A case study: The seismic stability of an upstream-raised tailings impoundment (part ii)

Michael James, Nicolas Lemieux, Denise Leahy

In the proceedings of: GEO2011: 64th Canadian Geotechnical Conference, 14th Pan-American Conference on Soil Mechanics and Geotechnical Engineering, 5th Pan-American Conference on Teaching and Learning of Geotechnical Engineering

Session: Earthquake Engineering & Geophysics

ABSTRACT: The seismic stability of an upstream-raised tailings impoundment was evaluated. The impoundment has an exterior shell of compacted, coarse tailings underlain by a drainage system. These elements augment the seismic stability by increasing the liquefaction resistance and limiting seepage pressures in the downstream slope. Analytical liquefaction analysis methods were developed for level ground conditions and may not be applicable given the initial static shear stresses expected within the downstream slope. Furthermore, seismically-induced excess porewater generation in the retained tailings can result in considerable horizontal loads on the retaining dike and the site response may be affected by the geometry of the impoundment. Therefore, numerical rather than analytical methods were used. The evaluation indicates that some zones of high excess porewater pressure development and liquefaction and of minor deformation could be expected within the impoundment but that the risk of instability is extremely low.

RÉSUMÉ: La stabilité sismique d'un parc à résidus miniers été évaluée. Le parc à résidus a une coque extérieure formée de résidus miniers grossiers compactés reposant sur un système de drainage. Ces éléments améliorent la stabilité sismique en augmentant la résistance à la liquéfaction et de limiter les pressions de infiltration dans le talus aval. Les méthodes analytiques d'évaluation du potentiel de liquéfaction ont été développées pour des conditions de terrain horizontal et ne sont peut-statique prévues dans le talus aval de la digue. De plus, les surpressions interstitielles ou la liquéfaction des résidus dans le parc à résidus générées par un tremblement de terre peuvent imposer à la digue de retenue une charge re au développement de surpressions interstitielles et de déformations limitées dans le parc à résidus et que le risque d'instabilité est extrêmement faible.

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Cite this article:
Michael James; Nicolas Lemieux; Denise Leahy (2011) A case study: The seismic stability of an upstream-raised tailings impoundment (part ii) in GEO2011. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GEO11Paper461,author = Michael James; Nicolas Lemieux; Denise Leahy ,title = A case study: The seismic stability of an upstream-raised tailings impoundment (part ii),year = 2011}