Geotextile Engineering : Application in Civil and Environmental Engineering

Shobha K. Bhatia Syracuse University, New York

ASCE Expo 2012

Outline

Introduction History Classification Properties Applications Innovations Conclusions

Geotextiles

Permeable textile used in conjunction with soil or rock.

Integral part of many manmade structures, such as levees, dams, roads, retaining walls, steep slopes, landfills and others.

ZIGGURAT – woven mat reinforcement

Ziggurat of Ur in Mesopotamia ~ 2500 B.C.

History Initially referred as “civil engineering

fabrics” or “filter fabrics.” First use in 1926:

Cotton fabric with hot asphalt (geomembrane kind of material) was field tested.

Polymer based woven industrial fabrics (geotextile) were used beneath concrete block revetments in late 1950s.

Early 1960s, geotextiles were typically woven polyproplene monofilament fibers.

Major Breakthroughs

In 1956, Dutch engineers used geotextiles to overcome dilemmas present in their Delta Works Scheme Hand woven from 100-mm wide 1-mm thick nylon strips

From 1960s, polymeric woven geotextiles were commonly considered in coastal protection works.

Major breakthroughs Mid 1960s, geotextile filters were

considered only on sites where granular filters were not readily available.

In 1968, FHWA monitored pavement overlay repair schemes where geotextiles were installed to control reflective cracking in asphalt surfacing.

First nonwoven needle punched polyster geotextile was developed by Rhone-Poulenc company in France.

Major breakthroughs Valcros Dam

In 1970, thick nonwoven geotextiles were used as filters beneath rip rap protection.

55Ft High Dam, Slity Sand ,30%<0.075mm. Polyester Continuous filament needle punched

nonwoven geotextile, 300g/m2.

Continuous trickle of clean water for 35 years.

At the same time, ICI started producing thinner heat bonded nonwoven geotextiles

Major Breakthroughs In 1973, three basic functions of

geotextiles were identified Separation Filtration Reinforcement

In 1974, drainage was added as fourth basic property.

By early 1990s, cushioning or protection was added as the fifth basic property.

VALCROS DAM, 55 ft (1970)

First Dam with Geotextile Filter

Manufacturer’s and sales

In 1957, after a tropical storm caused severe beach erosion at the home of the president of Carthage mills, he started working with engineers from Coastal Engineering Laboratories of University of Florida to use Carthage Mills fabrics to protect his property against future storms.

This resulted in first use of woven filter fabric in waterfront structures.

Manufacturer’s and sales

Research sponsored by AB Fodervavnader of Bora, Sweden, a small specialty weaving company resulted in the world’s first pullout test device.

Geotextiles The manufacturing of synthetic fibers

Transforming raw polymer from solid to liquid form.

Extruding fibers through spinneret, and Solidifying the fibers into continuous

filaments.

Various textile-forming technologies used to make: Woven ,Non-woven, Knitted and Stitch-

bonded

Geotextile Classification

Types Woven- weave pattern and fiber Plain Weave, Basket Weave, Twill Weave, satin weave

Non-woven -Spun Bonding

Knitted –seldom used

Warp Threads

Weft Thread

Weaving Direction

Fiber

Polymer Chip

Bonding

Winding

Fibers Geotextiles are made of synthetic

fiber Polypropylene (92%) Polyster (5%) Polyethylene (2%) Nylon (1%)

Yarns

Different types of yarn Monofilament fibers Heterofilament fibers Multifilament yarns Staple fibers Slit-film tapes Fibrillated yarns

Multi Filament Yarns

Slit Film Tapes

Different Type of Geotextiles

Natural Fibers Fiber types: natural (wood, straw, coconut,

jute), synthetic (PP, PET, nylon), and combinations (straw/coconut, wood/synthetic)

Fiber structure types: short, long, multifilament

RECP structure types: ECNs, OWTs, ECBs,

and TRMs

92 different degradable RECPs and 37 different non-degradable RECPs are available in the US

RECPs –

wood excelsior wood/synthetic blend

straw/coir

Coir Coir Jute

Types and Properties

20 different companies market geotextiles 87 Woven and 124 nonwoven geotextiles Properties-

Transportation Related Application Mass per unit area, percentage open area, Permittivity, puncture resistance, tear and grab strength,

survivability

Reinforcement Application Wide width tensile strength, creep limited strength

Geotextile consumption

Year 1970 1980 1990 1998

Millions of square meters ,North America

5 100 300 600

Million of square meters, Western Europe

10 60 250 App.400

Million square meters , Japan

100 (all geosynthetics)

