role of geosynthetics in civil engineering

Role of Role of Geosynthetics in Geosynthetics in Infrastructure Infrastructure

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SRINIVAS ANGADI SRINIVAS ANGADI M M TechTech

JNTU College of Engineering JNTU College of Engineering HyderabadHyderabad

"In the beginning, O Lord, you laid the foundations of the earth, and the heavens are the

work of your hands.”

“When He made this Earth very

thing is perfect and beautiful”

Earth becomes problematic place to live when Men disobeyed Creator.Construction in difficult sites becomes a tough job for engineersMy present topic give glimpse of new technology how they are dealing with weak soils.

IntroductionIntroductionIn the past, when dealing with difficult In the past, when dealing with difficult

sites for construction purposes, the sites for construction purposes, the conventional practice was limited to either conventional practice was limited to either replacing the unsuitable soils, or bypassing replacing the unsuitable soils, or bypassing them with costly deep foundations.them with costly deep foundations.

Additionally, the age-old problem of land Additionally, the age-old problem of land scarcity and the need to rebuild aging scarcity and the need to rebuild aging infrastructure in urban areas, increased infrastructure in urban areas, increased realization of seismic hazards, and regulations realization of seismic hazards, and regulations mandated for various environmental problems, mandated for various environmental problems, have been the impetus for the evolution of a have been the impetus for the evolution of a number of ground improvement techniques number of ground improvement techniques during the past 25 years. during the past 25 years.

IntroductionIntroductionInnovative ground modification Innovative ground modification

approaches are routinely used now to solve approaches are routinely used now to solve unique soil-related problems, and often are unique soil-related problems, and often are considered to be the most economical considered to be the most economical means to improve an undesirable site means to improve an undesirable site conditioncondition

Geosynthetics Geosynthetics have proven to be have proven to be among the most versatile and cost-effective among the most versatile and cost-effective ground modification materials. Their use ground modification materials. Their use has expanded rapidly into nearly all areas has expanded rapidly into nearly all areas of civil, geotechnical, environmental, of civil, geotechnical, environmental, coastal, and hydraulic engineering.coastal, and hydraulic engineering.

Genesis of Geosynthetics..Genesis of Geosynthetics..

Inclusions of different sorts mixed with soil have been used for thousands of years. They were used in roadway construction in Roman days to stabilize roadways and their edges.

These early attempts were made of natural fibres, fabrics or vegetation mixed with soil to improve road quality, particularly when roads were built on unstable soil. They were also used to build steep slopes as with several pyramids in Egypt and walls as well.

Genesis of Geosynthetics..Genesis of Geosynthetics..A fundamental problem with using

natural materials (wood, cotton, etc.) in a buried environment is the biodegradation that occurs from microorganisms in the soil.

With the advent of polymers in the middle of the 20th century a much more stable material became available. When properly formulated, lifetimes of centuries can be predicted even for harsh environmental conditions.

R & D..R & D..• Work Related to Geo-synthetics started in Work Related to Geo-synthetics started in

1960.1960.

• The International Geo-synthetics Society (IGS) founded in 1982.

• At present there are more than 20 Universities teaching various courses on Geo-synthetics.

• Geo-synthetics are available worldwide and the activity is robust and steadily growing.

Global Scenario of Geo-Global Scenario of Geo-syntheticssynthetics

Worldwide demand for geo-synthetics is projected to rise 5.3 percent annually to more than 4.7 billion square meters in 2014.

Strong growth in China is demonstrated by use of geo-synthetics in almost all government sponsored/controlled projects in various areas while such is not the case in India.

USA dominates the consumption, China Catching up quickly but India consumes less than 1.5%

There is a lot of scope and necessity to enhance the use of Geo-synthetics in India.

Types of GeosyntheticsTypes of Geosynthetics1. Geotextile1. Geotextile

Functions of GeotextilesFunctions of Geotextiles• Geotextiles are basically textiles in

traditional sense made from synthetic fibers. So this material is flexible, porous in nature and bio-undegradable.

• There are at least 80 specific application areas for geotextiles that have been developed to fulfill following major functions:

1. Separation 2. Reinforcement

3. Filtration & & Drainage 4. Moisture barrier (when impregnated)

FiltrationFiltration

Drainage- FunctionDrainage- Function

Separation - FunctionSeparation - Function

Reinforcement - Reinforcement - FunctionFunction

Separation Filtration and Drainage Separation Filtration and Drainage Functions of Geotextiles in Road Functions of Geotextiles in Road

ConstructionConstruction

Embankment Failure Modes and Reinforcement

2. Geogrids2. Geogrids

Geogrid -Geogrid -FunctionsFunctions

The use of geogrids in The use of geogrids in roadway and railroad roadway and railroad construction to reinforce construction to reinforce the base of the structure the base of the structure over soft soilsover soft soilsThe geogrid helps to The geogrid helps to increase the bearing increase the bearing capacity of the subgrade capacity of the subgrade soil while greatly soil while greatly reducing the loss of the reducing the loss of the aggregate cover aggregate cover material into weak, wet, material into weak, wet, or saturated subgrade or saturated subgrade soils.soils.

