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Incorporating inherent uncertainties in seismic liquefaction assessments

Event organised by Society for Earthquake and Civil Engineering Dynamics

31 January 2024

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Liquefaction assessments for tailings facilities have significant uncertainty, yet their results are typically presented as single-value deterministic factors of safety (FoSs) to compare against standard practice guidance. Some of the uncertainty is due to inherent material variability or measurement error associated with in situ testing techniques.

There is also a considerable – and often ignored – contribution from the transformation models used to convert in situ measurements to design parameters. For seismic liquefaction assessments, the key sources of transformation model uncertainty are from the empirical relationships relating standard penetration testing or cone penetration testing (CPT) results to cyclic resistance and residual undrained strength.

While the uncertainties associated with the material variability and measurement error will vary by site and can usually be reduced through additional investigation, the model uncertainties are constant and irreducible without further work.

This lecture will discuss how the transformation model uncertainties associated with CPT-based liquefaction assessments can be incorporated into design practice to estimate probabilities of failure and lead to very different outcomes than simply considering FoS alone.

Organised by

The Society for Earthquake and Civil Engineering Dynamics

The Society for Earthquake and Civil Engineering Dynamics

SECED promotes the study and practice of earthquake and civil engineering dynamics, including blast, impact, and other vibration problems.


Holly Williams

Holly Williams

SRK Consulting

senior consultant

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Holly Williams

Holly has an undergraduate degree in civil engineering and a master’s degree in data science.
She specialises in the application of data science and statistical approaches to incorporate risks and uncertainties into mine waste studies and designs.
Her experience includes tailings facility designs (from site-selection and alternatives assessments through to detailed design and construction oversight), dam break assessments, water balance studies, mine reclamation and closure designs, and risk assessments for wide range of projects in in Canada, USA, Mexico, Australia, South America, Europe, Russia, and Africa

For more information please contact:

Shelly-Ann Russell

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