Experimental and numerical study of crack propagation and coalescence in pre-cracked rock-like disks

• The pre-cracked disc specimens (Brazilian rock-like disc specimens) of rock-like materials are experimentally tested under compressive line loading.
• The development and coalescence of wing cracks may be the main cause of the breakage paths in rock-like disc specimens.
• The same specimens are numerically simulated by an indirect boundary element method known as displacement discontinuity method.
• A numerical simulation has been accomplished to study the effect of crack length and its orientation on the breakage path.

The pre-cracked disk specimens (Brazilian disks containing single and double cracks in the middle part of the disk) of rock-like materials were experimentally tested under compressive line loading. The specimens were prepared from Portland Pozzolana Cement (PPC), fine sands and water. The failure load of the pre-cracked disks was measured, showing the decreasing effects of the cracks and their orientation on the final failure load. The breakage process of the disks was studied by inserting single and double cracks with different inclination angles. It was observed that wing cracks are produced at the first stage of loading, and start their propagation toward the direction of compressive line loading. The same specimens were numerically simulated by an indirect boundary element method known as the displacement discontinuity method. Finally, a numerical simulation was conducted to study the effect of crack length and its orientation on the cracks coalescence and breakage path.