Application Research on a Pulsed Water Jet Slotting for Coal Roadway Excavation

For the problem that the stress of deep buried coal seam is high and the influence of single hole relaxing stress in advance drillhole is limited,which leads to more drillholes,longer drainage time and slower speed of coal roadway excavation etc.A new idea was proposed to solve this problem by using self-excited oscillations of pulsed water jets which can be intersected in the coal seam.This was proposed to increase the stress-relaxed scope of single hole,reduce the number of drillholes,and improve the speed of coal roadway excavation.This paper revealed the stress-relaxed law of cross slot by numerical simulation method in combination with self-excited oscillation pulsed jet coal and rock breaking mechanism,and optimized the pulse jet slotting in the process of excavation in coal roadway.Application in Ji_16-17-22302 wind lane at the Pingdingshan No.5 coal mine showed that the jet may penetrate 2.5 m or more into the coal seam,the total drainage quantity of the working face was increased by 3.37 times,the time to implement outburst prevention has been reduced by 54.4%,and the speed of excavation was doubled.