Centrifuge modeling studies on effects of composition on liquefaction of mine waste rock

Liquefaction behavior is investigated in four centrifuge modeling tests performed on loose mine waste rock composed of different ratios of gravel, sand, and fines. These specimens have similar shear wave velocity of about 117-128 m/s. Each centrifuge model was subjected to a 0.27-g sinusoidal base shaking amplitude. It was found that soil liquefaction was observed for all models with the exception of a model with a mixture of 70/30% gravel/sand. Dilative behavior was observed from the acceleration time histories for all models and was dependent on the excess pore pressure development and effective stress. Pore pressure dissipation during shaking was found in the models without fines. Degradation and distortion of shear stress-strain loops were also observed. Larger settlement and volumetric strain were observed after the tests for the models with fines. Based on the results from this study, an increase in sand and fines content causes an increase in liquefaction potential of mine waste rock.