Propagation of a crack in engineering materials including rocks can cause failure. Knowledge of the stress state under which a crack can propagate, and the trajectory it may follow during its growth are thus very important for stability of rock masses/materials and for safe design of structures in rocks and ceramics. In this paper, the surface’ effective shear stress of closed-crack was introduced into calculating the stress intensity factor (SIF). The value of SIF was calculated when cracks were in different length, different angle and differ...
