- Called an ‘adit’ in tunnelling parlance, a horse-shoe shaped excavation in the middle will open up two passages in opposite directions
- The 14.2-km-long tunnel is to be dug 700 metres below the surface.
- The New Austrian Tunnelling Method for constructing the tunnel. Blasting by explosives inside the tunnel to carve out a horse shoe-shaped bi-direction tunnel.
- A daily target of 2.5 m tunnelling in each direction.
- More than 41 lakh truck loads of haulage expected to be pulled out of the tunnel.
- Deadline for completion set at 72 months.
Sonamarg: The search is on for what would be the middle of the ZojiLa tunnel, as it is from where Asia’s longest and one of the world’s highest road tun- nels would be carved out, simultane- ously, in opposite directions.
Prashant Kumar, deputy general manager with Hyderabad-based construction company Megha Engineering and Infrastructure Limited (MEIL), which has been entrusted with construction of this key tunnel by the Government of India-owned National Highways and Industrial Development Corporation (NHIDCL), told Kashmir Reader that advice is being sought from leading tunnelling experts in the world as well as in India on how to arrive at the middle of the tunnel.
Called an “adit” in tunnelling parlance, Prashant said that it was vital for the whole construction as it could expedite the tunnelling job.
The construction company has already begun the job from the eastern portal in Minimarg area on Kargil side, digging a few meters deep inside the 14.2-km-long tunnel that is proposed to be dug 700 meters below the surface in the rugged, avalanche-prone mountainous terrain.
The company is also moving its machinery amid frigid conditions to brace up for work on the western portal in Sonamarg area, where work on one of the first sections has just commenced.
Prashant said that while the two fronts on east and west are being tackled, with boring in progress, an approachable intermediate access to this tunnel will open two more fronts that will be worked on in opposite directions and will catch up with the two ends that are in progress at Sonamarg and Minimarg.
“The task is locating such a point in this treacherous terrain from where our approach and haulage is easy,” he said, explaining that instead of working on a 14-kilometre tunnel, an adit will enable work on two 7-km tunnel sections.
Given the rugged nature of mountains around and the harsh climate, Prasant said that the search is on for an appropriate area from where the middle of the tunnel can be reached by men as well as heavy equipment to start excavations from there.
He said even though finding the adit is a hard task, the company will have to accomplish it by all means as it is critical for adhering to the completion time of the tunnel that has been fixed at 72 months.
He said that given that several tunnel projects are coming up in JK and neighbouring areas, the company is sticking to the tested techniques. The New Austrian Tunnelling Method will be used for the ZojiLa tunnel, he said.
This method involves not the use of a tunnel boring machine but of blasting by explosives inside the tunnel to carve out a horse shoe-shaped bi-direction tunnel that would be 9.5 meters wide and 7.57 meters high, and a daily target of 2.5 m tunnelling on each front is expected to be achieved.
About the challenges inside the tunnel, Prasant said that in tunnelling every meter is a challenge in itself. He said that hard rock is always better than fractured one or loose material, “but we expect both of these.”
Once inside the tunnel, though, the workers will not have to encounter the harsh cold climate outside, which goes down to minus 30-35 degrees Celsius in Minimarg and below minus 20 Celsius at the Sonamarg end.
“Inside the tunnel the temperature is always on the higher side,” Prashant said.
“Work will start in full swing after winters and till then we have time to stockpile all the material as well as move the machinery,” Prashant said, adding that the haulage coming out of the tunnel will be efficiently dumped keeping in view the fragile environment.
According to company estimates, more than 41 lakh truck loads of haulage is expected to be pulled out of this tunnel.
Aman Bhatt, one of the planning engineers with MEIL, said that if the haulage from the main tunnel is ferried on trucks carrying 12 cubic meter of load, it would need 41,11,045 such trips.
The company will also simultaneously work on the first section that is to be developed by constructing the 18.5 kilometre road towards the main tunnel reaching Baltal via Sonamarg and Nilgrath.
The existing road from another under-construction tunnel at Z-Morh to the main ZojilLa tunnel will also have to be widened.
This first section will have two small tunnels and five bridges. The main ZojiLa tunnel will also feature ventilation shafts which will be constructed for proper airflow.
The whole project will cost more than Rs 4,500 crore, but that is less than the cost of the earlier shelved ZojiLa project that had seen cost escalation to the tune of Rs 1,600 crore after it was abandoned by IL&FS Transportation Network, the road development arm of the crisis-hit Infrastructure Leasing & Financial Services (IL&FS). That project, though, involved building two separate tunnels, but the government has now decided to build a single two-way tunnel.
The GoI has also done away with a parallel emergency tunnel in the ZojiLa project, changing the initial design, which has led to halving the project cost to around Rs 4,400 crore.
The project is to be built on EPC (engineering, procurement and construction) mode.
A six-year-deadline has been fixed to complete the tunnel.
The tunnel will reduce the travel time through the ZojiLa Pass from 3 hours to just 15 minutes, and will also achieve the critical all-weather connectivity across the ZojiLa Pass on the Sonamarg-Kargil section of the strategic highway that connects Srinagar to Leh, which remains cut off for nearly six months due to snowfall during winter.
The work has begun only three months ago, and presently the company is consulting the best minds in the tunnelling profession to figure out a way to reach to the middle.