Research On Match Model Of Outburst Coal Similar Material Based On Orthogonal Test

The similar materials of protruding coal are made of pulverized coal,binder and water under a certain forming pressure.Similar materials are an important part of the simulation experiment of coal and gas outburst,and one of the important contents of the research of outstanding simulation experiments..The similarity between similar materials and raw coal determines the reduction accuracy of the prominent simulation experiments,while the similarity of similar materials with raw coal is mainly reflected in physical and mechanical properties,adsorption and desorption properties and porosity.In the standout simulation experiment,it is usually necessary to formulate corresponding similar materials according to the known raw coal parameters.The matching model of similar materials becomes a key issue in the formulation of similar materials.In order to improve the similarity between similar materials and raw coal,the matching model of similar materials is obtained.Based on the orthogonal experimental design method,the properties of similar materials in physical mechanics,adsorption desorption and porosity under different ratios are studied.The experimental data analysis summed up a matching model of coal-like similar materials,and verified the reliability of the matching model through design verification experiments,and achieved the following main results:（1）Research on raw materials and processes of similar materials.A binder comparison experiment was carried out to compare the effects of three binders of cement,gypsum and sodium humate on the uniaxial compressive strength and initial velocity of gas dispersion of similar materials.Among them,cement is more suitable as a binder for similar materials;The influence of molding water on the strength of similar materials determined that 14%is a reasonable molding moisture of similar materials.In terms of manufacturing process,the molding pressure has a great influence on the strength of similar materials,and the influence of loading rate on strength is relatively small.（2）Through the orthogonal test method,the cement ratio,sand ratio and molding pressure were selected as three influencing factors,and the uniaxial compressive strength,elastic modulus,initial velocity of CH4 release,and similar materials were tested under the combined action of three factors.The performance of CO2 emission initial velocity shows that the influence of uniaxial compressive strength and elastic modulus on cement ratio,molding pressure and sand ratio from the top to the bottom is the most important influence on the initial velocity of dispersion.The ratio of sand to cement and the influence of molding pressure are small;under the same ratio,the initial velocity of CO₂ emission of similar materials is about 30%higher than the initial velocity of CH₄.At the same time,the effects of three factors on the porosity of similar materials were tested under the influence of single factor.The results show that the molding pressure has the greatest influence on the porosity,and the porosity decreases with the increase of the molding pressure.The higher the molding pressure,the porosity.The rate of reduction is getting smaller and smaller,and the ratio of cement to sand has less effect on porosity.（3）Through the analysis of experimental data,a set of similar material proportioning model was established.The model can make different materials have different properties by adjusting the proportion of cement,sand ratio and molding pressure.The matching ratio parameters that can be achieved by the ratio scheme are:uniaxial compressive strength:0.73⁴.81MPa,elastic modulus:37.10²12.99MPa,initial velocity of CH₄ release:30¹3mmHg,initial velocity of CO₂ release:39¹5mmHg,porosity:3.31⁷.83%.Finally,by making similar materials with specified parameters and measuring their parameters,the measured values are compared with the model regression values to verify the reliability of the model.