Stability analysis of a calcareous rock slope on a variable dip syncline

The analysis of rock slope stability is a key step in the successful design and excavation of open-pit mines and quarries. In this study, rock mass characterization and different analyses were performed to assess the stability of the final slope of a calcareous quarry. The studied excavation is located on the near-axis flank of a syncline, in such a way that the stratification set varies its dip from some 40 on the nearest zone of the axis to 20 on the farthest zone, creating a slightly complex geometry. This situation requires a set of different approaches to assess the slopes stability. For the studied case, the proposed design of the entire open-pit quarry was received. All possible failure mechanisms of the quarry were identified and analyzed using limit equilibrium and numerical methods. The west slope, which was parallel to the stratification, featured a planar mechanism instability problem; therefore, it was analyzed in detail, and a new stable design was proposed. This paper describes the steps carried out to characterize the rock, discontinuities, and rock mass, as well as the different approaches used to obtain a stable design of the west slope.