Abstract: To research the deformation and failure mechanism of “three-soft” coal seams under blasting mining conditions in Zhengzhou mining area, by comprehensively using field measurement，theoretical analysis and numerical simulation, the deformation and failure depth and mechanism of mining floors in a typical coal face in Gaocheng Coal Mine were studied in this paper. The deformation and failure depth and stratum in the roadway floor of the “three-soft” coal seam, as well as the width and influence scope of peak stress ahead of the coal face were obtained by analyzing the monitoring data of strain sensors in boreholes at the haulage and ventilation roadways. On this basis, the engineering geological model for floor stress calculation was established, and the analytical solution of basic strain and the distribution law of deformation and stress in mining floor at different depths along with the face advancing were deduced and simulated by theoretical analysis and numerical simulation.

Key words: “three-soft”coal seam, mining floor, comprehensive analysis, deformation and failure, buffer action