Research On Blowout Mechanism And Control Technology For The Drainage Hole Of Taiyuan Formation Limestone

In the process of coal mine production,the advanced exploration and drainage depressurization technology has become more and more mature in solving the problem of working face with pressure mining.With the increase of coal mining depth,the ground stress of coal seam gradually increases,which makes the working face prone to the phenomenon of shotcrete hole during the drainage depressurization to some extent,and the drainage effect is not very ideal.In recent years the production of coal mine accident statistics report,according to the spray hole accident occurrence frequency and severity of rising trend year by year,so the paper stevenhirsch mine bottom alley pumping hydrophobic appeared in the process of decompression orifice problems,combining with the theory of coal and gas outburst,through theoretical analysis,laboratory research and numerical simulation,the method of combining the further reveal too limestone layer(water)nozzle mechanism.The specific research contents are as follows:Through theoretical analysis,summarized the influence of various factors on the spray holes phenomenon,is studied with the method of numerical simulation of different initial gas pressure,gas saturation,the initial formation permeability and orifice law under the initial ground stress,the results showed that the spray hole,in the process of gas pressure and permeability and water yield were positively correlated relationship,gas saturation and buried depth are negatively related with the water yield.The results show that the water permeability is positively correlated with the increase of pore pressure under the same stress level.At the same pore pressure level,the water permeability is negatively correlated with the increase of pore pressure.The variation of water pressure,permeability,ground stress,water inrush coefficient and water inrush with discharging time was studied by numerical simulation.The results show that in the drilling process,there exists stress concentration around the borehole.Under the stress concentration,the coal and rock will be compacted and destroyed.A prevention technology,the blowout preventer,is put forward,which is composed of T-shaped manhole mandrel,water drainer,separation box,gas collector and air duct.The main function of the device is to realize multi-stage separation and drainage of air and water.The research results of this paper are of great significance for understanding the characteristics of shotcreting holes in the process of drainage and pressure reduction in mine bottom suction roadway,putting forward effective prevention and control measures,and ensuring the smooth popularization of this technology and the safety of mine production.