综放采场初压阶段顶板稳定性与顶煤放出率关系探讨

Study on relationship between roof stability and recovery ratio of top coal at first weight period in fully-mechanized sublevel caving face

初次来压是综放采场矿压控制的重点之一,而顶煤从垮落到放完是一个动态过程,因此建立与顶煤放出率相关的顶板结构的稳定性判断准则是一个重要的理论课题。本文建立了综放采场顶板结构整体变形失稳和局部铰接失稳的力学模型;根据结构稳定理论和强度理论,得到了保持顶板结构整体变形稳定的顶板容许下沉量和保持岩块局部铰接稳定的顶板容许下沉量,通过与顶板回转下沉运动几何状态所决定的顶板下沉量的对比,分析了顶板结构整体变形稳定和岩块局部铰接稳定相统一的力学条件,从而建立与顶煤放出率相关的综放采场顶板稳定性判断准则;结合具体采场实例,给出了与顶煤放出率相关的综放采场顶板稳定性判断曲线和方法,为现场针对不同顶板设计合理的顶煤放出率,从而实现顶板的安全控制提供理论依据。

The first weight is the key of controlling mine pressure in fully-mechanized sublevel caving face. The course of top coal falling from beginning to end is a dynamic process. To set up the judgment rules of roof stability with the recovery ratio of top coal is an important theoretical problem. This paper establishes the mechanical model of the stability of the whole deformation of roof structure and the stability of partial contact of the main roof. Based on the structure stability theory and the strength theory, two kinds of limited convergence maintaining the stability of the whole deformation of roof structure and the stability of part contact of the main roof are obtained. According to the comparison of the two limited subsidence and the subsidence of roof caused by the movement situation of roof in the course of rotation, the unifying mechanical conditions between the stability of the whole transmutation of roof structure and the stability of part contact of the main roof are analyzed and the judgment rules of roof stability with the recovery ratio of top coal are established. Based on an example of fully-mechanized sublevel caving face, the judgment curve and method with the recovery ratio of top coal are put forward, the theoretical bases of designing the safe recovery ratio of top coal are provided for different roof, and the safe roof controlling is achieved at coal mine.