Roof movement and instability fracture characteristics in shallow-buried thin coal seam conventional mining faces

• Published in: Geomechanics and geophysics for geo-energy and geo-resources. Vol. 10; no. 1; pp. 1 - 20
• Main Authors: Zhang, Jihua, Rui, Qiao, Yang, Yushun, Chen, Jiarui, Shen, Wei, Yuan, Yue, Wang, Chengwu, Liu, Weili
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2024; Springer Nature B.V; Springer
• Subjects: Adaptability; Bending stresses; Coal; Coal mines; Coal mining; Control stability; Conventional working face; Deformation; Dynamic loads; Energy; Engineering; Environmental Science and Engineering; Exponential functions; Foundations; Fracture characteristics; Fracture mechanics; Geoengineering; Geomechanical challenges in the process of comprehensive utilization of closed/abandoned mines; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Instability; Load; Maximum bending; Mechanical analysis; Mechanics; Mining; Mining accidents & safety; Movement; Pressure; Roof movement; Stability analysis; Technical services; Theoretical analysis; Theories; Thin coal seam; Thin plates; Width; Work face; Roof movement; Fracture characteristics; Thin coal seam; Theoretical analysis; Conventional working face
• ISSN: 2363-8419; 2363-8427
• DOI: 10.1007/s40948-024-00738-0

The variation in the width of the mining face significantly affects the stability of the face, leading to potential roof fracturing and collapse. Additionally, strong mining pressure can manifest, severely impeding the safe production of coal mines. This study uses the No. 16705 conventional working face of Jinda Coal Mine as its engineering background to investigate the characteristics of roof strata movement and instability under conditions of variable-width mining in shallow-buried thin coal seams. First, the dynamic load of the roof strata is estimated based on the key strata theory. Next, a mechanical model of the immediate roof strata movement in the working face is established based on the theory of elastic thin plates, which has been used to reveal the impact of different dimensions of the overhanging plate structure and residual overhanging structures in the corner on roof movement and its associated fracture mechanics. The findings indicated that the maximum bending deformation, deformation moment, and bending stress all have an exponential function relationship with the roof width. Similarly, these metrics have an exponential function relationship with the overhanging span of the roof. In addition, these parameters all have a linear functional relationship with the size of the residual overhanging structures in the corner. Finally, the effect of roof instability on overlying pressure is analyzed, and both the initial fracture step length and cyclic movement fracture step length of the roof are estimated. These insights offer valuable scientific guidance and a theoretical foundation for analyzing the adaptability of load-bearing pillars pressure in thin coal seam mining faces, bearing significant relevance to safety production. Highlights A mechanical model was constructed by theory of the thin plate and the key layer that cloud analyze the initial and periodic roof breakages of conventional working face. During the periodic roof breakage phase, the mechanical response of the roof's bending under stress was more obvious than the initial fracture stage. The study can provide scientific guidance and technical support for the stability control of the working face roof and the selection of load-bearing pillars.