Transcript Seventh International Conference on Geosynthetics

TRAINING WORKSHOP ON
NON-WOVENS IN GEOTEXTILES
AT SURAT
5TH MARCH 2008
BY
S.K. PURI
CHIEF GENERAL MANAGER - NHAI
National Highways
• Total Length of NHs : 65,569 km (2% of
total road length)
• Roads carry 85% of Passenger and 70% of
Freight Traffic
• NHs carry about 40% of traffic
• NHAI is entrusted with implementation of
National Highways Development Project
(NHDP)
Components of NHDP
Phase
Length (Km)
Cost
(Rs crore)
Focus
I
Bal. 1738
Bal. 9071
Golden quadrilateral (GQ)- connecting DelhiMumbai-Chennai- Kolkata-Delhi Total Length 5846
II
Bal. 6736
Bal. 43623
North South& East west Corridors (NS-EW)
Total Length 7300
III
12,109
80,626
State capital connectivity,High traffic density,
Imp.centers of tourism &economic activity
IV
20,000
27,800
Widening & Strengthening to 2-lane with
Paved shoulders
V
6,500
41,210
Six laning of high density corridors
VI
1000 Km
16,680
Expressway for connecting important places
VII
(Being identified)
16,680
Ring roads to cities, flyovers, by-passes
SARDPNE
588
5208
Special Accelerated Road Development
Programme for NE
ICTT
Cochin
17
557
International Container Transhipment Terminal
Total
48,688
2,41,454
Definition, Type, Process and Properties
What is a Geotextile?
Any permeable textile natural or synthetic, used with foundation
soil, rock, earth, or any other geotechnical engineering related
material.
Types of Geotextile
Woven
Non-woven
Nonwoven Geotextiles
Method of production
Process
Form of fibre
Polymer
Continuous filament
PP/PE bi-component
PP
Heat-bonded
Staple fibre
PP
PP/PE mix
Nonwovens
Staple fibre
PP
PET
HDPE
Needle-punched
Continuous filament
PP
PET
Nonwoven Geotextiles
Needle Punched nonwoven
Thermally bonded nonwoven
Woven Geotextiles
Method of production
Process
Form of fibre
Polymer
Wide loom (beam)
Slit-flat tape
Fibrillated yarn
PP (HDPE)
PP
Wide loom (creel)
Multi-filament yarn
PET (PA)
<3.8m loom (beam)
Medium mono filament
with yarn
PP
Woven
HDPE
PA
Woven Geotextiles
Slit film tape-on-slit film tape
Extruded tape-on-extruded tape
Woven Geotextiles
PET multifilament woven fabric
Monofil woven fabric
Knitted Geotextiles
Method of production
Process
Stitched-bonded
Knitted
Form of fibre
Polymer
Nonwoven base with multi- PP or PET nonwoven
filament stitch yarn
PET stitching
Weft insertion
filament yarn
PET
Warp knitted
Multi-filament yarn
PET
Knitted Geotextiles
Knitted base
Upper surface
Physical Properties
Property
Value range
Specific gravity
0.9 – 1.7
Mass per unit area
135 – 1000 g/m3
Thickness
0.25 – 7.5 mm
Stiffness
Nil – 25,000 mg-cm
Mechanical Properties
Property
Value Range
Compressibility
Nil to high
Tensile strength (grab)
0.45-4.5 kN
Tensile strength ( wide width)
9-180 kN/m
Confined tensile strength
18-180 kN/m
Seam strength
50-100% of tensile
Cycle fatigue strength
50-100% of tensile
Burst strength
350-5200 k Pa
Tear strength
90-1300 N
Impact strength
14-200 J
Puncture strength
45-450 N
Friction behavior
60-100% of soil friction
Pullout behavior
50-100% of geotextile strength
Hydraulic Properties
Property
Value Range
Porosity (non wovens)
50-95%
Present open area (wovens)
Nil to 36%
Apparent opening size ( sieve
size)
Permittivity
2.0 to 0.075 mm ( # 10
to # 200)
0.02-2.2s-1
Permittivity under load
0,01-3.0s-1
Transmissivity
0.01 to 2.0 x10-3m2/min
Soil retention: turbidity curtains Must be evaluated
Soil retention: silt fences
Must be evaluated
Endurance Properties
Property
Value Range
Installation damage
0.70% of fabric strength
Creep response
g.n.p.if <40% strength is being used
Confined creep response
g.n.p.if <50% strength is being used
Stress relaxation
g.n.p.if <40% strength is being used
Abrasion
50-100% of geotextile strength
Long-term clogging
m.b.e.for critical conditions
Gradient ratio clogging
m.b.e. for critical conditions
Hydraulic conductivity ratio 0.4-0.8 appear to be acceptable
g.n.p. – generally no problem, m.b.e. – must be evaluated
Degradation Properties
Property
Temperature degradation
Oxidative degradation
Hydrolysis degradation
Chemical degradation
Radioactive degradation
Biological degradation
Sunlight ( UV) degradation
Synergistic effects
General aging
Value Range
High temperature accelerates
degradation
m.b.e. for long service lifetimes
m.b.c. for long service lifetimes
g.n.p.unless aggressive chemicals
g.n.p.
