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Deformation Behaviour and Damage Evolution of Carbonaceous Phyllite under Cyclic Triaxial Loading
Helin Fu1,2, Kaixun Hu1,2, Yue Shi1,2
1School of Civil Engineering, Central South University, Changsha 410075, China.
Materials (Basel, Switzerland)
|July 14, 2023
Summary
This study investigated rock deformation under cyclic loading, revealing how stress impacts elastic modulus and Poisson's ratio. Damage accumulation, crucial for understanding rock mechanics, shows distinct stages leading to shear failure.
Area of Science:
- Geotechnical Engineering
- Rock Mechanics
- Materials Science
Background:
- Rock deformation under cyclic loading is complex and under-researched.
- Understanding these behaviors is critical for infrastructure stability and resource extraction.
Purpose of the Study:
- To analyze the degradation process of carbonaceous phyllite under triaxial cyclic loading.
- To investigate the influence of confining stress on rock deformation and failure modes.
Main Methods:
- Conducted triaxial multistage constant-amplitude cyclic loading experiments.
- Monitored variations in elastic modulus (E), Poisson's ratio (υ), irreversible strain (ε), and energy evolution.
- Examined macro and micro failure modes.
Main Results:
- Elastic modulus (E) decreased stepwise with increasing stress levels and cyclically.
- Poisson's ratio (υ) increased with stress and cycles.
- Irreversible strain (ε) showed exponential relationship with stress, accumulating rapidly then slowly.
- Damage evolution exhibited deceleration, stability, and acceleration stages, with acceleration near failure.
Conclusions:
- Cyclic loading significantly degrades rock properties, affecting stiffness and strain accumulation.
- Energy evolution analysis effectively quantifies rock damage.
- Failure modes are primarily shear, with associated grain crushing, under these conditions.
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