The Influence of Single Key Stratum Location on Protection Layer Mining Effect

In order to research the influence of single key stratum location on the protective layer mining effects, FLAC^3D numerical simulation software is used to simulate the discharging pressure effect, displacement and inflation rate changes of protective layer when key stratum is in different locations. The results of the study show that the key strata is located above protective layer of 5 m, 15 m, 30 m, the discharging pressure coefficient is 0.25, 0.3 and 0.35, inflation rate is 4.3 ‰, 3.5 ‰, 2.2 ‰, and concludes that the discharging pressure degree is higher when key strata is closer to the protective layer.