Geotextile Reinforced Abutments on Soft Foundation - Reinforced Soil Engineering: Advances in Research and Practice - page 221

Table 4 Characteristics of the Geotextiles

Geotextile
code

Geotextile
type

m
(g/m 2 )

T max
(kN/m)

e max
(%)

J sec
(kN/m)

Structures

A (1) 20 (3) 45 (3) 50 (3) Sauipe, Bu,

Mucambo,
and Itarir´

Nonwoven 300

B (2) 22 (4) 15 (4) 128 (4) Subauma Woven 138

m ¼ mass per unit area, T max ¼ tensile strength, e max ¼ tensile strain at failure, and J sec ¼ secant

tensile stiffness corresponding to 5% tensile strain.
(1) Geotextile A is a nonwoven, needle-punched geotextile made of polyester commercially available
under the name of Bidim OP30.
(2) Geotextile B is a women geotextile, made polypropilene, commercially available under the name of
Propex 2004.
(3) Values obtained from wide strip tensile tests according to ASTM D4595.
(4) Results from wide strip (20 cm wide) tensile tests conducted under a 2%/min strain rate.

3 PERFORMANCE OF THE REINFORCED STRUCTURES

In general, in spite of the severe conditions of the foundation soil in terms of
compressibility, the reinforced structures have behaved well so far. However,
some problems caused by consolidation settlements and floods were observed
and are discussed below.
The Sauipe reinforced structure was the one presenting the greatest surface
settlements. This was mainly due to the fact that this structure was constructed
directly on the top sand layer, without piles in the foundation. Therefore,
significant vertical stress increments reached the soft clay layer underneath,
causing settlements. The maximum settlement observed reached a value of
0.29m at the wall face decreasing along a length of 21 m away from the wall. The
maximum horizontal displacement of the wall crest was equal to 5.5 cm, and the
wall face rotated with respect to its crest. The heavily reinforced mass behaved as
a rigid body regarding the neighboring soils. This pattern of wall rotation and
behavior has also been observed in model tests of geosynthetic walls on soft
subgrades (Monte, 1996; Palmeira and Monte, 1997) where the greatest face
horizontal displacements occur at the toe of the wall. Figure 7 shows some results
presented in Palmeira and Monte (1997) where the rotation of the wall face of one
of the model walls can be clearly seen, as commented above. Figure 8 presents a
general view of the surface of the highway showing the repairs in the asphalt cap
close to the reinforced structures that were required to maintain the road
operational after the settlements caused by the foundation soil consolidation.