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Geomechanics and Engineering
  Volume 31, Number 4, November25 2022 , pages 365-373
DOI: https://doi.org/10.12989/.2022.31.4.365
 


Damage characterization of hard-brittle rocks under cyclic loading based on energy dissipation and acoustic emission characteristics
Cheng J. Li, Pei J. Lou and Ying Xu

 
Abstract
    In order to investigate the damage evolution law of rock specimens under cyclic loading, cyclic loading tests under constant loads with different amplitudes were carried out on limestone specimens with high strength and brittleness values using acoustic emission (AE) technology and the energy evolution and AE characteristics were evaluated. Based on dissipated energy density and AE counts, the damage variable of specimen was characterized and two damage evolution processes were analyzed and compared. The obtained results showed that the change of AE counts was closely related to radial deformation. Higher cyclic loading values result in more significant radial strain of limestone specimen and larger accumulative AE counts of cyclic loading segment, which indicated Felicity effect. Regarding dissipated energy density, the damage of limestone specimen was defined without considering the influence of radial deformation, which made the damage value of cyclic loading segment higher at lower amplitude loads. The damage of cyclic loading segment was increased with the magnitude of load. When dissipated energy density was applied to define damage, the damage value at unloading segment was smaller than that of AE counts. Under higher cyclic loading values, rocks show obvious damage during both loading and unloading processes. Therefore, during deep rock excavation, the damages caused by the deformation recovery of unloading rocks could not be ignored when considering the damage caused by abutment pressure.
 
Key Words
    AE counts; cyclic loading; damage variable; energy dissipation; residual strain
 
Address
Cheng J. Li: State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,
Anhui University of Science and Technology, Huainan, Anhui 232001, China;
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, Anhui 232001, China
Pei J. Lou: School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, Anhui 232001, China;
Engineering Research Center of Underground Mine Construction, Ministry of Education, Anhui University of Science and Technology, Huainan, Anhui 232001, China
Ying Xu: State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,
Anhui University of Science and Technology, Huainan, Anhui 232001, China;
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, Anhui 232001, China;
Engineering Research Center of Underground Mine Construction, Ministry of Education, Anhui University of Science and Technology, Huainan, Anhui 232001, China
 

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