Metro Tunnel works could cause minor cracks in Melbourne Town Hall, St Paul’s Cathedral

CRACKS could appear in Melbourne Town Hall and St Paul’s Cathedral due to ground movement caused by Metro Tunnel construction, a key contractor has warned.

A KEY contractor building the $11 billion Metro Tunnel has warned that construction could cause cracks in Melbourne Town Hall and St Paul’s Cathedral.

The Cross Yarra Partnership has said, in fresh planning documents, that Melbourne Town Hall was at risk of “slight” damage and cracks up to 5mm wide.

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The report said that these cracks were often “easily filled” but that “redecoration is normally required”.

It also predicted damage to St Paul’s Cathedral would be “very slight” with cracks of up to 1mm.

St Paul's Cathedral could be affected by tunnel works. Picture: Eugene Hyland

The report, documenting the potential impact of ground movement from the works, found the overall risk to both landmarks “acceptable and manageable”.

But it recommended the ­potential impact on the Town Hall’s portico and clock tower, as well as the cathedral’s structure, be investigated further.

The planning documents also reveal that Cross Yarra Partnership has changed the design of the State Library and Town Hall stations. Instead of two separate tunnels connected by a passage, like at Parliament station, the new stations will have a “trilocular design”.

It will see three overlapping tunnels, creating a single platform with trains running either side, similar to stations in Paris and Moscow.

Melbourne Town Hall’s clock tower may also be impacted.

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The platforms, spanning 18.5m, will be some of the widest underground in the world.

The changes will need to be ticked off as part of planning scheme amendments.

The new station design, as well as changes to the tunnels’ curve in Parkville, will also ­require additional underground land acquisition.

A Metro Tunnel spokeswoman said the acquisitions would not affect any homes or workplaces.

Cross Yarra Partnerships was awarded the $6 billion ­station and tunnels package in December. The $11 billion ­project will add five new train stations and bore 9km twin tunnels under the CBD.

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