Minor to medium level collapses happen in tunnel projects usually: NHIDCL

Days after the rescue of 41 workers trapped in the Silkyara tunnel due to a partial collapse, an official on Friday said that minor to medium-level collapses occur at any tunnel project normally and these are corrected during the construction.

A rescue team on Tuesday pulled out all 41 workers trapped due to the collapse of a portion, around 200 metres from the entrance, of the under-construction Silkyara tunnel in a multi-agency operation that hovered between hope and despair for almost 17 days.

The 4.5 kilometres long Silkyara tunnel project in Uttarakhand, which is part of the central government's strategic 900-km 'Char Dham Yatra All Weather Road' aims to provide all-weather connectivity to four holy towns of Yamunotri, Gangotri, Kedarnath and Badrinath in Uttarakhand.

"Whenever any tunnel is being built, minor to medium-level collapse of the tunnel is a normal occurrence. We keep correcting it as and when it happens," National Highways & Infrastructure Development Corporation Ltd. (NHIDCL) director (admin and finance) Anshu Manish Khalkho told PTI.

NHIDCL is constructing the tunnel through Hyderabad-based Navayuga Engineering Company Ltd.

Responding to a question on the absence of an escape passage in the tunnel, Khalkho said, "As per the SOP (standard operating procedure), once the main tunnel construction is complete, the escape carriageway work is taken up."

Silkyara tunnel is a single tube tunnel and is divided into two inter-connected corridors by a partition wall.

Another senior road transport and highways ministry official said that each inter-connector corridor can work as an escape passage for the other.

"And the concept of escape tunnel/passage comes after only after completion of the project," he added.

Zojila Tunnel Project Head Harpal Singh had earlier said there could be several possible reasons for the collapse of the Silkyara tunnel.

"These could be poor geological investigation, under-designed ground support systems, mistakes during construction, poor data monitoring and mitigation measures during construction or poor supervision control," he explained.

Singh was of the view that "all highway and rail tunnels should be planned with an escape tunnel parallel to the main tunnel".

In 2021, in an interview with PTI, Union road transport and highways minister Nitin Gadkari had termed allegations that the Char Dham road project triggered landslides in Uttarakhand as 'misinformation' and asserted that the government is sensitive about ecology and environment while carrying out development projects.

Gadkari pointed out that now, the hilly terrains have been secured with the construction of a tunnel (beneath Chamba town).

A 2019 report headed by veteran environmentalist Ravi Chopra described the Char Dham project -- an ongoing road project that will connect the four important pilgrim towns of Badrinath, Kedarnath, Gangotri, and Yamunotri -- as "an assault on the Himalayas".

The committee recommended limiting the width of the road to 5.5 metres on the Char Dham project. However, in December 2021, the Supreme Court in its order allowed the road width to 10 metres.

The Supreme Court allowed double-lane widening of the Char Dham highway project in Uttarakhand, observing that the country's security concerns may change over time and the recent past has thrown serious national security challenges.

The judgment clearing the way for a double-lane paved shoulder (DL-PS) configuration for the project had come in the backdrop of the standoff between Indian and Chinese militaries in several areas along the LAC (line of actual control) in Ladakh. "The considerations for development of national highways in plains and in hilly and mountainous regions are not identical," it had noted.

Prime Minister Narendra Modi laid the foundation stone of the 'Char Dham Yatra All Weather Road Project' on December 27, 2016. The original deadline for the project was March 2020.