Optimization of roots and copper slag to reinforce soft soil using response surface method

Abstract

In this paper, roots and copper slag were used to overcome the weak-ness and reinforce the mechanical property of soft soil. The experiments were designed by the Response Surface Method (RSM), the content optimizing of the root permeated copper slag mixed soil for achieving appropriate values of shear strength and the final results evaluating were also conducted by RSM. Four independent variables including moisture content (12–21% by dry weight of the mixture), slag content (10–20% by dry weight of the mixture), roots content (0–1.1% by dry weight of the mixture), and aspect ratio of roots L/d (5–40) were studied and a generalized response model was built to predict the experimental results. The optimum contents of the four independent variables were suggested as 15.41% (moisture), 16.30% (copper slag), and 0.82% (roots) with an aspect ratio of 28.14, respectively. It can be concluded from the verification experiments that the predicted values of the soil mechanical property are almost equal to the experimental values, which validate the response model. Moreover, a typical subgrade model was built for proving the practical advantages of using the above-mentioned mixture as subgrade fill.