India’s First Undersea Tunnel
Mumbai will have the first undersea tunnel of India by the year 2023 which will part of the Coastal Road Project of the city. The undersea tunnels will be built as a part of the Mumbai Coastal Road Project which comprises the land-filled roads on the areas that are reclaimed from the sea, tunnels, bridge.
Key Points :
- The twin tunnels are 10.58 kilometers long, starting from the Marine Drive Promenade to the Worli Sea Face End of the Bandra-Worli sea link. These tunnels will start from Priyadarshini Park and end at Netaji Subhash Road in Marine Drive.
- There is a plan to connect South Mumbai to the north through this toll-free route, so that traffic can be made easier. It is the first undersea road tunnel in the country, which will pass through the Arabian Sea near Girgaon Chowpatty.
- Unlike the world’s large undersea tunnel, Mumbai’s tunnel is being built at relatively shallow depths. It is known that the Channel Tunnel, also called Eurotunnel, rail tunnel between England and France that runs beneath the English Channel. The Channel Tunnel, 31 miles (50 km) long, consists of three tunnels: two for rail traffic and a central tunnel for services and security.
- Tunnel Boring Machine (TBM) is being used for its excavation. TBM Is used in rock drilling and blasting methods and, as an alternative to traditional ‘hand mining’.
- The TBM is capable of building a clean tunnel, without causing much damage to the surrounding land by excavation.
- These undersea tunnels will be of two lanes, with one lane being used in emergency time. In case of emergency, cross section tunnel is also being constructed to connect these two tunnels.
- To solve the problem of leakage, drainage system is also designed. Additionally the tunnel requires ventilation.
- These tunnels cause problems due to the carbon monoxide emitted by cars. To vent these harmful gases, a ventilation system called Saccardo will be installed inside the tunnel.
Mumbai Coastal Road Project:
The project consists of roads, bridges and tunnels. The project was launched as part of a plan to connect South Mumbai with North Mumbai by a toll-free road.
How deep will these tunnels be within the ocean?
- These undersea tunnels in Mumbai city will be 20 meters below sea level, while Japan’s Seikan Tunnel is 100 meters below seabed.
- These twin tunnels are also being built very close to the coast in Mumbai, where the depth of the sea is not more than 4 to 5 meters.
Major challenges for the construction of tunnel under the sea:
- It is quite a challenge to construct a tunnel being built within the sea. There are two major problems in constructing a tunnel within the ocean – the collapse of the tunnel due to seawater pressure or, due to seawater leakage in the tunnel.
Safety measures for passengers in Twin Sea Tunnels:
- Each undersea tunnel will have two lanes, which will be 3-3.2 meters wide. These tunnels will also have an emergency lane.
- Even though these two tunnels will be different, 11 cross-section tunnels will be built to connect these twin tunnels to each other.
Source- The Hindu