Abstract: Based on low prediction accuracy and low index of outburst Phenomenon of the dynamic disaster in excavation working face under the special engineering geological mechanics environment in deep mining, combining with the strength difference of Xiayukou 2^# coal region and its gas unbalanced occurrence, the dynamic combination forecasting system for deep excavation working face of 2^# coal seam is built through theoretical analysis, experiment and field tests. The research shows that when the coal ore-body's structure is in classⅠ~ III, and the roof rock is hard and integral, The correlation between drilling cuttings S value and its particle size distribution index S_ξ is clear, and S_ξ prediction of rock burst hazard exceeds 30%; When the frontal structure of coal ore-body is in Ⅳ ~ Ⅴ and the thickening of coal seam is abnormal, the correlation between S value and S, Δh₂ value is not obvious, the difference of S, Δh₂ is significant, and the outburst danger exists when S≥6 kg/m, Δh₂≥120 Pa. In the tectonic stress abnormal area of fold and faults and the mining superimposed stress zone, the impact and outburst exists at the same time. There is no out burst predicted in field working face with the impact accuracy rate of 100%. The prediction index and critical value are reasonable and effective.

Key words: Deep excavation face, Dynamic disaster, Composite index, Dynamic prediction, Critical value