Numerical investigation on the crack resistance curve of thermally treated quartz‐diorite rock under mixed mode I + II loading.

To investigate the effects of thermal treatment and loading conditions on the crack initiation and propagation characteristics of quartz‐diorite, mixed mode I + II fracture tests were conducted by using three‐point bending (TPB) specimens. The numerical model, established on ABAQUS, couples the initial fracture toughness criterion and cohesive zone model to predict the crack initiation and propagation. The effects of thermal treatment and loading conditions on the crack propagation process, crack resistance curve, fracture path, and some fracture parameters at peak load have been analyzed and discussed. The results demonstrate that the thermal treatment has an obvious influence on the crack resistance curve of the specimen. The crack of the specimen will be dominated by the mode I fracture component with crack extension. The numerical results also show that the temperature and loading condition affect the crack length and fracture toughness at peak load. Highlights: The loading mode of the specimen changes to mode I loading with crack growth.Thermal treatment decreases the fracture resistance of rock under the same crack length.Mode I fracture resistance at peak load is insensitive to the variation of loading mode. [ABSTRACT FROM AUTHOR]