| Term | Definition |
| Actinic Degradation | The strength loss of a geotextile’s fibers or fabric due to exposure to UV light or accelerated weathering. NovaGeo fabrics are UV-stabilized to resist this. |
| Anchor Trench | An excavated ditch used during installation where the edges of the geotextile are buried to hold the fabric taut and secure it in place, especially on slopes. |
| Apparent Opening Size (AOS) | A standard technical specification defining the size of the smallest soil particle a geotextile will pass. It directly governs the filtration efficiency of a fabric in a drainage system. |
| Arching (Bridging) | The process where soil particles structure themselves over the voids of the geotextile, forming a natural, stable filter layer that prevents further soil movement. |
| ASTM | Acronym for the American Society for Testing and Materials, which publishes the internationally recognized standard test methods used for classifying and specifying geosynthetics. |
| Attenuation | In a protective or containment context, the ability of a geotextile layer to reduce the damage or impact of localized stress (e.g., preventing sharp stones from puncturing a geomembrane). |
| Biaxial Geogrid | A geogrid designed with strength properties primarily in two directions (machine and cross-machine), used for soil stabilization beneath roads and paved areas. |
| Biodegradable Geotextile | A fabric (often natural fiber or rPET) designed for temporary applications where decomposition is desired, such as short-term erosion control. |
| Blinding (Clogging) | The condition where fine soil particles block the inter-fiber openings at the surface of a geotextile, which reduces the fabric’s overall hydraulic conductivity and filtration capacity. |
| CBR Puncture Strength | The measure of a geotextile’s resistance to localized damage. It uses the California Bearing Ratio test method to determine the force required to puncture the fabric. |
| Continuous Filament | A manufacturing method for nonwoven geotextiles using long, uncut fibers that are thermally or mechanically bonded, resulting in high strength and uniform filtration. |
| Creep | The slow, time-dependent change in length or deformation of a material under a prolonged, constant load. Geotextiles used for reinforcement must have low creep values. |
| Cross-Machine Direction (CMD) | The direction of the fabric perpendicular to the continuous direction of manufacture. Often referred to as weft in woven geotextiles. |
| Denier | A unit of measure for the linear mass density of a fiber or yarn (weight in grams of 9,000 meters of yarn), used to classify the material used in the geotextile. |
| Drainage | The function where a geotextile or geocomposite collects and conveys liquid (water) within its own plane (in-plane flow), removing excess fluid from a structure. |
| Elongation at Break | The percentage increase in length of a geotextile specimen when it reaches its maximum tensile load capacity. High elongation is typical of nonwoven fabrics. |
| Erosion Control | The use of geosynthetic products to prevent the surface soil from being washed or blown away on slopes, banks, or shorelines. |
| Filter Cake (Soil Filter) | The graded, natural soil structure that develops immediately upstream of the geotextile, where retained soil particles form a stable layer that prevents further migration. |
| Filtration | A primary function where the geotextile acts as a permeable barrier, allowing water to pass through while retaining fine soil particles, preventing clogs. |
| Geocell | A three-dimensional, honeycomb-like polymer structure used for confinement and stabilization of infill material (soil, sand, gravel) on steep slopes and load platforms. |
| Geocomposite | A material combining a geotextile with another geosynthetic (e.g., a geogrid, geomembrane, or geonet) to perform multiple integrated functions. |
| Geogrid | A polymer structure with a regular network of openings, primarily used for high-tensile soil reinforcement in steep slopes, retaining walls, and load-bearing structures. |
| Geomembrane | An essentially impermeable polymeric sheet used as a liquid or vapor barrier, primarily for containment in landfills, ponds, and reservoirs. |
| Geonet | A net-like polymeric structure used to provide a high-volume flow channel for drainage in-plane, often protected by a geotextile to form a geocomposite. |
| Geosynthetic Clay Liner (GCL) | A factory-manufactured hydraulic barrier consisting of bentonite clay sandwiched between two geotextile layers, used for lining landfills and ponds. |
| Geosynthetics | The generic term for all synthetic materials (geotextiles, geogrids, geomembranes, etc.) used in contact with soil, rock, or other geotechnical materials. |
| Geotextile Fabric | The most common term for permeable technical textiles used with soil in construction, civil engineering, and landscaping for separation, filtration, drainage, or reinforcement. |
