Uttarakhand to come up with SOPs for tunnel construction after Silkyara incident
Uttarakhand Disaster Management secretary Dr Ranjit Kumar Sinha said they are examining the Silkyara tunnel incident, its causes, and safety gaps to introduce SOPs for the construction of tunnels to avoid such incidents in future
The Uttarakhand government will come up with standard operating procedures (SOPs) that need to be followed during the construction and maintenance of tunnels in light of the Silkyara incident in Uttarkashi.
Uttarakhand Disaster Management secretary Dr Ranjit Kumar Sinha confirmed the development and said, “We are examining the Silkyara tunnel incident, its causes, and safety gaps to introduce SOPs for the construction of tunnels to avoid such incidents in future.”
He said, “The SOPs, once introduced, would be applicable to state, central and joint projects in the state.”
“There are SOPs by the central government for tunnel construction and their maintenance but there are no such rule sets for the state. Technical experts are working on that,” he added.
Another official of the state government, who didn’t wish to be named, said, “The SOPs will involve detailing step-by-step guidelines and safety measures to ensure the efficient and safe completion of tunnelling projects. It will focus on project planning, risk assessment, site preparation, excavation, tunnel lining, equipment operation, quality control, and waste management”
Earlier, the Union Ministry of Road Transport and Highways announced that it would review the in-place SOPs for tunnel construction and maintenance to prevent Silkyara-like mishaps in future.
The ministry has sought details from all agencies that were involved in the 17-day rescue operation to take stock of the gaps and loopholes.
HT on November 27 reported that the geology report submitted to the Ministry before the commencement of the Silkyara-Barkot tunnel clearly stated that the proposed tunnel was to cross weak rock and adequate support structure needed to prop up the weak rock.
“From the surface geology, it may be anticipated that the rock type to be encountered along the diversion tunnels would be 20 per cent good (Class 2), 50 per cent fair (Class 3), 15 per cent poor (Class 4) and 15 per cent very poor (Class 4),” the report said. The major rocks in the area are weak sedimentary rocks, such as slate and siltstone, the report added.
In the report, it was also reported that there was no escape passage in the Silkyara tunnel, despite government guidelines recommending emergency exits for tunnels longer than 1.5 km. It was proposed to build a single tunnel with escape passage with Reinforced Concrete (RCC) partition, a document related to the project accessed by HT stated.
Also, four years before a portion of an under-construction Silkyara tunnel collapsed, residents of a local village had written to Uttarkashi district magistrate, alleging irregularities in the construction work of the tunnel by contractor, Navayuga Engineering Company Limited (NECL). In a letter sent to the district magistrate in April 2019, Subhash Jaguri, then pradhan (head) of Paul Gaon panchayat, alleged that NECL was carrying out the construction of the tunnel in “utter disregard” to set norms.
A portion of the 4.5-km-long tunnel being built between Silkyara and Dandalgaon on the Brahmakhal-Yamunotri National Highway — part of the Char Dham all-weather road project — caved in on November 12 following a landslide, trapping 41 workers from various parts of the country. The workers were evacuated after a 17-day painstaking rescue operation.