Pune-Mumbai Expressway: Rockfall protection work 30% complete, deadline revised

Additional rockfall protection work on the Pune-Mumbai Expressway’s Connecting Link will now be completed by November, with progress slowed by the heavy monsoon.

The earlier deadline had been set for the end of September. Maharashtra State Road Development Corporation officials told the Times of India that the reinforcement work is now around 30 per cent complete.

The work was recommended by IIT-Bombay after a major landslide on July 6. It involves installing high-tensile steel mesh and steel barriers to secure the hillside and prevent loose rocks and larger boulders from reaching the carriageway.

The July 6 landslide caused a 20-hour traffic jam on the expressway. Large boulders fell onto the road near the mouth of Tunnel 2 and damaged a false frame at its entrance.

Officials estimated that some of the rocks weighed between 17 and 20 tonnes. Water emerging from newly formed channels on the hillside also flowed onto the Mumbai-bound carriageway.

“But the steel mesh, procured from Switzerland, has been designed to contain loose rock and prevent them from reaching the road. The steel barriers will provide an additional line of defence against larger rocks that could dislodge from higher elevations of the hill,” a senior MSRDC official said.

The collapsed frame has been reinstalled as part of short-term measures.

“The short-term measures are being sped up, but mesh installation will need time,” another senior MSRDC official said.

The official said heavy rain had prevented the work from being carried out at full pace.

“Drilling, anchoring and mesh installation require relatively dry conditions. With the monsoon easing, rest of the work is being accelerated and is expected to be completed by Nov,” the official said.

An IIT-Bombay geotechnical and engineering team inspected the site a few days after the landslide and recommended measures to strengthen vulnerable sections.

Officials said the reinforcement work was being designed for an extreme weather event with a 1-in-1,000-year probability. The original protection system for the Rs 6,695 crore Connecting Link had been designed against a 1-in-100-year benchmark.