SINGAPORE — The new Marina Coastal Expressway (MCE) has been described as arguably “the toughest tunnelling project” the Land Transport Authority (LTA) has ever undertaken, said Senior Minister of State for Transport and Finance Josephine Teo at the opening ceremony of the S$4.3 billion expressway on this morning (Dec 28).

The 5-kilometre MCE, which will be Singapore’s tenth expressway, will be open to vehicles on Sunday at 9am.

As the first road tunnel to go beneath the sea, Mrs Teo said the 420-metre section that links the MCE between Marina East and Marina South also happens to be just 130 metres from the Marina Barrage.

She said as the barrage discharges large amounts of water during periods of heavy rain, currents in the construction area can be quite strong and not always predictable.

As such, even before constructing the tunnel box on the sea bed, the construction team had to build a temporary undersea wall about 270 metres into the sea, with a width of 100 metres — bigger than the size of three football fields combined.

Mrs Teo added the other challenge was building most of the tunnel through reclaimed land.

“The LTA engineers described the ground conditions as being similar to “peanut butter”,” said Mrs Teo.

More than 4 million cubic metres of soil were removed — enough to fill 1,700 swimming pools.

The MCE, together with the existing Kallang-Paya Lebar Expressway (KPE), will make the longest underground expressway in Southeast Asia.

KPE-MCE will have a continuous stretch of more than 12 kilometres. CHANNEL NEWSASIA