Numerical Investigation of Saturated-Unsaturated Flow and Stability Analysis of Tailings Dams Considering the Influence of Saline Solutions

Abstract

A tailings dam is normally constructed through self-consolidation with minimum compaction effort. Accordingly, special attention to the ultimate limit design in assessing the tailings dam instability condition is of primary importance. Furthermore, the existence of pore fluid chemical contaminants with high concentrations makes soil hydraulic and shear resistance properties subject to considerable changes.Therefore, this study aims to investigate the stability of a tailing dam using saturated-unsaturated flow analysis under 0.2 and 0.6 M sodium chloride solutions and pure water as a benchmark. To make the analyses as realistic as possible, recently developed solute-dependent hydraulic conductivity and water retention models are embedded into the numerical software. The results show that the saline-based model has higher pore water pressure than the pure water model due to more rainfall penetration by increasing the pore fluid salt concentration. Furthermore, increasing salt solution concentration enhances the tailing dam's drainagecondition, which leads to an increase in the dam's shear strength and, consequently, the factor of safety. Therefore, the stability of the tailings dam is improved by the combined impact of salt on both the flow and strength.