Long twin tube eight-lane tunnel, Bhoj to Morbe

The Bhoj to Morbe section is a spur of the Vadodara–Mumbai Expressway, and its hardest ground lies inside the Matheran eco-sensitive zone. Rather than cut across the hills, the alignment goes under them: a 4.16 km twin-tube, eight-lane tunnel, one tube for each direction of traffic.

RKC is building the section from Km 69.800 to Km 79.783 for IRCON, in EPC mode under Bharatmala Pariyojana (Phase II, Package XVII), with J. Kumar Infraprojects Ltd as key partner.

Scope of work

• Construction of an eight-lane access-controlled expressway, Km 69.800 to Km 79.783
• A 4.160 km twin-tube, eight-lane road tunnel through the Matheran eco-sensitive zone
• Approaches, drainage and the associated road works along the section

Driving through rock

The tunnel is advanced by drill and blast. At the face, drill jumbos bore the blast-hole pattern; crews charge the holes, clear the tunnel and fire; the muck is loaded out and the new ground is scaled and supported before the cycle begins again. Survey control keeps each round on line and level, so the two ends meet where the design says they should.

Working inside an eco-sensitive zone shapes every decision, from how spoil is handled to how the portals are formed. Going underground is itself the environmental choice: the forest above stays in place while the expressway passes beneath it.

Breakthrough

The breakthrough of the 4.16 km Morbe tunnel was marked with the teams who built it, underground, at the point where the drives met.

One tube for each direction, driven through the Matheran hills so the forest above stays where it is.