Compression characteristics of local filling gangue in Steeply Dipping Coal Seam

Coal gangue is widely used as a filling material in coal seam mining. During the gangue filling in steeply dipping coal seam, the loading rate, gangue gradation, and filling speed have an important impact on the deformation and failure of gangue, and further affect the bearing of gangue on overlying strata and the control of surrounding rock movement and deformation. Therefore, this article uses a self-made steel cylinder to conduct a gangue compression test on the HCT pressure testing machine. The research analyzes the influence of loading rate, gangue gradation, and filling rate on the deformation law of gangue in the compression process. After completing the test, the gangues with different particle size groups were rescreened, weighed, and recorded to analyze the crushing situation in the compression process. The results show that loading rate, gangue gradation, and filling speed have greatly influenced filling gangue's bearing capacity, deformation, and crushing rate. The larger the loading rate of gangue, the greater the bearing capacity and deformation of gangue, and the higher the crushing rate of gangue. The smaller the gangue gradation, the smaller the deformation, and the stronger the resistance to deformation. A more optimized gangue gradation ratio is obtained according to the distribution law of the mass proportion of gangue with different particle size groups after compression. The faster the filling speed of manual filling gangue, the greater the strength and deformation of the gangue body. Moreover, the faster filling speed can effectively improve when the strength reaches the peak and deformation tend to be stable. The results can provide theoretical guidance for the local filling of artificial gangue in the longwall working face of steeply dipping coal seam.