Investigation of Fracturing Process of Rock-Like Brazilian Disks Containing Three Parallel Cracks under Compressive Line Loading

The pre-cracked disk specimens (Brazilian disks containing three parallel cracks in the middle part of the disks) of rock-like materials are experimentally tested under compressive line loading. The tested specimens are prepared from portland pozzolana cement, fine sands and water in the rock mechanics laboratory. The breaking load of the pre-cracked disk specimens are measured (showing the decreasing effects of the cracks and their orientation on the final breaking stress). The fracturing process of the disk specimens is studied by inserting three parallel cracks with different inclination angles in the Brazilian type disks. The specimens are tested under compressive line loads just like in the conventional Brazilian tests. It has been experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of compressive line load. Then the same specimens are numerically simulated by a higher order indirect boundary element method known as displacement discontinuity method. The numerical results of cracks initiation and cracks coalescence are compared with the corresponding experimental results for various cases. It is shown that there is a good agreement between the numerical and experimental results.