ATAL TUNNEL – 8.8KM LONG & HIGHEST ALTITUDE TUNNELSeptember 4, 2020
Atal Tunnel, Rohtang (previously known as Rohtang Tunnel), named after former Indian Prime Minister Atal Bihari Vajpayee , is a highway tunnel built under the Rohtang Pass in the eastern Pir Panjal range of the Himalayas on the Leh-Manali Highway.
Description of Atal Tunnel
- The 8.8 km long tunnel is now complete. It’s a ₹4,000-crore project undertaken by the Border Roads Organisation. Atal Tunnel is a 10.5 m-wide single tube including a 1-meter footpath on both sides.
- There’s also a fireproof emergency tunnel built into the main bi-lane tunnel. Up to 3,000 cars and 1,500 trucks are expected to use the tunnel every day. The speed limit inside the tunnel is capped at 80 kmph.
- The world’s longest tunnel Atal Rohtang at such a height will provide all weather connectivity to remote areas like Lahaul and Spiti Valley.
- Remote border areas of Himachal Pradesh and Ladakh remain cut off from the rest of the country for about six months during winters. PM Modi says this tunnel will change the fortunes of the people of Leh, Ladakh and Kargil.
Contractors of the tunnel
- The construction contract of the tunnel has been awarded to Strabag-Afcons, a joint venture between India-based Afcons Infrastructure and Austria’s Strabag.
- The contractors were selected after the project was approved by the Indian Cabinet Committee on Security in September 2009.
- Australia-based SMEC (Snowy Mountains Engineering Corporation) will provide design and project management services until completion of the project.
- The feasibility study for the project was done by Rail India Technical & Economic Services (RITES).
Construction of the tunnel
- The work on the Atal tunnel began in July 2010. It is expected to take 63 months to complete the project. The tunnel will be constructed using drill and blast NATM (New Austria Tunnelling Method) techniques.
- Inclement weather and avalanches might prove to be hurdles in the construction of the tunnel. Disposal of the huge overburden could also be a major task. The average overburden for the tunnel will be 600m and the maximum 1,900m.
- The principal support system for the tunnel will be a combination of fibre reinforced concrete and rock bolt. Yieldable steel ribs will be used as additional support in poor rock areas.
- The Atal tunnel will have semi-transverse ventilation with fans to circulate air. The long distance of the tunnel and the high altitude have necessitated the special ventilation system.
- Construction of one of the two access roads was completed in 2005. The road connecting the south portal of the tunnel to Manali is 2.7km long. It will have 18 avalanche protection structures. The 23.8km north portal road will connect the tunnel to Manali-Sarchu road. The two roads are estimated to cost Rs1.8bn ($38m).
- The approach roads will initially help in carrying the construction material to the site. They will be later developed to meet the specifications of a National Highway double lane.
What is the strategic advantage of the Atal tunnel?
Cutting through the Pir Panjal range, the tunnel will reduce the distance between Manali and Leh by 46 km. The Rohtang Pass, to which the tunnel provides an alternate, is located at a height of 13,050 feet, and a journey from Manali Valley to Lahaul and Spiti Valley, which normally takes around five hours to negotiate, would now be completed in little over ten minutes.
While the Atal tunnel will be a boon to the residents of the Lahaul and Spiti Valley who remain cut off from the rest of the country in winters for nearly six months due to heavy snowfall, the tunnel will provide almost all-weather connectivity to the troops stationed in Ladakh.
However, for full all-weather connectivity, additional tunnels will have to be built on the Manali-Leh route so that the high passes on the axis do not impede movement due to snowfall. A 13.2 km long tunnel will have to be built to negotiate the 16,040 feet high Baralacha pass and another 14.78 km long tunnel will be required at the Lachung La pass at 16,800 feet. A third 7.32 km long tunnel will be required at Tanglang La pass at 17,480 feet.