CHINA MINE ENGINEERING

In order to study the influence of five factors, namely, initial gas pressure, coal seam porosity, drilling diameter, negative pressure and initial permeability, on the effective radius of gas extraction under the drilling, numerical simulation was constructed by COMSOL, and orthogonal experiments and analysis of polarity were used to explore the influence of the factors, and the equations were obtained by using linear regression analysis of the SPSS software. The results show that the Initial permeability has the greatest influence on the effective radius of gas extraction; the degree of influence of the extreme variance analysis is, in order of magnitude, the initial permeability, drilling diameter, the negative extraction pressure, the porosity, the initial gas pressure; the optimal combination of factor levels with the largest effective extraction radius is when the initial gas pressure is 1.2MPa, the porosity is 0.08, the drilling diameter is 94mm, the negative extraction pressure is 20kPa and the initial permeability is 1×10^-15m²; the coefficient of determination R²=90.6% in the multiple linear regression equation is a good fit.