Evaluation of the stability of a bullnose within Coedmore Quarry, Durban, South Africa

摘要

An assessment of the stability of a bullnose within Coedmore Quarry was conducted. The stability analysis was based on detailed scanline surveys and rock strength testing. Kinematic analysis of the discontinuity data was carried out and it can be concluded that a wedge failure was the most likely failure mechanism associated with the orientation of the discontinuities. The shear strength of the discontinuities was analysed and the estimated maximum normal stress acting beneath the slope was determined. The empirical determination of shear strength allowed for the back calculation of Joint Roughness Coefficient (JRC). The rock mass classification concluded that the slopes were stable. A slope stability analysis was conducted using the deterministic approach, resulting in a factor of safety > 1. Analysis based on the worst case scenario also rendered a stable slope but with a lower value of F. It must be noted that, in reality, the bullnose has been stable for several decades apart from small localized failures, which is consistent with field observations.