Investigation of the behavior of tailings earthen dam under seismic conditions

Abstract

Problem statement: A number of tailings earthen dams have failed during past earthquakes. The failure of tailings dam ultimately results into the release of the stored tailings waste deposit in the surrounding locality. To reduce such damage of tailings earthen dam, a detail method of seismic analysis is very much essential which can be used reliably for the design and construction. Approach: To establish a detail method of static and seismic analysis for a tailings earthen dam, in this study both the static and seismic analysis were performed for a typical section of tailings earthen dam. The whole analysis was performed using various software packages like FLAC 3D , TALREN 4, SEEP/W and SLOPE/W. Results: After FLAC 3D analysis it was observed that under the seismic loading condition the maximum displacement of the dam is about 66.7 cm, whereas by using the Makdisi-Seed method the maximum displacement was obtained as 57 cm. FLAC 3D analysis showed that the base level input acceleration gets amplified with the height of the dam and at the crest level the amplification is about three times. After slope stability analysis under seismic loading it was found that the factor of safety is 0.89, but under the static loading condition the minimum value of factor of safety was obtained as 1.22. Conclusion/Recommendation: From this analysis it was clear that the dam was unsafe under the seismic loading.