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ROAD
CONSTRUCTION
ON
SOFT
SOIL |
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Where applicable
Road pavement and at layers of high embankment on
soft soil, asphalt overlay and side slope protection are the main
application areas.
Why applied
Construction of road on soft soil normally encounters the problems like
construction of embankment, uniformly strong pavement and a good riding
surface. All the problems can be addressed economically with the use of
geotextiles. So, they are very popular engineering products both for
paved and unpaved roads. Jute geotextile is very useful for construction
of embankment on soft soil because it initially reinforces the soil and
drains out the excess water in soil consolidating it in a short time. It
may be applied in layers when the embankment is more than a metre high
to arrest lateral dispersion and slides (slip circles) followed by
uneven subsidence.
When laid on the sub-grade of road pavement it initially increases
bearing capacity of the soil, which with the drainage of excess water
consolidates and becomes stronger. The increased soil strength is
maintained until it is disturbed by some external forces because, when
the fabric loses its strength through degradation, drainage continues,
which keeps the sub-grade free from excess water preventing the
sub-grade from becoming soft and weak.
The bitumen macadam of a road may be treated with jute geotextile to
strengthen the surface and prevent reflecting cracks. It also enhances
durability of the surface due to reinforcement.
Slopes of roads on high embankments should be maintained carefully for a
durable performance particularly in the hilly regions. For the purpose
Jute geotextiles for slope protection may be applied. A particular
variety of the three may be selected depending on soil and slope
condition of the site.
The specifications of the geotextiles for road construction are cited
below.
Product specification
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Application Area |
Code |
Weight
(gsm) |
Width
(cm) |
Thickness
(mm) |
Pore size
(micron) |
Strength
(kN/m) |
Elongation
at break (%) |
| MD |
CD |
MD |
CD |
|
Embankment & Pavement |
BGW 760
Treated /
Untreated |
760 |
76 |
2 |
300 |
20 |
20 |
10 |
10 |
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Surface |
Woven |
600 |
122 |
4 |
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24 |
24 |
10 |
10 |
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Slope protection |
Woven
(Open Mesh)
BGW 292
BGW 500
BGW 730 |
Specification mentioned in
Slope
Protection Section |
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Packing
- Bales of desired length subject to maximum 800 m for pavement/
embankment construction, 600 m for surfacing of road and packing of
slope protection materials has been shown in Slope Protection.
Colour
- Natural for untreated and greenish for treated
How to apply
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| 1. |
For construction of high
embankment the standard sequence of construction with
geotextiles should be followed as shown in the plan. |
| 2. |
The fabrics should be laid with an
over lapping of at least 10 cm for side by side and 15 cm end to
end. The over lappings may be fixed with the ground with the
help of iron pegs if necessary. |
| 3. |
For protection of slopes of roads the methods have been
discussed in Slope Protection above.
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Construction Plan of high Embankment with Jute Geotextile
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Plan of Laying Jute Geotextile for a durable Unpaved Road
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Plan of Laying Jute Geotextile for a durable Paved Road
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Plan of Laying Jute Geotextile for a durable Surface of a Paved Road |
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