RETAINING WALLSRETAINING WALLSThe use of The use of geogrids in geogrids in retaining wall retaining wall applications is applications is viewed as an viewed as an extremely extremely efficient and cost efficient and cost saving method of saving method of design applicationdesign application



REINFORCED REINFORCED EMBANKMENTSEMBANKMENTSOVER SOFT OVER SOFT FOUNDATIONSFOUNDATIONSA popular A popular technique for technique for creating stable creating stable foundations over foundations over soft soils is termed soft soils is termed reinforced reinforced embankments over embankments over soft foundationssoft foundations

3. Geomembranes & Geosynthetic 3. Geomembranes & Geosynthetic Clay LinerClay Liner

Water Conveyance(Canal Water Conveyance(Canal Liners)Liners) Geomembranes Geomembranes and GCLs can be and GCLs can be economically employed to economically employed to reduce the seepage reduce the seepage through unlined irrigation through unlined irrigation canals or waterways. They canals or waterways. They are effective alternatives to are effective alternatives to concrete, asphalt or concrete, asphalt or compacted clay soils and compacted clay soils and can be used as an can be used as an expedient method to repair expedient method to repair poorly performing existing poorly performing existing linings or those that are linings or those that are rapidly deteriorating.rapidly deteriorating.

Geomembranes & GCL’s Geomembranes & GCL’s FunctionsFunctions

Solid Waste Solid Waste Landfill Landfill ContainmentContainmentLandfill Landfill applications for applications for geomembranes and geomembranes and geosynthetic clay geosynthetic clay liners (GCLs)liners (GCLs)include their use as include their use as bottom liners for bottom liners for waste and leachate waste and leachate containment, cut-containment, cut-off walls as well as off walls as well as landfill closures or landfill closures or covers.covers.


Other Uses…Other Uses…•Coal Ash Storage Coal Ash Storage SitesSites


• Surface Surface Impoundments/Impoundments/

Liquid ContainmentLiquid Containment (Pond Liners)(Pond Liners)

4. Geofoam4. Geofoam

Geofoam - FunctionsGeofoam - FunctionsGeofoam is used in geotechnical applications such as lightweight fill for construction on soft ground, for slope stabilization, and retaining wall or abutment backfill; From foundations to theatre seating to road embankments geofoam is inherently multi- functional

Geofoam - FunctionsGeofoam - Functions

A major advantage of using geofoam as fill material in embankments is that it is up to 50 times less massive than other lightweight fills

Geofoam - FunctionsGeofoam - Functions

5. Geocell5. Geocell

Slope erosion controlThe use of Geocell for erosion control applications eliminates complicated and expensive construction techniques. Geocells 3D structure provides a blanket of 'cells' on the slope surface which can be in-filled with a variety of materials depending on the application; either topsoil, aggregates, from sands and gravels to larger stones and cobbles.

This improves resistance to erosive forces such as rainwater run-off on steep or unstable slopes, or slopes exposed to severe hydraulic or mechanical stresses.

Slope erosion control

6. Geocomposites6. Geocomposites

Geocomposite - Functions• Geocomposite are basically combinations

of two or more different types of geosynthetic.

• Examples include: geotextile-geonet; geotextile-geogrid; geonet-geomembrane; or geosynthetic clay liner (GCL)

• The three main geocomposite material types are: drainage geocomposites, reinforcement geocomposites and fluid barrier geocomposites.

Usage of Geosynthetics in Usage of Geosynthetics in IndiaIndia

At Delhi Metro At Delhi Metro Rail Corporation LtdRail Corporation Ltd

Used for Protection, Used for Protection, Separation, Drainage Separation, Drainage between Top between Top Shotcrete Lining & Shotcrete Lining & Yellow Yellow Geomembrane sheetGeomembrane sheet


• ConstructiConstructing ng Protection Protection Wall Wall against sea against sea erosion of erosion of coast at coast at Kolak, Kolak, Gujarat.Gujarat.


