Mumbai-Ahmedabad high-speed rail project: Breakthrough of first mountain tunnel achieved in 10 months

Valsad (Gujarat) [India], October 5 : In a significant stride towards the ambitious Mumbai-Ahmedabad High-Speed Rail (MAHSR) corridor, the National High-Speed Rail Corporation Limited (NHSRCL) marked a major breakthrough on Thursday with the announcement of the successful completion of the first mountain tunnel in a period of 10 months.
Situated approximately 1 kilometer from Zaroli Village of Umbergaon Taluka in Valsad district, Gujarat, the tunnel's structure encompasses the tunnel itself, the tunnel portal, and connecting elements such as the tunnel entrance hood.
According to officials, the construction of this vital tunnel employed the innovative New Austrian Tunnelling Method (NATM).
The process includes the precise marking of drill holes on the tunnel face, drilling of holes, charging of explosives, controlled blasting, removal of muck (blasted rock pieces), and the installation of primary support.
This support comprises steel ribs, lattice girder, shotcrete, and rock bolts, tailored to the specific type of rocks as assessed by geologists after each blast.
Key features of the mountain tunnel include a total length of 350 meters, a tunnel diameter of 12.6 meters, a tunnel height of 10.25 meters, and a single-tube horse-shoe-shaped design. The tunnel will accommodate two tracks, contributing to the overall efficiency and capacity of the high-speed rail corridor, they said.
This accomplishment marks the commencement of a series of seven mountain tunnels that will be constructed utilizing the NATM Method, enhancing the progress of the Mumbai-Ahmedabad High-Speed Rail corridor towards its anticipated completion, officials added.