Impact of mining waste effluents on the shear strength of compacted lateritic soils used in waste containment dikes (DRC)

Hydraulic fracturing is the evoked main cause of dikes failure. Several authors analyzed the soils properties under mechanic and hydraulic solicitation. However, these analyses don’t take into account the chemical influence of liquid percolating the matrix of soil. This article analyzes the impact of liquid effluents emanating from ore concentrators on compacted lateritic soils behavior in waste containment dikes. It emphasizes shear strength parameters of compacted laterite and percolated by liquid effluents with different chemical nature. The tests include the shear strength measurements when the specimens were imbibed with different fluids. The results show that acid and basic liquid effluents affect shear strength parameters and the strain modules are modified. The effect of the initial suctions and the density before the imbibition was also investigated, which reveals that structural changes caused by initial saturation and density of specimens seem to be more important for explaining strength behavior than chemical interaction.