Study on the Initiation of Interface Crack in Rock Joints

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Fracture Mechanics

Background:

• Interfacial fracture in rock joints is a critical yet often overlooked aspect of jointed rock engineering.
• Understanding these fractures is essential for the stability and safety of rock structures.

Purpose of the Study:

• To propose a novel interface crack model for rock joints.
• To establish a reliable fracture criterion for predicting interface crack initiation.

Main Methods:

• Developed an interface crack model for rock joints.
• Analyzed stress intensity factor ratios to determine fracture modes.
• Established an interface fracture criterion incorporating the Mohr-Coulomb criterion and T-stress.
• Validated the criterion through laboratory and numerical testing.

Main Results:

• The proposed fracture criterion accurately predicts interface crack initiation.
• Increased cohesion (c) leads to a significant rise in mode II fracture toughness (KII).
• Relative critical size (α) has a greater impact than friction angle (φ) on crack initiation when mode I stress intensity factor (|KI|) is low.

Conclusions:

• The developed fracture criterion provides a robust method for predicting rock joint interface crack initiation.
• The study highlights the significant influence of cohesion, friction angle, and relative critical size on crack behavior.