Study on Roof Instability Effect and Bearing Characteristics of Hydraulic Support in Longwall Top Coal Caving

Zeng, Qingliang; Li, Zhaoji; Wan, Lirong; Ma, Dejian

doi:10.3390/app13148102

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…The studies on the relationship between top coal and hydraulic support in the roof control area are relatively focused on the process of top coal releasing at the back of the support: Krzysztof Skrzypkowski et al used the bearing capacity index "g" to evaluate the cooperation between the top of the support and the rock body to determine whether the conditions for maintaining excavation are stable [22]; Zeng Qingliang et al, based on the dynamic coupling numerical model of hydraulic support and top coal, determined the main influencing factors of hydraulic support working resistance, including fracture location, force and gangue distribution [23]. The problem of coal leakage between hydraulic supports has been raised in the research of comprehensive mining of extremely soft coal seam.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Yang,

Zhang,

Wang

2024

Energies

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Extremely loose and soft coal seams, with a Platts coefficient of less than 0.3, are easy to break in the process of integrated mechanized roof coal mining and are prone to spilling and piling up between the hydraulic supports, which is a safety hazard for the movement of equipment. The coal particles must be cleaned up manually, resulting in reduced resource recovery rates and lower mining face efficiency. To effectively mitigate and control the problem of coal spillage accumulation amidst hydraulic supports, this study utilizes discrete element numerical simulation to examine the characteristics of block size distribution and the spilling process during the crushing of highly loose and soft top coal. By taking into account various parameters associated with shelf spacing, this research identifies key factors for controlling arching and self-stopping phenomena in top coal particles. The study findings suggest that the uppermost coal layer undergoes significant fragmentation during the integrated mining process of loosely packed and soft coal seams, resulting in a higher probability of coal leakage issues observed near the rack’s coal wall side and at the end of the roof control area. The key factors contributing to the self-arresting of spilled coal particles include inherent characteristics of the coal body, particle diameter, and stand spacing. In this specific mine under investigation, an arch formation naturally occurs to prevent further leakage when the distance between stands is less than eight times the diameter of particles, and after process correction, the average time saving for a single shift of manual floating coal cleaning at the working face is about 2 h, and the proportion of time saving is more than 50~75%.

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Section: Introductionmentioning

confidence: 99%

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Yang,

Zhang,

Wang

2024

Energies

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Numerical Modeling of Engineering-Scale Jointed Coal Mass and Confining Pressure Effect

Zhang,

Wang,

Wang

et al. 2024

Applied Sciences

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In coal masses, joints serve as crucial components influencing mechanical responses and failure mechanisms. The joint distribution complicates the acquisition of physical parameters for engineering-scale coal masses, and traditional laboratory or in situ tests often suffer from inaccuracies and high costs. Therefore, examination of the dynamic properties of engineering-scale coal mass is generally performed by numerical simulations. This paper proposes a model construction approach using two-dimension Particle Flow Code (PFC2D) software to study the mechanical properties of engineering-scale jointed coal mass, addressing the limitations of conventional models by integrating scale effects, accuracy, and computational efficiency. Firstly, the distribution characteristics and mechanical parameters of the joints in the coal mass were obtained based on field statistics and laboratory experiments. The parameters of the laboratory-scale model were calibrated by the numerical matching method. The discrete element model for the engineering-scale coal mass was constructed by the step-by-step matching method. The confining pressure effect on the coal mass under a biaxial loading condition was studied, while the strength change, fissure evolution, and failure mechanism under different confining pressures and fissure degrees were investigated. Based on the simulation results, a quantitative relationship was established between the mechanical parameters, fissure degree, and confining pressure under compression conditions. Ultimately, the failure zone ahead of the working face and the distribution of the abutment pressure were assessed using the mechanics parameters of coal masses with diverse joint distributions.

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Study on the Damping Performance of the Arrangement of Half-Bowl Spherical Structure Under Impact Velocity

Ma,

Zhang,

Meng

et al. 2024

Processes

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During mine excavation, rock wall collapse can pose a safety risk to miners. Reasonably designed support equipment can prevent collapse and ensure a safe working environment. In this paper, a new half-bowl spherical rubber structure is introduced and modeled using Abaqus to study its damping ability under different impact energies. By comparing the support reaction forces and pressures of the A-S, R-S, and C-S structures, we find that the R-S structure, with a smaller number of half-bowl spheres, has superior energy absorption abilities and impact resistance. These findings support the designing and manufacturing of mining support equipment.

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Study on Roof Instability Effect and Bearing Characteristics of Hydraulic Support in Longwall Top Coal Caving

Cited by 3 publications

References 33 publications

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Numerical Study on the Characteristics and Control Method of Coal Leakage between Supports in Integrated Mining of Extremely Loose and Soft Coal Seams

Numerical Modeling of Engineering-Scale Jointed Coal Mass and Confining Pressure Effect

Study on the Damping Performance of the Arrangement of Half-Bowl Spherical Structure Under Impact Velocity

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