1. Role of Textiles in Soil
Erosion Control
Submitted to :
Prof. AlagiruSamy
Submitted by:
Ashutosh Shukla
2. Erosion is a natural process in which soil and rock material is
loosened and removed by the action of water, wind, and ice
The problem of soil movement due to erosive forces by moving
water and/or wind as well as by seeping water is called soil erosion.
Soil erosion and sediment controls are measures which are used to
reduce the amount of soil particles that are carried off of a land
area and deposited in receiving water.
Soil Erosion
3. Geological erosion
• Includes soil-forming as well as soil-removing, has contributed to the
formation of soils and their distribution on the surface of the earth.
Man-made erosion
• Includes the breakdown of soil aggregates and the increased removal of
organic and mineral particles; it is caused by clearing, grading, or
otherwise altering the land. Erosion of soils that occurs at construction
sites
Classification
4. Introduction to the types of erosion
Sheet erosion Occurs when thin layers of the top soil are moved by the force of the runoff water, leaving the surface
uniformly eroded
Rill erosion Caused by runoff water when it creates small, linear depressions in the soil surface
Gully erosion Large, wide channels carved by running water
5. Coarse fragments:
- are easily identified
- not many erosion issues
Fine earth portion:
- harder to identify
- has higher erosion potential
Know your soils
6. Soil Reinforcement & Errosion control using Geosynthetics
Geosynthetics :
The membranes used in contact with or within soil are termed as
geosynthetics.
They are used in subgrade stabilization, soil reinforcement, surface
erosion control, subsurface drainage etc.
Generally Polymer based - Polypropylene, Polyester, PVC,
Polyamide, Polyethylene
7. The ASTM (1994) defines geotextiles as permeable textile
materials used in contact with soil, rock, earth or any other
geotechnical related material as an integral part of civil
engineering project, structure, or system.
Geotextile
8. • Soil Reinforcement by Geotextiles
The structural stability of the soil is greatly improved by the tensile strength of the
geosynthetic material. This concept is similar to that of reinforcing concrete with steel.
Reinforcement function of geotextiles
Soil is a structure with high
compression strength but with low
tensile strength. Geotextiles being high
tensile strength materials are ideal to
increase soil quality and soil structural
stability Geotextile increase load
bearing capacity of soil through tensile
mechanism.
9. Erosion Control Mechanism and Role of Geotextiles
Erosion is caused by a group of physical and chemical processes by which the soil
or rock material is loosened, detached, and transported
the geo-textile protects soil surfaces from the tractive forces of moving water or
wind and rainfall erosion
Geotextiles are also used for temporary protection against erosion on newly seeded
slopes. After the slope has been seeded, the geotextile is anchored to the slope
holding the soil and seed in-place until the seeds germinate and vegetative cover is
established
Vegetation can form the best erosion control, but this is often difficult to establish.
The use of hydroseeding or seed impregnated fabric can be an effective method to
establish vegetation.
10. Condition of river bank with and
without geotextiles
Application of erosion control mat
(Vishakhapatnam, A.P.)
11. Different Textile Structures Used For Soil Reinforcement
Methods to use textile structures for soil reinforcement
Geosynthetics
Geotextile wrap-around revetments (GWRs)
Fibre reinforced sands
12. Geosynthetic Structures used for soil reinforcement
Biaxially
oriented
process
nets (BOP)
Erosion
control
meshes
Erosion
control
blankets
(ECBs)
Geogrids
13. Biaxially oriented process nets
Manufactured from polypropylene or
polyethylene resins
Extremely versatile in that composition,
strength, elongation, aperture size and shape,
colour and ultraviolet stability
Can easily be designed into the product for
specific site requirements
BOP nets have proven to be so adaptable
they are being used to create more complex
product
Installation of these products is less labor
intensive
15. Erosion control meshes
A step up from BOP nettings are woven polypropylene
geotextile erosion control meshes.
Twisted fibre erosion control meshes.
Theses high strength polypropylene meshes protect the soil
surface from water and wind erosion while accelerating
vegetative development.
Used for fostering vegetation on geosynthetically reinforced
steepened slopes
17. l-2-m wide biodegradable
Composed of straw, excelsior, cotton, coconut,
polypropylene or blends thereof.
Contain UV stabilizers for controlled degradation
Applications for the wide variety of blankets range
from protection of gradual to steep slopes to low or
moderately flowing channels
Erosion control blankets (ECBs)
19. Geogrids
These are plastic materials formed into a very open grid like
configuration with very large apertures.
bridge abutments to be constructed where the sill beam rests directly on
the Geosynthetic Reinforced Soil (GRS) block.
Grid made up of PVA works in textile grid applications to withstand
high alkali environments and especially the combination of lime and
cement stabilizers
PVA grids in cohesive soils where there appears to be a synergistic
effect resulting in higher strength and higher resistance to pull out
failure
22. TERMs versus PERMs
At this point an important distinction must be presented regarding the intended use of E &
SC materials.
For many installations vegetation alone will provide adequate long term erosion
protection.
Getting vegetation established requires a variety of techniques. Materials of a temporary
nature which facilitate vegetative establishment, then degrade, may be termed TERMs
(temporary erosion and re-vegetation materials).
Basically TERMs consist of degradable natural and/or synthetic components which
provide temporary erosion control and facilitate vegetative establishment. These short
term materials degrade leaving only vegetation for long term low to medium flow
resistance.
Site conditions requiring reinforced vegetation or revetment systems will require PERMs
(permanent erosion and re-vegetation materials).
23. Geotextile wrap-around revetments (GWRs)
GWRs are sand slopes that are reinforced with a geosynthetic
the material is wrapped and encapsulated with geotextiles to create a flexible revetment
A layer of geotextile is first placed at the site and sand is placed on top of it to produce a GWR
Loose ends of the geotextile are then folded back and inserted into the fill.
