GEOSYNTHETICS ENGINEERING: IN THEORY AND PRACTICE
Prof. J. N. Mandal
Department of Civil Engineering, IIT Bombay, Powai , Mumbai 400076, India. Tel.022-25767328email: [email protected]
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Module - 2LECTURE - 6
AN OVERVIEW OF GEOSYNTHETICS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Introduction Categories of geosynthetics
Geosynthetics scope and definitions
Raw materials and machineries
Composition of geosynthetics
Types of geosynthetics and functions
Geosynthetic functional applications
Multiple functions of geosynthetics
Design of geosynthetic
Sustainability using geosynthetics
OUTLINE
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
INTRODUCTION
In the past four decades, extensive research has beencarried out on geosynthetics around the world.
It is required to attain good design, good research and atthe same time good material and good constructiontechnique to overcome the educational and technicalchallenges. The dynamic and rapid growth of geosynthetic is exciting,emerging and vibrant in the field of civil engineering.
Today, more than twenty billion square meters ofgeosynthetics have exclusively been used in several millionprojects (Giroud, 2012).
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
The jute geotextile was successfully used on Strand roadin Kolkata in 1934 by Bengal PWD and subsequently inMyanmar during 2nd world war. The jute geotextile had alsobeen used for erosion control in 1980.
The revolutionary development of geosynthetics has beenstarted in the early 1970s in the field of construction industry.
Geosynthetics provide proper solution to design andconstruction problems in spite of climatic, geographic ortechnological differences.
The uniqueness of geosynthetics is that they ensuremultifunctional performances and simple to use and providegreat economical potential advantages.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Unmodified Reinforced Spun bonded
Melded stabilized e. g. calendared
Non stabilized
stabilized Non stabilized e. g. calendared
Melded Reinforced
Needle-punched (thick) Needle-punched (thin) Monofilament Multifilament Silt film
Non-oven knitted woven
Geotextiles
Permeable Impermeable
Synthetic Natural Synthetic Natural
Textiles Webbings
Combination products
Steel, polymers Palm leaf, wood, bamboo
Cotton, jute, reeds, grass
Geomembrane
Closed mesh
Open mesh
Strips
Geogrids Reinforced earth
Combination products
polymers
Geosynthetics classifications (After Rankilor 1981)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOSYNTHETICS SCOPE AND DEFINITIONS What are Geosynthetics?
Geosynthetic is a product made of polymeric/natural material usedwith soil and rock, or any other related geotechnical engineeringmaterials for the construction of Civil Engineering structure, orsystem.
Why would we want to use them?
Sustainable development and environment protection can go hand - and – hand.
It reduces maintenance cost and increases life. It saves substantial cost over alternative solutions. The quality can be controlled as manufactured in a factory It is widely available. It has generic specifications and easy to install.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Optimum technical properties of Geosynthetics:
It has excellent stress-strain behavior
It has good flexibility
It has excellent filtration characteristics
It has high water permeability
It can provides excellent mechanical protection
It can be welded together
It does not form by-products
It is highly resistant to chemical and biological attack, and
It is chemically ultraviolet stabilizedProf. J. N. Mandal, Department of Civil Engineering, IIT Bombay
When can we use them?
Low bearing capacity of the soil Excessive Settlement of soil Soft soil treatment (Reclamation of Land) Limited space for construction Land Saving To control and protect the environment Swelling soil Faster Construction Saving in time Saving in cost Sustainable environmental safety To maintain quality assurance / quality control (QA/QC)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Where can we use them?
Geotechnical Engineering
Transportation Engineering
Geo environmental Engineering
Coastal/Hydraulics/Water Resources Engineering
Mining Engineering
Agricultural Engineering
Earth quake Engineering
Bio Engineering
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
How can we use them?
We can use geosynthetics based on their major functionsand specifications. There are six major functions:
Separation
Filtration
Drainage
Reinforcement
Protection, and
SealingProf. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Who produce Geosynthetics?
Around the world there are many manufacturing companiesthat produce comprehensive range of Geosynthetics andany other related products used in Civil engineering andconstruction systems.
