Chennai Metro to go underneath historic Cooum

[Mad Indian]

CHENNAI: You take a train from Chennai Central to airport, a commute of 20 minutes. Within seconds, you will be darting at 80kmph, about 30 metres under the bed of the historic Cooum.

Welcome to metro rail of 2015, when commuters will plunge into the depths of Chennai, literally, untouched by the traffic over their heads. Till then, witness this unprecedented engineering feat - the making of twin tunnels on two corridors.

In a few months, giant tunnel boring machines will be quietly burrowing underneath the Cooum. "Chennai will soon see some engineering that has been done in a few cities abroad," said V Somasundaram, chief general manager, construction, Chennai Metro Rail Ltd. He was speaking at a function in SRM University, Kattankulathur.

The underground line from Washermanpet to Saidapet will be at its deepest point of 30.8 metres as it passes under the Cooum and the Beach-Egmore railway line opposite Ripon Buildings.

The line that comes from the high court area reaches metro's Central station in front of Ripon Buildings, turns left, crosses the railway line and the river and passes underneath the neighbourhoods of Chintadripet to reach the underground station at the new secretariat on Anna Salai.

Metro tunnels are made without cutting open the ground. Giant machines will bore the tunnels as the river flows above and suburban trains continue to operate above the surface. Traffic along Anna Salai and Poonamallee High Road will not be diverted during the boring. Two tunnels come one above the other near Central railway station. The Central-Anna Nagar route tunnel will be 23 metres below the surface, while the Washermanpet-airport route tunnel will run 28 metres under the ground.

Custom-made tunnel boring machines costing 60 crore each have been imported from Germany for the purpose. These machines have different types of cutting head suitable for sandy, slushy and rocky soil. Metro will use closed-face tunnelling machines because of the city's peculiar soil and water table.

"Rocks are found about 20 metres below Poonamallee High Road and the Cooum near the Central station. Machines suitable to cut across the rocks will be used to bore tunnels under the river," said the official.

Boring without cutting open the surface is going to be an engineering challenge because on some stretches the tunnels run under crowded neighbourhoods close to the foundations of highrises like LIC, and flyovers.

As the machines bore, air pressure and slurry generated will shore up the earth from collapsing. A sensor in front of the machine will continuously monitor soil and water pressure. As the earth above the tunnels is going to be balanced on the strength of air pressure, the tunnel boring machine is also called earth pressure balancing machine.

After drilling, the machine will install a ring made of reinforced concrete. But this will not prevent seepage. "Chennai has a water table at two metres for 60% of the year. So we plan to collect the seepage and pump it out of the tunnels. The alignment of the tunnel will dip a little to make it concave so that water will collect at one point on some stretches," said the official.

Metro rail plans to import 11 tunnel boring machines for drilling twin tunnels on two corridors. Boring will start at Washermanpet and the machine will proceed towards Manali, High Court, Central and then to Anna Salai. Another set of machines will be lowered at Shenoy Nagar. These will bore underneath Poonamallee High Road towards Tirumangalam.

"The Little Mount-Airport stretch will be completed by 2014, while the rest of the corridor will be completed by 2015," said Somasundaram.

Metro dips under historic Cooum - The Times of India

 

[Mad Indian]

 

[ant80]

I don't know how feasible this is going to be. A city in the state of Alabama in US tried the same thing, and failed. They actually tried to build a sewer underneath a river. Now that city filed for bankrupcy after spending more than 2million USD in removing an earth removal machine that got stuck under the river. I really don't want to see that happen in India.

 

[Mad Indian]

I don't know how feasible this is going to be. A city in the state of Alabama in US tried the same thing, and failed. They actually tried to build a sewer underneath a river. Now that city filed for bankrupcy after spending more than 2million USD in removing an earth removal machine that got stuck under the river. I really don't want to see that happen in India.

Lets see now shall we ?

 

[nitesh]

We will succeed, Chennai needs Metro, some times I feel Chennai Metro is more planned then Bangalore, and the pace of work is also great. Hope other state governments take cue from the problems faced by Chennai and Bangalore and start work on Metros early, before the situation goes out of control

 

[Yusuf]

We will succeed, Chennai needs Metro, some times I feel Chennai Metro is more planned then Bangalore, and the pace of work is also great. Hope other state governments take cue from the problems faced by Chennai and Bangalore and start work on Metros early, before the situation goes out of control

Bangalore metro is perfect and on track. Yes there was a little delay in opening reach one. But then such huge projects are bound to have little hick ups. Overall it is on schedule. It covers major residential and business hubs in Phase 1 and a lot more will be covers in phase 2. Add to thy mono rail feeder to metro. By 2013 end entire metro phase 1 will be operational. I see no delay in that. Even if there is a bit of a delay, it is understandable..

But yes, sharing of best practices and causes of concerns can be shared so that mistakes are not repeated when others go about constructing their metros.

BTW, all major tier 1 and tier 2 cities have plans for metro ready.

