Research On Timing Characteristics Of The Extracting Influence Radius Of The Pre-pumping Gas Drilling Hole

Gas disasters are the biggest threat to safe production in coal mine of our countryand gas drainage is the fundamental measures against gas disasters and accidents.Gasdisasters not only can solve the gas outburst and the gas gauge problem, but also makeuse of the gas as a clean energy.In addition, with the increase in coal production andmining depth, the number of China’s high-gas coal and gas outburst mine is increasingevery year.In these mines,coal winning and tunnelling not balance is most seriousproblem.The core key to solve this problem is how to quickly eliminate coal and gasoutburstvery.Within the stipulated time, gas content drops below8m3/t or gas pressuredrops below0.74MPa in the drainage area.So,reasonable hole has become one of thekey technologies to improve the efficiency of extraction of the coal seam drilling of gasand quickly eliminate coal and gas outburstvery.Reasonable hole of the pre-pumpinggas drilling hole is based on gas extraction radius of influence,and then there is arelationship between gas extraction radius and the permeability coefficient,drainagetime,borehole diameter.So,by studying the timing characteristics of the extractinginfluence radius of the pre-pumping gas drilling hole,Establish the quantitativerelationship model of the extracting radius of gas and the permeability coefficient,theborehole diameter, pumping time.It is meaningful to reasonable hole in mines.This paper combined the coal seam actual situation of Jiulishan of Henan CokingCoal Energy Company Limited,analysised of the factors affecting the mine gas drainagevolume using the method of multiple linear regression,getted the main factors ofaffecting the mine gas drainage volume which are effective total length of the coalhole,tons of coal drilling ength,100mm diameter drainage pipe percentage of totallength of drainage pipe.Through field testing and numerical simulation,for75mm,94mm,120mm and150mm four different borehole diameter, studied the relationshipbetween gas extraction radius and drainage time,the relationship between gas extractionradius and permeability coefficient,the relationship between gas extraction radius andborehole diameter. Research shows,gas extraction radius increases with the increase ofdrainage time,gas extraction radius increases with the increase of the permeabilitycoefficient,gas extraction radius increases with the increase of the borehole diameter. Established the quantitative relationship model of the gas extraction radius and thepermeability coefficient,the borehole diameter,pumping time,and the formula of thereasonable hole spacing.Provide the basis for the gas pre-pumping reasonable holespacing determine in Jiaozuo mining area.