Abstract: Gas drainage through strata is usually a way of gas control in outburst coal mine. Blasting in boreholes is useful for gas drainage through strata. Taking the blasting practice of Nantong coal mine as research background, the mathematical models of deep-hole blasting through strata are established. Using numerical simulation and verification test from the coal mine, the changes of dynamic stress are respectively studied for blasting holes and control holes; relations between strength of the stress field and drainage effect after the blasting are discussed. The research result shows that the layout of drainage holes and blast holes is associated with the characteristics of gas drainage crossing layer. Due to the blasting hole inclined cross coal seam, dynamic stress distribution of different coal seam sections is extremely uneven; the dynamic stress of center control hole is the biggest compared with other control holes. Under the condition of thin coal seam in Nantong mine, average value of destruction radius is 0.57 m when the charge length of blasting hole is 3.2 m. This value increases 20% more than that of blasting holes of other rows. Charge length of blast hole is an important factor affecting draining gross of gas. The average of gas drainage volume in blasting holes is 55% larger than that of control holes, and the average single-hole flow of blasting drill field is 49% larger than that of the non-blasting drill field’s.

Key words: deep-hole blasting through strata, gas drainage, numerical simulation, dynamic stress distribution