Indore Metro To Begin Underground Tunnelling With 1,000-Tonne TBM

Indore (Madhya Pradesh): Indore Metro is set to enter its biggest construction phase, with a giant Tunnel Boring Machine (TBM) imported from Thailand expected to begin tunnelling nearly 20 metres below the ground within the next month.

Weighing around 1,000 tonnes, the state-of-the-art machine is currently being assembled in the city.

The process is expected to take about a month, after which the TBM will be deployed near the Airport to begin excavation for Indore Metro's first underground corridor.

Designed to operate round the clock, the machine can excavate nearly 20 metres of tunnel every day.

Besides cutting through soil and rock, it will simultaneously install reinforced concrete tunnel lining, accelerating construction while ensuring structural strength and safety.

Airport-Kalani Nagar first underground stretch

The first underground section will run from Airport to Kalani Nagar, after which work on subsequent stretches will begin.

In all, around 12 km of the Indore Metro network will run underground, with officials estimating that the entire underground section will take four to five years to complete.

The TBM functions like a mobile underground factory. Its 6.5-metre-diameter rotating cutter head, fitted with heavy-duty steel cutters, continuously bores through soil and rock as the machine advances.

The excavated material is carried out through an internal conveyor system, preventing debris from accumulating inside the tunnel.

Tunnel lining built simultaneously

One of the TBM's key features is its ability to construct the tunnel lining even as it excavates. Hydraulic systems inside the machine install pre-cast concrete segments to form reinforced circular rings, creating the permanent tunnel wall.

Two parallel tunnels will be built—one for trains heading towards the city and the other for the return journey.

The Airport area has been chosen as the starting point because its relatively low population density is expected to make construction easier. An underground Metro station is also coming up there.

With the city's 17.5-km elevated Metro corridor nearing completion, the focus is now shifting underground. Most components of the TBM have already arrived in Indore in 11 trailers, paving the way for the next major milestone in the Metro project.