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Study on the Damage Mechanism and Energy Evolution Characteristics of Water-Bearing Coal Samples Under Cyclic Loading
https://orcid.org/0000-0001-9420-8635
Abstract In this study, cyclic loading–unloading experiments on coal samples with different moisture contents were conducted. The damage mechanism was investigated through acoustic emission (AE) monitoring. The validity of the average frequency and rise angle (RA–AF) correlation for the fracture evolution of water-bearing coal samples under cyclic loading was verified. The damage evolution equation of coal samples based on energy dissipation theory was proposed. The results show that at the same growth rates of damage variables for the three water-bearing coal samples, there is a characteristic stress σ' (σ' = 5.36 MPa, N = 3) in the evolution of damage variables of the samples. Under cyclic loading, the moisture content was negatively correlated with the damage variable during the initial damage stage, while the two were positively correlated during the accelerated damage stage. The total strain energy of the water-bearing coal samples increases with the increase in the loading cycles, and the higher the moisture content, the greater is the total strain energy. The results of cyclic loading–unloading experiments demonstrate that there is a correlation between the damage process caused by moisture content and stress in coal samples, and the evolution of dissipation energy and the development of hysteresis loops are both related to the presence of the characteristic stress σ'. The RA–AF scatter plot and probability density plot feedback of each period correspond to the characteristics of damage evolution. This study verifies the feasibility of RA–AF qualitative evaluation of fracture type evolution mode of water-bearing coal samples under cyclic loading.
Highlights The coal pillar dams of the underground reservoir are simplified to the model of coal samples with different moisture contents under cyclic loading.There is a characteristic stress σ' in the evolution of damage variables of the water-bearing coal samples under cyclic loading–unloading.Based on energy dissipation theory, the equations describing the damage evolution of water-bearing coal samples are established.Qualitative characterization of the evolution of fracture types within each cycle using RA–AF correlation was studied.
Study on the Damage Mechanism and Energy Evolution Characteristics of Water-Bearing Coal Samples Under Cyclic Loading
https://orcid.org/0000-0001-9420-8635
Abstract In this study, cyclic loading–unloading experiments on coal samples with different moisture contents were conducted. The damage mechanism was investigated through acoustic emission (AE) monitoring. The validity of the average frequency and rise angle (RA–AF) correlation for the fracture evolution of water-bearing coal samples under cyclic loading was verified. The damage evolution equation of coal samples based on energy dissipation theory was proposed. The results show that at the same growth rates of damage variables for the three water-bearing coal samples, there is a characteristic stress σ' (σ' = 5.36 MPa, N = 3) in the evolution of damage variables of the samples. Under cyclic loading, the moisture content was negatively correlated with the damage variable during the initial damage stage, while the two were positively correlated during the accelerated damage stage. The total strain energy of the water-bearing coal samples increases with the increase in the loading cycles, and the higher the moisture content, the greater is the total strain energy. The results of cyclic loading–unloading experiments demonstrate that there is a correlation between the damage process caused by moisture content and stress in coal samples, and the evolution of dissipation energy and the development of hysteresis loops are both related to the presence of the characteristic stress σ'. The RA–AF scatter plot and probability density plot feedback of each period correspond to the characteristics of damage evolution. This study verifies the feasibility of RA–AF qualitative evaluation of fracture type evolution mode of water-bearing coal samples under cyclic loading.
Highlights The coal pillar dams of the underground reservoir are simplified to the model of coal samples with different moisture contents under cyclic loading.There is a characteristic stress σ' in the evolution of damage variables of the water-bearing coal samples under cyclic loading–unloading.Based on energy dissipation theory, the equations describing the damage evolution of water-bearing coal samples are established.Qualitative characterization of the evolution of fracture types within each cycle using RA–AF correlation was studied.
Study on the Damage Mechanism and Energy Evolution Characteristics of Water-Bearing Coal Samples Under Cyclic Loading
https://orcid.org/0000-0001-9420-8635
Abstract In this study, cyclic loading–unloading experiments on coal samples with different moisture contents were conducted. The damage mechanism was investigated through acoustic emission (AE) monitoring. The validity of the average frequency and rise angle (RA–AF) correlation for the fracture evolution of water-bearing coal samples under cyclic loading was verified. The damage evolution equation of coal samples based on energy dissipation theory was proposed. The results show that at the same growth rates of damage variables for the three water-bearing coal samples, there is a characteristic stress σ' (σ' = 5.36 MPa, N = 3) in the evolution of damage variables of the samples. Under cyclic loading, the moisture content was negatively correlated with the damage variable during the initial damage stage, while the two were positively correlated during the accelerated damage stage. The total strain energy of the water-bearing coal samples increases with the increase in the loading cycles, and the higher the moisture content, the greater is the total strain energy. The results of cyclic loading–unloading experiments demonstrate that there is a correlation between the damage process caused by moisture content and stress in coal samples, and the evolution of dissipation energy and the development of hysteresis loops are both related to the presence of the characteristic stress σ'. The RA–AF scatter plot and probability density plot feedback of each period correspond to the characteristics of damage evolution. This study verifies the feasibility of RA–AF qualitative evaluation of fracture type evolution mode of water-bearing coal samples under cyclic loading.
Highlights The coal pillar dams of the underground reservoir are simplified to the model of coal samples with different moisture contents under cyclic loading.There is a characteristic stress σ' in the evolution of damage variables of the water-bearing coal samples under cyclic loading–unloading.Based on energy dissipation theory, the equations describing the damage evolution of water-bearing coal samples are established.Qualitative characterization of the evolution of fracture types within each cycle using RA–AF correlation was studied.
Study on the Damage Mechanism and Energy Evolution Characteristics of Water-Bearing Coal Samples Under Cyclic Loading
Xie, Hongxin (author) / Li, Xuehua (author) / Shan, Changhao (author) / Xia, Ze (author) / Yu, Liqiang (author)
2022
Article (Journal)
Electronic Resource
English
BKL:
38.58
Geomechanik
/
56.20
Ingenieurgeologie, Bodenmechanik
/
38.58$jGeomechanik
/
56.20$jIngenieurgeologie$jBodenmechanik
RVK:
ELIB41
Study on Damage Characteristics of Water-Bearing Coal Samples under Cyclic Loading–Unloading
| DOAJ | 2022