Open Air Open Air AuditoriumAuditoriumAt Kharghar, Navi At Kharghar, Navi Mumbai,Mumbai,Non Woven Non Woven GeotextileGeotextileIs used as Is used as Separator Separator between Top Soil between Top Soil & Drainage Layer& Drainage Layer

Meghalaya State Meghalaya State ElectricityBoard, ElectricityBoard, ShillongShillongFunction:Function: • • Flexible Earth Flexible Earth Retaining Wall.Retaining Wall.• • River / Coastal River / Coastal Erosion ControlErosion Control


Advantages of Geo-syntheticsAdvantages of Geo-synthetics• Cheaper in product cost, transport Cheaper in product cost, transport

and installation. and installation. • Can be designed (predictability)Can be designed (predictability)• Can be installed quickly with Can be installed quickly with

flexibility to construct during short flexibility to construct during short period.period.

• Consistent over a wide range of soilsConsistent over a wide range of soils• Space Savings Space Savings • Material Quality Control - More Material Quality Control - More

homogeneous than soil and homogeneous than soil and aggregates. aggregates.

• Better Construction Quality Control Better Construction Quality Control at siteat site

• Easy Material Deployment Easy Material Deployment

Advantages of Geo-syntheticsAdvantages of Geo-synthetics• Less Environmentally Sensitive Less Environmentally Sensitive • Improved performance and Improved performance and

extended lifeextended life• Increased safety factorIncreased safety factor• Compatible with field conditionsCompatible with field conditions• Increased service life of flexible Increased service life of flexible

pavement section by a factor of 2.5 pavement section by a factor of 2.5 to 3.0 for weak subgrades and by to 3.0 for weak subgrades and by 2.0 to 3.3 for moderate subgrades 2.0 to 3.3 for moderate subgrades

• Increase in allowable load bearing Increase in allowable load bearing capacity by 40 to 50%capacity by 40 to 50%

Geo-Synthetic at Economic Geo-Synthetic at Economic EdgeEdge• The cost of geo-synthetics The cost of geo-synthetics

applied usually between 3 to 5 applied usually between 3 to 5 per cent of the total cost of per cent of the total cost of projects. projects.

• For a number of projects, savings For a number of projects, savings of 30 per cent in total project of 30 per cent in total project costs have been reported.costs have been reported.

• Minimizes the regular repair and Minimizes the regular repair and maintenance costs directly. maintenance costs directly.

• Increase efficiency of structures, Increase efficiency of structures, minimize pollution and leads to minimize pollution and leads to efficient use of natural efficient use of natural resources. resources.

Geo-Synthetic at Environment Geo-Synthetic at Environment EdgeEdge

• Geo-synthetics are difficult or Geo-synthetics are difficult or impossible to degrade. However, impossible to degrade. However, in view of their inert nature they in view of their inert nature they can be disposed off without the can be disposed off without the danger of contamination. danger of contamination.

• Geo-synthetics assist the Geo-synthetics assist the environment by acting as a environment by acting as a containing barrier for toxic containing barrier for toxic materials.materials.

• Geo-synthetics provide sealing Geo-synthetics provide sealing and capping of pollution due to and capping of pollution due to chemicals released after road chemicals released after road and rail accidents into and rail accidents into groundwater areasgroundwater areas

Disadvantages of Geo-Disadvantages of Geo-syntheticssynthetics

• Long-term performance of the particular formulated resin being used to make the geo-synthetic must be assured by using proper additives including antioxidants, ultraviolet screeners, and fillers.

• Clogging of geotextiles, geo-nets, geo-pipes and/or geo-composites is a challenging design for certain soil types or unusual situations. For example, loess soils, fine cohesion less silts, highly turbid liquids, and microorganism laden liquids (farm runoff) are troublesome and generally require specialized testing evaluations.

• Handling, storage, and installation must be assured by careful quality control and quality assurance

Hindrances for the use of Geo-Hindrances for the use of Geo-synthetics in Indiasynthetics in India

• Lack of desired legislationLack of desired legislation• Lack of required standards on Lack of required standards on

geosynthetic products as well as on geosynthetic products as well as on design, construction and installation design, construction and installation guidelinesguidelines

• Lack of policy / regulatory initiatives Lack of policy / regulatory initiatives by the central and state governmentsby the central and state governments

• Lack of awareness of standards and Lack of awareness of standards and guidelines by the site engineers / field guidelines by the site engineers / field staffstaff

• Lack of national certifying and Lack of national certifying and accreditation agencies for geo-accreditation agencies for geo-synthetics in the countrysynthetics in the country

• Lack of R&D facilitiesLack of R&D facilities• Incompleteness of existing standards Incompleteness of existing standards

and guidelinesand guidelines

ConclusionConclusion• ItIt is essential to made the use of is essential to made the use of

Geo-synthectics mandatory in Geo-synthectics mandatory in India in order to have increased India in order to have increased efficiency with potential large efficiency with potential large cost saving, safety of structures cost saving, safety of structures and minimum environmental and minimum environmental pollution including large saving pollution including large saving of natural resourcesof natural resources

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