Understanding geotextiles and their barrier function
Geotextiles are used in construction for applications such as dikes, roads, embankments, and coastal protection projects. Geotextiles are favored as a product for their ability to serve multiple needs in a geotechnical context. The main functions of geotextiles — a permeable fabric — are soil layer separation, reinforcement, drainage, stabilization, and filtration, making them essential for the durability and performance of various infrastructure projects. Geotextiles are classified into woven, non-woven and knitted geotextiles. Woven geotextiles are made of polypropylene and are ideal for separation and reinforcement. Non-woven geotextiles are commonly made using the needle punch method, whereas knitted geotextiles are created by interlocking loops of yarn.
Geotextiles are commonly used in the following types of industries:
- Landfills and waste containment
- Erosion control and slope stabilization
- Road and highway construction
- Drainage and filtration systems
- Mining and ports
- Agricultural uses
- Coastal engineering projects
What are geotextiles made of?
Geotextiles are manufactured from synthetic materials such as- polypropylene, polyester or polyethylene. The respective materials are chosen for their tensile strength, longevity, and ability to withstand loads. Since these materials are used in extreme temperatures and varied soil pH conditions, they must withstand mechanical, chemical, environmental, and physical stress.
Key functions of geotextile
- Separation: By preventing intermixing, which helps avoid contamination and structural failure. This is useful in instances where separation is needed between layers . One common recommended application is landfill sites, where we see the need to separate waste materials, leachate and soil and ensure that there’s a separation barrier between them, while allowing gases and liquids to pass through. Due to the high tensile strength of the geotextile, alongside puncture resistance, it helps to maintain the integrity of the soil particles.
- Filtration: Geotextiles are permeable, allowing liquids to pass through while blocking larger soil, aggregate or stone particles. Serving as a separator and filter, geotextile intercepts the mixing of granular sub-base layers and stops stone particles from moving. This proves beneficial in maintaining the integrity of the surface or pavement structure, reducing the risk of failure. This is especially important in case of roadways, where geotextiles are used for pavement edge support. Another instance of its usage in filtration is for mining where in the application stops rocks and soil particles from entering drainage systems, leading to clogging. It also works to filter out contaminants from mine drainage water while stabilizing tailings, and waste rock dumps.
- Drainage: Geotextiles act as conduits in facilitating effective drainage in various applications like road construction and retaining structures. When it comes to road construction, and creating steep slopes, or retaining walls, considering the terrain type, geotextiles are included to reduce the hydrostatic pressure on retaining walls. By draining water from the subgrade, geotextiles help prevent hydrostatic buildup and distribute pressure laterally. At times, if drainage has not been planned correctly, it also leads to soil liquefaction which means lower strength of the soil to withstand pressure, most commonly from repeated loading.
- Reinforcement and soil stabilization: Geotextiles also serve a crucial reinforcement function in soil stabilization, particularly in the case of clayey subgrade soils. While we recommend geotextiles for subgrade reinforcement cautiously, in specific instances, it works as a valuable layer in the reinforcement for pavement design. The geotextile is placed between the soil subgrade and aggregate base course. This placement enhances the shear strength and ductility of the soil matrix. They effectively distribute loads and prevent soil failure which in turn works wonders in construction on previously unsuitable grounds or plastic soils. The upside of the shear strength improvement from geotextiles, when applied to subgrades, is it helps with load distribution and consequent load settlement.
Industries that need geotextile for engineering solutions
- Road construction: Geotextiles are widely used in road construction for improving stability and load bearing capacity, depending on the soil type, and the kind of structure within highway design it’s being used for. While geotextiles can provide a degree of soil stabilization and reinforcement due to their tensile strength and drainage properties in clayey or high water content soils, it’s key to think of it as a layer that complements the overall road construction design. In other words, geotextiles increase pavement life, by preventing the intermixing of subgrade and base course materials as one of the many applications within road construction
- Civil engineering: Within this application, we look at dams, canals, and water reservoirs and water treatment plants. Broadly, using geotextiles in these contexts tends to prevent soil erosion and piping, reduces seepage and hydrostatic pressure, filters out sediment and debris. By preventing migration of particles, it also maintains the integrity of the liquid and quality. In case of dams, they are used as a filter medium to prevent soil erosion and piping (internal erosion) in embankment dams. By placing the material downstream to a dam, to prevent soil migration, the fabric layer reduces pore pressure, and pressure build up. For canal lining, which is a loved application of geotextiles, the canal bed is lined with this material. This prevents soil erosion and water clogging, ensuring stability of the canal itself.
