Undrained shear strength selection within a critical state framework

May 6, 2026

Reliable evaluation of shear strength for tailings storage facility design requires consistent interpretation of stress history and consolidation state. This paper presents a method for selecting representative peak undrained shear strength ratio for uncompacted bauxite residue within a critical state–based, SHANSEP framework. Laboratory and field data are interpreted through yield stress ratio and state parameter (ψ), which together describe consolidation and density state. Bayesian updating is applied to combine multiple datasets and refine representative strength estimates. The approach results in peak undrained strength ratio that is consistent across consolidation domains and supported by both theoretical and empirical evidence.

Kirsten, L.H., Brandao, H.A., Walsh, D., Murray, L. 2025 " Undrained Shear Strength Selection Within a Critical State Framework,” in Proceedings of the SAIMM Tailings Conference, 3-4 March 2026, Johannesburg, South Africa: South African Institute of Mining and Metallurgy (SAIMM)