Growing market in China and India…………

Relative importance of geotextile functions in geotechnical applications

Application Separation Filtration Reinforcement Drainage Protection

Temporary and permanent pavements

1 2 2

Asphalt overlays 1 2 2

Railways 1 3 3

Embankment 3 3 1 3

Retaining walls and slopes 3 3 1 3

Erosion control 3 2 3 3 2

Subsurface drainage 3 1 Membrane protection 3 1

(1) Primary Function (2) Secondary Function (3) Tertiary Function

Geotextile Properties

Geometric Information

Measuring thickness at 2 kPa The test is performed to EN964 part 1 for a single layer products and to EN964 part 2 for multi-layer

2 kPa

Schematic

25 cm²

thickness

metal base

Sampling Measuring (mua)

Mechanical Properties Short-term tensile strength and dependent deformation Long-term tensile behaviour (creep/creep rupture) Long-term compressive creep behaviour (with/without Shear stress) Resistance against impact or punching

Static puncture test, rapid puncture Resistance against abrasion Friction properties

Direct shear, inclined plane test, pullout resistance Protection efficiency Damage during installation Geosynthetics or composites internal strength Geosynthetic reinforcement segmental retaining wall unit

connection testing

Testing machine with video-extensometer

Capstain clamp for geogrid with laser-extensometer

Mechanical Properties

ε

Tensile Tests

HD PE - M

PP/ PE - T PP - M

PP/ PET - T

Woven Fabrics, GeoGrids

10 20 30 40 50 60 70 80 90 100 strain %

20 10

30 40 50 60 70 80 90

100

Fm kN/m

1 2 3

4

5

Force - Strain behaviour of Geosynthetics

Tensile Creep and Creep Rupture EN ISO 13431 : 1996 ASTM)

Tensile creep tests give information on time-dependent deformation at constant load.

Creep rupture tests give time until failure at constant load.

A deformation measurement is not necessary for creep rupture curves.

Loads for creep testing are most often dead weights, often enlarged by lever arms.

Multiple Creep Rupture Rigs in a Temperature Controlled Chamber

Resistance To Static Puncture

Static Puncture Test: The Test CBR (EN ISO 12236 : 1996) The use of soil mechanics California Bearing Ratio (CBR) apparatus for this static puncture test, has resulted in the unusual name for this test.

A plunger of 50mm diameter is pushed at a speed of 50 +/- 10mm min onto and through the specimen clamped in the circular jaws. Measurement of force and displacement are taken. The test is widely used for geotextiles, it is not applicable to grids, and the test provides useful data for geomembranes.

CBR - device in testing machine

Inserting specimen in hydraulic CBR-clamps

Impact Resistance Test (CEN TC 189 WI 14; ISO 13428 draft)

Efficiency of protection materials can be tested by dropping a hemispherical shaped weight onto a specimen placed on a lead plate on a resilient base.

The impression in the lead and the condition of the specimen are recorded. Lighter round shaped drop weights are used for other geosynthetics. The deformation of a metal sheet under the tested material gives quantitative results.

Impact Resistance Test

Drop weight, lead platen, specimen under ring

Impact Resistance Test (performance test : BAW)

2 m

67.5 kg

Result of drop tests - no penetration

A heavy drop weight (67.5 kg) is dropped from 2 m height on the geosynthetic placed on sand and fixed in a ring. The result is a “penetration yes or no” decision.

The Test

Abrasion Resistance (EN ISO 13427 : 1995)

Emery cloth of a specific grade is moved linearly along the specimen. After 750 cycles the abraded specimen is tested to measure the residual tensile strength or hydraulic properties

Example of Apparatus with Sliding Block

Specimen before test

Specimen after abrasion test

Direct Shear Friction (EN ISO 12957 : 1998)

Reinforcing geosynthetics develop their tensile resistance by the transfer of stresses from the soil to the fabric through friction. The friction ratio is defined as the angle of friction, the ratio of the normal stress to the shear stress. Low normal stresses may be tested by an inclined plane test and higher normal stresses by direct shear or by pull out test.

