Analysis and Application of the Dynamic Stability of Overlying Multilayer Spatial Structures in Deep Coal Mine

With the deepening of mining, dynamic disasters appear in a large number in the coal mine,. and the stress distribution and stress concentration caused by mining act as the important factors that induce the dynamic disasters. The range of overlying strata movement related to the appearing of mine press go beyond the range of traditional plane model, and influence the mining stress field as overlying strata spatial structures. The movement and distribution of overlying strata spatial structures are the theory bases of studying stress condition and dynamic condition of dynamic disaster. According to the characteristics of sediment rock and the movement of strata of overlying multilayer spatial structures in deep coal mine. By using the dynamic stability judgment rules controlled by the top coal's recovery ratio, the author worked out the judgment curves of dynamic stability of overlying multilayer spatial structures and explained their application. This paper also analyzes the factors influencing the dynamic stability of overlying multilayer spatial structures. The suggested judgment rule and curve of dynamic stability have been tested by field experiments which achieved safe caving in isolated caving face by adjusting the top coal's recovery ratio. The theoretical basis of designing the safe top coal's recovery ratio can be provided according to different overlying strata, and the safe overlying strata controlling can be achieved in deep coal mining.