2023 – Assessment of Foundation Liquefaction for a Tailings Retaining Structure

Yuqi Tan, Behrooz Ghahreman-Nejad

In recent years, the world has observed the catastrophic impacts of tailings dam failures. Resulting impacts of these were many deaths and widespread environmental destruction. Liquefaction has been a major cause of tailings dam failure in the past and may occur in saturated soils under static or seismic loading conditions. Liquefaction may be considered as a constitutive behaviour of soil, and principles of physics and mechanics may be implemented to understand how it develops. In this paper, the trigger mechanism and deformation effect from the static liquefaction of a dam in a design scenario are evaluated using the Norsand Constitutive model implemented in FLAC program (Itasca group). The result shows that the deformation of an embankment may exceed the minimum design freeboard despite the limit equilibrium stability analysis meeting the Factor of Safety (FoS) requirement. The predicted excessive deformation of the embankment is resulted mainly from the static liquefaction of the foundation soil triggered by the change of stress state during construction and operation.

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