Three-Dimensional Stability Assessment of a Tailings Embankment Adjacent to an Existing Open Pit

DOI

10.2991/978-94-6463-900-1_27How to use a DOI?

Keywords

3D Slope Stability; Composite Failure Mechanism; Embankment-Open Pit Interaction

Abstract

This paper presents three-dimensional numerical analysis undertaken to assess stability of an existing tailings embankment dam located near the crest of an existing open pit that has previously experienced significant slope deformation. Two-dimensional limit equilibrium analysis indicated potential embankment instability via planar failure along a shallowly dipping regional fault below the foundation with toe breakout along antithetic shears. Three-dimensional stability analyses were undertaken for consideration of the three-dimensional nature of the failure mechanism and geometry.

The three-dimensional stability assessment comprised limit equilibrium analysis using SLIDE3D and finite element analysis using RS3. Both analyses were able to consider a local scale and global scale complex failure mechanisms involving rotational failure through the embankment, planar sliding along a shallow dipping fault, toe breakout along shears, possible side release along a secondary fault surface and/or rock mass. Material parameters considered in the analysis included undrained shear strength for tailing materials, non-linear strength function for the embankment material, Hoek-Brown failure criteria for in-situ rock and Mohr-Coulomb strength criteria for rock fill and weathered rock. Mohr-Coulomb strength parameters were also adopted for the fault surfaces and ramp shear which were modelled as discrete weakness surfaces. The model also incorporated hydrostatic groundwater conditions based on observations from vibrating wire piezometer monitoring data.

Factor of safety (FoS) results from the 3D limit equilibrium assessments and strength reduction factors (SRF) computed from the 3D finite element analysis indicated the embankment under consideration has a higher margin of safety than the marginal value estimated from the 2D analysis. Despite fundamental differences in the analysis algorithm, the RS3 predictions for SRF values are reasonably close to the FoS results from SLIDE3D analysis. In addition, there is a good match in the shape and extent of the critical failure surfaces assessed in both methods.

Copyright

© 2025 The Author(s)

Open Access

Open Access This chapter is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommercial use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

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TY  - CONF
AU  - Michael Habte
AU  - Daniel Strang
AU  - Dylan Mo
AU  - Philip Gerridzen
PY  - 2025
DA  - 2025/12/07
TI  - Three-Dimensional Stability Assessment of a Tailings Embankment Adjacent to an Existing Open Pit
BT  - Proceedings of the Rocscience International Conference 2025 (RIC 2025)
PB  - Atlantis Press
SP  - 283
EP  - 290
SN  - 2589-4943
UR  - https://doi.org/10.2991/978-94-6463-900-1_27
DO  - 10.2991/978-94-6463-900-1_27
ID  - Habte2025
ER  -