Glossary

Blinding

The condition in which soil particles block the voids at the surface of a geotextile, thereby reducing the hydraulic conductivity of the geotextile.

Clogging

The movement by mechanical action or hydraulic flow of soil particles into the voids of a fabric and retention therein, thereby reducing the hydraulic conductivity of a geotextile.

Confinement

Geosynthetic improvement of the ability to resist lateral movement of the aggregate.

Cross-Plane

The direction of a geosynthetic which is perpendicular to the plane of its manufactured direction.  Referred to in hydraulic situations.

Direction, cross-machine

The direction perpendicular to the long, machine, or manufactured direction (synonyms: woven geotextiles, weft direction).

Direction, machine

In textiles, the direction in a machine-made fabric parallel to the direction of movement the fabric followed in the manufacturing process (synonym: lengthwise, or long direction, and for woven geotextiles, warp direction).

Elongation

The increase in length produced in the gage length of the test specimen by a tensile load.

Elongation at break

The elongation corresponding to the maximum load.

Elongation, percent

For geosynthetics, the increase in length of a specimen expressed as a percentage of the original gage length (i.e., engineering strain).

Filament yarn

The yarn made from continuous filament fibers.

Fill

A deprecated term for filling.

Filling

The yarn running from selvedge to selvedge at right angles to the warp in a woven fabric.

Filling direction

See Direction, cross-machine.  Note: For use with woven fabrics only.

Filter cake

The soil structure developed upstream of a geotextile by separating the suspended soil from liquid as the mixture attempts to pass through a soil-fabric system.

Filter cloth

A deprecated term for geotextile.

Filtration/Drainage

Fabric to soil system that allows for free liquid flow (but no soil loss) across or through the plane of the fabric over an indefinitely long period of time.

Geocell

A three-dimensional structure filled with soil, thereby forming a mattress for increased stability when used with loose or compressible subsoils.

Geocomposite

A manufactured material using geotextiles, geogrids, geonets and/or geomembranes in laminated or composite form.

Geogrid

A deformed or nondeformed gridlike polymeric material formed by intersecting ribs joined at the junctions used for reinforcement with foundation, soil, rock, earth, or any other geotechnical engineering-related material as an integral part of a human-made project structure or system.

Geomembrane

An essentially impermeable membrane used as a liquid or vapor barrier with foundation, soil, rock, earth, or any other geotechnical engineering-related material as an integral part of a human-made project, structure, or system.

Geonet

A netlike polymeric material formed from intersecting ribs integrally joined at the junctions used for drainage with foundation, soil, rock, earth, or any other geotechnical-related material as an integral part of a human-made project, structure, or system.

Geopipe

Any plastic pipe used with foundation, soil, rock, earth, or any other subsurface related material as an integral part of a human-made project, structure, or system.

Geosynthetic clay liner (GCL)

Factory-manufactured hydraulic barriers consisting of a layer of bentonite clay or other very low permeability material supported by geotextiles and/or geomembranes, and mechanically held together by needling, stitching, or chemical adhesives.

Geosynthetics 

The generic term for all synthetic materials used in geotechnical engineering applications; it includes  geotextiles, geogrids, geonets, geomembranes, and geocomposites. 

Geotextile

Any permeable textile used with foundation, soil, rock, earth, or any other geotechnical engineering-related material as an integral part of a human-made project, structure, or system.

In-plane

The direction of a geosynthetic that is parallel to its long, manufactured, or machine direction.  Referred to in hydraulic situations.

Knit

Textile structure produced by interlooping ends of yarn.

Mass per unit area

The proper term to represent and compare to the amount of material per unit area (units are oz./yd.² or g/m²).  Often incorrectly called "weight" or "basis weight."

Modulus of elasticity

The initial linear portion of the stress-versus-strain test of a geosynthetic during its evaluation in a tensile strength test (units are lb./in.², kPa, lb./in., or kN/m).

Needle-punched

Mechanically bonded by needling with barbed needles.

Nonwoven

For geotextiles, a planar and essentially random textile structure produced by bonding, interlocking of fibers, or both, accomplished by mechanical, chemical, thermal, or solvent means and combinations thereof.

Normal direction

For geotextiles, the direction perpendicular to the plane of a geotextile.

Permeability

A generic term for the property that reflects the ability of a material to conduct a fluid or vapor through a porous media such as soil or geotextiles.  Properly called hydraulic conductivity.

Permittivity

For a geotextile, the volumetric flow rate of water per unit cross-section area, per unit head, under laminar flow conditions, in the normal direction through the fabric.

Post-Consumer Waste

Material waste generated by households or by commercial, industrial and institutional facilities in their role as end-users of the product, which can no longer be used for its intended purpose.

Pre-Consumer Waste

Material diverted from the waste stream during the manufacturing process.  Excluded is reutilization of materials such as rework, regrind or scrap generated in a process and capable of being reclaimed within the same process that generated the waste.

Reinforcement

Improvement of the system strength created by the introduction of a geosynthetic into a soil/aggregate system. 

Separation

Geotextile placed between dissimilar materials so that the integrity of both can remain intact or be improved.

Transmissivity

For a geotextile, the volumetric flow rate per unit thickness under laminar flow conditions, within the in-plane direction of the fabric.

Transverse direction

A deprecated term for cross-machine direction.

Ultraviolet degradation

The breakdown of polymeric structure when exposed to natural light.

Warp

The yarn running the length of the fabric in the machine direction when manufacturing woven fabrics.

Warp direction

See Direction, machine.  Note:  For use with woven fabrics only.

Weft

The cross-machine direction when manufacturing woven geotextiles.

Width

For a geotextile, the cross-direction edge-to-edge measurement of a fabric in a relaxed condition on a flat surface.

Woven

A planar textile structure produced by interlacing two or more sets of elements, such as yarns, fibers, rovings, or filaments, where the elements pass each other, usually at right angles, and one set of elements are parallel to the fabric axis.

Woven, monofilament

The woven fabric produced with monofilament yarns.

Woven, multifilament

The woven fabric produced with multifilament yarns.

Woven, slit-film

The woven fabric produced with yarns produced from slit film.

Woven, split-film

See Woven, slit-film.

Yarn

A generic term for continuous strands of textile fibers or filaments in a form suitable for knitting, weaving, or otherwise intertwining to form a textile fabric.  Yarn may refer to (1) a number of fibers twisted together, (2) a number of filaments laid together without twist (a zero-twist yarn), (3) a number of filaments laid together with more or less twist, or (4) a single filament with or without twist (a monofilament).