Discover how cutting-edge geological modelling is guiding Vienna’s metro extension from concept to construction, helping bridge uncertainties and build client trust.
By Oana Crisan
At this year’s World Tunnel Congress (WTC), industry leaders highlighted the importance of robust geological modelling—grounded in a thorough understanding of local geology—for tunnelling project success.
iC Group Associate Partner and Geologist, Jonas Weil, shared his insights on the Vienna metro extension and the evolving role of geological modelling to support the delivery of complex infrastructure.
Weil, who leads a team of 10 geologists in Vienna, has been involved with the city’s metro expansion project for more than 10 years. What began as a small modelling task has increased significantly in scope over time.
‘We have been developing this model for 13 years. We started on a small scale and now we have expanded this ground model to over half of the city of Vienna,’ said Weil.
The infrastructure owner recognised the value of 3D geological models and ultimately decided to make them a standard requirement for all ongoing Vienna metro extension projects.
Refining Vienna metro model as project grows
The geological models informed critical civil engineering decisions, including the excavation method selection and groundwater management.
Key considerations included whether there would be substantial groundwater or areas prone to settlement. As the project progressed, the models have evolved alongside major engineering milestones.
A unique aspect of the project is that, ‘it has been evolving over such a long time,’ said Weil. Meaning the geological models have continued to expand and be refined as the project progresses.
Managing the volume of information and stakeholders posed another unique challenge.
‘We have so many stakeholders that we are delivering partial models to, more than 10 different designers, to contractors, to grouting experts.’
Geological complexity added further hurdles, particularly in tracing thin layers of sand and gravel between boreholes.
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Thousands of data points in one place
To overcome these challenges, Weil’s team used Seequent’s innovative 3D modelling solutions.
‘The model was developed in Leapfrog, starting in Leapfrog Mining in the very early days, then we used Leapfrog Geo, [and] finally Leapfrog Works,’ Weil recounted.
‘We actually experienced the whole history of this product.’
The team also utilised the cloud-based collaboration platform Seequent Central for communication and client exchanges. The integration of data into a single source proved invaluable.
‘The biggest benefit is that a big amount of information is compiled in a single source and you can look at these thousands of boreholes in one place.
‘You can make 3D interpolations, which cannot be done with traditional methods, and you have this amazing viewer capacity. You can share it in 3D with the client, in the desktop viewer and, also with Central.’
A single unified view; essential on-site.
The interface between geology and civil engineering requires ongoing translation.
‘Our job is to translate the geology for the designers,’ Weil said, and to provide the geotechnical parameters needed for structural calculations.
‘It’s very important to agree in the beginning about the content of your model, about the goals, who’s going to use it… and it’s a very good tool to convince the client about the benefit of certain design decision, by vizualizing the ground conditions. That creates trust and confidence, you get invited for the next task, and you have a project that grows together.’
Weil urged young engineers to prioritise geological understanding.
‘Be a geologist, not just a modeller. If your geological understanding is wrong, your model is useless, no matter how sophisticated it looks.’
WTC industry experts also stressed the importance of trust built on transparency, consistency, and collaboration.
‘I’m looking forward to the next years and extending our model to the South as we continue to support the Vienna metro construction,’ said Weil.
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