- Mining operations: Since the mining areas typically has heavy loading and repetitive stress from haul roads, which ply trucks, it’s essential that the roads are stable, and unaffected by typical challenges such as differential settlement. Here, while reinforcing the haul roads, geotextiles are looked at as an option, depending on the terrain. The other common application is in the form of supporting soil in mine pit walls to prevent rockfalls. In mining operations particularly, slope stability for man made slopes, or natural ones is an important consideration —through the use of geotextiles, stability ratios are improved in regions prone to high water saturation. Even with tailing dams –dam-like structure behind the mining area, which stores the tailings (waste rock and water)–geotextiles are an important element in a liner at the bottom and sides of the tailing dam to prevent leakage and ensure containment. In some instances, it’s also used for capping to prevent erosion and dust generation.
- Agriculture: In agricultural spaces, where large tracts of land are involved, geotextiles come into use in innovative ways. The scope of geotextiles for farming, or agriculture covers three functions: improve drainage, irrigation, and soil conservation. Soil conservation in agriculture is a key goal since it determines many downstream outcomes of the land’s fertility. Geotextiles are used to wrap perforated pipes, improving drainage and reducing soil erosion. Their use ensures that soil doesn’t enter the drainage system and affords longevity. Lining irrigation canals with geotextiles, allows for reduced water loss, into the ground since the hydraulic gradient (water pressure) is reduced, which decreases the driving force behind seepage. This barrier also allows water to pass through, but the friction between the geotextile and the surrounding soil slows down the water flow, reducing seepage. As a result of this preventative action, it minimizes the formation of “pipes” or channels in the soil, which also leads to seepage and water loss. Soil conservation is driven largely for slopes or embankments, without which the risk of run off is typically very high.
- Oil and Gas: For the oil and gas industry, one of the greatest challenges is in maintenance of the pipelines which conduct these products. The most common or favored application comes in the form of pipeline protection, where in the pipes are wrapped with geotextiles to prevent soil from corroding the lines, and minimizing friction from the mechanical environment. Similarly, with storage canals, and ponds, or storage tank liners, it’s important to deploy geotextiles to prevent contamination. While access roads also benefit from the usage, the biggest improvement is for drilling pad construction since geotextiles also work to improve differential settlement under iterative stress and ensure a stable foundation for drilling.
- Waste Management: At Strata Geosystems, we consider ourselves as one of the foremost leaders in technical expertise in landfill management technology through our innovative design for old sites, and new sites, both. While often older sites need expansion, or capping, for newer sites, our design systems include geotextiles to effectively manage leachate collection and drainage. This is an important feature in our landfill design since it causes severe contamination, while leading to a lot of environmental stresses. As a result, we ensure our structures use geotextiles for a variety of functions, optimizing for all the issues a landfill site typically experiences –gas permeability, liquid contamination, and gas leaks. By placing geotextiles strategically in the layers of the site, we create a holistic system to address waste management challenges.
- Coastal engineering: With coastal engineering projects, managing the water levels against the shoreline and having a design for several scenarios means planning rigorously. The greatest threat to coastline projects is erosion — both surface and water-based — which can undermine the stability of geotechnical structures such as bridges, reclamations, seawalls, groins, breakwaters, and coastal revetments. Based on the structure being used, geotextiles can be placed to allow water seepage, such that it prevents soil loss–a porous wall of sorts which is placed behind the seawall. In other instances, they’re used to stabilize the structure, by disrupting wave patterns. They allow drainage, stabilize soil, and provide a foundation for vegetation growth, helping preserve shoreline integrity. Geotextiles are used to construct or reinforce revetments (sloping structures) along coastlines, which brings stability. By absorbing wave energy, the geotextile layer also works to reduce erosion and damage.
Advantages of using geotextiles in varied operations
Until the invention of geotextiles and its wide adoption, there were few materials that could serve so many functions within a singular application. Its ease of being used across industries, alongside its longevity makes it an indispensable geotechnical material –second to none. It’s superior in function for a wide number of reasons –right from soil stabilization, slope protection, soil reinforcement, to enabling permeability for the right materials.
- Cost-effectiveness: Geosynthetics are cost-effective and sustainable solutions for infrastructure, often proving cheaper than traditional methods. Additionally, geosynthetics shorten construction time, by substituting bulk materials and lowering the cost of aggregate use and transportation.
