Centrifuge Modeling of Saturated Mine Waste Rock Under Cyclic Loading
Centrifuge Modeling of Saturated Mine Waste Rock Under Cyclic Loading
This study investigates the dynamic response of mine waste rock with two different gravel-to-sand compositions using centrifuge model tests conducted at the University of South Carolinas geotechnical centrifuge facility. Two mixtures with gravel-to-sand ratios of 2.33:1 and 4:1 by weight were prepared with the same initial void ratio but result in different relative densities. Uniform cyclic loading was applied with peak base accelerations of 0.286 g and 0.210 g for the 2.33:1 and 4:1 mixtures, respectively. Despite the difference in shaking amplitude, both models experienced a similar cyclic stress ratio (CSR) of approximately 0.30 at the base. The 2.33:1 mixture generated higher excess pore water pressure, larger cyclic shear strains, and greater volumetric strain, indicating a more pronounced reduction in stiffness and strength. Excess pore water pressure in this mixture accumulated during the initial loading cycles and partially dissipated as shaking continued. Although both mixtures exhibited dilative behavior at low effective stress, their pore water pressure responses differed markedly. The 4:1 mixture developed excess pore water pressure that dissipated within each cycle without residual accumulation, reflecting a more stable cyclic response. In contrast, the 2.33:1 mixture developed excess pore water pressure of greater magnitude and accumulation and experienced more than twice the volumetric strain of the 4:1 mixture. These results demonstrate that gravel-to-sand ratio strongly influences the dynamic behavior of mine waste rock. Relatively small changes in particle composition significantly affect pore pressure generation, accumulation and dissipation behavior, deformation characteristics, and seismic stability, highlighting the importance of optimizing particle gradation and mixing to improve the seismic performance of mine waste embankments.
Inthuorn Sasanakul; P. Ruttithivaphanich; S. Dejphumee
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Special Session 7: Geotechnical seismic isolation based on sustainable geomaterials
https://doi.org/10.53243/ICPMG2026-175