Recent failures of upstream-raised tailings storage facilities (TSF) have led to stricter standards for assessing the tailings flow liquefaction hazards. Standard limit equilibrium analyses often overlook strain-softening and brittleness effects, which are crucial for understanding progressive failure.
This study uses a numerical procedure to assess the susceptibility of a typical upstream-raised TSF to flow liquefaction by applying undrained loads at the beach/berm of the dam and contractions at the starter dam. The methodology employs finite element models in Plaxis 2D and three advanced constitutive models -HSS, NorSand and CASM- to compare their performance.
The calibration of the models is based on a set of triaxial tests on gold tailings samples by Reid (2022), covering both drained and undrained shearing conditions with various pre-shearing state parameters, confining pressures, and anisotropic stress ratios (K0).
The dam construction is modeled, and trigger analyses are carried out assuming two representative state parameters for the tailings body. A comparison is presented in terms of loads and contractions triggering progressive failure, failure kinematics, and stress paths. Overall, a good agreement was found among the models, in terms of failure surfaces and magnitudes to trigger the failures.
Note: We congratulate Mauro for being awarded the International Bright Spark Lecture Award for this paper. It was presented at the Pan-American Conference on Soil Mechanics and Geotechnical Engineering in Chile in November 2024.
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