Risk models of slope excavations

Abstract

Quarry slope excavations are normally done by the bench blasting method or by the use of mining machinery. On the other hand, the stability of the quarry slope face is normally determined by the use of the deterministic method, or it may be defined by an index term known as the ‘factor of safety (FS)’. There are uncertain risks to some degrees that are associated with computed values of FS with the result that these values are thus never absolutely precise. An alternative measurement of stability can be employed (by the use of statistical analysis) to obtain terms such as ‘reliability index (β) and probability of failure [p(f)]’. In this study, three types of reliability models have been proposed. These modelling types were based on values of the safety margin, the most likely value of FS, and the data simulation, respectively. Probabilistic values obtained from each statistical model were compared with data obtained using the deterministic method. The risk of slope failures can be better defined and also the cost of operation optimised by the use of the improved reliability models.

Keywords:

• quarry slope excavation
• deterministic and reliability methods
• reliability models
• optimised operation cost

Acknowledgements

Financial sources from the University and from the Department of Primary Industries and Mines are highly appreciated. Thanks are due to our research team on their continuous works for several years. Generous permission of the authorised personnel to allow data be published is acknowledged.