Local fracture toughness testing of sandstone based on X-ray tomographic reconstruction

It is well known that the measured values of the fracture toughness of rocks are influenced by material heterogeneity, dimensions, boundary conditions, and asymmetric mechanical behavior. Consequently, the results obtained by standard testing methods developed primarily for homogenous materials with symmetric mechanical behavior, can significantly differ. The standard methods take global approach. Thus, they suppose that the material tested will...