Optimising Site Investigations using a Risk-Based Approach

Mark Jaksa and Michael Crisp

It is well accepted that, in civil engineering construction projects, the largest element of financial and technical risk generally lies beneath the ground. Indeed, structural foundation failure, construction over-runs and delays can often be attributed to inadequate and/or inappropriate site investigations. 

Unfortunately, geotechnical engineers have, at their disposal, limited guidance when designing the extent and nature of site investigations. Almost exclusively, the scope of geotechnical investigations is not governed by what is needed to characterise appropriately the subsurface conditions but, rather, is driven by budgetary constraints. A pressing need is to arm geotechnical engineers with a series of guidelines that link the scope of a site investigation to ground variability and the probability that the foundation will be under-designed, resulting in some form of failure, or over-designed, resulting in the foundation being larger and more costly than needed. This presentation outlines research currently being undertaken to develop such guidelines, focusing on the design of shallow and deep foundations in variable ground using the probabilistic techniques of random field theory and Monte Carlo simulation.


SIOPS (site investigation optimisation for piles using statistics) is a versatile command-line tool for optimising geotechnical site investigations, allowing the user to quickly analyse the performance of a wide range of investigations. Download on Github

Relevant papers, related to this presentation, can be found on ResearchGate.

About the speakers

Mark Jaksa Professor of Geotechnical Engineering, University of Adelaide

Mark Jaksa is Professor of Geotechnical Engineering in the School of Civil, Environmental and Mining Engineering at the University of Adelaide, Australia. He has been an academic for 30 years, before which, he spent 4 years practicing as a consulting geotechnical and civil engineer in Adelaide and Canberra in Australia. He has a Bachelor of Engineering (Honours) degree in Civil Engineering and a PhD, both from the University of Adelaide.
He has published more than 170 papers, chapters and reports on various aspects of geotechnical engineering research and teaching. His primary areas of expertise are in the characterisation of the spatial variability of soils, probabilistic analyses, artificial intelligence, ground improvement, unsaturated soils and enhancing learning in geotechnical engineering. He has received several awards recognising his contributions to learning and teaching in geotechnical engineering.

Mark is a former Chair of the Australian Geomechanics Society and immediate past Vice-President for Australasia and Treasurer of the International Society for Soil Mechanics and Geotechnical Engineering. He is also a past Chair of the ISSMGE’s Technical Committee, TC306, on Geo-engineering Education and a member of TC304, on Risk Assessment and Management.

Michael Crisp

Michael Perry Crisp received his Civil Engineering degree in 2016 from the University of Adelaide. Following an internship at Engtest, he has returned to the University where is he currently undertaking a Ph.D in geotechnical engineering, due to be completed at the end of 2019. In addition to researching his topic of ‘site investigation optimisation’, Michael has taken on a wide variety of roles such as: positions on multiple committees, the demonstration of various geotechnical laboratory tests, the supervision of research groups, tutor and head tutor of geotechnical and programming courses, and he has given a lecture series on effective communication.

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