Mechanical behavior of sandstone at various stages under cyclic loading

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Materials Science

Background:

• Understanding sandstone mechanical behavior under cyclic loading is crucial for infrastructure stability.
• Cyclic loading can induce progressive damage and failure in rock masses.

Purpose of the Study:

• To investigate the mechanical behavior of sandstone during different failure stages under cyclic loading.
• To characterize deformation, energy evolution, and acoustic emission (AE) at each stage.

Main Methods:

• A three-level cyclic loading path was applied to sandstone samples.
• Deformation response, energy evolution, and acoustic emission (AE) characteristics were analyzed.
• Mechanical behavior was assessed across initial crack closure, elastic deformation, and crack propagation stages.

Main Results:

• Distinct stage-specific mechanical responses were observed.
• In unstable crack propagation, elastic modulus decreased rapidly, damage energy increased, and AE events and energy surged.
• Peak stress reduction rates were significantly higher during unstable crack propagation compared to elastic deformation.

Conclusions:

• Sandstone's mechanical response is highly dependent on the cyclic loading stage.
• Acoustic emissions and energy surges correlate with internal crack propagation and coalescence during stress drops.
• The study provides insights into sandstone failure mechanisms under cyclic stress conditions.