Tunnelling without fear
Afconians overcome fear of Covid-19; Continue construction of Maharashtra’s longest road tunnel despite lockdown
Even as Covid-19 pandemic continues to inundate the country, and a wary Maharashtra Government lifts lockdown in phases, infrastructure construction has continued spasmodically across the state.
Afcons, working in two packages (2 &14) of the Mumbai Nagpur Super Communication Expressway, also known as the Maharashtra Samruddhi Mahamarg, adopted a cautious approach. Ensuring utmost safety of its workforce, the company planned its operations carefully and pressed on despite a nationwide lockdown.
Package 14, which starts at Taranganpada village and ends at Vashala BK village, is the highlight of the 701-km long, eight-lane expressway project. It comprises Maharashtra’s longest and widest road tunnels. The twin tunnels are 7.78km long and 17.6m wide.
Only few infrastructure projects were granted special permission to continue construction activities during lockdown. Afcons received the nod to continue tunnelling with a caveat to keep Covid-19 away from construction site and the workforce.
“The national lockdown became effective from March 25, 2020, and it was a critical period for us. We had to quickly shift focus from operations to immediate safety of the workforce. After proper scrutiny of our arrangements, and after they secured necessary permissions for work to resume, the MSRDC gave us the green light,” said Afcons’ Director, Hydro and Underground, Satish Paretkar.
Afcons could immediately mobilise men and machinery as the site had made arrangements to shelter the workforce. Tunnelling activities resumed on April 2, 2020, and structural works resumed by April 16.
“The quick turnaround was possible because our site team was alert, kept the workforce motivated, and, our headquarters made sure material and resources were available during lockdown. Due to SOP guidelines from government, underground activities were initially started with social distancing criteria. Open works were taken up later,” added Paretkar.
In the month May, the team completed 214.5m heading excavation from single face (north portal). “More than 200m excavation in such large diameter tunnelling in one month is a significant achievement especially during the pandemic,” said Package 14 Project Manager, Sekhar Das.
So far, more than 3,935m of tunnelling, 63.5m of ventilation vertical shaft, 71 pier foundations, and 20 I-Girder casting have been completed in the project.
Cut & Cover
The twin tunnels are an integral part of the project. Since the overburden is less in the starting chainage of the tunnel, cut & cover portion is required. This unique portion has its own challenges, which involves controlled blasting. Since a slope has to be maintained to reach the bottom of the tunnel face, the drill depth has to be adjusted and blasted accordingly.
“We are happy to exceed the planned turnover even in these difficult times. Our project has achieved three million Safe Man Hours without any LTA, which is a matter of pride for all of us,” said Das.
The project is extreme by any stretch of imagination. Cutting through a mountainous terrain in the Western Ghats, the expressway project is designed for speeds up to 120 kmph. To top this, the south portal of the tunnel, viaduct and inclined shaft are surrounded by a reserve forest without proper access.
The Afcons’ team developed access roads with proper gradient on the sloping Ghats section, including widening of hairpin bends.
“Afcons has the knowledge and experience of working in extremely tough terrains. We have constructed numerous tunnels, bridges, a 64-km highway, and the world’s highest single-arch railway bridge in J&K. We have also constructed the world’s longest motorable tunnel 3,000m above sea level in Himachal Pradesh. Package 14 is unique in its challenges. But I am confident that we can pull off this project on time,” said Paretkar.
We do not know how long it will take for the pandemic to subside. But we do know that Afcons is committed to gifting Maharashtra its longest road tunnel on time.
Watch an animation video below