Direct shear (EN ISO 12957-1)

The friction partners are placed one in an upper box, the other in the lower box. The lower box is moved at a concentrate of displacement (index testing: 1 mm/min) while recording force and displacement. The results for three normal stresses (50, 100, 150 kPa) are plotted, the value of friction angle is calculated

Section Through Shear box Test

Damage During Installation

The CEN-ISO standard applies a cyclic load to a platen (100 x 200) pressing via a layer of Corundum aggregate placed on top of the geosynthetic being tested. (Corundum is a trade name for a sintered aluminium oxide.

After 200 cycles between 5 kPa and 900 kPa maximum stress the specimen is exhumed and may be subject to a tensile test for the residual strength for reinforcement applications, or for filtration the hydraulic properties for filtration applications.

A performance test requires the soil and fill to be used on the site and the equipment to spread and compact the material.

Typical results of an index-test are shown

Material Before (left) and After (right) Damage Test

Characteristic Opening Size (EN ISO 12956 : 1999)

To determine, which grain size can passing through a geosynthetic and which is retained, a wet sieving test is used with a standard “soil”.

The ‘soil’ passing the geotextile is extracted from the water and sieved again.

A characteristic value O90- is calculated according to EN ISO 12956.

O90 = d90 of the ‘soil’ passing the geosynthetic

Dry Sieving

Hoop sizing Sagging Broken and irregular

glass beads Trapping within the

geotextile Electrostatic effects Time for the Test

Wet Sieving Hoop sizing sagging Great chance for error: a. Leakage between

sieves b. Analyzing passed

glass beads (<325 mesh) Glass bead clumping on geotextile Elimination of

electrostatic effects Time for the test

Pores with Glass Beads

Plan view Side view

0

10

20

30

40

50

60

70

80

90

100

0.010.11Diameter (mm)

Perc

ent F

iner

(%)

Mineral Oil

Silw ick

Porew ick

Product: Texel, 909 PET/PP, Staple, Needle-punched, Nonw ovenThickness: 2.3 mmPermeability: 0.45 cm/secAOS: 0.07-0.11 mm (Dry Sieving)Bubble Point: 0.116-0.135 mmO95: 0.098-0.11 mmO50: 0.069-0.076 mm

W2 - multifilament

Pore size, volume, permeability, density, surface area, and adsorption

Comparison of Wet Sieving & Bubble Point Method

0102030405060708090

100

0.010.11 Diameter (mm)

Perc

ent F

iner

(%)

Amoco 4510 Sample AAmoco 4510 Sample BAmoco 4510 Sample CAmoco 4510 Sample D

Bubble Point Method: 0.12 mm

0.12-0.068 mm

Durability Properties

Resistance to weathering

Resistance to microbiological

degradation (soil burial)

Resistance to liquids

Resistance to hydrolysis

Resistance to thermal oxidation

Durability Properties Geosynthetics may be used for temporary structures

such as access roads for construction sites or may be required for medium term applications until consolidation of soils makes them redundant.

Long-term applications are the main use (30 to 60 years for some in UK application or ; more than 120 years for landfills in most countries).

Therefore durability is an important requirement.

Resistance to Weathering (prEN 12224 : 1996)

Products exposed uncovered to light and products placed without cover-soil for service are tested by artificial weathering.

Exposure to UV-light of defined emission spectrum and rain at elevated temperature accelerates the test.

Tensile tests after exposure and reference to fresh specimen tensile strength loss in %. Tensile tests on exposed and fresh specimens can be used to determine the loss of tensile strength, normally expressed as a percentage of strength retained after exposure.

Exposure to Natural Weathering

Rainsplash erosion testing

Typical engineering properties of geotextiles used in geotechnical applications (after Lawson 1982)

Geotextile type Mass per Unit area (g/m2)

Apparent Opening size (AOS) (mm)

Volume water permeability

1/m2/s

Tensile Strength kN/m

Maximum Elongation

%

Woven • Monofilament • Multifilament • Tape

150-300

250-1300 90-250

0.07-2.5 0.2-0.9

0.05-0.10

25-2000 20-80 5-15

20-80 40-800 8-90

9-35 9-30

15-20

Nonwoven • Heat-bonded • Needle-punched

70-350

150-2000

0.01-0.35 0.02-0.15

25-150 25-200

3-25 7-90

20-60 50-80

Knitted • Weft • Warp

0.1-1.2

60-2000

2-5

20-120

300-600

12-15

Stitched-bonded 250-1200 0.07-0.5 30-80 30-1000 8-30

Application

Geotextile as reinforcement

Designing for Roadways reinforcement Unpaved and paved roads

Designing for soil reinforcement

Geotextile reinforced wall Geotextile reinforced foundation soil Geotextile to improve bearing capacity Geotextile to in situ slope stabilization

