Rockburst mechanism in soft coal seam within deep coal mines

Zhang, Junfei; Jiang, Fuxing; Yang, Jian‐Bo; Bai, Wushuai; Zhang, Lei

doi:10.1016/j.ijmst.2017.03.011

Cited by 82 publications

(33 citation statements)

References 14 publications

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“…With increased intensity of deep mining, disasters such as rock burst, coal and gas outbursts have become more frequent, seriously affecting the safety of coal production [1][2][3]. Coal mine safety is required for efficient coal production, and the prevention and control of rock and coal outbursts is an important component of overall mine safety.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

Zhu

Wei

et al. 2020

Energies

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To evaluate the influence of water content on the hard coal dynamic behavior, the dynamic tensile properties of saturated coal Brazilian disk (BD) samples were studied using a split Hopkinson pressure bar system, and dry samples were also tested as a control group. In the range of impact speeds studied, the tensile strength of the saturated coal is lower than that of the dry specimen. A synchronized triggering high-speed camera was used to monitor the deformation and failure process of dry and saturated coal samples, allowing analysis of the failure stages and mechanism of dynamic BD test, the broken mode was classified into three types, which can be classified into unilateral tensile failure, bilateral or multilateral tensile failure, and shear failure. Finally, fragments smaller than 5 mm in diameter were statistically analyzed. There is less debris in range of 0–5.0 mm for the saturated coal sample than for the dry coal. This study provides some information about the dynamic response of the hard coal for the relevant practical engineering.

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Section: Introductionmentioning

confidence: 99%

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

Zhu

Wei

et al. 2020

Energies

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“…17 Many researches have been conducted on MS monitoring in coal mines for several years, and a number of practical applications with a self-developed MS monitoring system have been performed. [18][19][20][21] These researches have laid the foundation for the application of MS monitoring in coal mines. 22,23 Meanwhile, MS has been studied depending on the theories and practices of dynamic disasters in coal mines.…”

Section: Introductionmentioning

confidence: 99%

Underground microseismic monitoring of a hydraulic fracturing operation for CBM reservoirs in a coal mine

Jiang

et al. 2019

Energy Science & Engineering

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Hydraulic fracturing can evidently improve the coalbed methane production in underground coal mines, but it is difficult to delimit the stimulated area accurately. In order to evaluate the stimulated area, microseismic (MS) monitoring technique is proposed to investigate the seismic responses of the induced fractures of hydraulic fracturing. Three coal seams were targeted to be treated in a coal mine. An array of geophones was set along the underground roadway to detect the MS signals caused by HF. In order to verify the result of MS monitoring, water content of each coal seam has been measured before and after HF treatment. The results showed that a series of MS events were detected during the entire HF process, and a sharp MS event usually occurred during the first hour of HF process. The energy of the sharp MS event had higher magnitude than others. The MS distribution exhibited complex morphological features. The directionless MS response was distributed over a radius of less than 40 m but tended to be significantly conjugated with a radius of more than 40 m. HF could stimulate both the coal seam and the rock layers nearby. The achievable stimulated area in the coal seam was determined to be 50 m × 50 m according to the MS density and water content. The stimulated area in terms of MS density was easily found to be broader than the area of water direct intrusion. The present study indicated that MS monitoring technique could potentially be used for evaluation of HF in underground coal mine.

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“…Rock bursts are worldwide geological disasters, and almost all mines in the various coal producing countries of the world have suffered from this phenomenon. To date, researchers in China and elsewhere have conducted a great deal of research on the following aspects of rock bursts (Zhang et al, 2017;He et al, 2016): (1) the occurrence mechanism, their instability. Zuo et al (Zuo et al, 2013) found that the failure of a combined coal-rock mass mainly occurred inside the coal, and the confining pressure, combination modes, and loading conditions played a very important role on the failure mode of the combined samples.…”

Section: Introductionmentioning

confidence: 99%

Tests on the dynamic failure rules of coal-rock composites

Qin¹

2019

Acta Geodynamica Et Geomaterialia

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Coal measure strata are composed of multiple interbedding strata with different hardnesses. A sudden release of energy that was stored in surrounding rocks of tunnels may induce a rock burst; however, the specific strata in which the energy is accumulated cannot be accurately determined, thereby leading to ineffective prevention and management techniques for rock bursts. To address this problem, this study conducted axial loading tests on three different types of rock specimens (coal, gritstone and fine sandstone) and their composite specimens, and ascertained the energy accumulation rules of various components of the composites prior to a buckling failure. According to the results: for the coal-bearing binary composite specimens, the energy accumulated in coal occupied 88.5 %, 79.0 %, 71.4% and 79.6 % of the total energy accumulated in the specimens respectively; for the binary composite specimens composed of gritstone and fine sandstone, the energy accumulated in gritstone took up 61.2 % and 76.5 % of the total energy accumulated in the specimens respectively; and for the ternary composites, the energy accumulated in the coal occupied 79.8 %, 74.0 % and 76.3 % of the total energy accumulated in the specimens respectively, followed by the energy accumulated in the gritstone (12.1 %, 22.0 % and 18.8 %), and finally by the energy accumulated in the fine sandstone (only 8.1 %, 4.0 % and 4.9 %). Accordingly, in the composite rock strata, a small amount of energy was stored, and energy accumulation was more difficult in competent rock with large elastic moduli, while non-competent strata with small elastic moduli were preferable with regard to energy storage and accumulation. It can thus be concluded that the energy in coal-rock composites was accumulated mainly in non-competent strata, i.e., non-competent strata were key energy strata; additionally, the greater the difference in the hardness of the various components, the stronger the impact effect on the composite specimen.

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Rockburst mechanism in soft coal seam within deep coal mines

Cited by 82 publications

References 14 publications

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

Dynamic Tensile Strength of Dry and Saturated Hard Coal under Impact Loading

Underground microseismic monitoring of a hydraulic fracturing operation for CBM reservoirs in a coal mine

Tests on the dynamic failure rules of coal-rock composites

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