 

[nitesh]

YB, I still don't understand the utility of mono rails, isn't the cost of setting up separate infrastructure will be more then strengthening of existing road network as feeder?

 

[Yusuf]

YB, I still don't understand the utility of mono rails, isn't the cost of setting up separate infrastructure will be more then strengthening of existing road network as feeder?

The idea is to get vehicles of the road and decongest it and provide an efficient and fast transportation.

Monorails compliment metros and are cheaper to build than metros.

Bangalore metro passes through high density areas of Bangalore. Mono rails on lesser ones. We cannot run metro on those routed as it will be more expensive.

 

[mayfair]

It is far easier and inexpensive to build a bridge across a river/rivulet/canal. Why this fascination with an under-the river tunneling?

 

[sob]

IMO Chennai messed up with the International airport in a big way when DMK bullied MMS so that it was not privatised.

Delhi airport today is at par with any international airport and had AAI been asked to do it then we all know what would have been the result.

 

[mayfair]

The idea is to get vehicles of the road and decongest it and provide an efficient and fast transportation.

Monorails compliment metros and are cheaper to build than metros.

Bangalore metro passes through high density areas of Bangalore. Mono rails on lesser ones. We cannot run metro on those routed as it will be more expensive.

Actually that is not entirely true. The initial costs may be lower (not significantly) but operating costs can be substantially higher for a monorail compared to a Metro. The reasons being

1. Mono rail carriages run on rubber tyres on concrete guideway. These tyres need to be continuously monitored and frequently replaced and they do not come cheap.

2. The monorail carriages must be built with light weight alloys, which are expensive and also need quite a bit of maintenance. This adds to the input and maintenance costs.

3. Monorails have limited passenger capacity and must operate on near capacity at all times to be financially viable. Since these are largely used as feeder systems, this is not very likely.

 

[nitesh]

The idea is to get vehicles of the road and decongest it and provide an efficient and fast transportation.

Monorails compliment metros and are cheaper to build than metros.

Bangalore metro passes through high density areas of Bangalore. Mono rails on lesser ones. We cannot run metro on those routed as it will be more expensive.

YB, not entirely true, roads can be de congested with Metro alone, and feeder bus services, if we can devise a plan for a single pass between BMTC and Metro, well myfair has explained the issue

 

[KS]

It is far easier and inexpensive to build a bridge across a river/rivulet/canal. Why this fascination with an under-the river tunneling?

O boy you know not of the Cooum..

 

[plugwater]

The idea is to get vehicles of the road and decongest it and provide an efficient and fast transportation.

Monorails compliment metros and are cheaper to build than metros.

Bangalore metro passes through high density areas of Bangalore. Mono rails on lesser ones. We cannot run metro on those routed as it will be more expensive.

The Hindu : Tamil Nadu / Chennai News : Monorail or Metro Rail: the pros and cons

 

[sob]

O boy you know not of the Cooum..

I would not like to travel over it. Prefer the underground route.

Slightly Off Topic, why don't we flush it with sea water so that once and for all it gets cleaned.

 

[plugwater]

Another blunder in JJ part i would say for giving up on Chennai metro phase II and going for 100km+ monorail.

 

[sob]

The Hindu : Tamil Nadu / Chennai News : Monorail or Metro Rail: the pros and cons

BRTS-- I will be ready to shoot anyone who recommends BRTS in India. Just come to Delhi and see the mess.

 

[mayfair]

O boy you know not of the Cooum..

I am afraid I do mate.

Not once during my visits to Chennai (there have been loads), have I had the good fortune to miss the sight of Cooum, Adiyar and the unforgettable Buckingham canal (a friend told me that quite a few Chennai denizens call it the Stinkingham canal. Aptly named, I say).

However, if DMRC can build enough bridges over Yamuna, which makes Cooum and Adiyar look like Gangotri, I dare say, Chennai Metro can at least contemplate dredging up the Cooum.

 

[Mad Indian]

Another blunder in JJ part i would say for giving up on Chennai metro phase II and going for 100km+ monorail.

Actually, i think thats the only blunder she did. Metro is messy to begin and work but better on the long run. This political removal of the metro was the omst unreasonable thing she ever did.

 

[Yusuf]

YB, not entirely true, roads can be de congested with Metro alone, and feeder bus services, if we can devise a plan for a single pass between BMTC and Metro, well myfair has explained the issue

No mate. Take Bangalore as example. It is a circular city unlink say Mumbai.

Now if you see Bangalore's residential and business hubs, it's passing through central bangalore with business areas in central and north as residences in south as well as central and west. So we have a north south line and an east west line connecting all the busiest areas of Bangalore.

No if you are staying in say Sarjapur area, you don't have metro connectivity. But you have this area coming up in a big way. Now for this area to be connected to the city, you either use the high traffic zone roads or you have a monorail connecting to the nearest metro station.

Monorail has its advantages as a feeder. That is why it has been successful in many cities. I like Singapore system. There the Metro, Mono and the Bus service are integrated. Where the metro does not go, there is monorail and where monorail cannot go, there is bus. There is no redundancy.