Analysis of mechanical behaviour and fracture interaction of multi-hole rock mass with DIC measurement

To study the mechanical properties and fracture behaviour of rock containing multiple cavities, uniaxial compression experiments were carried out on marble specimens with three rectangular cavities of different layouts. The fracturing behaviour was revealed by digital image correlation (DIC) measurement. Then, discrete element method (DEM) numerical simulations were performed and the stress evolution was analysed to reveal the influence of cavity layout on fracture behaviour and coalescence patterns between them. Results showed that stress evolution and failure coalescence pattern between two cavities can be directly or indirectly influenced by the third cavity. The compressive stress concentrated around the sidewalls of a cavity may suppress the propagation of tensile cracks from other cavities. Combining laboratory and numerical results shows that during the failure evolution, firstly comes the internal coalescence of cavities before instability point, then follows failure from the three-cavity system boundary to the specimen borders resulting in the whole instability.