Uttarkashi tunnel collapse: Experts raise questions on geological and geotechnical surveys for project

Accident spot located near Main Central Thrust of the Himalayas

By Trilochan Bhatt
Published: Tuesday 14 November 2023
40 laborers are trapped in a landslide in an under-construction tunnel for the Char Dham Highway Project near Silkyara in Uttarkashi district, Uttarakhand. Photo: Uttarkashi Police__

Forty labourers have been trapped for the last 60 hours after a portion of an under-construction tunnel collapsed in Uttarkashi district of Uttarakhand. The tunnel is located on the Yamunotri National Highway near Silkyara and was being constructed under the Chardham Highway Project.

Wide steel pipes about 900 millimetres in diameter have been pushed through the rubble to deliver oxygen, water and small food packets to the trapped workers, according to the district administration. The workers are safe and communicating using walkie talkies, officials said. 

Looking at the efforts so far to evacuate workers show that there was no proper security arrangement in place for the construction of the 4.5-kilometre-long tunnel. Earlier rescue plans included cutting the rock from above with a vertical drilling machine, however, the machine was unavailable at first.

Read more: Char Dham project: Is development equal to disaster?

When one was finally obtained from Uttarakhand Jal Sansthan under the state government, the plan had to be abandoned due to continuous landslides. 

The steel pipes were brought from Haridwar, about 50 hours after the incident, on the morning of November 14, 2023, along with auger drilling machines. A platform was created for the machine, which then drilled holes to push the pipes to reach those trapped. 

After this incident, geologists have once again  raised questions about the Char Dham Highway project. Geologist Naveen Juyal said mainly two types of incidents occur during tunnel construction in Uttarakhand — sudden release of large amounts of water and unexpected encounter of sheared rocks (worn by rubbing against each other).

The former Indian Space Research Organisation scientist also questioned whether geological and geotechnical studies were conducted during tunnel alignment. Such an investigation is conducted prior to any such construction and a report is provided to the construction agency. 

Read more: Curb colossal ecological destruction during Char Dham Yatra: NGT-appointed panel

The geological and geotechnical studies would be mentioned in the report if they were carried out, said Juyal. This raises another concern, what were the actions taken by the tunnel building company to avoid such an incident, if the studies were carried out? 

The Main Central Thrust (MCT) of the Himalayas passes a few kilometres north and northwest of the incident site, according to Juyal. This means that this area is extremely sensitive to earthquakes and frictional shear rocks are present in this area. 

“I had recently visited Dharasu Band near the tunnel site. A three-level road is being built in the region. Shear rocks were visible throughout the area and heavy construction here can be dangerous,” the scientist said. 

He added that time has come when responsibility should be fixed for such incidents. “Enough is enough. The daily progress reports of the projects should be thoroughly scrutinised, and the reports of geological and geotechnical investigations should be taken seriously,” Juyal said. 

According to SP Sati, chairman of the environment department at Uttarakhand University of Horticulture and Forestry, explosives were being used openly during tunnel construction and the landslide in Silkyara tunnel could be the result of a major explosion. 

Read more: Char Dham national highway has cost Uttarakhand its ecological balance

Sati claimed the tunnel was dug far ahead of the landslide’s location. “The occurrence of landslides at a place where work has been completed raises questions. The geological survey for this project may have been very superficial,” he said. 

The geological surveys required before embarking on such large projects in the Himalayan region are not being carried out, according to Ravi Chopra, the chairman of the High Power Committee formed by the Supreme Court to conduct the environmental assessment of the Char Dham National Highway project.

“Such surveys and investigations are both costly and time-consuming. Governments want projects completed with the least amount of money and in the shortest amount of time possible. Incidents like Silkyara are the result of this,” he said.

Meanwhile, Uttarakhand State Disaster Management Authority has announced the formation of a committee under the chairmanship of the director of Disaster Mitigation and Management Centre under the state government to investigate the Silkyara tunnel accident. 

Read more: Joshimath Sinking: Preparations for Char Dham Yatra begin; locals still clueless about permanent rehabilitation

The panel includes officers nominated by the deputy director general of the Geological Survey of India, officers nominated by the Director of Wadia Institute of Himalayan Geology, officers nominated by the Director of the Indian Institute of Remote Sensing and officers nominated by the Director of Geology and Mining Directorate as well as officials of the Uttarakhand State Disaster Management Authority. 

Geologists and senior geologists of Uttarakhand Landslide Mitigation and Management Centre have been made members of the committee as well. 

But the efficacy of the inquiry committee is also in question. “The panel is just for convenience,” said activist Indresh Maikhuri.

“If the environmental consequences of these schemes had been considered, the recommendations of the Supreme Court’s High Power Committee would have been implemented. Instead, the central government divided the 889-kilometer-long project into 53 sections to avoid the need for an environmental impact assessment,” he alleged. 

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