Study On The Effect Of Adding Water On The Outburst Potential Of Coal

Coal and gas outburst accidents will cause a lot of property and human losses.Coal mines have taken various hydraulic measures to prevent coal and gas outburst accidents.The quiddity of coal and gas outburst is an energy liberation process.In the process of coal and gas outburst,gas expansion energy and the elastic energy of the coal body provide the energy of coal and gas outburst.After the coal mine takes hydraulic measures,the water enters the coal seam,which reduces the mechanical properties of the coal body.Coal elastic energy,affecting gas desorption and gas expansion energy.In order to study the effect of added water on the potential of coal and gas outburst,and to provide a theoretical basis for hydraulic measures to reduce the risk of coal and gas outburst,the effects of added water on the effect of water on the mechanical properties of coal,the influence of elastic properties of coal,and the influence of moisture on gas desorption and gas expansion energy are analyzed.Based on this,study the effect of added water on coal and gas outburst potential.Using the rock triaxial test system,uniaxial compression experiments and uniaxial cyclic loading and unloading experiments were carried out on briquette coal samples with 0 %,1 %,2 % and 4 % moisture content.Remarks on the results of the research:After 0% increase in water content of the soot sample 4%,the decrease in the elastic modulus of the soot sample 50.2%,the decrease in the exponential index form of the soot sample,77.3%,and the increase in the soot plasticity,low resilience.The high-pressure water injection gas desorption device is used to inject water into the coal with gas adsorption equilibrium pressure of 2.5 MPa in the way of equal pressure water injection.The injected water is 0%,1.37%,3.63%,4.56% and 7.44%.The pressure is reduced and desorbed step by step according to the pressure gradient of2.5 MPa-2 MPa-1.5 MPa-1 MPa-0.5 MPa-0 PA.The research results show that: the water replaces part of the adsorbed gas in the coal,and the greater the injected water,the greater the gas displacement.The addition of water has an effect on the gas desorption amount,gas desorption rate and gas desorption index of drilling cuttings in each decompression and desorption stage after depressurization,and generally shows a decreasing trend with the increase of water content.Under the same moisture condition,the gas desorption amount in the low pressure stage is greater than that in the high pressure stage,and the moisture reduces the gas desorption amount;the moisture has a significant effect on the gas desorption rate in the early stage,and has a weak effect on the gas desorption late stage;the addition of water reduces the gas desorption stage in each stage.Drilling cuttings gas desorption index.With the increase of the moisture in the coal,the maximum elastic energy of the coal also showed a negative exponential decreasing trend.Within the experimental moisture range,the maximum elastic energy of the coal body decreased by 9.7 % for every 1 % increase in the moisture in the coal;the addition of moisture reduced the gas in the coal Expansion energy,within the experimental moisture range,for every 1 %increase in the moisture in the coal,the expansion energy of the gas in the coal decreases by 7 %-9 %.With the increase of added water,the gas expansion energy and elastic energy of coal body decrease in the process of coal and gas outburst,indicating that the increase of additional water reduces the potential of coal and gas outburst,and then weakens the risk of coal seam outburst.