Mumbai-Ahmedabad Bullet Train Project Achieves Milestone with Completion of Ghansoli Tunnel
Navi Mumbai, 30th May 2024: Excavation of the Additional Driven Intermediate Tunnel (ADIT), measuring 394 meters in length, at Ghansoli in Navi Mumbai marks a significant milestone for the Mumbai-Ahmedabad Bullet Train Project. This achievement will accelerate the construction of a 21-kilometre tunnel between BKC and Shilphata in Maharashtra.
The ADIT, an inclined shaft reaching a depth of 26 meters, will streamline the construction process by enabling the implementation of the New Austrian Tunnelling Method (NATM). It allows simultaneous access for tunnelling on both sides, facilitating the excavation of approximately 3.3 kilometres of the tunnel. Out of the total tunnel distance, 16 kilometres will be completed using Tunnel Boring Machines (TBMs), with the remaining 5 kilometres utilizing NATM techniques.
Commencing on December 6, 2023, the excavation of the ADIT was completed within a remarkable six-month period, involving 214 controlled blasts using 27,515 kilograms of explosives under expert supervision. High levels of instrumentation were employed to ensure the safety of the excavation process.
The ADIT, with internal dimensions of 11 meters by 6.4 meters, will provide direct vehicular access to the main tunnel during both construction and operations. Additionally, it can serve as an evacuation route in emergencies.
To guarantee safe excavation, a variety of monitoring instruments are being utilized, including Surface Settlement Points (SSP), Optical Displacement Sensors (ODS), Reflect Target (BRT) systems, Strain Gauges, and Seismographs.
Construction activities for the 21-kilometer tunnel, stretching from Mumbai Bullet Train station to Shilphata in Maharashtra, are progressing rapidly. Notably, a 7-kilometre section of the tunnel will pass beneath the sea at Thane Creek, representing a pioneering endeavour in India.
The single-tube tunnel will accommodate two tracks for up and down trains, with Tunnel Boring Machines featuring cutter heads of 13.6 meters in diameter employed for construction. This exceeds the typical cutter head size of 6-8 meters used for urban tunnels in Metro systems, as these tunnels typically accommodate only one track.
Furthermore, the ongoing construction of three shafts at BKC, Vikhroli, and Sawli will facilitate the construction of the 16-kilometre tunnel using TBMs, underscoring the project’s progress and commitment to innovation.
