Evolution of Microcracks in the Rock Deformation Process: X-ray Microtomography and Discrete Element Modeling

Abstract—In this study, we directly observed microcracks formed in a sample of rock under the action of uniaxial compressive load. Defects in the volume were detected by X-ray computed microtomography. A specific feature of the experiments is that a tomographic image of the sample was taken directly under mechanical load. Based on the analysis of tomographic slices, the fractal dimension and relative volume of microcracks were calculated at three stages of loading. Three-dimensional models of the defect structure were constructed to illustrate the change in the morphology of the main crack. Numerical experiments on the fracture of samples of heterogeneous materials were carried out using the discrete element model. The change in the fractal dimension of main cracks during their growth was investigated. Good agreement between the results of computer simulations and laboratory experiments has been established, which indicates the adequacy of the proposed model and allows in further studies to use it to study the behavior of local parameters that cannot be measured experimentally.