Geotextile encase columns, A continuously, radially, woven geotextile sock made from a variety of polymers. These socks form encased stone columns when filled with compacted sand, gravels or crushed rock for use in very soft soil where conventional ground treatments cannot be utilized.

http://www2.wrap.org.uk/downloads/MRF116_Geosystems_Guidance_Document_FINAL_February_2010.adb44eaf.8590.pdf

Basic Principles of Reinforced Soil

For reinforced soil to work, the soil and reinforcement must STRAIN

In a stable structure the strain in the soil and reinforcement are equal (i.e. there is strain compatibility)

The strain in the reinforced soil is influenced by: The stiffness of the reinforcement Properties of the soil The stress state of the soil

Analysis and Design Established geotechnical and stability methods

used Soil parameters generally considered in total stress

terms Three main failure mechanisms considered

- Rotational Stability - Lateral Sliding - Bearing Capacity

Lateral Sliding

Resistance to lateral sliding determined from active driving force

Geosynthetics/soil interface should be obtained from testing

Reinforcement

Soft Clay Foundation

Embankment fill

Reinforcement tension develops in the plane of the reinforcement

Tr Tr

Horizontal movement of fill, driven by active wedge

Foundation Extrusion

If soft soil thickness > embankment base width, a bearing capacity analysis will be required

If soft soil layer thickness < than the embankment base foundation width extrusion occurs at the toe.

Soft Clay Foundation

Embankment fill

Lateral extrusion of foundations due to settlement of fill

The solution to this mode of failure is to reduce the settlement by making the base stiffer (Geocell mattress)

Reinforcement

Case Study: Hetaoyu Coal Mine Processing Plant

Location: China Retaining wall

(1km x 140m) built adjacent to Jinghe River

PET geotextile used to reinforce soil

http://www.geosyntheticsmagazine.com/articles/0212_fla_hetaoyu_mine.html

35 June 8, 2002

High strength geotextiles for embankments on soft ground

Case Study: Levee WBV-72

Location: New Orleans, LA Levee (2.8miles long) has 2.4miles of

geotextile reinforcement Geotextile strengths used:

490 kN/m (21,500 sq yd) 650 kN/m (187,403 sq yd) 830 kN/m (172,071 sq yd)

Used as embankment reinforcement and separation http://www.geosyntheticsmagazine.com/articles/081712_huesker_levee.html

Case Study: Levee WBV-72 cont.

http://www.geosyntheticsmagazine.com/articles/081712_huesker_levee.html

Case Study: Fiber-Reinforced Roadway Embankment Soil

Location: Lake Ridge Parkway, Texas Originally constructed in the reservoir

of a proposed lake (1980s) Earth fill embankments were built (slope

ratio=3) to raise road over lake Slope failures occurred (2000s)

Repaired with fiber-reinforced soil 3” polypropylene fibers used to increase

shear strength

http://www.geosyntheticsmagazine.com/articles/0811_f2_sustainable_embankment.html

Case Study: Fiber-Reinforced Roadway Embankment Soil cont.

http://www.geosyntheticsmagazine.com/articles/0811_f2_sustainable_embankment.html

Case Study: Fiber-Reinforced Roadway Embankment Soil cont.

http://www.geosyntheticsmagazine.com/articles/0811_f2_sustainable_embankment.html

Geotextile as filter or drain

Pavement Stone base

Soil subgrade

Topsoil

450 mm

400 mm

300 mm

Crushed stone/ perforated pipe

GT

(GT Filter in Excavated Trench) (Crushed Stone & Perforated Pipe)

Geotubes in Dewatering Applications

Municipal Paper Sludge

Pulp and Paper Mill Sludge

Mineral Processing Sludge

Fly Ash Mining and Drilled

Waste Industrial By-Product Agriculture Waste

Case Study: Dewatering Solutions cont.

