This document discusses the use of geosynthetics in civil engineering. It begins with an introduction to geosynthetics, describing the different types including geotextiles, geogrids, geonets, geomembranes, geosynthetic clay liners, geopipes, geocomposites, and geocells. It then discusses the key functions of geosynthetics like separation, drainage, filtration, fluid barriers, reinforcement, and protection. The document provides examples of applications for geosynthetics in areas like pavements, retaining walls, drainage, erosion control, embankments, and reinforced foundations. It concludes by stating the benefits of geosynthetics like using local materials, employing un

1. ‫ﺑﻌﻨﻮان‬ ‫ﳏﺎﺿﺮة‬
:
Geosynthetics in Civil Engineering
(Multifunctional uses of geosynthetics in civil engineering)
‫ﺗﻘﺪﱘ‬
:
‫د‬
/.
‫ـﺪ‬‫ﻤ‬‫ﳏ‬
‫اﳊﺴﲔ‬
Mohammad Alhusein, PhD
Managing Partner
M: +971 552592001
E: malhusein@superarc.net
W: www.superarc.net

2. 1- CHALLENGES
2- INTRODUCTION TO GEOSYNTHETICS
3- FUNCTIONS OF GEOSYNTHETICS & APPLICATIONS
4- CONCLUSIONS

3. In recent years, while providing a solution, the Engineer has to
face increased challenges:
 Various site constraints like space, alignments etc.
 Tight time schedules
 Ensure max. usage of local resources (Material & Manpower), hence
Cost effective!!
 Least environment impact
 Long term performance & higher Cost benefit ratio over a larger period
of time (Least maintenance cost)
1- CHALLENGES

4. 1- CHALLENGES
SOLUTION !!!
USE OF APPROPRIATE GEOSYNTHETIC
MATERIALS OFFERS THE POSSIBILITY TO
SOLVE OR DRASTICALLY REDUCE THE
PROBLEMS

7. 2- INTRODUCTION TO GEOSYNTHETICS
ASTM D 4439 defines a geosynthetic as a planar product manufactured from a
polymeric material used with soil, rock, earth, or other geotechnical-related
material as an integral part of a civil engineering project, structure, or system.

8. The term ‘Geosynthetics’ has two parts:
 The prefix ‘geo’, GEO : referring to an end use associated with improving the
performance of civil engineering works involving earth/ground/soil.
 The suffix ‘SYNTHETICS’, (Dictionary meaning : prepared or made artificially
or combining separate elements to form a coherent whole) referring to the
fact that the materials are almost exclusively from man-made products.

9. 1. GeoTextiles (GT)
2. GeoGrids (GG)
3. GeoNets (GN)
4. GeoMembranes (GM)
5. GeoSynthetic clay liners (GCL)
6. GeoPipe (GP)
7. GeoComposites (GC)
8. GeoCells

10.  It is a planar, permeable, polymeric textile
product.
 Currently available geotextiles are classified into
the following categories based on the
manufacturing process:
 Woven Geotextile
 Nonwoven Geotextile
 Knitted Geotextile
 Stitched Geotextile

11.  It is a planar, polymeric product consisting of
a mesh or net-like regular open network of
intersecting tensile-resistant elements, called
ribs, integrally connected at the junctions.
 The ribs can be linked by extrusion, bonding
or interlacing: the resulting geogrids are
respectively called extruded geogrid, bonded
geogrid and woven geogrid.

12.  It is a planar, polymeric product consisting of a
regular dense network of integrally connected
parallel sets of ribs overlying similar sets at various
angles.
 At first glance, geonets appear similar to geogrids;
however, geonets are different from geogrids, not
mainly in the material or their configuration but in
their functions to perform the in-plane drainage of
liquids or gases.

13.  It is a planar, relatively impermeable, synthetic sheet
manufactured from materials of low permeability to control
fluid migration in a project as a barrier or liner.
 The materials may be polymeric or asphaltic or a combination
thereof.
 The term barrier applies when the geomembrane is used inside
an earth mass.
 The term liner is usually reserved for the cases where the
geomembrane is used as an interface or a surface revetment.

15.  Consist core of Bentonite
Clay sandwitched between
layers of thick nonwoven
geotextiles.
 Consists of Self repair
mechanism.

16.  It is a term applied to the product that is
assembled or manufactured in
laminated or composite form from two
or more materials, of which one at least
is a geosynthetic (geotextile, geogrid,
geonet, geomembrane, or any other
type), which, in combination, performs
specific function(s) more effectively than
when used separately.

