Mumbai-Ahmedabad bullet train project: Major milestone as first mountain tunnel breakthrough achieved in Valsad

A significant milestone was reached in the Mumbai-Ahmedabad bullet train project as the breakthrough in the first of the seven mountain tunnels was successfully achieved in Valsad, Gujarat. This accomplishment was made within a span of 10 months, as confirmed by the National High-Speed Rail Corporation Limited (NHSRCL).

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 kilometre away from Zaroli in Umbergaon taluka in Valsad in the neighbouring state and has been built using the New Austrian Tunnelling Method (NATM).

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-Ahmedbad 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 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 kilometres from Mumbai, officials said.