Considering Uncertainty for Estimating Shear Strength Parameters of Intact Rock Using Statistical Methods

One of the most critical steps in the design process of a rock structure by the limit equilibrium method is to determine the shear strength parameters. Because the prediction of these parameters is always accompanied by uncertainty. In such cases, if the range in which the actual shear strength parameters are located is obtained, the results are more reliable. Hence, in this paper, an applied technique based on probabilistic methods is developed. In the first step, by developing an innovative method for two widely used failure criteria, consist of Mohr-Coulomb and Hoek Brown, statistical samples of shear strength parameters are generated and latter, using the t distribution in which the shear strength parameters are located with confidence 95% are determined separately for the two failure criteria. The available data from the previous research are used for the case study. The results of the case study indicate that the prediction of shear strength parameters with the presented method is more accurate than the conventional methods.