Mechanism and risk assessment of overall-instability-induced rockbursts in deep island longwall panels

Zhu, Sitao; Feng, Yali; Jiang, Fuxing; Liu, Jinhai

doi:10.1016/j.ijrmms.2018.04.031

Cited by 60 publications

(34 citation statements)

References 20 publications

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“…During the course of mining, the overlying strata are shifted and stress is redistributed to the surrounding rock, resulting in abutment pressure. Failure to account for abutment pressure distribution leads to coal mine hazards, such as rockbursts, coal and gas outbursts, and roadway deformation and instability [1][2][3][4][5][6][7][8][9]. Forecasting and preventing these hazards, controlling the surrounding rock in mining roadways, determining a reasonable width for protection coal pillars, and designing the layout of mining roadways are all based on the distribution of abutment pressure.…”

Section: Introductionmentioning

confidence: 99%

Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

Han

Wang

et al. 2019

Advances in Civil Engineering

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Overburden key strata (KS) have a significant influence on abutment pressure distribution. However, current calculation methods for working surface abutment pressure do not consider the influence of the overburden KS. This study uses KS theory to analyze the overburden load transferred to coal-rock masses on both sides of the stope through fractured blocks in different layers of the KS in the fissure zone and KS in different layers of the curve subsidence zone. Using Winkler’s elastic foundation beam theory, we consider the fissure zone KS on the coal mass side and the curve subsidence zone KS as many elastic foundation beams interact with each other. A method to calculate the abutment pressure of the coal mass and the goaf was then established, considering the influence of the overburden KS. The abutment pressure distribution of working surface 207 after mining was then calculated using our method, based on mining conditions present in the Tingnan coal mine. The calculated results were verified using measurements from borehole stress meters and microseismic monitoring systems, as well as numerical simulations. In addition, the calculation results were used to determine a reasonable position for the stopping line and remaining width of the roadway’s protection coal pillar in working surface 207. The results of this study can be used to calculate the abutment pressure distribution of the working surface under a variety of overburden KS conditions. The results can also provide guidance for forecasting and preventing mine dynamic hazards, controlling the surrounding rock in mining roadways, determining reasonable widths for protection coal pillars, and designing the layout of mining roadways.

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Section: Introductionmentioning

confidence: 99%

Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

Han

Wang

et al. 2019

Advances in Civil Engineering

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“…Equation (8) shows that the main influencing factors are the elastic modulus of the overhanging hard roof, the inertial moment of the overhanging hard roof, the internal friction angle of the coal-rock interface, the cohesive force of the coal-rock interface, the dip angle of the coal seam, the supporting force coefficient, the lateral pressure coefficient, the thickness of the coal seam, the mining depth, the average unit weight of the overlying strata and the unit weight of the loess.…”

Section: Influence Factors Of the Ede Of The Overhanging Roofmentioning

confidence: 99%

“…Currently, the mining depth of most coal mines in China is over 1000 m. Due to the high geostress and complex geological structures, rockbursts occur frequently in deep coal seams, which are difficult to control and cause serious losses [2][3][4][5][6][7]. About 180 coal mines in China experienced rockburst hazards until 2017 [8]. Western China is gradually shifting from a strategic resource reserve area to a production area, becoming the main mining area in recent years.…”

Section: Introductionmentioning

confidence: 99%

“…Li et al [13] revealed the mechanism of rockburst induced within fault pillars through theoretical derivation. Zhu et al [8] revealed the stress distribution of deep island longwall panels and overlying strata by theoretical analysis and numerical simulation. Jiang et al [25] and Wang et al [20,26] researched the stress in an island panel subjected to periodic weighting by the Fast Lagrangian Analysis of Continua (FLAC) method and obtained that there is a higher rockburst risk at the location of the peak abutment stress.…”

Section: Introductionmentioning

confidence: 99%

“…A hard roof has a great influence on coal seam damage, because a high dynamic load is imposed on the coal when it breaks [34,35]. Zhu et al [8] found that the rockburst occurred in deep island panels is mainly induced by the overall instability of the coal and rock around the working face. Chen et al [36] reported that during hard roof breakage or slip instability, the rockburst will be induced easily under the influence of instantaneously releasing a large amount of elastic energy.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism and Prevention of Rockburst in Steeply Inclined and Extremely Thick Coal Seams for Fully Mechanized Top-Coal Caving Mining and Under Gob Filling Conditions

Song

et al. 2020

Energies

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The steeply inclined and extremely thick coal seams (SIETCS) under the condition of gob filling frequently suffer from the occurrence of rockbursts. Figuring out the mechanisms of rockbursts under this condition for taking targeted measures to mitigate rockburst hazards in SIETCS is of great significance. Using the typical SIETCS with an average dip angle of 87° at Wudong Coal Mine (WCM) as a case study, a mechanical model and elastic deformation energy (EDE) function of a “steeply inclined suspended roof structure” was developed, and the influence factors were analyzed by theoretical analysis. Simultaneously, the rockburst risk assessment was carried out based on the theory of a rockburst start-up. The pressure relief measures are optimized by comparing the pressure relief effects of three kinds of destress blasting schemes. The results indicate that the damage characteristics of rockburst are mainly floor heave, the sidewall’s inward deformation and roof subsidence. The damage degree of headentry on the roof side is more severe than that of tailentry, and the resultant impacts showed the directionality from the roof side to the coal side. The steeply inclined and suspended roof breakage is one of the main causes for the occurrence of rockbursts. The EDE of the roof increases with an increasing dip angle of the coal seam from 0° to 72.6° and then decreases as the dip angle increases. Furthermore, that increase is accompanied by the decrease of the lateral pressure coefficient and the supporting force coefficient. The EDE stored in the roof is sufficient to cause roof breakage and induce rockburst after the complete roof exceeds a certain length. The mechanism of rockburst in SIETCS for fully mechanized top-coal caving mining under gob filling conditions was proposed, i.e., “high compressive stress concentration plus breakage of the suspended roof-induced stress” rockburst, and this is further verified by ground destruction, microseismic (MS) monitoring and numerical modeling. The results also indicate that alternate deep and shallow hole-blasting modes are more suitable for pressure relief in SIETCS.

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Characteristics and contributing factors of major coal bursts in longwall mines

Zhao

Qin

Xiao

et al. 2022

Energy Science & Engineering

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Coal burst has become one of the most serious hazards in longwall coal mines of many countries, and extensive studies have been conducted on the mechanism, prediction, and prevention of coal bursts. However, most of these studies focus on qualitative descriptions of burst environments and specific case analyses. Few studies have been carried out to explore knowledge through a number of past coal bursts in longwall mines. The main objective is to quantitatively analyze the current burst‐prone conditions in longwall coal mines of China and to summarize corresponding lessons. A database consisting of 54 major coal bursts was established. The characteristics and contributing factors of involved coal bursts were analyzed quantitatively, and high‐risk areas that are common in coal mines were then identified. Finally, some suggestions and lessons were proposed. This study may help for identifying controlling factors and high‐risk areas at a specific mine, and it might provide insights into the control of coal bursts in longwall coal mines.

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Mechanism and risk assessment of overall-instability-induced rockbursts in deep island longwall panels

Cited by 60 publications

References 20 publications

Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

Method to Calculate Working Surface Abutment Pressure Based on Key Strata Theory

Mechanism and Prevention of Rockburst in Steeply Inclined and Extremely Thick Coal Seams for Fully Mechanized Top-Coal Caving Mining and Under Gob Filling Conditions

Characteristics and contributing factors of major coal bursts in longwall mines

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