This study presents experimental and numerical studies of hydraulic response on fiber-reinforced soils (FRS) subjected to seepage. A total of twenty upward seepage tests were conducted on unreinforced and fiber-reinforced sand specimen to assess the effects of soil density and fiber parameters (i.e., fiber content and length) on piping failure modes, hydraulic conductivity k and critical hydraulic gradient icr of FRS. A direct shear test was also carried out to obtain the FRS friction angle for determining the linear relationship between ϕ and icr of the FRS. A dataset of the FRS seepage test was compiled from the literature review and this study to evaluate the overall variation in k and icr as fiber content change. The seepage test results showed that as the fiber content increased, k decreased and icr increased. Short fibers have more reduction on k compare than longer fiber; however, fiber length has only a small effect on icr. The effect of the fiber on the dense sample (Dr = 70%) was greater than on the loose sample (Dr = 50%). The experimental results also revealed that the icr of FRS has a strong correlation with ϕ. Finally, by inputting the mechanical and hydraulic properties of the FRS obtained from experimental test of this study, two cases of numerical analysis were carried out on the upstream side of the flood-induced elevated water level of the unreinforced and reinforced embankments. The numerical results showed that the FRS backfill embankment can improve both mechanical and hydraulic performance. The use of FRS as a backfill can effectively delay the progress of seepage, reduce the soil piping potential, and improve the slope stability of the system subject to flood.

This study presents experimental and numerical studies of hydraulic response on fiber-reinforced soils (FRS) subjected to seepage. A total of twenty upward seepage tests were conducted on unreinforced and fiber-reinforced sand specimen to assess the effects of soil density and fiber parameters (i.e., fiber content and length) on piping failure modes, hydraulic conductivity k and critical hydraulic gradient icr of FRS. A direct shear test was also carried out to obtain the FRS friction angle for determining the linear relationship between ϕ and icr of the FRS. A dataset of the FRS seepage test was compiled from the literature review and this study to evaluate the overall variation in k and icr as fiber content change. The seepage test results showed that as the fiber content increased, k decreased and icr increased. Short fibers have more reduction on k compare than longer fiber; however, fiber length has only a small effect on icr. The effect of the fiber on the dense sample (Dr = 70%) was greater than on the loose sample (Dr = 50%). The experimental results also revealed that the icr of FRS has a strong correlation with ϕ. Finally, by inputting the mechanical and hydraulic properties of the FRS obtained from experimental test of this study, two cases of numerical analysis were carried out on the upstream side of the flood-induced elevated water level of the unreinforced and reinforced embankments. The numerical results showed that the FRS backfill embankment can improve both mechanical and hydraulic performance. The use of FRS as a backfill can effectively delay the progress of seepage, reduce the soil piping potential, and improve the slope stability of the system subject to flood.

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