Mumbai-Ahmedabad bullet train: ‘Breakthrough’ achieved in first mountain tunnel
Besides the tunnel in Valsad in Gujarat, the raid corridor will have six other mountain tunnels, all of which will be constructed using the New Austrian Tunnelling Method
The 'breakthrough' in the first of the seven mountain tunnels in the Mumbai-Ahmedabad bullet train project was achieved on Thursday (October 5) in Valsad in Gujarat in a span of 10 months, the National High Speed Rail Corporation Limited (NHSRCL) said.
An official also said contracts for the other six mountain tunnels have been awarded while digging work for the undersea tunnel connecting Bandra Kurla Complex in Mumbai to Shilphata in neighbouring Thane district had commenced.
An NHSRCL release said the tunnel in which ‘breakthrough’ has been achieved is located some 1 km away from Zaroli in Umbergaon taluka in Valsad in the neighbouring state and has been built using the New Austrian Tunnelling Method (NATM).
What is a breakthrough?
‘Breakthrough’ is an engineering term used when a tunnel being built from two ends meets in the middle.
"The structure comprises a tunnel, a tunnel portal, and other connecting structures like a tunnel entrance hood. The 350-metre long tunnel has a diameter of 12.6 metres and a height of 10.25 metres. The single tube horseshoe-shaped tunnel will have two high-speed train tracks passing through it," it said.
The Mumbai-Ahmedabad high speed rail corridor will have seven mountain tunnels, all of which will be constructed using the NATM that involves marking drill holes on the tunnel face, drilling holes, charging explosives, controlled blasting, muck removal, and the installation of primary support, it said.
The high-speed train corridor has a 21 km tunnel between Bandra-Kurla Complex in Mumbai and Shilphata in Thane district, and 7 km of this structure will be under Thane creek, making it the first undersea tunnel in the country.
The six mountain tunnels for which contracts have been awarded are in Kasabekaman, Chandrapada, Chandasar, Mithagar, Vasantwadi and Ambesari in Maharashtra's Palghar district, some 100 km from Mumbai, officials said.
The total cost of Mumbai-Ahmedabad High Speed Rail Corridor project is pegged ₹Rs 1.08 lakh crore.
As per the shareholding pattern, the government of India will pay ₹10,000 crore to the NHSRCL, while the two states involved, Gujarat and Maharashtra, are to pay ₹5,000 crore each. The rest comprises a loan from Japan.
(With inputs from agencies)