Case Examples of Terra-forming and Other Geotechnical Projects in the Adelaide Area

Dr Matthew Duthy and Dr Peter W. Mitchell

This presentation is an expansion of that given by Dr Duthy to the SA Heritage seminar held in Adelaide earlier this year. Dr Duthy’s presentation focused on European interaction with Adelaide’s landscape and natural resources. He outlined how those interactions were initially driven by physiological and safety needs such as for fresh water, food, shelter, flood immunity, and transport. This was later followed by economic development.

The presenters, who have a combined experience of 89 years with Adelaide projects since the 1970s, will outline a number of projects that were mainly driven by economic development, and that illustrate how natural geotechnical processes, sub-surface conditions and soil properties were overcome or otherwise accommodated.

Several case histories of footing systems to support building development will be outlined, including the observed load vs deflection behaviour of spread and mat footings, and movements of basements of multi-storey buildings constructed on unsaturated Adelaide clays in the Adelaide CBD.

Surface water drainage from the Adelaide plains and the coastal erosion of Adelaide’s foreshore will be discussed, and how these natural and ongoing processes have impacted on such projects as the Torrens Lake Weir, the Torrens Outlet, Witton Bluff stabilisation, and the Barcoo Outlet.

The successful construction of built infrastructure on the geologically recent, soft and compressible estuarine soils of the LeFevre Peninsula for several projects will be outlined, and measured load vs. settlement behaviour of embankments on soft soil will be presented.

The load vs deflection responses of several types of piles founded in Hindmarsh Clay (bulbous base, CFA, precast driven, concrete screw piles) will be outlined for building projects in the coastal zone, including Holdfast Shores and Outer Harbor.

About the speakers

Dr Matthew Duthy Technical Director for Geotechnical Engineering, GHD

Dr Matthew Duthy is a technical director for geotechnical engineering at GHD. He has over 35 years of specialist geotechnical engineering consulting experience, including stints in the UK and USA, as well as projects in all Australian states and the Northern Territory. However, the great majority of his professional experience has accrued in Adelaide and regional South Australia. Matthew is a former AGS SA Chapter chairman and committee member, and is currently an Adjunct Associate Professor at the University of Adelaide’s School of Architecture and Civil Engineering.

Dr Peter W. Mitchell Technical Director, Aurecon; Adjunct Professor, University of Adelaide

Dr Peter W Mitchell is a geotechnical engineer with over 54 years’ experience in major geotechnical engineering projects throughout Australia, South-East Asia and the South Pacific. He has been a regular speaker at SA Geomechanics and SA Footing group meetings throughout his career – his first being in March 1974. He is a Technical Director with Aurecon and is an Adjunct Professor with the University of Adelaide. In 2020 he was awarded Life Membership of the Australian Geomechanics Society recognising his “contributions of the highest order over an extended period”.

Presentation recording

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