Experimental study on mechanical and damage characteristics of coal under true triaxial cyclic disturbance

Duan, Manli; Jiang, Changbao; Yin, Wenming; Yang, Ke; Li, Jiazhuo; Liu, Qinjie

doi:10.1016/j.enggeo.2021.106445

Cited by 48 publications

(18 citation statements)

References 36 publications

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“…erefore, the deformation and fracture process of rock must be accompanied by the transformation of energy [21][22][23][24][25][26]. It is feasible to analyze the energy transformation characteristics of rock deformation and fracture process, and nd the appropriate energy transformation related features to describe the damage characteristics of rock.…”

Section: Damage Variable Based On Energy Dissipationmentioning

confidence: 99%

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Study on Damage Law of Raw Coal Based on Different Characterization Methods

Duan

Tang

et al. 2022

Advances in Civil Engineering

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The different damage variables equation based on strain, energy dissipation, acoustic emission (AE), and permeability characteristics under tiered cyclic loading were defined. The damage variables based on different characteristics were compared, analyzed, and found that there are similarities and differences between them. The results show that: (1) the law curve of single cycle damage based on residual deformation and permeability is the same. With the increase of cycle times, it decreases first and then gently increases, increased sharply before the failure. However, the law curve of single cycle damage based on energy dissipation and AE ring count shows that it first increases slowly and the adjacent failure increases rapidly. (2) The cumulative damage evolution law based on residual deformation and permeability show an obvious three-stage pattern; that is, first accelerates, then slows down, and then accelerates again. However, the cumulative damage evolution law based on energy dissipation and AE ring count shows an obvious two-stage pattern, that is, first gently increases, and increased sharply before the failure.

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Section: Damage Variable Based On Energy Dissipationmentioning

confidence: 99%

“…U is the total amount of all cyclic energy dissipation before failure. e speci c calculation method of energy dissipation can refer to the previous research literature [22].…”

Section: Damage Variable Based On Energy Dissipationmentioning

confidence: 99%

Study on Damage Law of Raw Coal Based on Different Characterization Methods

Duan

Tang

et al. 2022

Advances in Civil Engineering

Self Cite

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“…Therefore, in addition to understanding various mechanisms of microseismicity induced by human activities, 23,24 it is also necessary to discuss the negative impact of cyclic or fatigue loads generated by induced microseisms on hydraulic fracturing operations. The research in the mechanical behaviors of intact rock under cyclic or fatigue loads, the effect of stress amplitude, loading frequency, and loading direction on rock damage have been studied extensively 25–28 . Cerfontaine and Collin 29 concluded that the number of cycles to failure of rocks decreased with increasing amplitude and that the frequency was also proven to modify the fatigue life.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of fatigue load effect on the hydraulic fracturing behavior of granite

Zhu

et al. 2022

Fatigue Fract Eng Mat Struct

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Rock masses around fluid injection projects are usually subject to complex stress states, including hydraulic pressure, in situ stresses, and fatigue loads.Thus, a series of hydraulic fracturing experiments were performed on granite to simulate such stress states using the true triaxial dynamic testing system.Computed tomographic (CT) imaging was performed to identify the fatigue effects on hydraulic fractures. The results indicate that the increasing amplitudes of cyclic load applied on the minimum principal stress direction will change fracture initiation pressure and generate nonplanar and narrow fractures. When the disturbance direction was changed to the intermediate principal stress, the higher amplitude corresponds to the lower breakdown pressure and the shorter pressurize duration and leads to wider fractures. With the increasing disturbance frequency, complex fatigue cracks were generated, which might weaken the rock strength. The present experiments can enhance the understanding of the hazard of fatigue loads on hydraulic fracturing.

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“…But in soft coal seams where hydraulic fracturing has poor permeability enhancement effect, large-diameter borehole gas drainage is widely used, and good drainage effect has been achieved [24,25]. However, in deep mining, drilling, and other engineering activities, the mechanical and seepage characteristics of coal and rock will be significantly changed under the influence of cyclic loading or even stratified cyclic loading [26]. In addition, the geological conditions and gas occurrence conditions of coal seams are significantly different in different mines, and the main control factors affecting gas occurrence are also different.…”

Section: Introductionmentioning

confidence: 99%

Mining Stress Distribution and Gas Drainage Application of Coal Seam Group under Fault Influence

et al. 2022

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The existence of fault structures often seriously endangers the safe production of coal mines. In order to ensure the safe and efficient production of close coal seam group mines under the influence of faults, it is of wide engineering significance to study the gas occurrence and extraction technology between coal seam groups under the influence of faults. In this study, the mining and gas drainage of 13817 working face in Yueliangtian Mine were taken as the research background. Combined with theoretical research, laboratory analysis, and numerical simulation analysis, the pressure relief range of coal seam and the evolution characteristics of surrounding rock stress were studied, the coal and gas comining system under the influence of faults was determined, the gas drainage technology was optimized, and the effect was investigated and analyzed. The results show that the gas pressure reduction zone is formed in the range of 20 m and 6 m of the lower wall of F1 fault, and the pressure relief effect is good in the range of 40 m above the roof of the working face to 20 m below the bottom plate during the advancing process. The optimized gas drainage technology has a good effect on gas control in coal seam group mining under the influence of faults. The absolute gas emission of the working face is reduced to 28~36 m3/min, the gas concentration in the upper corner of the mining face is about 0.6%, and the gas concentration of the return airflow is reduced to less than 0.5%. The gas extraction rate of No. 8 coal seam is 52.9%, and the gas content in the fault zone is reduced by 60%, realizing the safe and efficient comining of coal and gas. The research results have certain reference and application value for mine gas control with similar mining conditions.

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Experimental study on mechanical and damage characteristics of coal under true triaxial cyclic disturbance

Cited by 48 publications

References 36 publications

Study on Damage Law of Raw Coal Based on Different Characterization Methods

Study on Damage Law of Raw Coal Based on Different Characterization Methods

Experimental study of fatigue load effect on the hydraulic fracturing behavior of granite

Mining Stress Distribution and Gas Drainage Application of Coal Seam Group under Fault Influence

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