Experimental investigation into damage and failure process of coal-rock composite structures with different roof lithologies under mining-induced stress loading

Chai, Yanjiang; Li, Dou; Cai, Wu; Małkowski, Piotr; Li, Xuwei; Gong, Siyuan; Bai, Jinzheng; Cao, Jinrong

doi:10.1016/j.ijrmms.2023.105479

Cited by 21 publications

(9 citation statements)

References 55 publications

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“…Many experts have studied the failure mechanism of coal-rock combined body through mechanical tests Zhang et al, 2023;Yang et al, 2022). Chai et al (2023) performed uniaxial static-cyclic loading tests on a series of combined bodies with different roof lithologies, and investigated the damage and failure process of combined bodies under mining-induced stress conditions, particularly the mechanical response and damage evolution of coal and rock under cyclic disturbance. Bai et al (2021) conducted uniaxial cyclic dynamic loading experiments with four different coal height ratios of combined bodies, analyzed the mechanical properties, failure modes, and wave velocity evolution of combined bodies, discussed the process of rock burst under coupled static and dynamic loads in rock-coal-rock combined body.…”

Section: Introductionmentioning

confidence: 99%

Coal-rock combined body failure mechanism based on crack distribution characteristics

Chen

2024

Acta Geodynamica Et Geomaterialia

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Many papers on axial compression tests of coal-rock combined bodies have observed the failure of rock components. However, the failure mechanism of the rock component has been the focus of debate among many scholars. One view is that the failure of the rock is due to the energy released during coal failure; the other view is that the failure of the rock is due to the inconsistent coal-rock lateral deformation resulting in tensile stress on the rock side of the coal-rock interface. In response to these two controversial failure mechanisms, coal-rock combined bodies with three coal-rock interface bonding methods (AB glue, direct contact, and graphite fluoride) were designed, and the axial compression tests were carried out. The results show that: (1) the damage cracks of the combined body are mainly distributed on the coal component, the stronger the interface adhesion, the easier it is to crack. (2) All three combined bodies showed rock component damage, and the number of cracks in the rock component was different at different interfaces of the combined bodies. The stronger the interfacial adhesion is, the easier it is to produce cracks, and the more the number of cracks in the rock component is. (3) The destruction of rock components is the result of energy transfer mechanism. Under the action of the test machine, the coal component is destroyed first, and a large amount of elastic energy is released instantaneously to the rock component, which reaches the energy storage limit of the rock and stimulates the destruction of the rock component. The tensile stress at the coal-rock interface plays a certain role in the propagation and penetration of cracks in the rock, but does not determine the damage of rock components. (4) The stronger the interfacial bonding, the greater the strength of the combined body. Based on the D-P criterion, the strength of coal rock at the interface of coal-rock combined body was analyzed. The strength of the coal body at the interface increases to a certain extent, and the strength of the rock mass at the interface decreases to a certain extent. ( 5) The stress distribution model of coal-rock combined body was constructed, and the internal mechanism of coal-rock component failure was further clarified. The coal and rock mass at the interface are the weak areas of the combined body, and the stress concentration in this area is the largest and the possibility of damage is the largest.

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Section: Introductionmentioning

confidence: 99%

Coal-rock combined body failure mechanism based on crack distribution characteristics

Chen

2024

Acta Geodynamica Et Geomaterialia

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“…Some laboratory and numerical simulation researches had been done on rock structure failure [20,21]. Dou and Drzezla [22] modified complex method of rock bumps hazard state in hard Coal Mines valuation. Haile and Bron [23] simulated coal burst experiment-evaluation of rock bolt reinforcement performance.…”

Section: Introductionmentioning

confidence: 99%

Microseismic fuzzy comprehensive evaluation method of coal burst - A case study in Zhaolou Coal Mine

Zhang,

Liang,

Lin

et al. 2024

Preprint

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Based on a coal burst in LW 1305 and combined with the curve of stress vs. strain, six multi-parameters are proposed to forewarn coal burst induced by static high-stress concentration and impact loading, containing microseismic (MS) activity S value, fault total area A(t) value, lacking of shock b value, statistical Z value, MS entropy value and the dominant frequency. The precursors mainly characterize the enhancement trend of S value, the suddenly and sharply rise of A(t) value, the continuous and abnormal lower b value, the increasing absolute value of Z sharply and large than 2, the continuous and abnormal decline of Qt value, and the dominant frequency moving to low-frequency band, respectively. The coal burst in LW 1305 was induced by the intrinsic static high-stress concentration and the external strong impact loading generated by fracturing of the key stratum. Essentially, a lot of micro-fissures inside the key stratum had initiated, converged and connected to form the macro-fracture above LW 1305, which was verified by the attenuation rate of K value. Considering the time-varying effect of the overlying stratum movement, the curves of the six multi-parameters have a good agreement with that of stress vs. strain, which indicates it is reasonable to take the observed zone as a whole system to investigate variation of the multi-parameters and fracturing of the key stratum. It is noteworthy that the MS multi-parameters should be combined with reasonable mining arrangement and corresponding prevention measures to monitor, forecast and control coal bursts in the field.

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“…Coal remains an indispensable fossil fuel in many countries and regions and plays an important role in the energy consumption structure [1][2][3][4]. As mining depth and intensity increase, the complex stress environment and geological structures have led to a variety of dynamic disasters during coal seam extraction, severely threatening mining safety [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Limitations of Upper Protective Layers as Pressure Relief Measures for Extra-Thick Coal Seam Mining: Insights from a Case Study

Chai,

Dou,

et al. 2024

Energies

Self Cite

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Upper protective layer (UPL) mining is extensively utilised as a pressure relief strategy to prevent outbursts and coal bursts. However, when the excavation height of the protected layer is substantial, the depressurisation efficacy of the protective layer may be diminished. This paper takes the Haishiwan coal mine in China as a case study and explores the stress evolution and influencing factors in the mining of extra-thick coal seam beneath the protective layer through theoretical analysis, numerical simulation, and field observation. The results indicate that increasing the excavation height of the coal seam will lead to the upward development of the collapse zone in the overburden of the goaf, with the “masonry beam” structure formed at a higher position by key strata blocks. The overburden above the masonry beam will be supported by the coal rock masse on both sides of the structure, leading to increased stress on the coal seam near the goaf and eliminating the depressurisation effect of the protective layer. Numerical simulation shows that factors such as faults, protective layers, interlayer spacing, and the height of coal seam excavation significantly affect the stress distribution in the protected layer. With the increase in interlayer spacing and the thickness of coal seam extraction, the stress reduction phenomenon of the UPL gradually decreases, especially with an abnormal stress concentration of the gob-side coal seam. Observations of Surface subsidence and the distribution of mining-induced seismic events corroborate the conclusions of theoretical analysis and numerical simulations. The results offer valuable guidance for the mining of extra-thick coal seams and the selection of the UPL.

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Experimental investigation into damage and failure process of coal-rock composite structures with different roof lithologies under mining-induced stress loading

Cited by 21 publications

References 55 publications

Coal-rock combined body failure mechanism based on crack distribution characteristics

Coal-rock combined body failure mechanism based on crack distribution characteristics

Microseismic fuzzy comprehensive evaluation method of coal burst - A case study in Zhaolou Coal Mine

Limitations of Upper Protective Layers as Pressure Relief Measures for Extra-Thick Coal Seam Mining: Insights from a Case Study

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