Hypoplastic modelling of sandy silt tailings behaviour under general loading conditions

The behaviour of sandy silt tailings under general loading conditions is important for assessing slope stability, below slope conditions and other geotechnical applications. Constitutive models used in numerical applications are usually calibrated and validated under axisymmetric loading. It is therefore essential to examine whether they can also predict soil behaviour in other relevant and more general loading scenarios. This study tests the hypoplastic constitutive model of von Wolffersdorff (1996) for sandy silt gold tailings under a wider range of stress and strain paths. The model was calibrated using drained and undrained triaxial compression tests. Validation used independent drained and undrained triaxial extension, torsional shear at constant Lode angle with fixed principal stress direction, and simple shear tests. The loading paths cover consolidation, peak states, and critical states. Our results show that hypoplasticity reproduces key trends in tailings behaviour across various paths. The simulations capture the evolution of the Lode angle and the rotation of principal stresses under non-axisymmetric loading, including plane-strain conditions often used to idealize slopes, which supports applying hypoplasticity to problems involving principal stress rotation in plane-strain, such as tailings dams. • Hypoplasticity reproduces sandy silt tailings behaviour across general loading paths. • The model captures stress rotation and Lode angle trends relevant to tailings slopes. • One parameter set lets the model reproduce behaviour for two sample preparations.