g.n.p.
Major problem unless protected
m.b.e.
Actual record to date is excellent
TYPICAL PHYSICAL PROPERTIES OF GEOTEXTILES
Function
Strength range
kN per m
Mass per unit area
gm per sq m
Roll width
Metre
Roll length
Metre
Separation
0.5 – 5
70 - 500
3.8 to 5.5 (4.5)
50 to100
Filtration
0.3 – 2
70 - 250
2.5 to 4.5
50 to100
Drainage
1–5
500 - 2000
1.5 to 5.5
25 to 50
Reinforcement
30 - 1000
N/A
3.8 to 5.5
or strips
50 to100
or Defined
The polymers used for Geotextile
DENSITY
POLYMER
PE, PP
PET
g/cm3
0.90 to 0.95
1.38
Abbreviation:
PE: Polyethylene
PP: Polypropylene
PET: Polyester
MELTING
STRAIN
UNITS
ºC
%
110 to 170
>100
>240
10 to 15
CREEP
CREEP
HIGH
LOW
Durability Test Methods for Geotextile
EN 12447
Geotextiles and geotextile-related products - Screening test
method for determining the resistance to hydrolysis in water
EN 12226
Geotextiles and geotextile-related products - General tests for
evaluation following durability testing
EN 14030
(ISO 12960)
Geotextiles and geotextile-related products -Screening test
method for determining the resistance to acid and alkaline
liquids
Geotextiles and geotextile-related products - Screening test
EN ISO 13438 method for determining the resistance to oxidation at elevated
oxygen pressure
Geotextiles and geotextile-related products - Microbiological
EN ISO 12225 resistance (soil burial)
Functions and properties of Geotextiles
The functions of Geotextiles
 Separator
 Reinforcement
 Drainage
 Filter
 Container
 Energy absorber
APPLICATIONS FOR GEOTEXTILES
Roads
Railroads
Liquid waste
Solid waste
Retaining walls
Reservoirs, dams
Drainage systems Erosion protection
1 ROADS
1.1 APPLICATIONS IN FILTRATION AND DRAINAGE
applications
Pavement drains
Sub-horizontal drains
Curtains
Trenches
Settlement acceleration
materials
Geotextiles
Geocomposite drain
(PVD)
1 ROADS
1.2 APPLICATIONS IN EROSION CONTROL
SUPERFICIAL EROSION
silt fences
MATERIALS
GEOTEXTILES
Detain carried particles:
during construction,
before vegetation or
under wind effects
1 ROADS
1.3 APPLICATIONS AS BARRIER
MEMBRANE-ENCAPSULATED SOILS - moisture barrier
maintenance of base material properties
for use in
low cost pavements
in:
wet regions
expansive clays
good base soils (lateritic soils,..)
Materials
asphalt impregnated geotextiles
reinforced geomembranes
geogrids (when hard cracking)
1 ROADS
1.4 SEPARATION AND REINFORCEMENT MATERIALS
SEPARATION
GEOTEXTILES
GEOCOMPOSITES
REINFORCEMENT
GEOGRIDS
GEOTEXTILES
GEOSTRIPS
2 BENEFITS OF GEOSYNTHETIC SEPARATORS
2.1 TYPICAL APPLICATIONS
Located at the interface between soil and aggregate
-prevent contamination
-avoid build-up of pore pressure
-avoid loss of granular material
sub-base/sub-grade interfaces
embankments
2 BENEFITS OF GEOSYNTHETIC SEPARATORS
2.2 MECHANISMS
Avoid granular material penetration
Puncture resistance
Filtration
Pore size and permeability
Interlock advantages
Tensile resistance
3 BENEFITS OF GEOSYNTHETIC REINFORCEMENT
3.1 PAVEMENT SYSTEMS
3.1.1 ASPHALT OVERLAY
3.1.2 BASE/SUBGRADE
3.2 EMBANKMENTS OVER SOFT SOILS
3.3 SLOPES AND WALLS
3.1 PAVEMENT SYSTEMS
3.1.1 ASPHALT REINFORCEMENT
new roads
Increase in fatigue life
Reduction in rutting
maintenance of existing roads
3.1 PAVEMENT SYSTEMS
3.1.1 ASPHALT REINFORCEMENT
MECHANISMS
GEOTEXTILE
GEOGRID
WITHOUT REINFORCEMENT
3.1 PAVEMENT SYSTEMS
3.1.1 ASPHALT REINFORCEMENT
Note:
thin nonwoven geotextiles can be used when
cracking still keeps the aggregates interlocking
(tensile characteristics are not required)
The asphalt impregnated geotextile do not acts as
a reinforcement, but as a protector layer and a
moisture barrier.
