Study on overburden failure characteristics in deep thick loose seam and thick coal seam mining

Liu, Weitao; Pang, Lifu; Xu, Baichao; Sun, Xi

doi:10.1080/19475705.2020.1737584

Cited by 30 publications

(15 citation statements)

References 22 publications

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“…On‐site monitoring often relies on microseismic monitoring systems, drilling holes, and other means with which to achieve the goal of mine safety; research into gas‐bearing coal samples 13‐14 and has also involved use of acoustic emission 15 and Hopkinson pressure bar experimental systems 16 ; floor stress 17 ; and displacement 18 are also used as laboratory‐test‐based monitoring methods. To quantify cracking, some studies into crack density 19,20 and fractal dimensions 21,22 have been conducted. Scholars have successively proposed O‐shaped circle theory, 23,24 double‐circle theory, 25 the theory of the elliptic paraboloid zone, 26 etc.…”

Section: Introductionmentioning

confidence: 99%

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Xiao

Han

Shuang

et al. 2021

Energy Science & Engineering

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To prevent outbursts and extract the gas, it is necessary to investigate the structure of the key layer and the evolution of cracks during coal mining over a large height. A physical similarity model with a geometric similarity ratio of 1:100 and a strike length of 2 m was established on the basis of prevailing geological and mining conditions. Stress sensors and microseismic equipment were adopted to monitor the collapse characteristics of different key layers through variations in stress and energy. The research results showed that: The displacement of the overlying strata exhibited group motion characteristics marked by the key layer and there was zone of rapidly increasing stress in the goaf behind the working face before and after the fracture of the key layer. Through the analysis of microseismic events, fissure density, and fractal dimension, we found that: before and after the primary key layer fractured, the energy loss in the microseismic event accounted for 27% of the total, the fissure density also changed abruptly from 8 cracks/m to 10 cracks/m and the slope of the fractal dimension curves changed from 0.00243 to 9.94801 × 10−4. Then a gas drainage model suitable for this condition was constructed. When the primary key layer had not fractured, the cracks below fully developed to form a gas migration channel and a gas enrichment area, and gas boreholes could be arranged therein. After the primary key layer had been fractured, the rate of crack development decreased, the permeability would increase, and the gas concentration would increase. The boreholes could still be arranged in the gas migration channel. This study elucidated the control role of the primary key layer from multiple angles and provided experimental guidance for gas drainage over large‐mining heights and during complex key layer mining.

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Section: Introductionmentioning

confidence: 99%

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Xiao

Han

Shuang

et al. 2021

Energy Science & Engineering

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“…Some scholars at home and abroad have conducted a lot of research on the failure height of thick coal seams. Liu et al studied overburden failure characteristics in deep thick loose seam and thick coal seam mining [4]. Wang al.…”

Section: Introductionmentioning

confidence: 99%

“…Wang et al studied the process of overburden failure in steeply inclined multiseam mining: insights from physical modelling [15]. Liu et al used numerical simulation software FLAC3D to investigate overburden failure characteristics in deep thick loose seam and thick coal seam mining [4]. Xu et al analyzed the overburden migration and failure characteristics after mining shallow buried coal seams with thick loose layer based on actual measurement data and simulation results [16].…”

Section: Introductionmentioning

confidence: 99%

Height of the Fractured Zone in Coal Mining under Extra‐Thick Coal Seam Geological Conditions

Sun

Zhu

et al. 2021

Advances in Civil Engineering

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The height of the fractured zone caused by coal mining is extremely significant for safely mining under water, water conservation, and gas treatment. At present, the common prediction methods of overburden fractured zone height are only applicable to thin and medium-thick coal seams, not suitable for thick and extra-thick coal seams. In order to determine the overburden fractured zone distribution characteristics of extra-thick seam mining, failure process analysis method of overlying strata was proposed based on key strata theory. This method was applied to 15 m coal seam of Tongxin coal mine, and fractured zone height was determined to be 174 m for 8100 panel. EH4 electromagnetic image system and borehole televiewer survey were also conducted to verify the theory results. The distribution of the electrical conductivity showed that the failure height was 150–170 m. Observation through the borehole televiewer showed that the fractured zone height was 171 m. The results of the two field test methods showed that the fractured zone height was 150–171 m, and it was consistent with the theory calculation results. Therefore, this failure process analysis method of overlying strata can be safely used for other coal mines.

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“…Zhu et al (2020) confirmed that the transition layers of the bedrock layers and the loose layers has a support effect on mining subsidence. Liu et al (2020) found that the thick loose layer formed a bending collapse zone, fracture development zone and caving zone during the mining process through simulation analysis, and derived a prediction model based on elastic mechanics. Xu et al (2020) studied the movement laws of the overlying bedrock while mining shallow buried coal seams under thick loose layers.…”

Section: Introductionmentioning

confidence: 99%

Research on the establishment of a mining subsidence prediction model under thick loose layer and its parameter inversion method

Chen

et al. 2021

Earth sci. res. j.

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Most of the coal mining in China is underground, which will inevitably cause surface deformation and trigger a series of geological disasters. Therefore, it is essential to find a suitable method to forecast the ground sinking caused by underground mining. The most commonly used prediction model in China is the probability integral model (PIM). But when this model is used in the geological condition of mining under thick loose layers, the predicted edge of the sinking basin will converge faster than the actual measured sinking situation. A geometric model (GM) with a similar model shape as the PIM but with a larger boundary value was established in this paper to solve this problem. Then an improved cuckoo search algorithm (ICSA) was proposed in this paper to calculate the GM parameters. The stability and reliability of the ICSA were verified through a simulated working face. At last, the ICSA, in combination with the GM and the PIM, was used to fit 6 working faces with the geological mining condition of thick loose layers in the Huainan mining area. The results prove that GM can solve the above-mentioned PIM problem when it is used in geological mining conditions of thick loose layers. And it was obtained through comparative analysis that the GM and the PIM parameters can take the same value except for the main influence radius.

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Study on overburden failure characteristics in deep thick loose seam and thick coal seam mining

Cited by 30 publications

References 22 publications

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

The effects of key rock layer fracturing on gas extraction during coal mining over a large height

Height of the Fractured Zone in Coal Mining under Extra‐Thick Coal Seam Geological Conditions

Research on the establishment of a mining subsidence prediction model under thick loose layer and its parameter inversion method

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