Crack nucleation mechanism of rock fracture

Engineering geological disasters caused by rock damage evolution are closely related to the evolution of crack nucleation. This study developed a damage evolution model of granite under uniaxial loading based on multi-source acoustic emission (AE) data, including AE events time, spatial distribution, and AE energy. The spatial clustering degree of crack evolution was evaluated by visualizing the three-dimensional (3D) AE events and integrating them with the 3D Ripley’s K function. A 3D automatic reconstruction algorithm for crack nucleation bodies was developed, combining the DBSCAN clustering algorithm and Alpha Complex Shape. This approach allows comprehensive quantification of the morphology, number, and volume of crack nucleation bodies, representing an improvement over most existing methods. The crack nucleation growth factor (CNGF), defined by the ratio of crack nucleation body volume to quantity, was introduced to investigate the progressive damage process in rocks further. This helps enhance the understanding of the crack nucleation and damage mechanisms involved in rock crack propagation. It provides valuable insights for both the inversion and prevention of rock-related geological hazards.