Performance of nonwoven geotextile-reinforced walls under wetting conditions: laboratory and field investigations

Abstract

The first geosynthetic retaining wall in Brazil was constructed in 1984 as an instrumented 10 m high geotextile-reinforced soil wall with a poorly draining backfill. This structure has been showing excellent performance throughout its service life, even after long periods of rainfall. In the past, the excellent performance of the wall had been attributed to the influence of soil confinement on the geotextile strength properties as well as the comparatively high interface shear strength between the fine soil and the nonwoven geotextile. Now there is also evidence of the beneficial effect of the internal drainage capacity when using nonwoven geotextiles as reinforcements. In order to clarify the understanding of the performance of the pioneer history case wall (SP-123 wall) and the effect of nonwoven geotextiles as reinforcements of fine-grained soils, full-scale laboratory models of geotextile reinforced walls were tested under wetting conditions. Results from the instrumentation have shown no significant positive water pressures and relatively small displacements even after intense periods of precipitation. The consistency between field and laboratory investigations provides strong evidence in support of the use of nonwoven geotextiles to reinforce poorly draining soils.

Unsaturated soil–woven geotextile interface strength properties from small-scale pullout and interface tests

“…However, results reported in these studies seem to indicate that in fine-grained soils, the added drainage capability of a geocomposite could more than compensate the interlocking hindrance due to the existence of a nonwoven geotextile, which is consistent with the findings of other related studies on marginal quality soils (e.g. Zornberg and Mitchell 1994;Mitchell and Zornberg 1995;Portelinha et al 2013aPortelinha et al , 2013b. Khoury et al (2011) used a modified direct shear apparatus to study the effect of matric suction on soilgeotextile interface behaviour.…”

Pullout Behavior of Different Geosynthetics—Influence of Soil Density and Moisture Content

“…The GTX ( Figure 2C) consists of mechanically bonded (needle punched) continuous filaments of polypropylene. Several laboratory and field studies have shown the beneficial effect of using non-woven geotextiles as reinforcement elements of fine-grained soils (poorly draining soils) due to their internal drainage capacity (Tan et al, 2001;Portelinha et al, 2013). Indeed, the hydraulic properties of non-woven geotextile reinforcements can assist in the pore-water pressure dissipation, hence improving the internal stability of the reinforced structure.…”

Direct shear behaviour of residual soil–geosynthetic interfaces – influence of soil moisture content, soil density and geosynthetic type

“…Despite the problems arising from the use of poorly draining backfill, some studies have reported excellent performance of GRSS constructed with fine-grained soils reinforced with nonwoven geotextiles (Tatsuoka and Yamauchi 1986;Benjamim et al 2007;Portelinha et al 2013). The hydraulic properties of nonwoven geotextiles can help to dissipate pore-water pressures, contributing to the internal stability of the structure (Ling et al 1993;Tan et al 2001).…”

“…The hydraulic properties of nonwoven geotextiles can help to dissipate pore-water pressures, contributing to the internal stability of the structure (Ling et al 1993;Tan et al 2001). As the reinforcement layers are able to provide internal drainage, the drainage capacity of the backfill is increased (Portelinha et al 2013).…”