- Versatility: Geotextile s are versatile due to their multifunctional capabilities in civil engineering. They serve as filters, separators, reinforcements and drainage systems, enhancing soil stability and soil erosion. They are available in woven as well as non-woven form which makes them suitable for various environmental conditions and applications and hence helpful in infrastructure projects.
- Durability: Geotextiles are tough against damages from chemicals, UV radiations, and biological factors, ensuring long lasting performance.
Geotextile by Strata Geosystems
The aperture size is a critical design factor, influencing the geogrid’s ability to stabilize soil through interlock and confinement, and directly impacting both tensile and junction strength. It’s worth noting that ultimately, the aperture size impacts the tensile strength, and ultimate junction strength –which is why it’s a factor to consider. The physical properties of a geogrid roll determine its load-bearing capacity and the extent of soil coverage it can effectively stabilize.
What makes Strata’s geotextile unique?
- Exceptional tensile strength- StrataTex HSR offers a wide range of tensile strengths, from 50 kN/m to an impressive 800kN/m. This makes it an exceptional option for supporting soil layers, reinforcing soil layers and ensuring the durability of both paved and unpaved roads.
- Superior permeability- StrataTex HSR allows water to pass through efficiently, improving soil stability and reducing the risk of water-induced damage. This feature is especially helpful in making unpaved roads more stable and strengthening the soil. By doing this, it reduces the chances of water causing damage and helps the structure stand stronger for helping the structure remain stable over time.
- Low elongation, high strength- StrataTex HSR is highly recommended for soil reinforcement, load transfer and basal reinforcement applications due to its maximal tensile strength and minimal stretching.
- Efficient use of resources- StrataTex HSR optimizes resources through its wider widths, and customizable lengths, minimizing waste and improving resource efficiency. This design helps in project efficiency across various applications, from building unpaved roads to executing complex load transfer tasks.
- Certified excellence- StrataTex HSR is a highly reliable choice for reinforcing base layers and constructing base roads. Additionally, Strata’s geotextile has undergone rigorous testing in GAI-LAP accredited laboratories, which ensures the product meets expected standards. It also holds both CE and ISO certifications, which demonstrates its strong commitment to quality and dependability in various geotextile operations.
- Outstanding stability- employs a special knitting process that boosts its stability , making it the go to option for geotextile projects that require exceptional strength, like load transfer and basal reinforcement. This one-of-a-kind technique ensures the material is easy to work with and provides a smooth, trouble-free experience during installation and use.
Case study : StrataWeb reinforced crane hardstand – IOCL Paradip
Strata enhanced the crane hardstand at IOCL Paradip Refinery, Odisha, using StrataWeb geocell and StrataTex HSR. The aim was to increase the foundation’s bearing capacity to support a 1600-ton crane on weak, clay soil. The site faced hardships due to its close proximity to the sea and high rainfall, necessitating a robust solution. While traditional methods suggested deep pile foundations, Strata’s modern approach used geocells to surpass the required bearing pressure of 300 kPa/sqm. Thirteen crane pads were constructed, ensuring stability for the plant’s 15 year design life.
StrataTex HSR reduced settlement risks by providing separation and tensile strength. The use of StrataWeb allowed for fast installation with unskilled labor, decreased aggregate thickness, and delivered a stable foundation for heavy loads, demonstrating efficiency and durability.
Case study 2: Strata’s innovative stabilization for NH2 project in Bihar
Strata implemented a stabilizing solution for the Varanasi- Aurangabad stretch of NH-2, focusing on the flyover at CH.931+030 in Bihar. The project utilized StrataWeb geocells and StrataTex HSR geotextiles to reinforce soil structures efficiently. This approach was important for stabilizing the fine sandy silt typical of the area. Strata opted for basal reinforcement and avoided extra excavation which significantly reduced disruption to adjacent service roads. It is worth noting that 750 mm of fill was replaced which proved very useful in enhancing sheer strength and stability. Hence, the incorporation of StrataTex HSR added high tensile strength, and effectively separated the layers, significantly enhancing the overall durability of the structure. StrataTex HSR surpassed a safety factor of 1.3, ensuring reliable support and highlighting its effectiveness in soil reinforcement. This approach provides reliable reinforcement in challenging soil conditions while promoting efficient resource use, bettering structural integrity and side-by-side minimizing construction impact.
StrataTex HSR offers a high-performance solution for soil reinforcement, engineered for strength, durability, and adaptability. With exceptional tensile strength, low elongation, and superior permeability, it ensures long-term stability for projects. Choose StrataTex HSR for your upcoming project and discover the forefront of geotextile technology. To contact Strata Geosystems, please click here!