Use of Taguchi Method to Evaluate the Hydraulic Conductivity of Lignocellulosic Fibers-Reinforced Soil

Population growth and the subsequent need for the development of infrastructures along with lack of lands with appropriate geotechnical properties have made soil improvement more common. This is while the use of traditional materials in civil engineering projects has raised questions over their environmental impacts. Lignocellulosic fibers, considered as an eco-friendly and renewable source, can be suitable materials to replace traditional additives. In this investigation, three types of lignocellulosic fibers including softwoods bleached pulp (S.W.), old containers pulp (O.C.), and wheat straw soda high yield pulp (W.S.) were used as reinforcement materials. Moreover, Taguchi’s design of experiment (DOE) was used to determine the optimum conditions corresponding to three curing times. The Taguchi analyses indicated 2 percent of 1 mm-long S.W. fibers would lead to the lowest hydraulic conductivity while 1 percent of 1.5 mm-long O.C. fibers and 1 percent of 0.5 mm-long W.S. fibers would contribute to the lowest hydraulic conductivity coefficients among 7 and 14 days-cured specimens, respectively. Furthermore, according to the analysis of variance (ANOVA), fiber content was the most effective parameter on the hydraulic conductivity coefficients of 1 and 14 days-cured specimens. This is while fiber length was the most influential one on the hydraulic conductivity of 7 days-cured specimens. The results of this paper indicated the high potential applications of such statistical methods in geotechnical engineering.