protector layer - retards crack propagation by deviation
moisture barrier – increases life time after cracking
3.1 PAVEMENT SYSTEMS
3.1.2 SOIL STABILIZATION
“The use of a geosynthetic placed at the sub-grade/fill interface to increase the
support of construction equipment over a weak or soft sub-grade”
Applications
Temporary roadways
Initial construction lift of permanent ways or embankments
Area constructions platforms
3.1 PAVEMENT SYSTEMS
3.1.3 BASE AND SUB-BASE REINFORCEMENT
The use of a geosynthetic placed as a tensile element at the bottom or
within a flexible pavement base or sub-base to:
-increase the service life
-obtain equivalent performance with a reduced structural section
-avoid subsidence problems (sinkholes)
Applications
Permanents ways
Parking lots
Airport taxiways
Container loading facilities
Railway tracks
3.1 PAVEMENT SYSTEMS
3.1.4 ADVANTAGES
-cost savings in construction and maintenance
-increase of service life
-decrease or eliminate over-excavation and required granular fill
“in pavements systems, life cycle cost analysis are important
to show additional maintenance cost savings”
3.2 EMBANKMENTS OVER SOFT SOIL
3.2.1 Applications
-basal reinforcement
-piled embankments with basal reinforcement
-reinforcement over areas prone to subsidence
3.2 EMBANKMENTS OVER SOFT SOIL
3.2.2 Basal reinforcement mechanisms
rotational stability
bearing capacity
foundation extrusion
3.2 EMBANKMENTS OVER SOFT SOIL
3.2.3 Piled embankments basal reinforcement
design
Ultimate limit states
Pile group capacity
Pile group extent
Vertical loading shedding
Lateral sliding
Overall stability
Serviceability analysis
Reinforcement strain
Foundation settlement
3.2 EMBANKMENTS OVER SOFT SOIL
3.2.4 Construction
3.3 REINFORCED SLOPES AND WALLS
3.3.1 applications
landslide reparation
bridge abutment
increase working area
reduce filled area
reduce filling material
3.3 REINFORCED SLOPES AND WALLS
3.3.2 types
reinforcement spacing
Walls (angle of inclination larger than 80o)
Steep slopes
Block walls
.
3.3 REINFORCED SLOPES AND WALLS
3.3.2 types
3.3 REINFORCED SLOPES AND WALLS
3.3.3 benefits
Economical solutions
Rapid and simple construction method
Allows construction in difficult terrain
Allows use of cheaper fill material
Satisfactory appearance structures
Environmental:
reduce damaged areas and
reduce natural material extracting
4. REQUIREMENTS AND TECHNICAL PROPERTIES
Mainly mechanical characteristics
Tensile strength (ISO 10319)
Seam tensile strength (ISO 10321)
Puncture resistance (ISO 12236)
Impact test (ISO 13433)
Mainly hydraulic characteristics (for separation)
Opening size (ISO 12959)
Permeability normal to the plane (ISO 11058)
Technical Requirement as per MoSRTH
Specifications for use in subsurface drains
• Breaking load not less than 10 kN/m
• Minimum Failure strain of 10%
• Apparent opening size 0.22mm – 0.43 as
soil properties
• Allow water flow @ not less than
10lit/sqm/sec
• Minimum puncture resistance of 200 N
• Minimum tear resistance of 150N
Technical Requirement as per MoSRTH
Specifications for use in Highway Pavement
•
•
•
•
•
Minimum Tensile strength 36.3 Kg
Elongation 50%
Asphalt Retention 10 kg/10sqm
Melting Point 150C
Surface Texture- heat Bonded on one side
only
Technical Requirement as per MoSRTH
Specifications for use in Protection Works
•
•
•
•
•
•
Aperture : Rectangular, square or oval
Colour : Black
Strength : Min 10kN/m
Elongation: Max 15%
Form : GR1-GG3 standards
Life : Min 8 years
Typical Specification of NHAI
Separation and drainage
Properties
Units
Fabric
PHYSICAL
Grab Tensile Strength
KN
0.900
Grab Tensile Elongation
%
50
Mullen Burst
KPA
2750
Puncture
KN
0.575
Trapezoid Tear
KN
0.355
UV Resistance
%@hr
70/500
Apparent Opening Size (AOS)
Mm
0.150
Permittivity
Sec
1.5
Flow Rate
1/min/m2
3225
Life Period
Years
120
HYDRAULIC
MINIMUM AVERAGE ROLL VALUES
Typical Specification of NHAI
Soil Reinforcement
Sl.
