Chennai Metro Rail has been taking measured steps as it begins tunnelling underneath the city’s giant, old landmark — Anna flyover or Gemini flyover. Though there were plans earlier to avoid the flyover, one tunnel now will partially cross the flyover, sources said.
According to sources in Chennai Metro Rail Limited (CMRL) and the Highways Department, of the two tunnels, one would travel along the service lane near the U.S. Consulate up to the clover of the flyover (the curved portion that takes motorists to Nungambakkam High Road) and then turn left to reach Teynampet.
The other tunnel would run beneath the flyover via the approach ramp until the statue of the horse. It would then take a turn at the clover and run alongside the other tunnel.
‘Will be over in a week’
The tunnelling work is being now carried out between Thousand Lights and AG-DMS. The work on both tunnels near the flyover is likely to be over in a week’s time, officials said.
“But it may take about a month for the tunnels to reach the final point — AG-DMS — when the entire tunnelling work for phase I will be complete,” he said.
Metro Rail officials claim they have taken various precautions to ensure the flyover is not affected in any way during the tunnelling.
“In the Anna Salai area, the soil conditions are mixed and we have placed optical prisms, building settlement markers and tilt meters and employed very close monitoring of the work to see there is no damage to the flyover,” an official said.
Highways dept. wary
Meanwhile, fearing damage to the structure, which is the oldest flyover in the city, the Highways Department wrote to CMRL sometime back, stating that close monitoring of the tunnelling work should be done and that the safety of the flyover should be ensured at all times. The department also told CMRL they would be held responsible for any damage to the facility that was inaugurated in July 1973.
Every day, around 2 lakh vehicles pass through Anna Salai.
A former engineer of the department said the flyover has a shallow foundation. “The depth would be within 3 m. The footings are large though. If the road beneath caves in, the flyover will surely be in trouble. CMRL must be doubly cautious about the work since the tunnel will run to half the length of the 500 m long flyover,” he said.
