Orthogonal experimental study on proportioning model construction ofsimilar materials of outburst coal seam

The outburst coal similar material is the basis for the coal and gas outburst simulation experiment.The similarity of the coal similar material needs to be considered comprehensively regarding the mechanical properties,adsorption/desorption characteristics and pore characteristics.In order to solve the problem that the similarity between coal and gas outburst similar materials and raw coal is not high,this paper uses cement ratio,sand ratio and molding pressure as three main influencing factors,the effects of various factors on the uniaxial compressive strength,elastic modulus,initial velocity of dissolution and porosity of CO2 and CH4 adsorbed by similar materials were studied by orthogonal experiment and single factor experiment.The experimental results show that the uniaxial compressive strength and elastic modulus of similar materials increase with the increase of cement ratio and molding pressure.The initial velocity of dispersion decreases with the proportion of cement and sand,and the porosity increases with the molding pressure decrease.Through the analysis of variance and multiple linear regression analysis,the quantitative relationship between the three influencing factors and the experimental indexes of similar materials were obtained,and the multi-factor matching model of outburst coal similar materials was constructed.According to the model,the matching data of the target similar materials could be obtained.The experimental results show that the error of the ratio model in the mechanical index is less than 20%,and the error in the initial velocity and porosity of the dispersion is less than 10%.Finally,using the constructed similar material ratio model to produce the protruding coal,the self-developed large-scale coal and gas outburst simulation test system successfully carried out the coal and gas outburst simulation test under high stress,which further confirmed the reliability of the proportioning model.