Constitutive modelling of unsaturated gold tailings subjected to drying and wetting cycles

The strength and deformation properties of tailing materials are strongly affected by their hydromechanical history including the cycles of desiccation and re-saturation they undergo due to the often layered deposition process. The current study reviews the fundamental characteristics of some of the commonly used constitutive models for partially saturated soils, namely Barcelona Basic Model (BBM), Glasgow Coupled Model (GCM), and a dilatancy-based model by Buscarnera and Nova Model (BNM) in predicting the hydromechanical response of tailing materials. In particular, we investigate the strength and shortcomings of each model and compare their capability of capturing the salient trends during drying/wetting cycles, as well as during shearing. Based on comparison with experimental data, modifications are suggested for the models, specifically related to a realistic formulation of the water retention curve and its hysteresis. The results point to a potential trade-off in the accuracy of the constitutive models in capturing the volumetric responses during the drying/wetting cycles on one hand, and the stiffness and strength characteristics during the shearing phase on the other.

Automated summary

This study reviews the characteristics of commonly used constitutive models for partially saturated soils, and compares their ability to predict the hydromechanical response of tailing materials. Modifications are suggested for the models, particularly in relation to a realistic formulation of the water retention curve and its hysteresis, based on comparison with experimental data. The results indicate a potential trade-off between accurately capturing the volumetric responses during drying/wetting cycles and the stiffness and strength characteristics during shearing.