Study on the mechanisms of crack turning in bedded rock

Crack turning is difficult to study by performing physical experiments and field tests due to the multiple and complex cracking processes that occur in bedded rock. Stress concentration around a pre-existing flaw can induce the initiation and propagation of one or two macro-cracks. Hence, crack turning can be observed and analysed. In the present study, the failure of flaw-containing bedded rock is simulated, and the simulation replicates most of the phenomena observed in similar physical experiments. Five types of crack turning at bedding planes are observed during the cracking process. The results reveal that crack turning corresponds to not only tensile cracks but a combination of tensile and shear crack segments. Furthermore, crack turning corresponds to not only the continuous propagation of a single macro-crack but also the coalescence of two macro-cracks. By analysing force and displacement results, some intrinsic mechanisms are also revealed, which is beneficial for the study of bedded rock failure.

Automated summary

The study found that crack turning in bedded rock involves five types, and not only includes tensile cracks but also a combination of tensile and shear crack segments. In addition, crack turning involves not only the continuous propagation of a single macro-crack but also the coalescence of two macro-cracks.