By jaya

1. By- Jayaprakash Behera

2. Geotextile
are
permeable
fabric &
separate
 Filter,
 Renforce
ment,
 Protect
or drain Geo Drains Geo Separations
MSE
Reinforcement

3. GEOTEXTILE FUNCTIONS
AND MECHANISMS
Separation
 Reinforcement
 Filtration
 Drainage
 Sealing

4.  Separation is defined as, “The introduction of a flexible porous
textile placed between dissimilar materials so that the integrity
and the functioning of both the materials can remain intact or be
improved
Bituminious
Courses
Aggregate
Bases
Geotextile
Layer
Subgrade
Designed
Thickness

5.  It is defined as “the equilibrium geotextile-to-soil system that allows for adequate
liquid flow with limited soil loss across the plane of the geotextile over a service
lifetime compatible with the application under consideration
Bituminious Courses
Aggregate Bases
Geotextile Layer
Aggregate Drainage
Layer
Subgrade

6.  To perform this function the
geotextile needs to satisfy two
conflicting requirements: the
filter’s pore size must be
small enough to retain fine
soil particles while the
geotextile should permit
relatively unimpeded flow of
water into the drainage
media. A common application
illustrating the filtration
function is the use of a
geotextile in a pavement edge
drain.

7. Geotextile acts as a
reinforcing element in a soil
mass or in combination with
the soil to produce a
composite that has improved
strength and deformation
properties;

8.  The classic application of a geotextile
as a liquid barrier is paved road
rehabilitation.
 Minimizes vertical flow of water into
the pavement structure.
New Overlay
Reflective Crack
without Paving Fabric
Old Pavement
Base Course
PavementCrack
withPavingFabric

9. Woven Fabrics
Non-Woven fabrics
Knitted fabrics

10. Flexible paved Road Construction
Drainage application
Pavement Overlays

11. MAJOR APPLICATIONS OF
GEOTEXTILES
 Separation of Dissimilar materials
 Between drainage layers in poorly graded filter blankets
 Between old and new asphalt layers
 Reinforcement of Weak Soils and Other Materials
 To reinforce embankments
 To aid in construction of steep slopes
 As basal reinforcement over soft soils
 To bridge over cracked or jointed rock
 To create more stable side slopes due to high frictional
resistance

12.  Beneath stone base for paved roads and airfields
 Around crushed stone surrounding under drains
 Around perforated under drain pipe
 As a flexible form for restoring scoured bridge pier
bearing capacity
 Between backfill soil and weep holes in retaining walls
 Between backfill soil and gabions
 As a filter beneath precast blocks

13. As a drain behind a retaining wall
As a drain at the base of retaining wall
As a replacement for sand or wick drains

19. BAND DRAINS /
PREFABRICATED
VERTICAL DRAINS (PVD These are geocomposites formed of a hollow cored, geotextile wrapped drainage
element (geonet) inserted vertically into soft ground to speed up the consolidation
process.
Prefabricated Vertical Drain Installation of PVD

20. BAND DRAINS /
PREFABRICATED VERTICAL
DRAINS (PVD) AT KOLKATA

21.  The initial purpose of the test, 35 years ago, was to determine if and which fabric
would perform effectively as a geotextile in a separation application under an
unpaved road. (A test of durability was not part of the initial purpose).
 It showed that Typar 3401 could perform that function very effectively, even
though it was not specifically designed for that use and was installed with
inadequate “safety factors” – too little base cover for the extreme loads it was
subjected to “saturated”, wet, conditions.
 The loads used in the initial testing would normally require a minimum of 2.5X
the base used and the tests were conducted after heavy rain. A severe test to say
the least. The fabric, Typar 3401 has performed the separation function for 35
years and is still working.