Geotextile Reinforced Abutments on Soft Foundation - Reinforced Soil Engineering: Advances in Research and Practice - page 219

Table 2 Characteristics of the Reinforced Structures

Bridge
span (m)

Foundation
treatment (1)

Structure h (m) s (m) l t (m) l b (m) n

Sau´pe 80 2.00 0.3 3.2 3.2 7 None

0.2-0.3 (2) Suba´ma 75 1.75 3.2 3.2 6 Piles

0.2-0.3 (2)

B´ 40 7.30 3.2 8.9 28 Piles

Mucambo 60 2.70 0.3 5.3 3.25 8 Piles

Itarir´ 40 3.80 0.3 3.2 3.2 12 Piles

h length of

the reinforcement layers in the upper part of the structure, l b ¼ length of the reinforcement layers in
the lower part of the structure, n ¼ number of reinforcement layers. See also Figs. 3 - 6 .
(1) Type of solution for load-transference to stronger foundation layers below the reinforced zone.
(2) 0.2-m spacing between reinforcements along the lower part of the structure (first 2.5m from the
base) and 0.30-m spacing along the upper part of the structure.

¼ height of the reinforced structures, s ¼ spacing between reinforcement layers, l t ¼

piles with caps (1 0.3 m) with 1.25-m spacing in a square pattern. The

reinforced wall layout is schematically shown in Fig. 5 . The fill material used
was a clayey sand (Table 3) . The foundation soil for this wall consists of a 2-m-
thick sand layer overlaying a 3-m-thick organic clay (Table 1) . The
reinforcement type for this structure was a woven geotextile, hereafter referred
to as geotextile B, made of polypropelene, with 0.3-m spacing between
geotextile layers and with a length of 3.2m. This reinforcement is commercially
available under the name Propex 2004, and its main characteristics are
summarized in Table 4 .

£ 1 £

2.2.4 Itarir´ River Structure

The reinforced structure in this case was 3.8 m high and was also constructed on
0.25-m-diameter piles with 1 0.3 m caps with 1.25-m spacing in a square

pattern. The reinforced wall layout is schematically shown in Fig. 5. The
foundation soil is formed by a 1.7-m-thick top clayey sand layer over a 9.5-m-
thick soft to medium organic silty clay, as shown in Table 1 . The variation of
undrained strength with depth for the soft clay layer is presented in Fig. 2a.
Nonwoven geotextile A (Table 4) was also used in this case with a spacing
between layers of 0.3m and a reinforcement length equal to 3.2m.

£ 1 £

2.2.5 Mucambo River Structure

For the crossing of the Mucambo River, a 2.7-m-high geotextile reinforced
retaining structure was built as part of the abutment for a 60-m-span concrete
bridge. The base of the reinforced structure (3.25m long) was built on a
concrete slab supported by concrete piles (0.25-m-diameter, 1.25-m spacing in