Model And Applied Research Cemented Filling Body Strength

For filling system, the strength of fillbody directly affects the stability of surrounding rock and fillbody, operation sequence as well as stress variation process of stope, therefore, it plays a decisive role in mining security. Along with the depletion of surface and shallow resources, exploitation of mineral resources has reached deep mining step by step which causes a series of problems like thickness and grade of ore body decreases, ground pressure increase and soft rock increases, could result in further more difficult exploitation technique deposit and prominent mine security issues. So the filling system has been used widely. Therefore, according to the characteristics and requirements of mine filling, more in-depth researches on factors affecting strength of fillbody, strength characteristics of fillbody and strength prediction model is very significant.Based on the experimental materials provided by Jinchuan No.2diggings and the Dahongshan Iron Mine, the authors designed255basic tests of cemented filling strength under different ratio of aggregate by means of orthogonal method. Based on experiment data, the research mainly concentrates on the factors which affect strength of cemented fillbody. After deep analysis on experiment data, the authors summarized the rules of various influencing factors and concluded their respective advantages, disadvantages and application conditions basing on regression analysis of existing strength prediction model. At last, a new strength prediction model of waste rock-tailings cemented filling was put forward.Through lots of researches and analysis, in the paper the following conclusions are made:〤ement content, void ratio and water-cement ratio are adequately considered in Mitchell&Wong strength prediction model. The model can reflect the relationship between factors and strength precisely and has certain applicability. However factors like cement-sand ratio and concentration that can influence strength of fillbody have not yet been considered in the model of Mitchell. In addition, it is unable to elimination dimensional. These deficiencies greatly restrict the application scope of the model.②Arioglu strength prediction model focuses on water-cement ratio which is important for fillbody strength, and establishes the relationship between water-cement ratio and uniaxial compressive strength as well as the relationship between cohesive strength and uniaxial compressive strength. The equation is not only simple and clear but also intuitional reflects the internal relations between these two values. The fitting result using test which features higher correlation coefficient and small error shows there is a close nonlinear relationship between water-cement ratio and the strength. However factors like aggregate accumulation compactness, concentration and cement-sand ratio that can influence strength of fillbody have not yet been considered in the model of Arioglu. The single factor is considered, which directly affect the model can be used widely in practice.③After analyzing empirical formula in cemented fillbody of classified tailings, it is found that the formula is not suitable for strength prediction of waste rock-tailings cemented filling because fitting results are not convergent.On basis of deep analysis of factors influencing cemented fillbody strength and its influence rules, the authors put forward a new strength model of waste rock-tailings cemented filling:RUCS=k×RC×Φ×eCr>×(W/C)α which is Factors such as aggregate accumulation compactness, water-cement ratio and cement grade and their influence on fillbody strength are comprehensively considered in the new model. Test data analysis results shows that the new equation has higher fitting accuracy and smaller error, the regression equation is highly significant. In addition to, aggregate accumulation compactness, water-cement ratio and aggregate volume concentration are dimensionless quantity, which is beneficial for regression analysis. Strength dimension is same with cement degrade dimension RC. In summary, the new strength prediction model has the highest applicability in predicting strength of waste rock-tailings cemented fillbody, can be completely used for the preliminary calculation of parameters design value in actual filling engineering.