A tunnel measuring 21 km, including 7 km of India’s first undersea rail tunnel, will be built by the National High Speed Rail Corporation Ltd for the Mumbai-Ahmedabad high-speed rail corridor or the bullet train project. A contract to this effect was signed with the Afcons Infrastructure Limited on Thursday, making it one of the most challenging contracts to be executed for this project.
Three tunnel boring machines (TBM) will be used to make about 16 km of the tunnel portion and the remaining 5 km will be through the new Austrian tunnelling method (NATM).
“Construction of 21 km of tunnel is one of the most challenging contracts of Mumbai-Ahmedabad HSR (high-speed rail) corridor, which includes construction of the country’s first twin track undersea rail tunnel of 7 km at Thane Creek. Three tunnel boring machines and NATM will be used for the construction of this tunnel,” said NHSRCL managing director Rajendra Prasad.
The technical bids of this tender were opened in February, while the financial bids were opened in April. The 21-km tunnel will be between the underground station at Bandra Kurla Complex (BKC) and Shilphata in Maharashtra. It will include the nearly 7-km undersea tunnel at Thane Creek and will be the first such rail tunnel to come up in the country. It will be a single tube channel to accommodate twin tracks for up and down routes.
“As many as 39 equipment rooms at 37 locations will also be constructed adjoining the tunnel location as part of the package. To construct this tunnel, TBMs with a cutter head of 13.1 metre diameter will be used. Usually 5 to 6 metre diameter cutter heads are used for urban tunnels used in MRTS (mass rapid transport system),” read a statement by the NHSRCL.
This tunnel will be about 25 to 65 m deep and three shafts at BKC, Vikhroli and Sawli, at approximate depths of 36, 56 and 39 m, will facilitate the construction. In February, News18 had visited the BKC site where the only underground station of the project will come up. Chief project manager UP Singh had told News18 that to speed up the work on the intertidal zone, tunnelling will be done from both sides.
The total length of the bullet train corridor is 508 km – 156 km in Maharashtra, 4 km in Dadra and Nagar Haveli, and 384 km in Gujarat. The maximum operational speed will be 320 kmph and the total time taken for the trip will be 2.58 hours. There will be three depots – one in Maharashtra’s Thane and two in Gujarat’s Surat and Sabarmati. The operational control centre will be at Sabarmati.