Numerical modeling of coal wall spall in a longwall face

Bai, Qingsheng; Tu, Shihao; Chen, Min

doi:10.1016/j.ijrmms.2016.07.031

Cited by 67 publications

(48 citation statements)

References 23 publications

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“…The gradually compacted property could be modeled by the Double‐Yield model . In this paper, the stress‐strain relationship of rock mass in caving zone is given by using the theory of crushed rock compaction put forward by Salamon

σ_{v} = E_{0} ε / false(1 - ε false/ ε_{m} false)

where

σ_{v}

is the vertical stress in goaf, MPa;

E_{0}

is the initial elastic modulus of the intact rock, MPa;

ε

is the current vertical strain;

ε_{m}

is the maximum vertical strain.…”

Section: The Deformation and Failure Mechanismmentioning

confidence: 99%

“…21 In this paper, the stress-strain relationship of rock mass in caving zone is given by using the theory of crushed rock compaction put forward by Salamon. 22 where v is the vertical stress in goaf, MPa; E 0 is the initial elastic modulus of the intact rock, MPa; is the current vertical strain; m is the maximum vertical strain. E 0 could be determined by formula (5).…”

Section: The Constitutive Model Of the Caving Zonementioning

confidence: 99%

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Failure mechanism of the large‐section roadway under mined zones in the ultra‐thick coal seam and its control technology

Tai

Xia

Meng

et al. 2019

Energy Science & Engineering

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Aiming at serious deformation and failure of large‐section coal roadway under mined zones in ultra‐thick coal seam, its deformation and failure characteristics are analyzed based on the field measurement. This paper reveals the mechanism of roadway roof separation, roof leakage, and right rib extrusion. Based on the mechanism, two kinds of secondary support schemes are proposed, that is, “grouting + I‐steel support + bolt” (scheme I) and “grouting + U steel support + anchor + anchor cable” (scheme II). The industrial experiment is carried out at 1070 auxiliary transportation roadway in Tashan Coal Mine. The measured results show that the roadway roof separations of the secondary support scheme I and II are only 1/11 and 1/46 of the original support scheme, respectively, while the lateral displacements of the roadway are only 1/7 and 1/44 of the original support scheme. It could be seen that the deformation and failure of the roadway surrounding rock have been well controlled.

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σ_{v} = E_{0} ε / false(1 - ε false/ ε_{m} false)

where

σ_{v}

is the vertical stress in goaf, MPa;

E_{0}

is the initial elastic modulus of the intact rock, MPa;

ε

is the current vertical strain;

ε_{m}

is the maximum vertical strain.…”

Section: The Deformation and Failure Mechanismmentioning

confidence: 99%

Section: The Constitutive Model Of the Caving Zonementioning

confidence: 99%

Failure mechanism of the large‐section roadway under mined zones in the ultra‐thick coal seam and its control technology

Tai

Xia

Meng

et al. 2019

Energy Science & Engineering

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“…In the FLAC 3D software, the elastic parameters consist of the bulk modulus K and shear modulus G, therefore, Equation (1) can be expressed as [29]:…”

Section: Energies 2017 101005mentioning

confidence: 99%

Numerical Modelling of Mechanical Behavior of Coal Mining Hard Roofs in Different Backfill Ratios: A Case Study

