Influence of surface erosions and cracks in tailings dams safety
DOI:
https://doi.org/10.24849/j.geot.2020.149.05Keywords:
Safety of dams, portfolio analysis, anomaliesAbstract
The increasing number of ruptures of tailings dams imposes constant advances in the techniques of safety assessment of these structures. Portfolio analysis is considered the most agile assessment technique in the safety assurance routine; however, its application is often subjective and dependent on the evaluator's expertise. In this sense, this article presents the results of the evaluation of the influence of erosions and cracks on the safety of tailings dams aiming at the decrease of subjectivity in portfolio analysis. Five typical dams, both upstream and downstream raised, were simulated with varying strength parameters of the landfill and tailings, totalling a universe of 90 dams. Surface erosions and cracks of small, medium and large magnitudes were simulated as well as the combined effect of these anomalies. The results indicated the loss of safety margin for erosions of 3.5%, 7.0% and 10.5% and for cracks of 8%, 16% and 24%. The results for the combined simulations revealed that the overlap of effects can be approximated by the simple sum of the loss of safety margin of the anomalies ascertained. It is concluded that the field anomaly survey technique for evaluating the impact on the safety of tailings dams is valid, indicating that it is possible to apply the portfolio analysis with less subjectivity of the evaluator. It is also concluded that this technique can be expanded and contribute to frequent evaluations and safety assurance of tailings dams.
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