Mechanical Model and Analysis on Movement of Rock Strata between Coal Seams in Pillar Upward Mining of Left-Over Coal

Feng, Guo Rui; Zheng, Jing; Ren, Ya Feng; Zhong, Cong Ming; Kang, Li Xun

doi:10.4028/www.scientific.net/amm.58-60.393

Cited by 4 publications

(6 citation statements)

References 1 publication

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“…where a represents the contact area of the block per unit width, and η c is the corner compression factor; η c is set to 0.3. η e is defined as the horizontal thrust comprehensive environmental influence factor, which represents the weakening effect of the environment on the compressive strength and is determined through experiments [19]. By substituting Equations ( 11) and ( 12) into Equation (13a) and rearranging them, Equation (13b) is obtained.…”

Section: Condition For Rotation Instabilitymentioning

confidence: 99%

“…This method accounts for the stability of the rock strata structures at the floor of the upper coal seam but does not provide stability conditions and quantitative determination methods for the balanced surrounding rock stratum. Guorui Feng [18,19] proposed a determination criterion for the upward mining of residual coal, centering the method around the "stability of the controlling stratum structures". It determined the feasibility of upward mining based on the stability of the interburden strata structures.…”

Section: Introductionmentioning

confidence: 99%

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A Disturbed Voussoir Beam Structure Mechanical Model and Its Application in Feasibility Determination of Upward Mining

Zhang,

Wang,

Cui

et al. 2023

Energies

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China is endowed with a large quantity of residual coal resources that require upward mining. The stability of interburden strata structures and accurate determination are crucial for safe mining. Therefore, we established a mechanical model of disturbed voussoir beam structures of interburden strata in upward mining. The model was solved, and stability analysis and instability mechanism analysis were conducted. Based on this model, a new method for determining the feasibility of upward mining was proposed and applied to the upward mining of coal seam No. 7 in Baijiazhuang Coal Mine. A physical simulation experiment and numerical simulation were conducted to validate the method. Through research, it was found that the model had two instability mechanisms: rotation instability and sliding instability. When the disturbance load crossed the critical block of the structures, the model was most likely to experience sliding instability. When the disturbance load acted entirely on the critical block, rotation instability was more likely to occur. The result of the determination, performed using the new method, showed that there was no rotation instability or sliding instability in the interburden strata structures of coal seam No. 7, indicating that the coal seam could be mined upward. This result was consistent with the determinations using the statistical method, “three-zone” method, and balanced surrounding rock method. Physical and numerical simulations revealed that the upward mining of coal seam No. 7 caused the subsidence, rotation, and separation compaction of the interburden strata structures but that the structures remained stable. The results indicate that the proposed model and method have accuracy and applicability, being able to guide the practical feasibility determination of upward mining.

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Section: Condition For Rotation Instabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Disturbed Voussoir Beam Structure Mechanical Model and Its Application in Feasibility Determination of Upward Mining

Zhang,

Wang,

Cui

et al. 2023

Energies

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“…Studies from similar simulation tests and site investigations demonstrated that: the thick and hard strata, termed as ‘dominant strata’, plays a controlling role in bearing the overburden and guaranteeing the safety of upward mining [ 30 , 58 ]. Based on the stratigraphic and geomechanical information collected at Baijiazhuang coal mine, limestone with an average thickness of 7.5 m can be regarded as the dominant strata.…”

Section: Vertical Stress Of Interburdenmentioning

confidence: 99%

“…The residual coal seam over abandoned workings is also a typical resource, which is distributed in many coalfields across China [ 30 ]. It has considerable reserves and enormous excavation potential.…”

Section: Introductionmentioning

confidence: 99%

Vertical stress and stability of interburden over an abandoned pillar working before upward mining: a case study

et al. 2018

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Upward mining of the residual coal seam over an abandoned pillar working is one of the effective measures to alleviate the contradiction between limited resources and increased consumption. Interburden stability over an abandoned pillar working plays a significant role in guaranteeing the safety of upward mining; however, it has not yet been extensively studied and understood. In this study, the vertical stress of the interburden over an abandoned pillar working was first investigated. The mechanical model of the interburden was established and the damage conditions were analysed. Then, the stability of the interburden over 38502 abandoned workings in Baijiazhuang coal mine was determined by mechanical analysis and field monitoring. The results show that: (i) Vertical stress of the interburden over abandoned mining zones is clearly lower than the initial stress, indicating the existence of a de-stressed effect. Moreover, vertical stress of the interburden over residual coal pillars is greater than the initial stress, which is the evidence of a stress concentration effect. (ii) The interburden over an abandoned pillar working should be regarded as an elastic rectangular plate supported by generalized Kelvin bodies in mechanical modelling. (iii) The interburden over abandoned mining zones may experience two damage stages. In the first stage, initial plastic damage appears at the central region of interburden. In the second stage, the plastic damage evolves from the central point to the surrounding areas. (iv) The mechanical analysis and field monitoring both indicate the initial damage occurred at the central region over 38502 abandoned workings in Baijiazhuang coal mine before upward mining. Related rock control measures should be implemented in that region to guarantee the safe mining of the residual coal seam.

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“…Numerous researchers have conducted extensive research on the structure of rock strata in upward mining, yielding significant findings. Feng et al [10][11][12] discovered that, in the residual mining area using the caving method, interlayer rock strata breakage in 2 of 17 upward mining resulted in a neatly arranged and mutually squeezed "block beam-semiarch" structure due to the shear dilation effect. Ma et al [13] found that the extraction of the lower coal seam alters the structure of overlying rock strata and the distribution pattern of mine pressure in the upper coal seam.…”

Section: Introductionmentioning

confidence: 99%

Calculation Method of Support Load Zoning and Mechanism of Mine Pressure Behavior in Upward Mining Face across Half of the Goaf along the Panel Direction

Zhang,

Ma,

Feng

et al. 2024

Processes

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The 1515 mining face in Yongming Coal Mine was upward mined across half of the goaf along the panel direction. In this paper, the methods of field measurement, theoretical analysis, and numerical simulation were used to study the overlying rock fracture structure, support load characteristics, and the mechanism of mine pressure behavior across half of the goaf. The results indicate that the support load of the 1515 upward mining face across half of the goaf along the panel direction exhibits distinct zoning characteristics. The maximum support load is 1.37 times the minimum support load. The development height of the roof separation in the up-mining area is 1.74 times that in the entity coal area, at 9.1 m and 5.22 m respectively. The height of separation and hanging roof length increase and decrease, respectively, along the initial rock fracture area, tensile fracture area, structural fracture area, and compacted fracture area. Based on the definition of the variation coefficient “m” for immediate roof height and hanging roof coefficient “n”, a partitioned method for calculating support loads in the upward mining face across half of the goaf was proposed. Finally, the key parameter values for support loads in each zoning were provided and validated.

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Mechanical Model and Analysis on Movement of Rock Strata between Coal Seams in Pillar Upward Mining of Left-Over Coal

Cited by 4 publications

References 1 publication

A Disturbed Voussoir Beam Structure Mechanical Model and Its Application in Feasibility Determination of Upward Mining

A Disturbed Voussoir Beam Structure Mechanical Model and Its Application in Feasibility Determination of Upward Mining

Vertical stress and stability of interburden over an abandoned pillar working before upward mining: a case study

Calculation Method of Support Load Zoning and Mechanism of Mine Pressure Behavior in Upward Mining Face across Half of the Goaf along the Panel Direction

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