In a groundbreaking development, the National High-Speed Rail Corporation Ltd (NHSRCL) has embarked on the construction of India’s first undersea rail tunnel, spanning 21 kilometers from Bandra Kurla Complex (BKC) in Mumbai to Shilphata in Thane. A crucial component of the Mumbai-Ahmedabad bullet train project, this tunnel will traverse 7 kilometers beneath the sea, employing cutting-edge techniques like the Tunnel Boring Machine (TBM) and New Austrian Tunneling Method (NATM).
Key Highlights:
Undersea Rail Tunnel: The tunnel’s total length is 21 kilometers, with a 7-kilometer stretch beneath the sea, connecting BKC and Shilphata, Thane.
Construction Methods: Advanced methods, including TBM and NATM, will be utilized. TBMs with a 13.6-meter cutter head diameter will cover approximately 16 kilometers, while the remaining 5 kilometers will be constructed using NATM.
Tunnel Depth: Ranging from 25 to 57 meters below ground level, the tunnel’s deepest point will be 114 meters beneath the Parsik hill near Shilphata.
Shafts and Portals: Three shafts at BKC, Vikhroli, and Sawli, Thane district, along with an inclined shaft at Ghansoli, will aid construction. Portals at Shilphata and ADIT Portal are also integral parts of the project.
Construction Progress: Key milestones include the completion of secant piling work at Shaft 1 (BKC), ongoing excavation at Shaft 2 (Vikhroli), and excavation progress at Shaft 3 (Sawli). Portal work has commenced at Shilphata, marking the NATM end of the tunnel, and the construction of the ADIT Portal is underway for additional access.
Challenges and Mitigations: Challenges include controlled blasting techniques to minimize noise and air pollution, construction in densely populated areas with existing utilities, and proper disposal of excavated material under regulatory supervision.
Supporting Facilities: Concurrent construction of supporting facilities such as gantry cranes, labor colonies, and site offices is facilitating the overall progress of the project.
The Mumbai-Ahmedabad bullet train project takes a significant stride forward with the initiation of the undersea rail tunnel, a key milestone in enhancing high-speed rail connectivity.
