CHENNAI: Chennai Metro Rail has to burrow only 450 metres more to complete the entire tunnelling under the first phase of the Chennai Metro.Thee much awaited breakthrough in the first tunnel boring machine (TBM) in the 3.7 km longest continuous tunnel drive stretch from Government Estate to AG-DMS under Phase I of Chennai Metro was achieved on Wednesday.
The breakthrough, which was expected on Tuesday, was delayed due to technical glitches as the TBM failed to reach its destination.“The breakthrough was successfully made around 3 pm on Wednesday after a worn out cutting tool on the cutter head of the tunnel boring machine was changed,” a Chennai Metro rail spokesperson said.
This is the longest section of continuous tunnel drive section as part of Phase I since drive-through concept was adopted wherein the tunnels pass through stations before the base level excavation takes place.
The tunel boring machine had completed its drive along the LIC station, Thousand Lights station beneath the busiest arterial road of Anna Salai and beneath Gemini flyover while crossing several buildings along the route.
With the completion of tunnelling from Government Estate to AG-DMS, the complete tunnel in downline will be available from Saidapet to Washermanpet. The second tunnel boring machine is ready for breakthrough after completing the balance length of around 450 metres of tunnel drive. It is likely to be completed by next month.
Initially, the work of the stretch from may Day Park to AG-DMS was given to joint venture of Gammon-Mosmetrostroy. However, Mosmetrostroy abandoned work and the contract was terminated. The contract was later awarded to Afcons Infrastructure Limited and works commenced on May 20, 2016.