| Grab Tensile Test | A common quality control (index) test where a central portion of a wide fabric specimen is gripped in a testing machine to determine the tensile strength and elongation. |
| Heat-Bonded Nonwoven | A nonwoven fabric where fibers are bonded by applying heat and pressure, partially melting the fibers at their intersection points. |
| High-Strength Geotextile | Generally refers to high-performance woven fabrics, often made from polyester, specifically engineered to provide maximum tensile strength for critical reinforcement projects. |
| Hydraulic Conductivity | The ability of water to flow through the geotextile in the normal direction (cross-plane), expressed as a flow rate per unit area and hydraulic gradient. |
| Machine Direction (MD) | The direction of the fabric parallel to the continuous process of manufacture. Often referred to as warp in woven geotextiles. |
| Minimum Average Roll Value (MARV) | A statistical quality control term that specifies the minimum average property value (e.g., strength, flow rate) a manufacturer guarantees for a roll of fabric. |
| Needle-Punched Nonwoven | A nonwoven fabric where fibers are mechanically interlocked by repeated punching with barbed needles, resulting in a thick, highly permeable felt-like fabric. |
| Nonwoven Geotextile | A felt-like fabric made by bonding synthetic fibers. Its porous structure makes it excellent for filtration, drainage, and separation in a wide range of applications. |
| Permeability | A critical material property that quantifies how easily water can flow through the geotextile. High permeability is essential for effective filtration and drainage. |
| Permittivity (ψ) | The volumetric flow rate of water per unit cross-sectional area per unit head, a common measure of a geotextile’s hydraulic conductivity in the cross-plane direction. |
| Polyester (PET) | A synthetic polymer used in geotextiles, often offering higher tensile strength and better creep resistance than PP, suitable for high-stress reinforcement. |
| Polypropylene (PP) | The most common, cost-effective synthetic polymer used in geotextiles, offering good strength, durability, and resistance to chemical and biological decay. |
| Reinforcement | The function where a geotextile or geogrid transfers tensile forces to the soil mass to increase stability and strength, such as in steep slopes or MSE walls. |
| Riprap | A layer of large, angular stones used to stabilize riverbanks or slopes against erosion. Geotextiles are placed beneath riprap as a filter and separation layer. |
| Seam Strength | The tensile strength of a joint created when two rolls of geotextile are connected (usually by heat-seaming or stitching) and is measured as a percentage of the parent fabric’s strength. |
| Separation | A primary geotextile function that prevents the intermixing of adjacent, dissimilar materials (e.g., keeping fine subgrade soil separate from coarser road base aggregate). |
| Slit-Film Woven | A woven geotextile made from flat, tape-like yarns. It offers high tensile strength and is typically used for road base stabilization and separation. |
| Soil Stabilization | The process of using a geotextile or geogrid to improve the strength, stiffness, and load-bearing capacity of the underlying soil, a key use in road construction. |
| Staple Fiber | A manufacturing method for nonwoven geotextiles using short-cut fibers (staples) that are consolidated by needle-punching or chemical bonding. |
| Subgrade | The natural soil layer beneath a road, embankment, or pavement structure. Geotextiles are placed on the subgrade to provide separation and stabilization. |
| Sustainable Geotextiles | Fabrics made from eco-friendly materials, such as recycled polymers (rPET) or natural fibers, supporting green building and environmental compliance. |
| Tear Strength | A measure of a geotextile’s resistance to the force required to continue a tear in the material, important for survivability during aggressive installation. |
| Tensile Strength | The maximum force per unit width a geotextile can withstand before it breaks or ruptures, the key mechanical property for reinforcement and survivability. |
| Transmissivity (θ) | A measure of the volumetric flow rate per unit width in the plane of the geotextile (in-plane flow), crucial for drainage applications. |
| Uniaxial Geogrid | A geogrid designed with strength properties primarily in one direction (Machine Direction), used for wall and slope reinforcement where the force is unidirectional. |
| UV Stabilization | The process of adding chemical inhibitors to the polymer during manufacturing to protect the geotextile from degradation caused by ultraviolet (UV) radiation exposure. |
| Woven Geotextile | A strong, durable fabric produced by interlacing yarns. It is the preferred choice for applications requiring high strength and stabilization under heavy loads. |