Dredging Research DPC
soils to make them usable,” he told direct financial support,” he simulate the sedimentation
DPC, “including conditioning and added, “as well as two process and predict
drying in the summers – yes, even in senior technical experts the behaviour of the
the rainy northwest of England! – then – Prof John Atkinson consolidated material.”
using them for further bank building. and myself – to offer
“We’ve also used lime or cement in-kind support BETTER QUALITY
treatment on occasions, though it’s hard amounting to a value “At the moment
work and often too costly to gain the of $150,000 over the we’re focusing on
desired advantages. But I can see this life of the project. Brisbane,” Prof
project really changing the economics And there’s keen Sivakugan continued,
and encouraging sustainable beneficial interest from other
Enthusiastic –
“but Australia
use of marginal materials.” Coffey senior principals,
David Tonks
has major ports in
including Ian Pedlar – Fremantle, Melbourne
SOUTHERN HEMISPHERE who’s been involved in port and elsewhere. We believe
Coffey senior principal Dr Jay dredging work in Victoria over anything we do here can also
Ameratunga said the Australian research a long period – and of course be extended to other areas
project, concentrating on the Port of David Tonks who’s written – and even worldwide.”
Brisbane’s ongoing (until 2025–2030) several technical papers on Dr Ameratunga
Fisherman Islands construction and dredged materials.” added that the
reclamation area, would look at how James Cook dredged material was
to turn dredged clay into a stable and University’s head of essentially natural,
usable engineering fill material. The port civil and environmental unadulterated
will supply dredged mud samples. His engineering, Prof mud and was in
view is that breakthroughs in this area Siva Sivakugan, said plentiful supply. As
would be extremely beneficial to ports the research project a consequence, the
as it would give them an opportunity to would have two key material offers great
look at innovative ways of reclaiming components: laboratory
Brisbane project –
potential to become a
and developing their lands. It could studies and numerical
Jay Ameratunga
useful resource.
also lead to major improvements in the modelling. Some of the “The material has high
way ports managed dredged materials numerical models will clay content so it’s not
throughout the world. be verified against ground suitable for most engineering
Photos:
“The Port of Brisbane currently improvement field trials conducted purposes because it retains air
extracts around 500,000m
3
of mud at Brisbane. pockets and takes a very long time to
every year and this has to be disposed “Part of the project will involve settle and compact,” he said. “What Cof
of in some way,” he said. “Our project is physical testing of samples and trying this research intends to do is find a way
fey
looking at ways to turn that poor quality to figure out what the properties of the to improve the quality of the soil to
Geotechnics/Port
material into usable engineering-grade material are, how it behaves on its own, make it stiffer and make the settlement
fill. This would mean that the port could and how it behaves when you mix it with quicker so it can be used for purposes
not only save on fill materials such as additives such as lime or cement,” he said. like clean landfill in land reclamation
sand, but also maximise the amount of “The main things we’ll be testing are and in paved roads.
dredged material that can be reused. the strength and consolidation properties “What we are doing isn’t new, but
“This has obvious benefits for the – how it behaves when settling. This it is innovative in the sense that we’re
of
environment and would make the entire will determine the possible uses of the finding a new application for an
Brisbane
dredging process more sustainable material in an engineering context. existing idea.”
in the long term,” Dr Ameratunga “We’ll also be doing numerical Port of Brisbane reclamation and
added. “Coffey will be providing modelling,” he added, “so we can land development manager Peter
What If It’s Contaminated?
DPC asked if the project would extend to contaminated dredged sediment?
“We’re not looking at contaminated material,” Prof Sivakugan said. “We have to make sure
that the material we test is not contaminated and take necessary precautions.
“In contaminated material, there are environmental issues that have to be addressed, which
is beyond the scope of our project. We would like to limit our study to the geotechnical
considerations. In fact, once we understand the constituents of the dredged mud, we’ll consider
making similar samples in the laboratory by artificial sedimentation in a controlled environment.
That way we’ll get reproducible samples.”
www.dpcmagazine.com 27 D R E D G I N G A N D P O RT C O N S T R U C T I O N A P R I L 2 0 0 9
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