2. Geotextiles- more aptly Geosynthetics –
belong to the class of Technical Textiles
under GEOTECH category.
Geotextiles are generically of two
varieties—one variety is made of
synthetic polymers (petrochemical
derivatives) and the other of natural
fibres (such as jute, coir)
Geotextiles are intended to improve
engineering performance of soil on or in
which it is laid
2
3. Jute Geotextiles
Jute Geotextiles (JGT)-as the name suggests –is made of
bast fibres of jute plants—a renewable agri-resource under
cultivation in the Ganga-Brahmaputra delta for centuries.
Presently under cultivation in other areas/countries as well
The British were the first to discover the potential of jute fibre
for flexible packaging (sacks) after elaborate tests
The features of jute fibre conform to technical requirements of
geotextiles, besides its added advantage of being eco-
concordant, abundant availability, and industry-expertise to
make customized JGT
3
4. High moisture absorbing capacity
Excellent drapability (the best of all GTs)
High modulus of elasticity
Low extension-at-break
High roughness co-efficient
Excellent spinnability
Bio-degradability with mulching & soil-nourishing properties
Annually renewable resource with abundant availability
Economical &
Eco-friendly
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5. JGT matches its man-made counterpart in the three basic functions of a geo textile. They
are Separation, Filtration, Drainage. Besides,
Along-plane drainage capability (i.e. transmissivity ) of JGT is higher than its man-
made counterpart.
Fineness of jute fiber enables manufacture of JGT according to the specified
porometric features
High Roughness Co-efficient of jute ensures better load transference & confining
action on soil
JGT has far greater water absorbency than all other GTs –a quality which enables
sustained release of the absorbed water, thus creating a congenial micro-climate
for better growth of vegetation
JGT – Basic Functions
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6. Strengthening of road by improving CBR
Slope management
Protection of river bank against erosion
Stabilizing embankments
Prevention of railway track settlement
Consolidation of soft soil
Control of surface soil detachment
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7. Slope Management with JGT
Roads built on high embankments and slopes at construction sites require
preventive measures to control erosion of slope surface.
Slopes erode due to:
Detachment of top soil by K E of rain drops
Flow of rain water (surface run-off)
Severe wind
Surface soil erosion can be controlled by reducing the velocity of surface run-off
& entrapping detached soil particles.
Wind-induced soil erosion can be controlled by suitable JGT- cover
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8. Remedial Concept
•Universal Hydrological Equation in its simplest form states
precipitation surface flow + through flow ( sub-surface flow ) +
storage.
•If through-flow and on-land storage can be increased, surface run-
off gets reduced.
•Through-flow depends on hydraulic conductivity of the soil. Storage
can be facilitated by creating micro-barriers on the slope. Such
micro-barriers also decrease the velocity of surface flow.
•JGT is the ideal material that fulfills the requirements, besides
facilitating fast growth of vegetation on its bio-degradation as a
result of its mulching properties and by increasing the hydraulic
conductivity of soil.
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9. Soil Erosion Process on a Slope
RAIN
- - - -- - -- -
XC
belt of no erosion
FLOW
active
erosion
deposition of
sediments
D
a
d
bb’
e
c’ c
material in suspension
overland flow
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10. Direction
of laying
Jute Geotextile
Fixing nail
Graded slope
Grass plant
Toe anchor
(150 mm x 150mm)
150
Shoulder anchor
(150 mm x 150mm)
150 mm
50 mm
Fixing nail
(II Gauge wire)
+
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11. Role of JGT in Filter-cake formation in soil
FILTER CAKE FORMATION
IN SOIL
IS AN OPTIMAL STATE OF
SOIL CONSOLIDATION
TRIGGERING GRADUAL
DEVELOPMENT OF
EFFECTIVE STRESS
WITHIN A SOIL
MASS, THUS ENABLING IT
TO BEAR GREATER LOAD.
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12. The surface vegetation prevents the direct impact of water droplets
to the surface of soil.
Leafs of the large trees stores rain water for some time and after
wetting a large surface area, a reduced amount of water is getting to
the soil surface.
Stems and shoots roughen and loosen the ground to enable water to
infiltrate more easily.
Finally it reinforces the slope by binding the loose soil with it’s root
network
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13. Durability of JGT
Loss of strength of JGT after a year is NOT a drawback – for, by that
time, JGT provides a self-sustaining sub-grade for most soils.
The gain in strength of the sub-grade compensates the loss of strength
of JGT within the same time frame
With the passage of time dependence on JGT for soil stability continues
to decrease
However there is need to ensure JGT-durability ranging from 2 to 4 years
(depending on the application-type) by special treatment. Eco-friendly
durability treatments have been developed by IIT, KgP & IJIRA
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14. The answer is NO. Optimal consolidation
(development of effective stress) is seen to take place
within the effective life of JGT
N.B. Effective life of JGT may be enhanced by specially
developed eco-friendly water-repellent treatment
(developed by IIT Kgp & IJIRA
Necessity of JGT or, for that matter, of any GT ceases after
filter-cake formation.
Bio-degradability of JGT is thus not a technical disadvantage.
Additionally JGT lends environmental advantage to the
construction
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17. SLOPE COVERED WITH VEGETATION
LAYING OF JUTE GEOTEXTILE AFTER DRESSING
OF SLOPE
HILL SLOPE GUWAHATI-
SHILLONG ROAD AT SONAPUR
Fig 3
Fig 4
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18. Fig 7. Leveling of the damaged road with
earth
Fig 5. Condition of Damaged Road
Fig 8.Finished road after 7 years of
construction
Fig 6. Laying of JGT over sand
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