As part of the ambitious project of bullet train for Mumbai-Ahmedabad, at least seven Indian companies have shown interest in the construction of an underwater tunnel. The National High Speed Rail Corporation Committee (NHSRCL) official said, “Seven Indian companies participated in the preliminary meeting bid to construct the ‘undersea’ tunnel of the Mumbai-Ahmedabad High Speed Rail (MAHSR) corridor. Tender for construction of the tunnel in the sea has been called and bids have been invited till 19 February 2021.
The bullet train project will have a 21 km long underground corridor from BKC to Kalyan Shilphata in the state of Maharashtra. The official said that about seven km of this underground corridor is under the Thane creek. Of this, a 1.8 km long section will be developed below the sea level. While the remaining part of the stretch is to be built under mangrove marshland on either side of the creek.
The official said the tender is for the development of the tunnel, which includes testing as well as commissioning of a double-line high speed railway for the tunnel boring machine (TBM) and the project using a new Australian tunnelling method. The geotechnical investigation of the undersea tunnel area was first carried out by a team of engineers from NHSRCL, RITES and Japan’s Kawasaki Geological Engineering firm. To study the structure of the ocean floor, a static refraction technique (SRT) survey was carried out by the team, in which a high-energy sound wave is drawn from below the surface of the water towards the seabed, as well as the sequence of the evoked sound wave mapping was also included. To determine the density of rock below the ocean floor. The team also submitted a final report with NHSRCL.
Last year, NHSRCL awarded civil contracts for the construction of 64 percent MAHSR alignment, including five HSR stations at Vapi, Bilimora, Surat, Bharuch, Anand / Nadiad, train depots in Surat and a 350-meter mountain tunnel.
Bullet trains are expected to run at a speed of 350 kilometres per hour, covering a distance of 508 kilometres in about two hours. Trains on the route take seven hours and planes take about an hour. On September 14, 2017, Prime Minister Narendra Modi and Japanese Prime Minister Shinzo AB laid the foundation stone for the HSP project of 1.08 lakh crore rupees ($ 17 billion).