With the increasing engineering activities on mining and construction in complex geological environments (e.g. deep mining, construction in cold regions, and construction of nuclear waste repositories), the stability of rock engineering under various geological environments has attracted attention both from academics and engineering practice. It is well known that the natural rock mass is made up of heterogeneous materials with various discontinuities. Rock failure occurs through a complex process involving crack propagation and coalescence of discontinuities.

The different engineering conditions can change rock fracture behaviours significantly, and the special rock fracture mechanics models are required. More specifically, the degradation in fracture toughness, fracture characteristics, and fracture behaviour in rock masses in complex geological environments require more attention. The current understanding of how cracks initiate and propagate in the rock mass, namely the fracture mechanism of jointed rocks, is limited, which requires research from theoretical analyses and experimental tests to numerical simulations to be conducted to tackle this challenge.

The aim of this Special Issue is to gather original fundamental and applied research concerning fracture characteristics of rocks under different engineering conditions, such as thermal shock, freeze-thaw cycle, dry-wet cycle, acid-alkali corrosion, etc. Contributions on fracture mode, fracture toughness, fracture surface morphology, micro-fracture mechanism, crack coalescence modes and failure criteria are especially encouraged. Both original research papers and review articles are welcome.

Potential topics include but are not limited to the following:

• Damage and crack evolution in jointed rock masses
• Rock fracture toughness under different conditions
• Morphology of rock fracture surfaces
• Micro-mechanism of rock failure in different geological environments
• Numerical simulation of failure process of fractured rocks
• Real-time SEM observations of rock failure processes
• Acoustic emission technology to track rock cracks
• Crack coalescence modes and the failure criteria