Cyclic Resistance of Intact Fine-Grained Tailings: Observations Drawn Through Application of a Model Developed for Natural Silts

Abstract

Numerous, globally-distributed tailings storage facilities (TSFs) are located in active seismic regions. Seismic instability of TSFs can result in significant damage to civil infrastructure, serious environmental consequences, and potential fatalities. Assessments of the cyclic resistance of silty tailings are complicated owing to the potential differences in soil fabric relative to natural silts due their anthropogenic nature, limited tailings-specific in-situ test correlations, and their relatively young, depth-varying age. A recently-developed suite of cyclic resistance models for the cyclic resistance ratio, CRR, of intact, natural silts is evaluated for the purpose of predicting the cyclic resistance of fine-grained non-plastic and plastic mine tailings and identifying data gaps for future development of tailings-specific cyclic resistance models. Comparison of the cyclic resistance of intact specimens of silty tailings collected from the literature are made to that estimated using the newly developed cyclic failure models considering their plasticity index, PI, and overconsolidation ratio, OCR. The direct comparison of the observed and model-estimated CRR is facilitated by corrections for stress path and loading frequency. The importance of gradation, particle morphology, tailings ore mineralogy, plasticity, and aging/stress history is explored to identify knowledge gaps on the variables contributing to cyclic resistance of silty tailings.