Analysis of Crack Propagation Mechanism in Rock-Like Specimens Using Displacement Discontinuity Method (DDM)

The rocks with pre-existing cracks are normally under compression. Study of the propagation mechanism of these pre-existing cracks is important in the design of rock structures. In the present paper، a coupled numerical-experimental analysis of crack propagation، cracks coalescence and breakage process of brittle solids such as rocks and rock-like specimens are studied. The pre-cracked cylindrical specimens of rock-like materials (using specially made rock-like specimens from Portland Pozzolana Cement (PPC)، fine sand and water) tested under compressive loading. Several tests accomplished on the rock-like specimens containing two cracks to evaluate the final breakage path in these samples. The effect of the orientations of these two cracks with a constant spacing on the crack propagation paths and cracks coalescence have been experimentally investigate. These results show that the changing in the orientation of the second crack affect the crack growth and coalescence paths. The same specimens simulated numerically by an indirect boundary element method known as displacement discontinuity method. The numerical and experimental results obtained from the tested specimens compared with each other and showing good agreements between the corresponding values. The accuracy، validity and effectiveness of these approaches are quite evident by comparing these experimental and numerical results.