Study on mechanism of end face roof leaks based on stope roof structure movement under repeated mining

Li, Qiang; Wu, Guisheng; Kong, Dezhong; Han, Song; Ma, Ze

doi:10.1016/j.engfailanal.2022.106162

Cited by 30 publications

(11 citation statements)

References 24 publications

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“…Te initial coal seam cracks that form as a result of the coal seam's opening and growth widen and connect to form a fracture network, which changes the coal seam's gas fow state from difusion to nonlinear seepage to linear seepage and improves the coal's permeability. Te desorption impact of coal adsorption gas may also be increased by an increase in cracks, allowing more adsorbed gas to be transformed into free gas and accelerating extraction while decreasing the gas amount in the coal seam and enhancing gas extraction efciency [25][26][27][28][29].…”

Section: Principle Of Staged Hydraulicmentioning

confidence: 99%

Research and Application of Coal Seam Permeability Improvement Technology by Sectional Directional Hydraulic Fracturing

Wang

2024

Shock and Vibration

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To address the challenging issue of gas control in the working faces of the Hegang mining area, based on segmented directional hydraulic fracturing technology, ABAQUS simulation software was employed to simulate and analyze the fracturing process of coal-rock masses under the action of segmented hydraulic fracturing. The study focused on the engineering application research within the mining roadway of the 23# coal seam in the Junde Coal Mine, China. The results indicate that the numerical simulation analysis reveals elliptical patterns in the stress, strain, and fracture width variation of the coal-rock masses influenced by the fracturing action. The width of the fractures exhibits a periodic variation pattern, initially increasing and then slightly decreasing with the injection of water pressure. Additionally, each successive variation shows a decreasing magnitude. After applying segmented hydraulic fracturing technology, the average gas extraction concentration increased by a maximum of 1.73 times, the average mixed flow rate increased by a maximum of 2.16 times, and the average gas extraction pure quantity increased by a maximum of 3.10 times. Segmented hydraulic fracturing can effectively improve gas extraction efficiency, reduce coal seam gas content, and have a depressurizing effect on coal-rock layers. The research findings provide new means for safe and efficient coal mining, particularly in enhancing gas extraction efficiency, alleviating strata pressure, and preventing gas disasters.

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Section: Principle Of Staged Hydraulicmentioning

confidence: 99%

Research and Application of Coal Seam Permeability Improvement Technology by Sectional Directional Hydraulic Fracturing

Wang

2024

Shock and Vibration

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“…Through theoretical analysis, predecessor clarified that the rotation angle of the key block B of the main roof has a great relationship with the crushing degree of the immediate roof in the end face area, and the rotation angle has a great relationship with the mining height of the working face 38 . The strength of the surrounding rock of the roof reflects its bearing capacity of the upper strata and the gangue of the upper coal seam goaf, and also affects the crushing degree of the immediate roof in the end face area.…”

Section: Analysis On Influencing Factors Of Stability Of End Face Roofmentioning

confidence: 99%

Failure analysis and prediction of roof instability in end face under repeated mining using early warning system

Kong

et al. 2023

Preprint

Self Cite

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The overlying strata of the lower coal seam is easy to be collapsed causing the roof caving accident at the end face of the mining working face under repeated mining in close-distance coal seams. In order to predict the roof instability of the end face, the mechanical model of the granular arch structure is established in this study to further analyze its main influencing factors. The results show that the mining height of the working face, the advancing speed, the distance of coal seams, the tip-to-face distance, the strength of the surrounding rock and the support setting the load of the support are the main influencing factors on the roof caving of the end face. Subsequently, the prediction model of roof instability in the end face under repeated mining is constructed through the radial basis function neural network (RBFNN) and the above main influencing factors are regarded as input layer indexes. Meanwhile, the roof subsidence, coal wall deformation and support load are determined as the output layer indexes. The predicted results are closer to the results of sample tests. Finally, the early warning system, including monitoring and early warning, data query, emergency management, user management, and system settings, is designed to monitor roof conditions of the end face and timely warn the roof accidents. The field application proves that the system has good practical value, which is of great significance to prevent the end face roof disaster under repeated mining.

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“…Li et al investigated the movement of roof structures under repeated mining and its impact on the stability of the end-face roof. The direct fracture and hinged structure fracture of the cantilever beam structure under repeated mining is a significant reason for the end face roof leaks and support failure (Li et al, 2022b). Lai et al utilized the borehole TV system and the acoustic emission system for physical similarity simulation monitoring.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of stress transmission and feasibility of mining the lower coal seam under repeated mining in close-multiple coal seams

Yang,

Li,

et al. 2024

Front. Earth Sci.

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Mining in an upper coal seam results in the redistribution of vertical stress within a lower coal seam until a new equilibrium state is attained. Close-multiple coal seams mining faces the occurrence of multi-goafs and a complex stress environment. Based on a case study of close-multiple coal seams with repeated mining in the Qianjiaying coal mine, a stress distribution model of the floor in the coal seam striking range was established by optimizing the load form of the abutment pressure. The floor stress state after primary and repeated mining of upper coal seams was analyzed in a visual and quantitative manner. The concentrations of vertical stress, horizontal stress, and shear stress are all located in the floor under the coal rib after primary and repeated mining. The curve of stresses gradually levels off as the depth of the floor increases, indicating a diminishing influence of mining-induced stress from the upper coal seam. Based on the stress analysis by numerical simulations, the overall lower coal seam remains in a state of large-scale stress relief. Stress relief occurred twice under repeated mining, which indicates that the lower coal seam has favorable mining feasibility. The results of the study can provide scientific guidance to prevent mining accidents.

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Study on mechanism of end face roof leaks based on stope roof structure movement under repeated mining

Cited by 30 publications

References 24 publications

Research and Application of Coal Seam Permeability Improvement Technology by Sectional Directional Hydraulic Fracturing

Research and Application of Coal Seam Permeability Improvement Technology by Sectional Directional Hydraulic Fracturing

Failure analysis and prediction of roof instability in end face under repeated mining using early warning system

Mechanism of stress transmission and feasibility of mining the lower coal seam under repeated mining in close-multiple coal seams

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