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Downtown Line digging a delicate operation

Contractors had to consider existing MRT line, road traffic and buildings

Published on Dec 21, 2013 8:49 AM

Digging a tunnel just 70cm away from a live MRT line on which trains filled with passengers run - that was just one of the many challenges that had to be overcome in constructing Downtown Line 1 (DTL1).

The six-station, 4.3km DTL1, which passes through the Central Business District and the Marina financial district, gives commuters a more convenient route from Chinatown to Bugis when it opens tomorrow.

On Wednesday, Land Transport Authority deputy director for DTL1 Tan Kok Jin told The Straits Times just how much work went into it, especially since it had to be constructed in an area already densely built up, and down.

For one thing, contractors had to build a section of the new line's tunnel on top of another through which trains on the East-West Line run.

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Background story


There was a store selling porcelain, and its shelves would vibrate when we were pounding the ground. Our guys helped carry its products to the floor.

- LTA deputy director for DTL1 Tan Kok Jin


THE DTL1 team faced constraints in the dense downtown area.


Problem: Insufficient space to divert traffic, unable to close lanes due to heavy traffic flow

Solution: Build temporary viaduct


Problem: Insufficient headroom for foundation work due to bridge linking OG Building and People's Park Centre

Solution: Use a specialised low-headroom machine


Problem: Need to mine under existing East-West Line

Solution: Pump cement into ground to solidify it, then insert large pipes to hold up ground before excavation.