This paper proposes a procedure for standardizing the assessment of the vulnerability of tailings dams to flow liquefaction using numerical methods.
The procedure consists of five steps: i) simulating the behavior of tailings and strain-softening materials with a constitutive model able to capture liquefaction and strain softening; ii) calibrating the model to reproduce the expected peak and residual undrained strength ratios, and brittleness; iii) simulating the construction and operation of the dam as a coupled flowdeformation analyses; iv) applying a set of standard triggers that disturb the balance of the dam, as “undrained” actions, and increasing them monotonically until failure is observed; and v) reporting the outcome.
Three disturbing actions are recommended, that represent ultimate states of the dam and that cover most of the known causes of tailings dam failure: i) an increase in the phreatic surface; ii) a toe contraction; and iii) a load at the crest.
The vulnerability of the dam is evaluated by analyzing if one or more of the failure modes: i) produces loss of containment; ii) involves brittle or progressive failure; iii) has a trigger value within the plausible range for the dam.
