Abstract

A geotechnical assessment of mine tailings state conditions using the static cone penetration test performed at different tailings storage facilities (TSF’s) will be presented in this paper. Both tailings evaluated herein are deposited as a slurry (hydraulic deposition) and have similar grain-size distribution curves. A set of Cone Penetration Tests (CPTu) with pore pressure measurements were performed at each site to evaluate the state of the tailings. To assess the contractive-dilative behavior classical methodologies were adopted such as i) the contractive/dilative boundary suggested by Robertson (2016) ii) the approach suggested by Plewes et al. (1992) and cited by Jefferies and Been (2016) and iii) the yield stress ratio method proposed by Mayne and Sharp (2019). Partial drainage effects will be identified with classical methodologies. The results were compared to evaluate the difference and limitations of each methodology. Comments on the similarity between the two tailings evaluated herein will also be presented to explain the differences in behavior due to aspects such as mineralogy, gradation, stress history and deposition.

Abstract

In geotechnical site characterization, Cone Penetration Testing (CPT) is a fundamental method for evaluating subsurface conditions of granular materials such as sands, silts, and non-plastic tailings. This study advances CPT simulations by incorporating the fabric anisotropy variable A into the SANISAND-F model and utilizing the Material Point Method (MPM), with a specific focus on the role of evolving fabric within an anisotropic critical state framework. The objective is to deepen the understanding of how the evolving fabric of soils influences macroscopic site characterization outcomes. Through carefully controlled initial conditions, including void ratio and confining pressure, the study aims to demonstrate the impact of fabric anisotropy on CPT resistance measurements. Assessment of the evolution of material state based on the key constitutive ingredient of the model allows for explaining the reason behind the respective values of cone tip resistance observed from the CPT simulations, considering fabric anisotropy and the anisotropic critical state framework. This approach enhances the modeling of this site characterization method, providing a more comprehensive framework for interpreting soil mechanical behavior and enhancing predictive modeling capabilities