Developing the Geological Model for Sydney Metro

Earlier this week at the Metro Rail Summit 2018, Dr. David Och, Principal Engineering Geologist at WSP shared insights about the geological model for the iconic Sydney Metro project.

The project will provide a faster and more reliable service for customers, catering for an extra 100,000 commuters per hour across Sydney with trains running every four minutes in peak periods.


Since 2014, Dr. Och has led a technical team to sample and test the soil and rock conditions below the sea floor, in preparation for Stage 2 of the project, Sydney Metro City and Southwest.


Dr. Och’s presentation looked at how the geological model for the Sydney Metro was developed using an integrated approach that included multi-staged site investigations and marine geophysical surveying.


He says, “At the beginning of the project, very little geotechnical information was available that covered the area of interest in Sydney Harbour. This meant the area presented a critical design risk.


“Our understanding of the sediment and rock conditions was critical to the design development and the identification of the geotechnical risks that could be realised during tunnelling below the harbour.”


“Implementing a multi-staged site investigation program ensured that the site’s evolving geological landscape is adequately assessed and addressed in design models,” says Dr. Och.


“Ongoing collaborations between the site investigation, geotechnical design and the project teams was key to supporting the development of the geological model.


“Our geotechnical investigation has enabled us to choose the right tool to build this tunnel under the harbour – a specialised tunnel boring machine (TBM) that is pressurised and almost as long as two A380 jets end-to-end. Five mega-sized TBMs will be used on Sydney Metro City and Southwest, with the first TBM going into the ground before the end of the year.


“In Sydney, this was the first time a 13-tonne sonic drill rig was used over water to drill 30 metres below sea level as part of our geotechnical investigation,” concluded Dr. Och.


With 20 years’ experience in delivering some of New South Wales’ most transformational infrastructure projects Dr. Och is an industry leader and serves as the Geotechnical Lead for the Sydney Metro City and Southwest project.


Once completed, Sydney Metro City and Southwest will provide a new generation of world-class fast, safe and reliable trains easily connecting customers to where they want to go.


More About the Project

Sydney Metro is currently Australia’s biggest public transport project. Stage 1 and 2 of the standalone railway will deliver 31 metro stations and more than 66 km of new metro rail. Stage 2, Sydney Metro City and Southwest, includes 15.5 km of twin tunnels along with seven new underground stations between Chatswood and Sydenham. Stage 3, Sydney Metro West is Sydney’s next underground metro railway linking the Parramatta CBD to the Sydney CBD and a once-in-a-century infrastructure investment that will transform the way Sydney moves for generations to come.


Sydney Metro services start in 2019 in the Northwest, and 2024 in the City and Southwest.


For more information on Sydney Metro, please click here.


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