The NHSRCL invited bids for the construction of a 21-km long tunnel in Maharashtra state, India’s first 7-km long underwater tunnel for the Mumbai-Ahmedabad High-Speed Rail Corridor. The tunnel will be situated between the Bandra-Kurla Complex underground station and Shilphata in the state of Maharashtra.
The 7-km undersea tunnel at Thane Creek (intertidal zone) will be the first sea tunnel to be built in the country. It will be a single tube tunnel that will accommodate twin tracks for both up and down tracks. As part of the package, 39 instrument rooms will also be constructed at 37 locations around the tunnel.
TBM with a 13.1-meter diameter cutter head will be used for the construction of this tunnel. Usually, a 5-6 meter diameter cutter head is used for urban tunnels used in the MRTS-Metro system. Three tunnel boring machines will be used to make about 16 km of the tunnel and the remaining 5 km will be done through the New Austrian Tunneling Method (NATM).
The tunnel will be about 25 to 65 meters deep from the ground level and the deepest construction point will be 114 meters below Parsik hill near Shilphata. BKC (under package C1) will facilitate the construction of three shafts at Vikhroli and Savli at an estimated depth of 36, 56 and 39 meters respectively.
The 42-meter inclined shaft at Ghansoli and the tunnel portal at Shilphata will facilitate the construction of an about 5 km tunnel through the NATM tunnelling method. (See Scheme in Annexure 1) The last date for submission of bids for the C2 package is 19 January 2023.
Bids for the design and construction of the underground Bandra Kurla Complex High-Speed Rail Station with a cut and cover length of 467 meters and ventilation shafts of 66 meters at Mumbai, Maharashtra under the C1 package were invited on 22 July 2022 and the bids are to be submitted. The last date is 20 October 2022.