Large-Scale Direct Simple Shear Testing for Properties of Coarse Tailings Subject to Cyclic Loading

This thesis focuses on large-scale direct simple shear (LDSS) testing to analyze the behavior of coarse mine tailings subject to cyclic loading. The motivation behind this research stems from recent failures of tailings dams, prompting mine owners globally to reassess the safety of their tailing’s impoundments. Testing was carried out at the Arizona State University (ASU) Enamul and Mahmuda Hoque geotechnical laboratory using a unique LDSS device. Cyclic shearing, at different levels of strains, under constant normal stress test was carried out to investigate the modulus reduction and damping behavior of the tailings. Constant volume tests were conducted to simulate the undrained behavior of the tailings and provide insight to the tailings’ liquefaction potential. In both the constant normal stress and constant volume tests the tailings were sheared to the strain limit of the device to assess the post-cyclic shear behavior of the tailings. Testing was also conducted on tailings from the same parent material after screening the larger particle to evaluate the effect of the particle size. The thesis also includes recommendations for improving future test results. This thesis provides valuable insights on the behavior of coarse mine tailings which ultimately contributes to enhancing safety and environmental sustainability in the mining industry.