Mechanical characteristics of the surrounding rock and interlayer distance effect under mining protected coal seam

摘要

Based on the mining technical condition of 1252(1) working face, mechanical characteristics of the surrounding rock and the protected seam were further studied during protective layer mining.The results show that pressure relief degree of the protected seam is largest in the middle of goaf on the strike.Stress distribution obvious heterogeneity of the protected seam on the dip.Stress distribution obvious interlayer distance effect of the protected seam, which outstandingly embodied as Unloading zone width and stress-concentrated area.Pressure relief effect and stress concentration have dual effects, if spacing of layers increase, then the stress concentration degree decrease, pressure relief effect reduce.