Experimental and numerical study on crack development characteristics between two cavities in rock-like material under uniaxial compression

The understanding of failure mechanisms of rocks containing multiple cavities is important for stability assessment of rock excavations in rock engineering applications. However, published research is still limited on the failure mechanism between cavities and quantitative assessment of the crack development characteristics for different cavity configurations. In this research, specimens containing two cavities were investigated for their displacement characteristics and failure mechanisms under uniaxial compression. Digital image correlation (DIC) was used to measure the displacements of the specimens in experiments, while the failure process was modelled using the Particle Flow Code (PFC) software. A density-based clustering method was used to detect micro-crack clusters and the well-known statistical tool of Principal Component Analysis (PCA) was applied innovatively in this work to define the macro-cracks. The clustering method was further developed in this work for vector analysis so that the displacement vectors around macro-cracks could be classified into different types based on the failure mechanism to understand the crack development characteristics. The crack development between two cavities and failure mechanism for different geometrical configurations were subsequently studied in detail using experimental and numerical results.