ON THE CRACK PROPAGATION MECHANISM OF BRITTLE ROCKS UNDER VARIOUS LOAING CONDITIONS

The crack propagation mechanism of rocks under tensile and compressive loading conditions has been investigated. A higher order indirect boundary element method using special crack tip elements has been used to solve the various example problems in rock fracture mechanics. It is concluded that the brittle rocks fail due to the mixed mode fracture propagation under both tensile and compressive loading conditions. The micro-cracks are initiated due to tensile or tensile and shear under tensile loadings and due to tensile and shear under compressive loadings. The final crack propagation is due to tensile or induced tensile for both loading conditions. Several example problems solved numerically and the results are compared with both analytical and experimental results. The results are compared with the corresponding results given in the literature and show good agreements with the analytical or observed experimental results.