Numerical Modeling of Crack Propagation Mechanism in Jointed Rock Slopes Using Displacement Discontinuity Method

In the jointed rock masses such as rock slopes، the joints considered as cracks in which their tips are the weak points for fracture initiation. Some of the numerical codes for the stability analysis of jointed rock masses have considered only blocks movement on the surfaces of the existing fractures. The tips of these rock joints may act as the fracture creation points and some new discontinuities containing high stress intensity points or plasticity situation may develop. The purpose of this research is to simulate the stable or unstable crack propagation mechanism in the rock bridge area and the cracks coalescence phenomena until the blocks can be created in the fractured rock slopes using linear elastic fracture mechanics (LEFM) theories. Thus، combining the displacement discontinuity based indirect boundary element method (called the higher order displacement discontinuity method) with the maximum tangential stress criterion and programming it by Mathematica software has been used for the crack analysis in this study. The fracture types or modes of fracturing predicted and the crack propagation and cracks coalescence estimated in the rock bridge area for several examples of typical rock slopes. After cracks propagation and coalescence، blocks velocity and shear displacement on new discontinuities obtained as high stress concentration points or plastic mode zones using a distinct element method (UDEC).