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India’s Widest And 4th Longest Road Tunnel

Introduction:
This project is also a part of the 700 km Mumbai-Nagpur Expressway project. The longest tunnel is coming up on “Hindu Hridayasamrat Balasaheb Thackeray Maharashtra Samruddi Mahamarg” at Igatpuri in Nashik. The tunnel will connect Tarangpada village in Nashik to Vishala village in Nashik of Maharashtra. The length of the tunnel is 7.78 kilometers. It will be another point of attraction in Maharashtra besides the tourist hotspot of Igatpuri in Nashik district. The tunnel will reduce the vehicular congestion significantly and also cut the time travel between Mumbai and Nagpur from 14 to 15 hours to 8 to 9 hours.

Fig 1: The widest Twin-tunnel in Maharshtra
Fig 1: The widest Twin-tunnel in Maharshtra
Courtesy: Knocksense.com

Construction of the Project
The construction company involved in the Project is Afcons Infrastructure Ltd. The construction process was started on September 3, 2019. The right-hand side of the tunnel was completed on August 2021 by the teams of Afcons on Package 14 of the Greenfield project of Mumbai-Nagpur Super Communication Expressway. Besides the longest tunnel, the Afcons package has two small viaducts of length 900 meters and 1.2 km. It will enable the passage to the wild animals in the forested region where the expressway will not be fenced. Because, the tunnel will link Thane and Borivali, will pass under the Sanjay Gandhi National Park. The cost of the expressway will be built at a total cost of 55000 crores. It will have another two smaller tunnels of length 1.10 km and 300 meters long beside a vertical shaft to provide ventilation to the tubes. It is the widest tunnel in India having a width of 17.5 meters on each side and a length of 7.78 km.

Fig 2: The tunnel during construction
Fig 2: The tunnel during construction
Courtesy: The Times of India

The work for the project was started in September 2019. The first work of digging up was started by the drilling-blasting method at an average speed of 200 meters for nine months and achieving the highest speed of 258.40 meters at one point. They executed 3.3 km from a single tube by providing ventilation through a vertical shaft of 70 meters. The balance works of the construction include road laying and mechanical, electrical, and plumbing works. The design speed of the tunnel is 120 km/hr and it covers the gradient of 160 meters from near the hilltop close to Igatpuri to downhills near Vashala through the valley.

According to a report, a total of 1500 workers led by 150 engineers completed the end-to-end connectivity of the tunnel in a record two years. According to a report by Deccan Herald, the feat of completing the construction work in two years was achieved by the Australian tunneling method of sequential excavation by Afcons Infrastructure. The tunneling was done efficiently and proactively by following the highest safety standard.

The list of longest tunnels in the country:

1.Shyama Prasad Mukharjee tunnel
Connecting Chennai-Nashri; Location-Jammu & Kashmir
Length: 9.3 km, width: 13 m

2.Atal Tunnel
Under Rohtang Pass; Location: Himachal Pradesh.
Length: 9 km, width: 10 m

3.Banihal Quazigund Tunnel:
Pir Panjal; Location- Jammu & Kashmir
Length: 8.6 km, width: 7m

4.Igatpuri Twin Tunnels
Kasara Ghat, Maharashtra
Length:8 km, Width: 17.5 m each

The total project cost was Rs 2745 crores. The twin project is also called Package 14 of the Mumbai –Nagpur Expressway project. The tunnel will have water hydrants, supervisory control, and data acquisition for fast communication and monitoring. The Igatpuri site is prone to heavy rainfall, so at that site, the tunnels have been designed to be lined with water conduits to avoid waterlogging. To avoid surveillance disruption during turbulent weather, secure systems of data procurement have also been installed there. A shade roofing was also designed on the Igatpuri side to avoid ingress of water inside the tunnel. The span of roofing covers 0.2 km on either side of the tube.

Conclusion:
The project is expected to expedite the construction process of the Mumbai- Nagpur Expressway. The project also aims to streamline travel within Maharashtra, to improve tourism as well as increase inter-city comfort.

References:

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

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