Infiltration into an embankment reinforced by nonwoven geotextiles

The hydraulic behaviour of permeable geosynthetics within unsaturated embankments subjected to infiltration is examined using the finite element method. The van Genuchten - Mualem model is employed to evaluate unsaturated hydraulic characteristics for both the soil and nonwoven geotextile. Using pore-water pressures obtained from the finite element analysis, stability analyses are conducted for the embankments, and the contribution of the nonwoven geo- textile to stability is evaluated with reference to the observed performance of instrumented embankments. A numerical study is also conducted to examine the effect of geotextile configuration on the performance of reinforced embank- ments subject to infiltration. This study shows that nonwoven geotextiles may retard water flow in situations where the pore pressure is negative, whereas they act as a drainage material in situations where pore pressures are positive. It is also shown that the contribution of the nonwoven geotextile to the stability of the embankment as a drainage material is much less substantial than its role as a reinforcing material.