Chennai Metro Rail’s tunnel boring machine Flamingo to reach Kutchery Road in November

The tunnelling process commenced at Light House in September last year. The TBM weighing about 700 tonnes has drilled 852 metres as of now and the second machine Eagle is not very far off and has crossed 732 metres

Chennai Metro Rail’s tunnel boring machine (TBM) Flamingo, which began boring from the longest station — Light House — will reach Kutchery Road in Mylapore by November end.

A part of corridor 4 of the ₹63,246-crore phase II project, the tunnelling process commenced at Light House in September last year.

Though not as tough as the stretch between Greenways Road to Adyar, tunnelling has been fairly difficult from Light House to Kutchery Road too.

According to officials of Chennai Metro Rail Limited (CMRL), out of the 1.2 km, the TBM Flamingo which weighs about 700 tonnes and launched at Light House has drilled 852 metres as of now and will land at Kutchery Road in two months. The second machine Eagle is not very far off and has crossed 732 metres.

“The TBM has just entered Kutchery Road now. The stretch was a little challenging to tunnel because the geology here was a combination of silty sand with rock outcrops at some places. We had to change the cutter head (a component of the TBM) quite a few times already. Though we had to bore through some old structures, so far, we didn’t face road cave-in or settlement issues. We are constantly monitoring the structures and it will continue,” an official said.

The TBM had to drill underneath a school, a consular office and many such buildings.

Unlike the other stretches where the upper track was bored first, followed by the downward track, here, it was different. Kutchery Road has been planned as a stacked station wherein, the two tunnels are built one below the other. “Usually, tunnels are built in a station in a parallel manner (side by side). But due to lack of land availability and space, the tunnels are designed differently here. So, the lower tunnel is built first, followed by the upper tunnel,” a source said.

Also, in a departure from the other stretches, the TBM will not make a breakthrough at Kutchery Road. It will cross this station and proceed further and make a breakthrough at Thirumayilai Station. “Since Thirumayilai is the junction station and located close to Kutchery Road, it will be better to create a shaft at Thirumayilai alone. But it may take at least another six months to complete the shaft at Thirumayilai, by which time this TBM will be ready to make a breakthrough,” he added.

Published - September 28, 2024 08:52 pm IST