Uttarkashi: It’s been a year since the Silkyara tunnel collapse in Uttarkashi district of Uttarakhand made headlines nationally and internationally. However, construction pace couldn’t be accelerated due to debris accumulation inside the tunnel. Now, three drift tunnels are being built to remove the debris.
On November 12 last year, 41 workers were trapped inside this tunnel when a section of under-construction tunnel suddenly collapsed and these entrapped workers were rescued after 17 days after large-scale rescue efforts involving various agencies and international experts.
Accumulated debris is still a challenge
Following the incident, all the safety measures were taken to prevent further collapse inside the tunnel. Even some changes were made to enhance safety in the tunnel, but the pace of construction could not be sped up effectively. Still 211 meters of tunnel construction is yet to be completed and the debris in the collapse area still remains a challenge. The cavity created inside the tunnel after collapse couldn’t be treated. Even though experts from Austria are helping in removing the debris.
Three drift tunnels to remove the debris inside the tunnel
On the advice of experts, three drift tunnels are being built to remove the debris spread over an area of 55 metres. As per the agencies involved in the construction, by using the cement, the debris is being converted into solid and drift tunnels are made through drilling inside the solidified debris. Under this procedure, one drift tunnel was built in September. With the help of this drift tunnel, approximately eight lakh cubic meters of water accumulated in the tunnel was dewatered. The second tunnel is 40 percent complete, while construction work on the third one has not yet begun.
Drilling and grouting with fiberglass rock bolts to protect the drift tunnel
According to construction company officials, drilling and grouting are being done with 70 mm fiberglass rock bolts to protect the drift tunnel. Currently, 3,000 such bolts have been ordered from China, as they are not available in India. These rock bolts are being used to treat cavities caused by landslides and to strengthen the drift tunnel. They can be cut and removed later as per the tunnel’s design.
Construction company started work from Barkot side
After the accident, on January 23, 2024, the Ministry of Road Transport and Highways received orders to resume construction. Navayuga Engineering Company began work from the Barkot side of the tunnel, starting with the escape tunnel, heading on tunnel face, benching, and invert. On the Silkyara side, an escape tunnel was constructed using hume pipes and an RCC box over a 120-meter area between the tunnel entrance and the landslide zone. Learning from the accident, NHIDCL and the involved company are closely monitoring the construction to ensure there are no lapses.
70 percent work has been completed on the tunnel so far
This tunnel is being constructed at a cost of Rs 1,119.69 crore. This work started on July 9, 2018, which was to be completed by July 8, 2022. Now the date for completion of this work has been fixed as January 28, 2026. So far only about 70 percent of the work has been done. According to Anshu Manish Khalkho, Director, NHIDCL, “The construction of Silkyara tunnel is underway. When the accident happened on Diwali last year, about 450 meters of tunnel excavation work was remaining. Currently, 211 meters are remaining. Three drift tunnels are being built to remove the debris. Means 70 percent work is almost completed.”
29 workers did not return to work
Of the 41 workers rescued from the Silkyara tunnel after being trapped for 17 days, only 12 have returned to work. Most of these workers were employed under contractors. Prior to the accident, the project had 800 workers, but this number has now decreased to around 500.
Construction of Baukhnag temple is going on in Silkyara
During the Silkyara tunnel accident, the local deity Baukhnag gained attention. Prof. Arnold Dix, President of the International Tunneling and Underground Space Association, was seen praying at a small temple outside the tunnel during the search and rescue operation. Additionally, ministers and officers from the state and central government who visited the site for inspection also worshipped the Baukhnag deity. Responding to the local villagers’ request, the Navayug company began constructing a temple near the tunnel’s entrance. Currently, the temple’s roof and dome are under construction.
Sheer negligence of the implementing agency and construction company
In September this year, a high-level committee submitted a detailed investigation report to the Ministry of Road Transport and Highways. The report highlighted serious negligence by the implementing agency and the construction company, raising questions about safety standards.
2,400 meters from the Silkyara side and 1,640 meters from the Barkot side have been excavated till 12 Nov, 23
Construction of the 4,531-meter-long Silkyara tunnel, part of the Chardham All Weather Project on the Yamunotri Highway, began in 2018. The National Highways and Infrastructure Development Corporation (NHIDCL) had entrusted Navayug Engineering with the project. By Diwali on November 12 last year, 2,400 meters had been excavated from the Silkyara side and 1,640 meters from the Barkot side. However, an accident occurred in the Silkyara tunnel at 5 am on November 12, 2023.
