A CRITERION FOR FRACTURE ANGLES IN ISOTROPIC BRITTLE ROCKS

Abstract

The Coulomb criterion for shear failure is extended to predict fracture angles under general triaxial stresses, where the cohesive strength and the coefficient of internal friction are no longer considered constants and are functions of the intermediate and the minimum principal stresses.
Fracture angles calculated on the basis of the new criterion developed here agree with those obtained experimentally by other researchers within experimental errors.