Abstract: In order to reduce the filling cost of a copper mine, the influence of single factor or multi factor interaction on the strength of filling body was explored. 24 groups of different proportions were designed to analyze the influence of slag content, mass concentration and cement-sand ratio on the uniaxial compressive strength of filling specimens. The slag content, mass concentration and cement-sand ratio were set as the explanatory variables X₁, X₂, X₃ respectively, and the uniaxial compressive strength was set as Y, and the experimental data was stepwise regression analyzed by software SPSS,and the accuracy of regression was verified by response surface method. The results show that: slag content and uniaxial compressive strength of specimens are positively correlated, the higher the cement-sand ratio, the greater the strength growth. The maximum growth rate of 28 d strength is 138.2%. The influence weight of single element on uniaxial compressive strength is mass concentration and cement-sand ratio, and slag content has no significant influence. Two or more factors have influence on uniaxial compressive strength under the interaction, only the slag content and cement interaction have a significant effect on the strength. The equation expressions of the two methods are basically consistent, which proves the reliability of the regression. The regression fitting degree is 97.76%, and the fitting value is very close to the experimental value, so the regression equation can be applied to the filling experiment of the mine.

Key words: slag, unclassified tailing, cemented filling, stepwise regression analysis, interaction, response surface method