Li¹,

Zhou²,

Zhang³

et al. 2017

Energies

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Abstract:In coal mining hard roofs are one of the main factors causing the occurrence of rock bursts in working panels. To solve this problem, the solid backfill coal mining (SBCM) technique is proposed and used as an effective measure to prevent the rock bursts induced by hard roofs. However, due to the different backfill ratios of working planes, the control effects on hard roofs are quite unique. By using a numerical simulation, this study simulates the deformation of hard roofs and distributions of stress and strain energies in different roof-control backfill ratios, so as to reveal the control mechanisms of SBCM on hard roofs. The results show that, when the roof-controlled backfill ratio are 0, 40% and 60%, the ratio exerts no influence on the distributions of advanced abutment stress and strain energies. While for roof-control backfill ratios of 82.5%, 91% and 93%, the advanced abutment stress and strain energies decrease significantly, but the increment of the ratio exerts little influence on the decrease. When the roof-control backfill ratio reaches 97%, the advanced abutment stress and strain energies again decrease. In this context, the stress concentration factor is only 1.5 and the peak strain energy is 544 kJ/m 3 , the stress concentration factor and peak strain energy decrease by 45.7% and 63.9%, respectively, compared with the caving method. As the roof-controlled backfill ratio rises, backfill materials tend to support hard roofs, thus significantly preventing dynamic hazards.

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“…8,9 Therefore, in China FMMTLMH has become the common method for extracting thick coal seams whose thickness is less than 7.0 m as this method has lower roadway driving rate, and a high coal recovery rate among other advantages. [12][13][14][15] For example, as shown in Figure 1, a large number of support failure accidents (e.g., support closure and hydraulic leg damage) occurred during periodic weighting in FMFLMH8218 in Jinhuagong coal mine. 11 Although relatively popular, there is a lack of FMMTLMHrelated theoretical research, which leads to frequent coal wall falls, roof falls, and hydraulic support failure accidents, which affect coal production and its efficiency.…”

mentioning

confidence: 99%

“…11 Although relatively popular, there is a lack of FMMTLMHrelated theoretical research, which leads to frequent coal wall falls, roof falls, and hydraulic support failure accidents, which affect coal production and its efficiency. [12][13][14][15] For example, as shown in Figure 1, a large number of support failure accidents (e.g., support closure and hydraulic leg damage) occurred during periodic weighting in FMFLMH8218 in Jinhuagong coal mine. This accident affected coal production for 81 days, and resulted in loss of 89.4 million yuan.…”

mentioning

confidence: 99%

Determination of working resistance based on movement type of the first subordinate key stratum in a fully mechanized face with large mining height

Zou

2019

Energy Science & Engineering

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The increase in extraction height will increase the mining‐induced overlying strata failure height. In this scenario, the strata pressure behavior is strong in a fully mechanized face with large mining height (FMFLMH), which frequently causes coal wall falls, roof falls, and hydraulic support failure accidents (e.g., support closure and hydraulic column damage). The key to solving these issues is to determine support's working resistance of the FMFLMH. In this paper, comprehensive theoretical analysis, numerical simulation, and field observation were applied to determine the support's working resistance in the FMFLMH based on movement type of the first subordinate key stratum (SKS 1). First, six kinds of movement types of SKS 1 in the FMFLMH are found and defined by theoretical analysis and numerical simulation, which are the direct caving movement type of cantilever structure (direct caving), the double‐sided rotation movement type of cantilever structure (double‐side rotation), the quadratic rotation movement type of cantilever structure (quadratic rotation), the alternative movement type of cantilever structure hinged structure (alternate hinged), the voussoir beam structure movement type (voussoir), and the short voussoir beam structure movement type (short voussoir), respectively. Besides, based on this, the support load calculation model of each movement type was established, and a formula for the support working resistance of each movement type was obtained. Finally, the correctness of the formulae for the support working resistance under six types of movement of SKS 1 were verified using measurement data from four FMFLMHs in China. These research results have important guiding significance for reasonable selection of support and ensuring safe mining of the FMFLMH.

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Numerical modeling of coal wall spall in a longwall face

Cited by 67 publications

References 23 publications

Failure mechanism of the large‐section roadway under mined zones in the ultra‐thick coal seam and its control technology

Failure mechanism of the large‐section roadway under mined zones in the ultra‐thick coal seam and its control technology

Numerical Modelling of Mechanical Behavior of Coal Mining Hard Roofs in Different Backfill Ratios: A Case Study

Determination of working resistance based on movement type of the first subordinate key stratum in a fully mechanized face with large mining height

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