A light at the end of the tunnel

Project

Rohtang Tunnel

Year

2006-ongoing

Location
India
Client

India’s Border Road Organisation and the Ministry of Defence

8.8

long

10,000

above sea level (general altitude)

3,000

vehicles to pass all year round

The need for a tunnel through the Rohtang Pass to reach Lahaul was discussed as early as 1860 by the Moravian Mission. Nearly 160 years later, the project is close to becoming a reality.

Below the rugged beauty of the snow-covered Rohtang Pass in the eastern Pir Panjal range of the Himalayas, teams of engineering specialists in fluorescent safety wear move carefully among cranes, support structures and construction equipment. They are building the Rohtang Tunnel, set to be India’s longest road tunnel at 8.8km. After nearly a decade under construction and despite challenges including heavy snowfall, avalanches and extremely difficult geographic conditions, the ambitious tunnel project is scheduled for completion in 2020.

At an altitude of 13,000 feet, the Rohtang Pass is only open for four months out of the year due to unpredictable snowstorms and blizzards. Almost 20,000 people in remote regions are cut off from the rest of India.

There are currently almost 20,000 people living in Lahaul and Spiti, some of the remotest parts of India, who are cut off from the rest of the country during the six months from November to May every year due to snow-bound weather conditions. A helicopter service run by the state government airlifts around 3,500-4,000 people requiring medical care and other emergencies from the tribal areas every winter through a network of 19 or so helipads across the Rohtang Pass alone. Thousands live in Kullu and other parts of the state during winter, unable to visit their families and hometowns until road connectivity resumes.

Currently, the Kullu Valley is connected to the Lahaul and Spiti Valleys through the Rohtang Pass – a high mountain pass at an altitude of 13,000 feet that is only open for four months out of the year due to unpredictable snowstorms and blizzards. The name Rohtang comes from Persian/ Farsi words Ruh+ Tang which means pile of corpses.

After nearly a decade under construction and despite challenges including heavy snowfall, avalanches and extremely difficult geographic conditions, the ambitious Rohtang Tunnel is scheduled for completion in 2020.

Once completed, the Rohtang Tunnel will be a life changer, providing these regions with safe, all-weather access to the rest of India and reducing travel distance by about 47km. Constructed at an average 10,000ft above sea level, the horseshoe-shaped tunnel will be the world’s longest tunnel at such high altitudes.

SMEC was engaged by India’s Border Road Organisation and the Ministry of Defence in 2006 to provide detailed engineering and advisory services on the project. During the nearly ten years since construction commenced, SMEC’s team of tunnel experts have leveraged innovation and technical skill, along with grit and determination, to contend with poor rock flowing conditions, avalanches, blizzards and other challenges. Advanced techniques including forepoling, lattice girders, pipe roofing, pre-grouting and chemical grouting have been applied. The design was also modified in the middle of the project to provide a deep invert for all round circular ground support.

While not fully operational yet, the tunnel is being used by emergency vehicles and in the winter of 2018 was used to evacuate hundreds of people stranded in the Lahaul region after heavy unseasonal snow.

The completed Rohtang Tunnel will facilitate two-way traffic and is designed to cater to up to 3,000 vehicles per day in any weather conditions at a maximum vehicular speed of 80 km per hour. It will enable residents to travel and sell their agricultural produce in towns, as well as boost tourism by providing all year access to Leh and Lahaul, underpinning the socio-economic development of the region.

Project
Rohtang Tunnel
Year

2006-ongoing

Location
India
Client

India’s Border Road Organisation and the Ministry of Defence

8.8

long

10,000

above sea level (general altitude)

3000

vehicles to pass all year round

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