Probabilistic approaches to estimating variation in the mechanical properties of rock masses

Abstract

The probabilistic method of estimating mechanical characteristics of a rock mass is discussed, based on Monte Carlo simulation. The simulation results and the input data used for the simulation are analyzed using extreme value statistics. The analysis indicates that the mechanical properties obtained from simulation, laboratory and field tests, follow the third type asymptotic distribution of the smallest values. This analysis reveals the nature of the inherent variability of the mechanical properties of rocks. The proposed approach provides a viable means of assessing the variability of the rock mass properties which cannot be accomplished by experimental means. These computed rock mass characteristics will help rock engineers to arrive at a more rational design of underground structures, compared to traditional design methods based on deterministic approaches.