Aliha - Fatigue and Fracture Lab., Department of Mechanical Engineering, Iran University of Science and Technology Narmak, Tehran
Ayatollahi

Crack growth in rock materials generally occurs due to a combined effect of shear and tensile loads. Therefore, assessment of rock fracture esistance under combined mode I-II is inevitable. Although there are numerous experimental data in the literature for combined mode I-II fracture toughness of rocks, the available fracture theories are not able to predict the fracture toughness values obtained from some of the experimental results. In this research, a modified fracture theory is used for predicting the combined mode I-II fracture toughness of brittle materials like rocks. It is shown that the modified theory can provide much better predictions for the experimental data reported from fracture tests conducted on a synthetic soft rock.

Fracture resistance, Combined mode, Rock, Crack