Uttarakhand tunnel collapse highlights Himalayan fragility and the need for escape routes

It’s been eight days since the 41 workers got trapped inside the Barkot-Silkyara tunnel.

WrittenBy:Hridayesh Joshi
Date:
   

It’s now Day 8 for the 41 workers trapped inside the Barkot-Silkyara tunnel in Uttarkashi. On November 18, a delegation headed by the prime minister’s former advisor Bhaskar Khulbe reviewed the situation on the ground, even as the government last week promised that “all coordinated efforts” were being made to “evacuate the stranded workforce”.

Holding meetings with top officials, Khulbe told the press it may take “five, six or seven days” to rescue the workers.

“We are working on a five-pronged strategy instead of a single plan,” he said. “We will drill [the mountain] at different places both vertically and horizontally. A machine has been sourced from The Netherlands which will help us drill the hill horizontally.”

The ordeal for the workers began in the early hours of November 12, when a portion of the tunnel – currently under construction as part of Uttarakhand’s Char Dham Mahamarg Pariyojana – collapsed. With pipes set up to funnel food, oxygen and water to the workers, the government used machines to try and free them. This included an American Auger drill, which can cut through 70 metres of rock, but all the attempts failed. On November 18, drilling was stopped.

So, despite the government’s assurances, relatives of those underground are terrified. It’s also led to several questions – mainly, why is there no way out for the trapped workers? What safety norms were followed during its construction?

Experts have now called for a “safety audit” of all new and ongoing projects in the state.

At ground zero, Newslaundry spoke to some of them on what went wrong.

Where was the ‘escape passage’?

The Char Dham Mahamarg Pariyojana is the Uttarakhand government’s dream all-weather highway project, inaugurated in December 2016 at a cost of Rs 12,000 crore. The Barkot-Silkyara tunnel project was announced in 2018 – a 4.5 km, two-lane, bi-directional tunnel that would reduce the distance between Gangotri and Yamunotri by almost 20 km. At a cost of Rs 1,383 crore, the tunnel was expected to cut down travel time for pilgrims by 45 minutes.

The project is under the purview of the National Highways & Infrastructure Development Corporation Limited, a state-owned company. In June 2018, NHIDCL signed a contract for Rs 853.79 crore with Hyderabad-based Navayuga Engineering Company Limited for engineering, procurement and construction.

Navayuga was also one of the sub-contractors in the construction of the Samruddhi Expressway in Maharashtra, where 17 people died in August after a crane collapsed. 

In the current crisis, the government’s press release said the workers had been carrying out “reprofiling work” when a “collapse occurred” at 5.30 am on November 12. 

There are mixed opinions on how it happened.

SP Sati, a geologist and professor of environmental science at the Uttarakhand University of Horticulture and Forestry, told Newslaundry, “Though construction companies never accept they use explosives in their work, we have seen repeated violations in the past. I am of the firm opinion that the ultimate trigger in the tunnel’s collapse was a major jerk. This should be investigated. The use of heavy explosives cannot be ruled out.”

Why didn’t the tunnel have an escape route? Crucially, when the government sanctioned the tunnel project in February 2018, it clearly stated that it would include an “escape passage”.

PC Nawani, former director of the Geological Survey of India, said it isn’t possible to manage such projects without escape routes. 

“You require escape routes not only to save lives and facilitate rescue work – as is needed now – but also to make the supply of material easy in the tunnel,” he pointed out.

The sensitivity of the Himalayas

Tunnels are increasingly becoming an essential part of road, rail and hydropower projects in countries like Europe, China and the United States. In India too, they’re popping up in projects across the Himalayas. The Rs 16,000-crore Rishikesh-Karnaprayag project will comprise over a dozen tunnels, one of which will be among the longest in the country at 15 km.

But given that the Himalayas are an ecologically sensitive region, due care is imperative.

Nawani, who is also a former director of the National Institute of Rock Mechanics, said, “Europe has many big tunnels because they have low tectonic activity and stable mountains. But we have made tunnels in Himalayan regions, including in Bhutan, Nepal, Northeast India, Uttarakhand and Pakistan...We use the same technology being used the world over but in India, the engagement of specific experts is not happening adequately.”

For example, he said, these projects require oversight from an expert engineering geologist. “But often contractors with no knowledge carry out the work,” Nawani said. “They are usually only concerned about their costs and that’s where the problem starts.”

Geologist Naveen Juyal is a senior scientist at the Physical Research Laboratory in Ahmedabad and was a member of a Supreme Court-appointed committee to review the Char Dham project. He told Newslaundry the tunnel is “safer than roads” in some ways since it avoids the “collateral damage faced during the building of roads due to destabilisation caused by widening the road”.

Yet the Himalayas are “unstable”, Juyal pointed out, so there must be a detailed study of rock mass before tunnelling.

“A proper geological and geotechnical survey is required in some projects,” he told Newslaundry. “I am sure that if a proper study was done, we would have known about the weakness of rocks in this mountain.”

The diameter and shape of the tunnel can also impact safety.The Barkot-Silkyara tunnel is 13 metres wide and nine metres high.

“People often think and care only about the tunnel’s length. But it’s important to keep in mind the shape and diameter too,” said Nawani. “Is it a circular tunnel or horseshoe shaped?...We must constantly monitor how the rock mass behaves, whether it is stable or not. We have to see whether the diameter of the tunnel is the same or squeezing, whether equipment deployment works properly or not.”

He added, “But in such small projects, nobody bothers about these details.”

Juyal flagged other safety aspects that must be monitored, such as the careful study of the region’s hydrology. In the absence of such a survey, one might puncture the water source while drilling – leading to disaster.

“Once that happens, not only will water start gushing out of the tunnel and deplete water sources in surrounding areas, but it may also cause collapsing on the roof and side-walls if they are made of weaker rocks,” he said. 

This is critical because the nature and strength of the rock is not the same all along the project. Drilling and cutting will require changes at different phases.

But these norms might be circumvented in the race to complete a project.

“You drill through the rock mass which is strong. Then you come across a weaker zone which is highly deformed. If I encounter a weaker zone while drilling, my excavation plan will be different,” Nawani explained. “I will not do any blasting. There will not be more than one-metre excavation in that area. We will have to immediately provide additional support to the rocks. In such a situation, the progress of the work will be slow.”

If this is ignored and the project “moves in a conventional way without adhering to prescribed norms”, he warned, then “today or tomorrow, the load of material will create a problem and such incidents can happen”.

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