Chenani-Nashri tunnel: How IL&FS Transportation pulled off the challenge

Pulling off an engineering marvel is not something that happens every day. If we talk about recent times then the construction of the Chenani-Nashri tunnel (aka Dr. Syama Prasad Mookerjee Tunnel) comes as a perfect example of that. A 9-kilometer-long tunnel that is part of the four-lane Jammu-Srinagar highway in the state of Jammu and Kashmir.

The Chenani-Nashri tunnel project was initiated in 2011 with the aim of reducing the travel time between Jammu and Srinagar, the two major cities of Jammu and Kashmir, and providing all-weather connectivity to the region. The area is prone to landslides and other natural disasters, which often result in the closure of the existing highway for days or even weeks.

IL&FS Transportation Networks Limited, a leading infrastructure development and finance company in India pulled off this miracle. The company was responsible for the design, construction, and operation of the tunnel, which was built using the latest technology and engineering techniques.

The Challenges

• The terrain of the area was challenging, as it is located in the Himalayan mountains with steep slopes and unstable rock formations, which made the excavation and construction process difficult and risky.

• Work was affected by severe weather conditions, including heavy snowfall and landslides, which caused delays and added to the complexity of the project.

• The area also has a high seismic activity, which required the use of advanced techniques and materials to ensure the safety of the tunnel in the event of an earthquake.

• Project faced significant opposition from local residents, who were concerned about the impact of the tunnel on their livelihoods and the environment. This resulted in delays and protests, which further added to the complexity of the project.

Construction Process:

• The construction began with the excavation of a 13.15-meter-wide and 12.5-meter-high horseshoe-shaped tunnel through the Himalayan mountains.

• Tunnel was excavated using a road header machine, which used a rotating cutter head to break the rock and a conveyor belt to remove the debris.

• Excavated tunnel was then reinforced with steel mesh and sprayed with a layer of shotcrete, a type of concrete that is sprayed onto the surface to provide support and prevent erosion.

• The final step was the installation of the tunnel's electrical, ventilation, and fire safety systems, including the construction of emergency exits, fire hydrants, and a ventilation system that pumps fresh air into the tunnel and removes smoke in case of a fire.

The tunnel is one of the longest road tunnels in India and was completed in a record time of five years, despite the numerous challenges. The tunnel has several features that make it unique, including a state-of-the-art ventilation system, an emergency lighting system, and a fire detection and suppression system. The tunnel also has a fully automated traffic control system, which ensures the smooth flow of traffic and minimizes the risk of accidents.

The Chenani-Nashri tunnel was inaugurated by the Prime Minister of India in 2017 and has since become a major landmark and tourist attraction in the region. The tunnel has significantly reduced the travel time between Jammu and Srinagar, from 12 hours to just 5.5 hours. It has also improved the connectivity and accessibility of the region, which has led to the growth of tourism and other industries in the area.

The success of the Chenani-Nashri tunnel project demonstrates the importance of investing in infrastructure development and the benefits that it can bring to a region. The project has also set an example for other infrastructure projects in India and has shown that with the right technology, engineering, and management skills, even the most challenging projects can be successfully completed.