3D analysis of longwall face stability in thick coal seams

Song, Gaofeng; Chugh, Yoginder P.

doi:10.17159/2411-9717/2018/v118n2a6

Cited by 27 publications

(17 citation statements)

References 9 publications

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“…e main factors affecting the stability of the composite roof structure are considered to be the lithology of strata, strata thickness, number of strata, strata location, and interlayer cohesive force. e comprehensive strength index of the composite roof is introduced to analyze stability; however, the equation does not consider the influence of strata location, number of strata, and interlayer cohesion force [13][14][15]. e application of this equation has certain limitations.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process

Xiong

Dai

Wang

2019

Advances in Civil Engineering

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The composite roof structure of coal roadway is complex, and its stability is related to lithology of strata, strata thickness, number of strata, strata location, and interlayer cohesive force. Based on a simplified model of the composite roof structure, simulation test, analytic hierarchy process (AHP), and Matlab, programs are employed to comprehensively analyze the structural stability of roofs. The structural stability of the composite roof is demonstrated to decrease with the lithology of strata, strata thickness, and interlayer cohesive force and increase in number of strata and distance of hard-and-thick strata from the roadway. The decreasing order of influence of these factors on the composite roof structure is as follows: lithology of strata, strata thickness, number of strata, strata location, and interlayer cohesive force. Lithology of strata is the main factor affecting stability. The bending strength decreases with the increase in number of strata, and the influence of strata position on stability decreases from the first layer to the fourth layer. According to the AHP, an expression for the comprehensive influence coefficient (k) for the stability of the composite roof structure is proposed, and the surrounding rocks are divided into three levels using this equation: grade I with 0.7 < k < 1 (stable), grade II with 0.4 < k < 0.7 (slightly stable), and grade III with 0 < k < 0.4 (unstable). A scientific basis to evaluate the stability and control of the composite roof of a complex structure is thus provided.

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Section: Introductionmentioning

confidence: 99%

Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process

Xiong

Dai

Wang

2019

Advances in Civil Engineering

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“…The face failures can be divided into structural failure and functional failure . Stress normally exceeds peak coal strength in abutment pressure zones around the longwall face.…”

Section: Introductionmentioning

confidence: 99%

“…Parametric analysis has been performed based on the theoretical models to assess the influence of seam height, depth of cover, seam inclination, coal mechanical properties, and shield performance on face stability . In addition, a number of numerical and physical modeling studies of longwall face failure have been performed to reproduce the progressive development of face collapse with face advance . Important factors such as gob stiffness, shield stiffness, and shield loading characteristics were also included.…”

Section: Introductionmentioning

confidence: 99%

“…The face failures can be divided into structural failure and functional failure. [13][14][15][16] Stress normally exceeds peak coal strength in abutment pressure zones around the longwall face. The coal mass around abutment zones may fracture or yield; it may not fall since it is relatively confined laterally and is unable to deform.…”

mentioning

confidence: 99%

“…21,22 In addition, a number of numerical and physical modeling studies of longwall face failure have been performed to reproduce the progressive development of face collapse with face advance. 14,[23][24][25][26] Important factors such as gob stiffness, shield stiffness, and shield loading characteristics were also included. These studies have provided broad-based observations on how these factors affect face failure.…”

mentioning

confidence: 99%

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Optimization of face flexible bolting and grouting technology for longwall face support under difficult geological conditions

Yang

Song

et al. 2019

Energy Science & Engineering

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Longwall face fall in the open face area is one of the most difficult ground control problems in mining thick coal seams in China especially under difficult geological conditions. This paper has proposed a new flexible bolting and grouting technology for face support. The flexible support method includes face support using flexible coir ropes and face grouting with cement and accelerator mixtures. Numerical and laboratory studies of pullout tests are performed to further improve the flexible support performance including optimization of boreholes and flexible bolts diameters, and selection of grouting materials. The results show that (a) The optimized rope‐borehole diameter ratio is around 0.5 to ensure the best face reinforcement; (b) The grouting material (a mixture of ultrafine cement, mineral powder and sodium silicate) shows advantages of low cost, effective waste disposal, reduced setting time, and good pullout limit force and is recommended for industrial application with sodium silicate at a proportion of 10% by weight and mineral powder at 30%. The application of the new flexible bolting and grouting method in Chenmanzhuang mine shows improved face stability and reduced capital cost.

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Numerical Modeling Study of the Geo-mechanical Response of Strata in Longwall Operations with Particular Reference to Indian Geo-mining Conditions

et al. 2019

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3D analysis of longwall face stability in thick coal seams

Cited by 27 publications

References 9 publications

Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process

Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process

Optimization of face flexible bolting and grouting technology for longwall face support under difficult geological conditions

Numerical Modeling Study of the Geo-mechanical Response of Strata in Longwall Operations with Particular Reference to Indian Geo-mining Conditions

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