No.
Minimum Partial FOS for calculation of 100 Woven PP
years long term design strength (TD) in based
accordance with BS-8006:1995 requirements
geotextiles
Woven PET
based
geotextiles
1
Partial FOS for deformation (at 40 C to meet
less than 0.5% post construction strain
requirement for retaining wall cases)
6.0
2
Partial FOS for variations in manufacture from
control specimens (fm 11)
1.0 (use only 1.0 (use only
MARV)
MARV)
3
Partial FOS for extrapolation of creep test data
(fm 12)
1.10 (10000
hours creep)
1.10 (10000
hours creep)
4
Partial FOS for construction/ installation
damage (susceptibility to damage) [fm 21]
1.83
2.44
5
Partial FOS for potential chemical (at 40 C) and
biological degradation. (Environment) [fm 22]
1.10
1.15
3.0
Distribution of Geotextiles in the United Kingdom
Roads
Rail
Structures
Drainage
Erosion
Dams
Canals
Tunnels
Solid Waste
Liquid Waste
Embankments
Other
Nonwovens
Wovens
Knitted
Extruded
55
5
2
10
3
1
1
2
6
6
4
5
65
3
10
2
2
~
1
~
2
2
10
3
10
~
15
15
5
~
~
~
5
5
45
~
35
10
20
5
2
~
~
~
5
5
15
3
Distribution of Geotextile Use in South Asia
Percentage distribution of Geotextile type in the South Asia
Extruded
Knitted
Wovens
Nonwovens
15%
5%
35%
45%
Percentage distribution of Geotextile type per application
Extruded
Knitted
Wovens
Nonwovens
Roads
Rail
Structures
Drainage
Erosion
Dams
Canals
Tunnels
Solid Waste
Liquid Waste
Embankments
55
5
2
10
3
1
1
2
6
6
4
35
8
25
2
2
~
1
~
2
2
10
10
~
15
15
5
~
~
~
5
5
45
35
10
20
5
2
~
~
~
5
5
15
History of Geotextiles in India
• Used commercially since early ’80s
• However, during ’80 – ’90 the use was restricted to
separation, filtration and drainage application for both nonwoven and woven type
• Indian manufacturer like Hitkari, Tata Mills etc.
participated in production of non-woven type for civil
engineering application
• Major boost in usage came after 1995 with major ports and
highway development projects.
• Application included marine protection below rip-raps and
armour layers for separation and filtration for land
reclamation projects.
History of Geotextiles in India
• Application in river Training works and erosion control also
started
• National Highways saw the application in drainage,
embankment protection, base course stabilization and separation
below highway embankments, also protection against erosion.
• Growing usage for environmental projects such as landfills,
waste storage etc.
• MSE block walls are also a major end user, specially for low –
medium heights using geogrids and high strength woven
Geotextile
• Now there are 10-15 non-woven as well as woven Geotextile
manufacturer besides several unorganized participations
Few Examples of NHAI Projects
Project
Purpose
Qty.
Visakhapatnam
In Marshy/ Slushy Soils
1,08,100 sqm
Vallarpadam,
Cochin
Geotextile (non woven) as
separation/ filtration layer
4,30,260 sqm
Tuticorin
Below sub-grade
2,55,000 sqm
Paradip
(i) for high embankment over land
drains
(ii) below sub-grade
1,04,250 sqm
40,640 sqm
JNPT Package II
(SH-54 & Aamra
Marg)
Woven geotextile below
embankment
64,600 sqm
THANK YOU FOR YOUR ATTENTION