Abstract: To improve the prevention technology and effect on gas and coal dust explosion in coal mine,the flame proof performance of active explosion isolation system has been studied in a large scale roadway,based on different explosion energy and powder concentration.The dynamic distribution characteristics of explosion isolation barrier of active roadway isolation system are tested,using a high speed camera for measuring the formation process in the open space.The stored powder which continues to act for more than 5 000 ms in the space can form an effective section of 8.04 m2 at 120 ms,and cover a distance of 20 m at 1 200 ms.It is believed that the driving gas pressure is the direct factor affecting the dynamic distribution and coverage distance of the flameproof barrier.On this basis,the large scale underground roadway with a section of 7.2 m2 is used to conduct the explosion propagation test and explosion isolation test of gas (coal dust) explosion.The propagation characteristics of explosion pressure wave and flame front in the experiment process are further analyzed.It is found that the powder isolation barrier can effectively attenuate the pressure wave and extinguish the explosion flame.When the powder concentration is low,the explosion flame will pass through the flameproof barrier.The powder concentration addition exerts a stronger effect on explosion isolation.When the powder concentration reaches 277.8 g/m3 in the gas explosion isolation experiment,the explosion over pressure reduces to 36.4 kPa at 40 m.And the explosion overpressure at 70 m decreases to 54.0 kPa in the gas and coal dust explosion isolation experiment when the powder concentration increases to 625.0 g/m3.Compared with the explosion propagation experiment of the same intensity,the maximum pressure both decreases by more than 60%.In the explosion isolation experiment of gas (coal dust) explosion,the explosion proof barrier formed by driving nitrogen and powder has the effects of cooling,isolating,consuming free radicals on the combustion reaction system.With the concentration increase of powder particles,the flame propagation speed significantly decreases.The maximum flame speed in the whole propagation process moves forward and appears at the front of the flameproof device,and the explosion flame is completely extinguished within the area of 20 m behind the flameproof system.