National High Speed Rail Corp. Ltd (NHSRCL), a special purpose vehicle (SPV), inked a contract with the Shapoorji Pallonji subsidiary, Afcons Infrastructure, for the construction of a 21 km long tunnel in Maharashtra for the upcoming Mumbai-Ahmedabad bullet train corridor Thursday.
The contract, valued at Rs 6,397 crore, is inclusive of India’s first 7 km long undersea rail tunnel.
Following the opening of the technical bids in February this year, financial bids for the tender were opened in April.
Describing the tender involving the undersea tunnel in the intertidal zone located at the Thane Creek near Mumbai as one of the most challenging parts of the corridor, managing director NHSRCL Rajendra Prasad, remarked, “Three tunnel boring machines (TBMs) and the New Austrian Tunnelling Method (NATM) will be used in the construction of this tunnel.”
The 21 km long tunnel will span the underground stations at the Bandra-Kurla Complex and Shilphata in Maharashtra. To be a single tube structure, it will accommodate twin tracks for both the upward and downward movement of trains.
A total of 39 equipment rooms at 37 locations will also be constructed in the adjoining tunnel location as part of the package.
TBMs with a cutter head of 13.1 metre diameter will be used in construction. In comparison, boring of tunnels for mass rapid transport system (MRTS) projects such as the metro rail only requires TBMs with 5-6 metre diameter cutter heads.
Three TBMs will be used in boring 16 km of the tunnel portion, while the remainder 5 km will be done using NATM.
Once completed, the tunnel will run from a minimum depth of 25 metre to a maximum depth of 65 metre from the ground level.
In other significant developments in the project, more than 60 km of viaduct has been completed in Gujarat, while preliminary work has commenced on the Bandra-Kurla station of the corridor.
Launched in September 2017 by Prime Minister Narendra Modi and his Japanese counterpart the late Shinzo Abe, the project was initially expected to be completed by 2023. However, owing to delays in land acquisition in Maharashtra and the countrywide lockdown announced in March 2020 to contain the first wave of the Covid-19 pandemic, the deadline is now extended.
The trial run of the first bullet train is planned on the 50-km stretch between Surat and Bilimora in 2026.
