In order to expedite the construction of 21 km long tunnel between Bandra Kurla Complex and Shilphata, the National High Speed Rail Corporation Limited (NHSRCL) has excavated the 394 metre long Additionally Driven Intermediate Tunnel (ADIT) at Ghansoli, for Mumbai-Ahmedabad Bullet Train Project.
The ADIT will give direct vehicular access to the main tunnel during construction and operations, and may also be used for the purpose of evacuation process in emergency situation.
The excavation work for ADIT, which started on December 6 2023, took six months to finish and included 214 controlled blasts using 27,515 kg explosives under supervision of experts with a high level of instrumentation.
Excavation of ADIT, which is a 26-metre-deep inclined tunnel will pave way for onwards construction of another 3.3 km tunnel through New Austrian Tunnelling Method (NATM), by allowing simultaneous access for tunnelling approximately 1.6 metre on each side.
Mumbai-Ahmedabad Bullet Train Project
Out of 21 km of tunnelling work, 16 km is through Tunnel Boring Machines and remaining 5 km is through NATM.
The construction activities related to 21 km long tunnel from Mumbai Bullet Train station to Shilphata in Maharashtra is progressing at a fast pace, NHSRCL officials said. “The 7 km stretch of this tunnel will be under the sea at Thane Creek which is an intertidal zone. This is the first of its kind tunnel to come up in the country,” officials added.
The 21 km long tunnel will be a single tube tunnel to accommodate two tracks meant for up and down tracks of the bullet train. To construct this tunnel, Tunnel Boring Machines (TBMs) with cutter heads of 13.6 metre diametre will be used.
NHSRCL has targeted to complete bullet train project by 2028. The train is pegged to reduce travel time between Mumbai to Ahmedabad to three hours.
The under construction three shafts at BKC, Vikhroli, and Sawli will facilitate the construction of 16 km long tunnel through Tunnel Boring Machines.
