Abstract: Cyclic loading induces crack formation in rock, which weakens its structural integrity. It is crucial to investigate the damage evolution process. Acoustic emission (AE) and resistivity monitoring technology can effectively track rock damage by detecting changes in fracture patterns. Integrating AE and resistivity parameters allows for a comprehensive characterization of damage progression during cyclic loading and unloading. This study employed AE and resistivity monitoring to examine damage in sandstone specimens with varying moisture contents under cyclic loading. Computed tomography (CT) scans were utilized to map crack distributions post-fracture. Using AE and resistivity parameters, damage variable equations were developed, leading to the derivation of a constitutive model for uniaxial cyclic loading and unloading. The results demonstrate that the damage variable equations accurately capture the damage evolution of sandstone during loading and unloading. The close agreement between the constitutive model’s predictions and experimental data highlights its practical utility for studying cyclic damage in sandstone.

Key words: sandstone, acoustic emission, resistivity, uniaxial grading cyclic loading and unloading, damage constitutive equation