Location: Midlands, England Pumping sludge into filtration

geosynthetic tubes (“Sedi-Filter”) Sediment remains but water drains out

Sediment removed to landfill

Ideal before attempting to deepen canals

http://www.geosyntheticsmagazine.com/articles/101310_sediment_bag.html

Case Study: Dewatering Solutions

http://www.geosyntheticsmagazine.com/articles/101310_sediment_bag.html

Waste Containment Liners with Geotextiles

Different Drains Mebra Drain Amerdrain

Installation

Prefabricated Vertical Drains

PIPING SYSTEM

Application – Seperation

Geotextile as a separator

http://www.typargeotextiles.com/PDFs/TG-Landfills.pdf

Erosion Control

Slope Protection with Geotextile

Silt Fence

South Channel

A1

A3

A2

Case Study: Incheon Grand Bridge

Location: Incheon, South Korea Reclamation dikes had to be built

during construction Geotextiles were used

Cost-efficient Met construction and time requirements

Close-ended fabric tube with filling ports for sand input Cost more than $2 million

http://www.geosyntheticsmagazine.com/articles/0211_fla_incheon_bridge.html

Case Study: Incheon Grand Bridge cont.

http://www.geosyntheticsmagazine.com/articles/0211_fla_incheon_bridge.html

Case Study: PEMEX Marine Facilities

Location: Tabasco, Mexico Beach erosion problems Sand-filled geotextile tubes used under

oil conduction pipes in the surf zone Previously at risk to collapse due to loss

of sand foundations Geotextile tubes also used as a

submerged breakwater along the coast http://www.geosyntheticsmagazine.com/articles/0410_f3_tubes.html

Case Study: PEMEX Marine Facilities cont.

http://www.geosyntheticsmagazine.com/articles/0410_f3_tubes.html

Future Trends and Innovative Products

http://boingboing.net/2012/01/19/intelligent-geotextiles-wired.html

Intelligent Geotextiles- Geo detect System- Structure Health Monitoring System

Reactive Core Mat

http://remediation.cetco.com/LeftSideNavigation/Products/ReactiveCoreMat/tabid/1359/Default.aspx

Future Trends DUAL FUNCTION GEOSYNTHETICWRAPPED PVD Provides structural stability due to the high tensile and shear

strength of the geosynthetic Can bear the shear stresses generated by the mandrel

Reduces the zone of disturbance and remolding Also reduces the effects of smear by preventing the finer soil

particles to enter the drain core

ELECTRO-CONDUCTIVE PVD Employs the process of electro-osmosis in attempting to

reduce the smear effects cations in the diffused double layer of water moves towards the vertical drain (acting as cathode) and get discharged, thus carrying the pore water along with for drainage.

Innovative Products and Future

The use of flat weft knitting technology to manufacture natural fiber geotextiles for reinforcement applications

Superior over mid range synthetic geotextile used for soil reinforcement

(Anand,2008)

Innovative Products and Future

Reducing fiber diameter to nanoscale, a significant increase in specific surface area to the level of 1000m2/g

Future geotextiles could be nanocomposites which might not only change their effectiveness, but applications

(Ko 2004, Koerner 2000)

Innovative Products and Future

By taking advantage of the recent development and changes in design aspects, companies have increased weights from 16 oz. / sy. to 28-32 oz. / sy.

Use of polyester for manufacturing of geotextiles has many advantages over traditional polypropylene (“Advancements in geomembranes and geotextiles” – Reuben Weinstein)

Case Study: TenCate Mirafi H2Ri

Location: Alaska Water-wicking geotextile used below

roads in frozen tundra Road damage common due to uneven

soil moisture freezing differently Tested on the Dalton Highway and

now used in Alaska and Canada

http://www.geosyntheticsmagazine.com/articles/102611_tencate_award.html

Case Study: TenCate Mirafi H2Ri cont.

http://www.geosyntheticsmagazine.com/articles/102611_tencate_award.html

CIVIL Draintube© FTF Embankment drainage

Portneuf / mer – Road 138 : Quebec – sept. 2008

• Replaces traditional granular layers and two geotextile filters

• Can replace up to 3 ft. of granular drainage

• Effective solution for cuts, fills and soft soils

CIVIL Draintube© FTF Embankment drainage

Installation Backfill

The entire job

Autouroute 50 Major project in 2009 with Transports Québec 2,5 km of road

Afitex - 20+ years in the drainage & environmental markets Texel - 40+ years in geosynthetics

Draintube© technology

Geosynthetic Instrumentation

Conclusions

Questions

What are three different types of geotextiles that can be used for civil engineering applications?

What are the most important properties of the geotextiles when they are used as a reinforcing member?

What is the difference between index and performance test? Where would you get the information about the geotextile’s

properties? Give two specific examples where geotextiles is used as a

filter and as a separator. Give example of two innovative geotextilse that have been

developed recently.