17.  A three-dimensional, permeable,
polymeric honeycomb or web structure,
assembled from geogrids and special
bodkins couplings in triangular or square
cells.
 It is produced in the factory using strips of
needle-punched polyester or solid high
density polyethylene (HDPE).

18.  A 3D permeable, polymeric structure
made of coarse and rigid filaments
bonded at their junctions used to
reinforce roots of vegetation such as
grass and small plants and extend the
erosion control limits of vegetation for
permanent installation

20.  A plastic pipe (smooth or corrugated with or without
perforations) placed beneath the ground surface and
subsequently backfilled
GEOPIPE

23.  Non-corrosiveness
 Highly resistant to biological and chemical degradation
 Long-term durability under soil cover
 High flexibility
 Minimum volume
 Lightness
 Ease of storing and transportation
 Simplicity of installation
 Speeding the construction process
 Making economical and environment-friendly solution
 Providing good aesthetic look to structures.

24.  Geosynthetics have numerous applications.
 They always perform one or more of the following
basic functions when used in contact with soil,
rock and/or any other civil engineering-related
material
 Separation
 Drainage
 Filtration
 Fluid barrier
 Reinforcement
 Protection.

25.  If the Geosynthetic material has to be placed between two dissimilar
materials like soft soil and granular fill to prevent intermixing and to enhance
the functioning of both material then it is known as “Separation”.
 Figure shows that the geosynthetic layer prevents the intermixing of soft soil
and granular fill, thereby keeping the structural integrity and functioning of
both materials intact.

26.  This function can be observed if a geotextile layer is provided at the
soil subgrade level in pavements or railway tracks to prevent pumping
of soil fines into the granular subbase/base course and/or to prevent
intrusion of granular particles into soil subgrade.

27.  Figure shows that the geosynthetic
layer adjacent to the retaining wall
collects water from the backfill and
transports it to the weep holes
constructed in the retaining wall.
 It should be noted that while
performing the filtration and drainage
functions, a geosynthetic dissipates
the excess pore water pressure by
allowing flow of water in plane and
across its plane.

29. Preloading and vertical drains

31. Typical Applications of geosynthetics as drainage material
 Pavement edge drains
 Interceptor trenches on slopes
 Drainage behind abutments and retaining structures
 Relief of water pressure on buried structures
 Substitute for conventional drains
 Leachate collection and gas venting
 Drainage mats in horizontal applications e.g. roofing
 PVDs for accelerated consolidation of clay soils

32.  A geosynthetic may function as a
filter that allows for adequate
fluid flow with limited migration
of soil particles across its plane
over a projected service lifetime
of the application
 Figure shows that a geosynthetic
allows passage of water from a
soil mass while preventing the
uncontrolled migration of soil
particles.

33.  A geosynthetic may function as a
filter that allows for adequate
fluid flow with limited migration
of soil particles across its plane
over a projected service lifetime
of the application
 Figure shows that a geosynthetic
allows passage of water from a
soil mass while preventing the
uncontrolled migration of soil
particles.

35. (a) A use of geotextile filter; (b) a use of drainage geocomposite.

52. • Principal functions when a properly designed geosynthetic is installed within the track
structure.
• Separation, in new railway tracks, between soil subgrade and new ballast;
• Filtration of soil pore water rising from the soil subgrade beneath the geosynthetic, due to
rising water conditions or the dynamic pumping action of the wheel loadings, across the plane
of the geosynthetic;
• Lateral confinement-type reinforcement in order to contain the overlying ballast stone;
• Lateral drainage of water entering from above or below the geosynthetic within its plane
leading to side drainage ditches.

55.  Surface stabilization: (surficial erosion control) A geosynthetic provides
surface stabilization when it is placed on a soil surface to restrict movement
and prevent dispersion of surface soil particles subjected to erosion actions of
rain and wind, often while allowing or promoting growth of vegetation.
 Vegetative reinforcement: A geosynthetic provides vegetative
reinforcement when it extends the erosion control limits and performance of
vegetation.

62. GarmatTM Erosion Control Mat
(Mahanadi Coal Fields, Talcher, Orissa)
Before After

69. Embankment over
weak foundation soils:
(a) embankment on
uniform weak
foundation soil;
(b) embankment on
locally weak foundation
soil with lenses of clay
or peat, or with
sinkholes (after
Bonaparte and
Christopher, 1987)

71. Reinforced foundation soils supporting footings of structures.

78.  Geosynthetics enables the use of local materials.
 Unskilled labour can be employed.
 Innovative solutions to solve different problems
economically
 The GeoSynthetics are really to be considered as a
third revolution in the field of civil engineering as no
branch of civil is untouched by its use