilphata in the State of Maharashtra. A seven-kilometer undersea tunnel at Thane Creek (Intertidal Zone) will be the first undersea rail tunnel to come up in the country. This tunnel will be about 25 to 65 meters deep from the ground level.
The tunnel will be a single tube tunnel to accommodate twin tracks for both up and down way. 39 equipment rooms at 37 locations will also be constructed adjoining tunnel locations as part of the package.
To construct this tunnel, TBMs with a cutter head of 13.1 Meter diameter will be used. Usually, 5-6 Meter Diameter cutter heads are used for urban tunnels used in MRTS – Metro system. Three tunnel boring machines will make about 16 km of the tunnel portion and the remaining 5 km will be through New Austrian Tunnelling Method (NATM).
Three shafts at BKC (under package C1), Vikhroli, and Sawli at approximate depths of 36, 56, and 39 Meter depths respectively will facilitate the construction. The inclined Shaft of 42 Meters at Ghansoli and the Tunnel portal at Shilphata will facilitate the construction of approx, 5 km of the tunnel through the NATM tunneling method.
