Geosynthetics in geotechnical engineering is usually a sheet or planer product manufactured from a polymeric material that is used with soil, rock or other geotechnical related materials as an integral part of a civil engineering project. They are supplied in roll form and used in many geotechnical applications. few polymers (plastic) common to every day of life are related to geo-synthesis. The most common are: polyolefins and polyester, although rubber, fiber, glass and natural materials are sometimes used.
Types of Geosynthetics in geotechnical engineering
5. Geosynthetic clay lines
Geotextile is a permeable, flexible textile-like fabric of control permeability used to provide filtration, separation or reinforcement in soil, rock and waste material.
Geo-membrane is essentially an impermeable polymeric sheet used as a barrier for liquid or solid waste containment.
Stiff or flexible polymer grid-like sheets with large apertures (voids) used primarily as reinforcement of unstable solid and waste material.
Stiff polymer net like a sheet within plain openings used primarily as a drainage material with landfills or in soil and rock masses.
5. Geosynthetic clay liners
Pre-fabricated bentonite clay layer incorporated between geotextile or geo-membranes and used as a barrier for liquid or solid waste containment.
Geo-pipes perforated or solid wall polymeric pipes are used for the drainage of various liquid.
Application / Function of Geo-Synthetics
Geo-synthesis can be used as filters to prevent soil from migrating into the adjacent material such as drainage aggregate which allows water to flow through the system.
Geo-textile or Geo-composite can be used as drainage or conduit by allowing water to drain from or through it.
Geo-synthesis can be used as a separator to separate two dissimilar materials and to prevent them from mixing such as the use of geotextile between fine-grain sub-grade and granular base course below a roadway.
Geo-grid or geotextile can be used as reinforcement to increase the shear strength of the soil, thereby providing a more suitable structural material. For example use of geogrid to reinforce a steep slope or to strengthen a base course in a pavement layer.
5. Erosion control
Geo-synthesis can be used to minimize the erosion of soil due to the flow of water at high speed.
The primary advantages of geo-synthetics
1. Relatively low cost for many applications.
2. Ease and convenience for many applications.
3. Quick and effective protection against erosion problem.
4. The design methodology is available for many uses.
5. May be removed or reused if economically feasible.
6. Many varieties of geo-synthesis are available for a specific use.
Limitation / Disadvantage of geo-synthetics
i. Effectiveness may be reduced drastically if the geo-synthesis is properly selected designed or installed.
ii. Many geo-synthesis are sensitive to light degradation and must be protected during installation.
iii. Geo-synthesis that is not degradable should not be used where their presence or appearance
is aesthetically unacceptable.