Abstract:

In order to clarify the laws of mining induced overburden failure and ground pressure behavior in deep mining face with large mining length, taking the No. 22010 working face of Chaochuan Mine as the research background, the mechanism of mine pressure behavior in deep mining face with large mining length was studied using numerical simulation, theoretical analysis and field measurement. The numerical simulation results show that the overlying rock fractures development during the working face mining can be devided into four stages: fracture generation, fracture expansion, separation development and fracture compaction. The maximum height of water-conducting fissured zone is 87. 98 m, and the fracture mining ratio is 18. 72; Based on the fractal geometry theory, the multi-stage development characteristics of mining fracture field are clarified, and the fractal evolution function of mining fracture is constructed by Levenberg-Marquardt algorithm. According to the fractal evolution results, the mining fracture field is divided into water-conducting fissured area, collapse fissured area, fissure compaction area, separated layer development area, bending subsidence area and surface subsidence area; By constructing the mechanical model of the thin plate structure of the basic roof in the large mining length working face, the relationship between the stress distribution of the thin plate structure and the boundary support conditions as well as the shape coefficient is clarified, and the plastic development process of the initial fracture of the basic roof structure is clarified. Finally, the quantitative relationship between the limit load and the structural scale under the critical state of the initial fracture of the basic roof thin plate structure is established; The field monitoring results show that the roof pressure of the large mining length working face has the “arch” distribution characteristics of large in the middle and small at both ends. The research results provide a theoretical reference for the safe mining and zoning treatment of the deep buried large mining length working face.