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To assess the stability of slopes, mining and geotechnical engineers frequently use empirical rock mass classification and characterisation systems. These methods are practical and often very useful in the preliminary design stage. Slope mass rating (SMR) system is one of the commonly used empirical methods to assess the stability of slopes. The SMR is obtained correcting basic rock mass rating (RMR) using four joint adjustment factors that consider the geomechanical relationship between the slope face and the joint affecting rock mass as well as the excavation method used. The factors included in the SMR system such as basic RMR, and correction factors involve some drawbacks such as uncertainties sourced from qualitative criteria, sharp class boundaries and fixed rating scales. These drawbacks are sourced from the complex nature of rock mass. To deal with these uncertainties, the fuzzy set theory is applied in this study to reliably determine basic RMR and adjustment factors. It was seen that fuzzy set theory can sufficiently cope with the common drawbacks in the determination of factors included in the SMR system. [ABSTRACT FROM AUTHOR]

Graphs, numbers, pictures and engineering judgement are among the most important factors in engineering design and implementation. This study is the first of a research project which has addressed 3D potential zones of rock mass failure and relaxation. It presents results of applying numerical-empirical 3D engineering curves used for predicting stope stability and mining dilution, especially in longitudinal blasthole underground mining operations. A state-of-the-art 3D elasto-plastic finite element technique developed by CANMET was utilized in conjunction with a non-linear unified strength criterion and case histories to develop these curves. These could assist mine operators in making economic decisions on ground control, mine planning and feasibility assessments that will ensure a safe working environment. Limitations in applying the curves will be discussed. [ABSTRACT FROM AUTHOR]