Mining-induced mechanical response of coal and rock at different depths: a case study in the Pingdingshan Mining Area

To explore the mining-induced mechanical response of coal at different depths, laboratory testing results and field initial geostress data are combined with the geological conditions to study the differences in mining-induced stress and deformation characteristics of the coal and rock at five different depths (300, 600, 700, 850, and 1050 m) by using FLAC(3D)software. The results show that with increasing mining depth, the abutment pressure increases, and the abutment pressure along the excavation direction at 1050 m is 7 times that at 300 m. With increasing mining depth, the deformation of the roof abscission layer gradually increases, and the deformation along the excavation direction at 1050 m is 4.6 times that at 300 m. The numerical simulation results are consistent with the field monitoring results, meaning that the results are reliable. By further forecasting the mining-induced stress and deformation characteristics of coal and rock deeper than 1000 m (namely, at 1200, 1500, and 1800 m), it is concluded that the abutment pressures at 1200, 1500, and 1800 m are 9, 11, and 14 times that at 300 m, and the roof abscission layer displacements at 1200, 1500, and 1800 m are 6, 8, and 10 times that at 300 m, which coincides with the large deformation trend observed in deep roadways. These results have a certain guiding significance for deep energy exploration and deep coal exploitation.