Major work is set to ramp up next month on Australia’s biggest public transport project –the Metro Tunnel – with extensive geotechnical investigations now complete.

Premier Daniel Andrews joined Minister for Public Transport Jacinta Allan at the project’s huge storage facility in West Melbourne, where nearly 10 kilometres of soil and rock samples are housed.

Over the past two years, more than 270 boreholes have been drilled up to 50 metres deep along the Metro Tunnel alignment.

The samples collected show that the sedimentary rock beneath the city was formed 416 to 440 million years ago.

They provide critical information about ground conditions under the city, which will inform the design and construction of the Metro Tunnel and its five new underground stations.

With geotechnical investigations complete, work is set to ramp up next month on the $10.9 billion mega-project.

Early next month, City Square will be surrounded by hoarding and closed for several years while construction crews dig more than 11 storeys below the city to build the brand new underground station.

Construction will continue at Franklin and A’Beckett Streets in April, and in and around St Kilda Road at Domain.

The acceleration of Metro Tunnel works will coincide with a massive construction blitz across Victoria, which will affect services on the Cranbourne, Craigieburn, Frankston, Pakenham, Sandringham and South Morang lines.

There will also be disruptions on a number of regional lines, including the Geelong and Warrnambool lines which will close in mid-April to enable $4.4 million worth of track and signalling works.

Track and other infrastructure work will also affect tram services on routes 8, 12, 78 and 109 next month. For a full list of disruptions and to plan your journey, visit ptv.vic.gov.au.

Quotes attributable to Premier Daniel Andrews

“Melbourne needs the Metro Tunnel and we’re getting on with it. Geotechnical investigation is now complete and major work about to start.”

“This project will create thousands of local jobs and free up space in the City Loop to run more trains, more often across Melbourne.”

Quotes attributable to Minister for Public Transport Jacinta Allan

“The Liberals wasted four years, leaving people stuck in traffic and stranded on crowded trains.”

“These works are building a better transport system to get you home sooner every night. I know they will be disruptive but they will be worth it.”