CATEGORIES OF GEOSYNTHETICS• Geotextiles (Knitted, Nonwoven, Woven)• Geogrid (Bonded, Extruded, Knitted, Woven)• Geomembrane (Bituminous, Elastomeric, Plastomeric)• Geonets• Geosynthetics Clay Liner• Geocomposite drains (PVD, Geonets or Geospacers)• Geopipes
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
• Geostrips
• Geospacers
• Geocomposite
• Glassgrid
• Geoarmour
• Geoblanket
• Geofoam
• Geomats
• Geocombs
• Geotextile container
• Geotextile bags
• Geotextile tubes •Geo coir
• Geo jute
• Bamboo
• Geocell / Geoweb
• Gabion
• Fiber
• Hybrid geosynthetics
• Electro kinetic geosynthetics
• Smart Geosynthetics
• Geo straw
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
RAW MATERIALS USED FOR THE PRODUCTION OF VARIOUS TYPES OF GEOSYNTHETICS
• Polypropylene (PP)• Polyethylene (PE)• Polyamide/ Nylon (PA)• High density polyethylene (HDPE)• Low density polyethylene (LDPE)• Linear low density polyethylene (LLDPE)• Medium density polyethylene (MDPE)• Very low density polyethylene (VLDPE)• Chlorinated polyethylene (CPE)• Chloro-sulphonated polyethylene (CSPE)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
• Polystyrene (PS)
• Polyester or polyethylene terephthalate (PET)
• Polyvinyl chloride (PVC)
• Chlorinated Polyethylene (CPE)
• Ethylene Propylene diene terpolymer (EPDM)
• Expanded polystyrene (EPS)
• Geo Jute (GJ)
• Geo Coir (GC)
• Bamboo (B)
• Sisal (S)
• Straw (SW)Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
RAW MATERIALS USED FOR THE PRODUCTION OF VARIOUS TYPES OF GEOSYNTHETICS
Raw materials Geosynthetics
PP, PET, PE, PA, GJ, GC, S, SW Geotextiles
PET, PP, HDPE, GC, B, S Geogrids
PVC, PP, HDPE, LLDPE, VLDPE,
CPE, CSPE, GJ
Geomembranes
HDPE, MDPE,GJ, GC, S, SW Geonets
HDPE, PP, PVC Geopipes
EPS Geofoams
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
COMPOSITION OF GEOSYNTHETICS
Geosynthetics are made of different types of fibers or yarns:
Monofilament Silt-film monofilament Multifilament Silt-film multifilament Staple fibers Staple yarnStable fibersFilamentsSilt films
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Woven geosynthetics and knitted geosynthetics can bemade of yarns as follows:
A monofilament yarnA spun yarnA multifilament yarnA fabricated yarn andA slit film yarn
The nonwoven geosynthetics can be made of stablefibers or filaments. The arrangement of fibers is randomand bonded together with the following systems: Mechanical bonding Chemical bonding Heat/ Thermal bonding Resin bonding
Spray bonding Spun bonding Stitch bonding
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Manufacturing of Geogrid
Strata India (Courtesy to Mr. N. Dalmia)Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Tensar International (1996, 1997 and 1999)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
DIFFERENT TYPES OF GEOSYNTHETICS
GEOTEXTILES (GT) Nonwoven geotextileWoven geotextile
Woven geotextiles supplied by manufacturers
Nonwoven geotextiles supplied by manufacturers
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Nonwoven Geotextiles:
Mechanically bonded non-woven
Thermally bonded non-woven
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Woven Geotextiles:
Monofilament-on-multifilament Multifilament-on-multifilament
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOGRIDS (GG)
Woven geogrids: Yarns are weaved perpendicular toeach other
Bonded geogrids: Two or more sets of strands arebonded together perpendicular to each other
Knitted geogrids: Yarns are knitted togetherperpendicular to each other
Extruded geogrids: Geogrid polymer is made of sheetform
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GLASS GRIDS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEONETS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOMEMBRANE
Geomembranes are of two types:
Calendared geomembranes are polyvinyl chloride (PVC),polyethylene (PE) and ethylene interpolymer alloy (EIA).
Extruded geomembranes are high-density polyethylene(HDPE), Low-density polyethylene (LDPE), very flexiblepolyethylene (VFPE) and polypropylene (PP).
Geomembranes are made of relatively impermeable thincontinuous flexible plastic sheets or rubber materials. It hassmooth or rough surfaces either on one or both sides.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Different types of geomembranes supplied by the manufacturers
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOCOMOPITES (GC)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOCOMPOSITE EROSION CONTROL MATS
Geocomposite Erosion control mat supplied by manufacturers
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOSPACERS / GEOSTRIPS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOSYNTHETIC CLAY LINERS (GCL)
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOTEXTILE TUBES
Schematic view of geotextile tube
GEOPIPES
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOFOAMGeofoam blocks or slabs are made of expandedpolystyrene (EPS) or extruded polystyrene (XPS). It is avery lightweight material with high void content and itsdensity is very low compared to the soil.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOCELL/ GEOWEB
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GEOTEXTILE CONTAINERS
GEOMATTRESS/ GEOTEXTILE BAG
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
NATURAL GEOTEXTILE
Geojutes supplied by manufacturers
Geocoirs supplied by manufacturers
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
GABIONS
FIBERS
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
ELECTROKINETICS GEOSYNTHETICS: These arebasically quick drainage materials. These are electricallyconductive geosynthetics. It performs soil consolidation byelectro-osmosis process.
GEOBLANKET: It is made of synthetic or naturalbiodegradable permeable materials. It is used fortemporary erosion control with vegetations.
GEOMAT: It is a three dimensional permeable material. Itis made of bonded filaments. It can be used for permanenterosion control problems. The roots of grass and smallplants act as reinforcement for vegetation.
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
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Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay
Prof. J. N. Mandal
Department of civil engineering, IIT Bombay, Powai , Mumbai 400076, India. Tel.022-25767328email: [email protected]
Prof. J. N. Mandal, Department of Civil Engineering, IIT Bombay