A second geotextile layer is laid on top and the procedure is repeated until the layers reach to the designed height
The structure resists overturning because of its weight
Even it resists seaward sliding because of the geosynthetic’s tensile strength.
Advantages
They are useful for protection against
waves and currents,
Other structures can be constructed
directly upon them,
Total construction and life cycle costs are
generally lower than those of hard
structures
24. Recent developments obtained from small-scale model tests
The only recorded model tests involving GWR were conducted at the large wave flume at Hannover, Germany
(Saathoff and Kohlhase, 1986). Model tests were performed on a three-layer geotextile structure; they were
tested with waves up to 1.3m (Fig. left). The GWR structure suffered only slight deformation. Based on those
model test results, a GWR was constructed at the island of Sylt in Germany
Cross section of model tests at the large wave flume in Hannover and prototype constructed in Sylt,
Germany. Previous model test and prototype of wrap-around revetments
25. Fibre reinforced sands
Reinforcing soils using tension resisting elements is an attractive means of improving the
performance of soil in a cost effective manner.
The use of random discrete flexible fibres mimics the behaviour of plant roots and gives the
possibility of improving the strength and the stability of near surface soil layers
The discrete fibres are simply added and mixed randomly with soil, much like cement, lime, or other
additives
Fibres some times used in combination with other admixtures such as cement and fly-ash to increase
the shear strength of the soil
Classification
McGown classified soil reinforcement into two major categories
1. Ideally inextensible- includes high modulus metal strips that strengthens soil and inhibits both internal
and boundary deformations. Catastrophic failure and collapse of soil can occur
2. Ideally extensible inclusions- include relatively low modulus natural and/or synthetic fibres, plant roots;
and geosynthetics. provide some strengthening but more importantly they present greater
extensibility
27. Applications of fibre reinforced soil
Using natural and/or synthetic fibres in geotechnical engineering is
feasible in different fields
pavement layers (road construction),
retaining walls,
railway, embankments,
protection of slopes,
Soil-foundation engineering.
Geogrid Applications For Reinforced Soil Slope Protection
Provision of Geotextiles Against Subgrade and Embankment Erosion
Geosynthetics for Highway Pavements
28. 28
Jute Geotextiles
• Jute Geotextiles (JGT)-as the name suggests –is made of bast fibres of
jute plants—a renewable agri-resource under cultivation in the Ganga-
Brahmaputra delta for centuries. Presently under cultivation in other
areas/countries as well
• The features of jute fibre conform to technical requirements of geotextiles,
besides its added advantage of being eco-concordant, abundant
availability, and industry-expertise to make customized JGT
29. JGT matches its man-made counterpart in the three basic functions of a geo textile. They are
Separation, Filtration, Drainage. Besides,
Along-plane drainage capability (i.e. transmissivity ) of JGT is higher than its man-made counterpart.
Fineness of jute fiber enables manufacture of JGT according to the specified porometric features
High Roughness Co-efficient of jute ensures better load transference & confining action on soil
JGT has far greater water absorbency than all other GTs –a quality which enables sustained release
of the absorbed water, thus creating a congenial micro-climate for better growth of vegetation
29
JGT – Basic Functions
30. High moisture absorbing capacity
Excellent drapability (the best of all GTs)
High modulus of elasticity
Low extension-at-break
High roughness co-efficient
Excellent spinnability
Bio-degradability with mulching & soil-nourishing properties
Annually renewable resource with abundant availability
Economical &
Eco-friendly 30
Advantages of JGT
31. Conclusion
•Geotextiles, specially JGT is an effective technical
facilitator in building stronger and stable slopes with
the added advantage of lending eco-concordance
by reducing carbon footprint & ensuring overall
economy.
32. References
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soil reinforcement by using natural and synthetic fibers. Construction and Building Materials 30 (2012)
100–116.
Chao-Sheng Tang*, Bin Shi, Li-Zheng Zhao. Interfacial shear strength of fiber reinforced soil. Geotextiles
and Geomembranes 28 (2010) 54–62.
Fauziah Ahmad*, Farshid Bateni, Mastura Azmi. Performance evaluation of silty sand reinforced with
fibres. Geotextiles and Geomembranes 28 (2010) 93–99.
Nilo Cesar Consoli a, Ma´ rcio Antoˆnio Vendruscolo, Anderson Fonini, Francisco Dalla Rosa. Fiber
reinforcement effects on sand considering a wide cementation range. Geotextiles and Geomembranes 27
(2009) 196–203
Radoslaw L. Michalowski, Jan C˘ erma´. Strength anisotropy of fiber-reinforced sand. Computers and
Geotechnics 29 (2002) 279–299
33. Ashis Mitra, Visva-Bharati University. Geotextiles and its Application in Coastal Protection and Off-
shore Engineering.
Ennio M. Palmeira, Fumio Tatsuoka, Richard J. Bathurst, Peter E. Stevenson, Jorge G. Zornberg.
Advances in Geosynthetics Materials and Applications for Soil Reinforcement and Environmental
Protection Works. EJGE.
Kazuya Yasuharaa, Juan Recio-Molinab. Geosynthetic-wrap around revetments for shore protection.
Geotextiles and Geomembranes 25 (2007) 221–232.
Chaosheng Tang, Bin Shi_, Wei Gao, Fengjun Chen, Yi Cai. Strength and mechanical behavior of short
polypropylene fiber reinforced and cement stabilized clayey soil. Geotextiles and Geomembranes 25
(2007) 194–202.
Dr. Bipin J Agrawal. Geotextile: it’s application to civil engineeering – overview. National Conference on
Recent Trends in Engineering & Technology.
References …..Contd…..