School of Civil, Environmental and Mining Engineering

Finding better foundations for structures in soft ground

James Doherty

Associate Professor James Doherty

CEME

November 2014

James Doherty and his colleagues are helping the construction industry come up with better ways of building structures in soft soils and clay—by testing proposed foundations to the point of failure.

Part of his research is to be used collaboratively in a global competition for civil engineers and he’s also developing web-based applications to take some of the guesswork out of designing better foundation systems.

Associate Professor Doherty is a geotechnical engineer who specialises in numerical modelling at the School of Civil, Environmental and Mining Engineering (CEME) at the University of Western Australia.

The research undertaken through CEME will end up helping provide better foundations for infrastructure such as bridges and rail lines; buildings; and even oil and gas structures built at the bottom of the ocean.

“Obviously, you only get one go at building a big piece of infrastructure so you want to be able to predict how it behaves before you build it,” Associate Professor Doherty says.

“So we use numerical modelling tools to build models that capture the important physical mechanisms that take place and simulate those so we can design things such as foundations.”

He says engineers are generally pretty good at determining the capacity of foundations and how strong they are.
What you also need to do is monitor ground movement in softer grounds such as clays and seabed sand.

“Typically, it’s not the strength of a foundation that governs it size or cost, it’s how much we think it’s going to move, its serviceability,” he says.

“A foundation that might move a little bit and cause damage to the structure it is supporting might be a long way from actually failing.”

Part of the research is being undertaken at Ballina in NSW in conjunction with the University of Newcastle and the University of Wollongong.

“At Ballina, we’ve got a soft clay research site where we load up a shallow foundation in soft clay to the point where it fails, and we monitor the full load displacement response,” he says.

“The idea is to see if we can forecast what happened to those foundations using the information we collect as part of our site investigation.”

The research is to be used as part of an international competition for engineers.

“We are going to make all the data available – the size of the footing and the rate we loaded it up to, plus we’re going to make available a lot of the in situ laboratory testing – and we’re going to ask engineers from around the world to predict what happened to the footings,” he says.

He says the Eastern States university partners are interested how such foundations behave in soft soils that support infrastructure such as embankments for rail bridge crossings. Whereas in WA, the emphasis is different.

“This project is more aimed at shallow foundation responses, probably more with applications for subsea infrastructures such as those in the offshore oil and gas environment,” Associate Professor Doherty explains.

With the offshore oil and gas industry, cutting edge developments – such as Gorgon and Prelude – increasingly involve subsea collection structures and pipelines rather than raised platforms.

"Understanding how this stuff works is important,” says Associate Professor Doherty.

“I guess my focus is on numerical modelling because I see it as a powerful tool that can solve lots of potentially important problems and I try to keep it as industry-focused as possible.”


—Tony Malkovic


 

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Tuesday, 8 March, 2016 9:20 AM

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