Development of a new approach to determine the representative joint set with enhanced reliability

A reliable estimation of the discontinuity orientation of a joint set is of great importance in rock mechanics studies and interpretations. Common approach for determination of the joint set orientation is based on deterministic approach without considering the reliability of calculations. Nowadays, statistical and probabilistic methods are widely used to investigate uncertainties in the input data as well as validating the output of calculations and outputs where the emphasis is placed on identification of unknowns in analyzes. In this study a new method was presented for calculating the representative discontinuity plane of a joint set based on the Monte Carlo simulation method and the results were then compared with the conventional method. Evaluation of deterministic and probabilistic methods were carried out using distinct element method which showed that the proposed method is more suitable compared to the conventional method due to enhanced reliability in calculation as well as simulating based on considering the statistical distribution function and sampling from them. This advantage can be clearly seen for orientations fall in the edge of hemisphere projection. Furthermore, results of this study showed that when the joints are located on one side of the stereonet, the conventional method has a reliability more than 98%. in determining the dip and dip direction of representative discontinuity plane of a joint set while for orientations fall in the edge of hemisphere projection the reliability is reduced to more than 95% for the dip direction and more than 87% for the dip.