Proposing a Model for Prediction of Compaction Parameters of Clay Subgrade Soil Stabilized with Portland cement and Iron Ore Mine Tailing By Means Of RSM Method

The purpose of this study is to provide a model for predicting the dry density of the clayey subgrades stabilized with Portland cement and iron ore mine tailing (IOMT) materials. For this purpose, Portland cement with 0, 6, 9, 12 and 15% and iron ore mine tailing with 0, 10, 20, 30 and 40% was added to clay soil, and then the compaction test was performed using modified proctor method on 25 different compounds and a database of 125 records was prepared. Then, using a response surface method (RSM), a model was proposed to predict the density of the clay subgrade stabilized with IOMT and Portland cement. Input variables in this model include moisture content, percentage of iron ore mine tailing and percentage of Portland cement, and the output variable is dry density of the stabilized clay soil. The regression coefficient of the developed model was 0.9634 which indicates the high accuracy of this model. Also, the predicted R2 (0.9416) indicates its logical compatibility with the adjusted R2 value (0.9551), with respect to a difference less than 0.22 among them. Finally, based on the developed model, two diagrams were developed to predict the maximum dry density and the optimum moisture content of clay subgrade stabilized with Portland cement and iron ore mine tailing. Regarding the results of this study, it is possible to predict the optimum moisture content as well as maximum dry density of the clay subgrade with low plasticity stabilized with Portland cement and iron ore mine tailing.