Analytical and Numerical Methods in Mining Engineering (Feb 2022)
Key group analysis based on DDA method for rock slope stability analysis
Abstract
Inhomogeneity and discontinuities play a key role in the resistance and behavior of rock masses. Today engineers have a wide range of methods to analyze the stability of rock slopes. Due to its simplicity and speed of evaluation, static analysis methods continue to play a special role in the stability assessment of jointed rock slopes. One of the most well-known static methods used in the stability analysis of rock slopes is the Key Block method (KBM), which is based on key block finding and analysis. In this method, if none of the key blocks are unstable, it implies that rock mass is stable. Occasionally, the combination of several stable blocks has led to the formation of a group of blocks that sometimes leads to instability. Therefore, the stability analysis of the jointed rock masses leads to study groups of blocks that are potentially dangerous for the stability of a rock slope. The Key Group method (KGM), with its progressive approach, finds these critical groups and focuses the stability calculations on these groups. Until now, methods SKGM, PKGM, OKGM have been proposed to remove the limitations of this method and its development. In order to increase the efficiency, accuracy, and speed of this method and to develop it in three dimensions, it is decided to combine it with one of the numerical methods. The standard Discontinuous Deformation Analysis method (DDA) is an implicit method based on the finite element method. This is a sophisticated numerical method for modeling the quasi-static and dynamic behavior of rock block systems in discontinuous rock masses. The goal of this paper is to use the potency of the numerical method of DDA to analyze the candidate key group. For this purpose, the DDA computer program was developed with Mathematica programming language and combined with the KGM software. The resulting package, after selecting the key group by the KGM method, proceeds to analyze it with the DDA method. Two examples are solved illustrating the reasonable results and the efficiency of this developed method compared to that of the original KGM and SKGM. The results validated the proper accuracy and good performance of the procedure developed in this research.
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