Analysis For Seismic Stability And Permanent Displacement Of Clay-lined Tailing Stacks

More tailings stacks are required to have a bottom liner system to prevent leakage. However, dynamic response analyses for this type of tailings stacks are relatively lack. Therefore, it is important to study seismic stability and permanent displacement of lined tailings stacks. A finite difference model of a clay-lined tailings dam was developed using the computer program FLAC. Two-dimensional seismic response analysis was performed to study the impact of the clay liner on the permanent displacement of the tailings stack during an earthquake. It was found that the maximum horizontal displacement on the crest of the tailings dam from the numerical simulation was only slightly larger than that from the conventional simplified method,indicating the validity of the numerical simulation. The parameter analyses showed that the shear strength of the bottom clay liner had a significant impact on the seismic responses of the tailings stack. Although the clay linerhelped to reduce the maximum horizontal acceleration applied on the tailings dam, the yield acceleration of the tailings dam quickly decreased with decreasing shear strength of the clay liner. When the shear strength of the clay decreased to approximately one half of the shear strength of the tailings,the failure surface changed from a circular shape to a wedge shape through the bottom clay liner, accompanied by a sharp increase in permanent horizontal displacement of the tailings dam. These research results possess a certain reference value to the design of lined tailings stacks in earthquake zones.