Uttarkashi tunnel collapse: Govt working on new SOPs for tunnel construction and rescue operations

Tunnel Rescue Mission

The government will work with international experts to come out with new standard operating procedures (SOPs) to be followed in cases of tunnel collapse.

This follows the successful rescue of 41 workers, who were stuck inside the under-construction Silkyara tunnel on the Char Dham route for 17 days.
National Highway Authority of India (NHAI) Member Vishal Chauhan had on November 28 said that once rescue operations are completed the government will carry out an audit of all ongoing tunnel projects and also take lessons from the Silkyara tunnel operations to come out with new SOPs for incidents of tunnel collapse.

"We will take lessons from this too and see how we can improve our SOPs (standard operating procedures) and how we can improve our designs to make these projects safer. Once the operation is completed, these things will happen then," Chauhan said.

Roping in the experts

He added that the Delhi Metro Rail Corporation (DMRC) and Konkan Rail Corporation (KRC), which have extensive expertise in tunnelling, have been assigned the task of the review, he said.

Apart from working with the DMRC and the KRC, the government has also asked micro tunnelling expert Chris Cooper and the president of the International Tunnelling and Underground Space Association Arnold Dix to work with the government to come out with new SOPs to be followed in cases of tunnel collapse.

"The MoRTH has asked the two international tunnelling experts who worked as part of 'Operation Zindagi' to help come out with an improved SOP of tunnel rescue operations," a senior government official said.

He added that the improved SOPs will be implemented as soon as the six-member expert committee to probe the cause of the collapse comes out with its report on the cause of the incident.

Another official aware of the ongoing discussions said while Indian safety standards for tunnel operations were in line with the international benchmarks, the geology, and complexity of Himalayan construction require a unique methodology to be followed.

"The Himalayan geology is not predictable, which is why more safety measures and rescue measures need to be adopted to avoid such incidents in the future," the second official said.

The MoRTH and the NHAI are looking to complete the audit of the ongoing under-construction tunnel projects and come out with new SOPs by the end of January 2024.

The government's decision to come out with new SOPs for tunnel construction and rescue operations comes after questions were raised over the ambiguity currently existing in the SOP regarding tunnels, particularly in the case of steeply inclined ones.

The tunnel guidelines stipulate the provision of steps for rapid evacuation in the event of haulage failure. However, officials say that railways is the only entity mandated to construct escape micro tunnels with stairs, given the presence of rail tracks on the surface. For two-lane tunnels, the SOP lacks clarity on whether steps for quick exit are mandatory.

While the rescue operations involved in the safe evacuation of the 41 workers have garnered praise from across the world, environmental experts have criticised the construction practices being used for building the tunnel.

Initial investigation reports also suggest that the Silkyara tunnel did not have an emergency exit and was built through a geological fault.

Preliminary findings indicated the collapse may have been caused by a geological fault, known as a "shear zone", a member of the six-member expert committee to probe the cause of the collapse said.

A shear zone is a thin zone within the Earth's crust or upper mantle that has been strongly deformed, due to the walls of rock on either side of the zone slipping past each other.

In the upper crust, where rock is brittle, the shear zone takes the form of a fracture called a fault. The methods used to protect weak sections depend on the length and strata of the shear zone. This includes the use of forepoles, rock bolts, steel ribs, or shotcrete to reinforce the zone.

There was also no escape passage, despite government guidelines recommending emergency exits for tunnels longer than 1.5 km.

On-site reports have also revealed that no trench cages or safe tubes were used for the workers working in unprotected parts of a trench. Trench cages serve a crucial role in safeguarding workers from potential cave-ins; however, they are not designed to shore up or provide support to trench walls on their own.

The six-member expert committee includes Shantanu Sarkar, Director of Uttarakhand State Disaster Management Authority Dehradun; Khaing Shing Lurai, Scientist at Wadia Institute of Himalayan Geology; Sunil Kumar Yadav, Scientist at Geological Survey of India; Kaushil Pandit, Senior Scientist at Central Building Research Institute (CBRI)Roorkee; GD Prasad, Deputy Director of Geology and Mineralogy Department; and Tandrila Sarkar, geologist from USDMA Dehradun.

Environmental concerns

Environmentalists like Ravi Chopra have pointed out that practices, such as using dynamite and large drills, cause landslides and tunnel collapses.

For the development of the Himalayan region, ecological concerns should be addressed first, Chopra said. Sustainable development demands approaches that are both geologically and ecologically sound, he said.

Chopra had resigned last year as chairman of a Supreme Court-appointed high-powered committee on the Char Dham all-weather road, expressing disappointment over a Supreme Court order limiting the panel's jurisdiction to only two 'non-defence' stretches of the project.

Harshapati Uniyal, former advisor to the state planning commission, also said that construction methods for the Char Dham all-weather highway, especially for widening roads, are unacceptable.

"These all-weather roads are a tragedy for Uttarakhand, especially because of the wrong techniques being used for their widening. The river valley alignment cannot be considered safe. If you disturb the slopes, disasters like landslides are inevitable," Uniyal said.

He added that in the underground tunnel of the project passing near the hill town, cracks had appeared in nearby buildings and roads.

The project has faced criticism from environmental experts and some work was halted after hundreds of houses were damaged by subsidence along the routes.

The impact of the whole project was not properly assessed before construction started, a report by a Supreme Court-appointed expert committee said in July 2020.

"The panel will have to investigate not only steps taken for disaster management but also whether proper precautions were taken during the blasting, besides construction and design of the tunnel," said Hemant Dhyani, an environmentalist, referring to the panel formed to probe the collapse.

Dhyani, who was a member of the Supreme Court-appointed committee, said that his committee's recommendation of "building a narrow tunnel of 7-8 metres width has been ignored, leading to more blasting and increased risk of collapse".

"There are a series of lapses," he said, adding that more than 200 likely landslide locations have been created due to hill excavations, dumping of debris and choking of water flow during the whole project.

"We hope better sense would prevail and the government would take corrective measures," he added.

Social activist Shivanand Chamoli, who has been vocal on these issues, said that considering the sensitivity of the Himalayas, development projects should be examined from every aspect before permission is given.

"If development work is carried out in a haphazard manner, disasters will definitely occur," Chamoli said.

The 4,531 metre-long Silkyara tunnel is part of the Char Dham project of the MoRTH. Navayuga Engineering Co is constructing it on behalf of the National Highways & Infrastructure Development Corp Ltd (NHIDCL) for Rs 853.79 crore.

The tunnel was being constructed for the benefit of the Char Dham pilgrims as it would save their travelling time by around one hour, avoiding steep, mountainous and narrow roads, prone to accidents and landslides.

According to the government the existing road, if widened, would have completely destroyed the rich flora and fauna of the Radi top mountains, with a thick cover of Rhododendron vegetation.