Experiment and numerical simulation on cracking behavior of marble containing double elliptic holes under uniaxial compression

Abstract When a rock mass has undergone a long period of geological structural change, various defects such as pores and cracks. Here, the effects of defects on the mechanical properties of a rock mass were investigated. In this research, the strength, deformation and crack evolution behavior of marble containing double elliptic holes under uniaxial compression were evaluated by experiment and numerical simulation. The experimental results show that the dip angle α affects the strength, ultimate failure mode, crack initiation and propagation of marble specimens. As the dip angle increase, crack initiation loci transfer from the elliptic hole surface to the tip. For the ultimate failure mode, the cracks are mainly tensile when α is low, the cracks are mainly shear cracks when α approaches 75°, at 90°, the marble specimen is subject to tensile failure. ANSYS/LS-DYNA was used to simulate the marble specimens containing double elliptic holes, the numerical simulation results show good agreement with the experimental results. Analysis of tensile stress contours in a marble specimen and the different stress states at measuring points. Showed that tensile cracks initiate in the middle of the elliptic hole surface when the dip angle is small, and then the initial position of the tension crack shifts to the tip with increasing dip angle. This is consistent with the experimental findings in which there is no joint crack between the two elliptical holes in the marble specimens when the dip angle is small. A rock bridge fracture appears between the elliptical holes when α is close to 90°.