Subcritical crack growth in geological materials

A review is presented of the experimental data on subcritical crack growth in geological materials. The main parameters describing subcritical crack growth are the critical stress intensity factor K c , the subcritical crack growth limit K o , and the stress intensity factor‐crack velocity (K‐v) relationship between K o and K c . The K‐v data are presented in terms of an equation in which the crack velocity depends on stress intensity factor...