Propagation mechanism of neighboring cracks in rock-like cylindrical specimens under uniaxial compression

The mechanism of cracks propagation and coalescence of neighboring cracks existing in precracked rock like cylindrical specimens has been studied experimentally and numerically by considering multiple cracks in the middle part of each specimen. The pre-cracked cylindrical specimens of rock like materials are experimentally tested under uniaxial compression in a rock mechanics laboratory. Then these experiments are numerically simulated by a modified higher order displacement discontinuity method (HODDM) using cubic displacement discontinuity elements and three special crack tip elements for crack tip behavior to increase the accuracy of the Mode I and Mode II stress intensity factors (SIFs) obtained based on linear elastic fracture mechanics (LEFM) theory. The crack propagation and coalescence paths of the internal inclined crack are estimated by implementing a suitable iteration algorithm of incremental crack length extension in a direction predicted by using the maximum tangential stress criterion. The numerical and experimental results are compared showing the validity, applicability and accuracy of the present work. Finally, a numerical simulation has been accomplished to study the effect of interaction among neighboring cracks on the SIFs.