Excavation for a 394-meter tunnel in Navi Mumbai, a crucial phase of the Mumbai-Ahmedabad bullet train project, has been successfully completed by the National High Speed Rail Corporation Ltd (NHSRCL). The excavation, which began on December 6, 2023, was concluded within six months, marking a significant milestone for the construction of a 21 km tunnel between the Bandra-Kurla Complex and Shilphata in Maharashtra.
Using the New Austrian Tunnelling Method (NATM), the tunnel at Ghansoli will allow simultaneous access for tunnelling about 1.6 meters on each side. A total of 214 controlled blasts were executed under expert supervision, ensuring safety through extensive instrumentation. The completion of this tunnel, known as ADIT, will provide direct vehicular access to the main tunnel during construction and operations, and may also serve as an evacuation route in emergencies.
Out of the 21 km tunnel, 16 km will be excavated using tunnel boring machines (TBMs), while NATM will be employed for the remaining 5 km. Notably, a 7 km stretch of this tunnel will pass under the sea at Thane Creek. Concurrently, construction of shafts at BKC, Vikhroli, and Sawli near Ghansoli is in progress to support the tunnel excavation through TBMs.
As per the shareholding pattern, the central government will contribute Rs 10,000 crore to the NHSRCL, while Gujarat and Maharashtra will each contribute Rs 5,000 crore. The estimated cost of the Mumbai-Ahmedabad bullet train project stands at Rs 1.08 lakh crore, with Japan providing the remaining funds through a loan with a minimal interest rate of 0.1%.
The NHSRCL highlighted that construction activities for the 21 km tunnel from the Mumbai bullet train station at BKC to Shilphata are advancing rapidly, indicating significant progress in the ambitious project.