关键词: 浅埋煤层, 相似模拟试验, 老顶结构, 砂土层载荷, 支架工作阻力

Abstract: This study is to improve the theory of overlying strata response and control during typical shallow coal seam longwall mining. A total of 22616 working face of Shendong coalfield was taken as an example. Similarity simulation experiment, theoretical analysis and field application were used to investigate the fracture characteristics of the overlying main roof and the load transfer effect of sandy soil stratum during the typical shallow buried coal seam longwall mining. A new method was proposed for calculating the supporting force in the period of roof weighing of the shallow stope, and it was further applied to determine the working resistance of support on site. Research results show that at the moment of the instability of the breaking main roof sliding, the dynamic loading occurr violently and the bench of overlying strata subsides obviously. The friction between sandy soil column leads to a certain transfer effect on the surface sand load but not its total self-weight acting on the bedrock. Hence, the load transfer effect of sandy soil stratum and the conditions of bedrock weight were taken into full account in this study. The rock column method was introduced to correct the classical mechanics model parameters of the main roof structure. Moreover, mathematical models of roof supporting force were improved during weighting in the shallow stope. Results show that the maximum working resistance of support is 10 506.8 kN per support during the first weighting of stope roof and the value is 7 475.26 kN per support during periodic weighting. It is proven that calculated results agree well with the field observation data. ZY11000/24/50 type hydraulic support is adopted to control the roof of stope, which perfectly meets the requirements of support force. Thus, both the safety and high-efficiency of mining in working face are well achieved. Therefore, this study provides important references for the determination and selection of the working resistance in the typical shallow coal seam of the longwall working face.

Key words: shallow coal seam, similarity simulation experiment, main roof structure, sandy soil stratum load, support working resistance