9 Huge Chinese-made tunnel boring machines will soon be in action in Chennai for the Metro Rail project. Two machines are expected to arrive in the city in a couple of weeks. They are likely to be launched from January 15 at Washermenpet and Shenoy Nagar where two underground stations are coming up as part of the project, according to a source in the know.

Eleven machines will be used to excavate the underground sections. Of this, eight machines are being supplied by the German company Herrenknecht, which has already transported two machines from its plant in China.

Chennai, home to ten million inhabitants, has over three million vehicles creating daily traffic congestion. To improve the public transport, the Chennai Metro is being implemented with two metro corridors with a total length of 45 km.

Chennai Metro Rail Ltd (CMRL), which is implementing the rail project, has awarded two of the major contracts amounting to $569 million to a joint venture comprising Indian infrastructure group Afcons and the Russia-based Transtonnelstroy. The contracts include the design and construction of nine underground stations and nearly 9 km of tunnels.

The two contracts cover a 5.5 km length from Egmore to Washermenpet (five stations) and a 3.1km length from Thiurmangalam to Shenoy Nagar (four stations).

According to a press release issued by CMRL, factory acceptance test of precast segment moulds has been completed in Korea and China. The pre-cast yard for tunnel segment is being set up at Vanagaram, Thiruneermalai and Muttukadu.

Meanwhile, CMRL has started issuing notices to property owners in a few areas where the project is being implemented to seal the bore wells and open wells. This is ahead of the preparation for the tunnelling work.

The metro project runs on two corridors – Washermenpet in North Chennai to the airport, and Chennai Central to St Thomas Mount. A portion of the Metro rail alignment between Washermenpet and Saidapet, and between Central and Tirumangalam runs as underground tunnels. Tunnel boring of 6.6 metre diameter twin tunnels are slated to be taken up from March 2012, says a press release issued by the company.

In a few locations where the alignment goes under residential areas, it is necessary to close existing bore and open well within a restricted zone of 16.5 m on both sides from the centre of alignment for tunnelling.

An alternative borewell will be provided close to the houses or in case it is not required, a compensation of Rs 1 lakh will be given to the owners. The underground metro corridors are constructed at a depth of nine metre beneath the ground.

Tunnelling will not lead to any environment problems not have any impact on ground water in the locality. The company will take precautionary measures to ensure safety of the building and structures, the release said.

>raja@thehindu.co.in