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The “critical state” of our tailings dams…

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by ARQ Geotech- Katy O’Brien, Thomas O’Brien & BRT Beric Robinson

CivilEngineeringSaice/Vol30No3April 2022

Over the last few decades, design requirements for tailings storage facilities (TSFs) have become more elaborate and demanding. A critical state approach shows much merit as a tool to aid in assessing
liquefaction trigger mechanisms.

CONCLUSION
Realistic assessment of TSF stability beyond simplified, conservative assumptive analysis is necessary. The triggering assessment methodology presented here is an example of the type of rigorous approach which will be necessary to accomplish this.  This article demonstrates that by utilising CSSM constitutive models and finite element analysis, the stress and strain state of upstream tailings facilities can be  realistically analysed and predicted under normal and abnormal loading conditions. Findings indicate that despite the presence of contractive saturated tailings, liquefaction does not necessarily ensue under all plausible triggering events. The development and incorporation of complex non-linear constitutive models into FEM analytical tools enables the application of realistic and representative engineering  assessment of contractive TSF stability, as opposed to the overly conservative historic assumption of residual strength in limit equilibrium analyses.