Woven Geotextile Research Articles

Effect of Testing Mechanisms on the Load-Strain-Time Behavior of Geosynthetic Reinforcements

Abstract This study compares how geosynthetics behave under load, under strain, and over time when subjected to confined tensile tests in soil, employing two commonly used mechanisms in research. One test type simulates a reinforced layer, where tensile loads are indirectly applied to the geosynthetic via stresses transferred from the soil. In contrast, the other test applies tensile loads directly to the geosynthetic material using clamps while under soil confinement. The objective is to elucidate how these testing mechanisms might yield differing in-soil tensile characteristics for different geosynthetics. The study involved conducting load-strain-time tests on samples of nonwoven and woven geotextiles, as well as a geogrid, under varying sustained loads over a 120-h period within a sand clay soil providing soil confinement to geosynthetics at different surcharge levels. The results suggest that soil confinement plays a significant role in shaping the load-strain-time behavior of geosynthetics. Furthermore, it was noted that the impact of testing mechanisms on this behavior is contingent upon the type and stiffness of the geosynthetics, as well as their interaction with the confining soil. In general, in-soil tests in which tensile loads are mobilized by geosynthetics and transferred from the soil provide more confident results for better simulating operation conditions. Tests that directly apply tensile loads to the geosynthetic while maintaining stationary soil confinement may yield misleading results, especially for geosynthetics that have poor interaction with the soil.

Geotextile filtration characteristics in piping rescue under extreme soil-retained state

Geotextiles have significant potential in rescuing backward erosion piping (BEP) occurring in levees. To investigate the filtration characteristics of woven geotextile for BEP prevention under the extreme soil-retention state, laboratory experiments were conducted using woven geotextiles with different pore sizes. The extreme soil-retention characteristics of the geotextile were analyzed, and the optimal relationship between filter pore size and particle size of the protected soil was explored. Additionally, the impact of fine particle content of the protected soil on the filter’s filtration performance was studied. The results indicated that, for the medium sand and silty sand tested, the filter still met soil retention requirements when the ratio of the geotextile’s equivalent pore size (O95) to the protected soil’s characteristic particle size (d85) was 5.2 and 4.3, respectively. With the increase of filter pore size, the clogging degree of the filter showed a trend of rapid decrease followed by an increase, indicating that there was an optimal matching relationship between the filter aperture and the particle size of protected soil. When woven geotextiles are used for preventing BEP, to ensure optimal filtration performance of the filter, the recommended values for O95/d85 in medium sand and silty sand are 5.2 and 3.3, respectively.

Laboratory evaluation of wicking geotextile for moisture reduction in silty sands at different fines contents

The effect of fines content on the performance of the wicking geotextile is not clear. This study developed a simple moisture reduction test method to quantify the effectiveness of the wicking geotextile in reducing moisture in silty sands at four different fines contents and four different waiting periods. The sand was prepared at an initial moist condition based on its average field moisture capacity. A wicking or non-wicking woven geotextile was placed in the middle of a soil column. The effect of a geotextile on the moisture content of the sand was evaluated by measuring their gravimetric moisture contents at different distances from the geotextile at different times. Test results show that the amount of moisture reduced by the wicking geotextile decreased with the content of fines in the silty sand. On the contrary, the non-wicking geotextile obstructed water flow, hence moisture accumulated on it. The moisture content profile in the soil column indicated the influence zone by the wicking geotextile in the silty sand, which depended on the fines content. The percent of soil moisture content reduction by the wicking geotextile identified the limit of the fines content for the effectiveness of the wicking geotextile.

3D DEM investigation of shear behavior and interaction mechanism of woven geotextile-sand interfaces

This paper presents a numerical study on the investigation of microscopic mechanism governing the interaction of woven geotextile and angular sand employing the 3D discrete element method (DEM). The surface texture and tensile properties of the geotextile were simulated using overlapping spherical particles, and the angular sand was simulated using rigid blocks. The DEM models were fully calibrated based on previous experimental data. The shear and dilation zones of sand near the interface were quantitatively determined based on particle displacement gradients. Analysis of contact forces was conducted to explain the microscopic mechanism behind the macroscopic strength evolution. The influence of geotextile surface roughness on the shear strength of the geotextile-sand interface is also discussed. The results show that the failure mode of the woven geotextile-sand interface is a combination of particle sliding failure along the geotextile surface and shear failure of the sand within the shear zone above the interface. There is a rapid redistribution of contact forces prior to reaching peak shear resistance, and the average normal contact force within the shear zone remains relatively constant after the peak shear stress is achieved. A completely developed shear zone stabilizes soil deformation, typically after achieving the peak shear resistance.

Design and Implementation of Large-Scale Hard Rock AMD Dewatering and REE Production

To develop a domestic Rare Earth Elements (REE) supply chain the Hydraulic Preconcentrate (HPC) produced at the Horseshoe bend treatment plant (HSB) was evaluated as a potential source for feedstock. After the clarifiers were flipped to the desired pH set points, a total of 24 Geobags were repeatedly filled and allowed to passively dewater. The Geobags evaluated were comprised of a mix of Woven, Non-woven, and Capillary Channel Fiber (CCF). The bags were constructed with either a composite of woven and nonwoven or only woven geotextile. Half of the bags of both types also included “fins” made of CCF to evaluate their impact on dewatering. Column Filtration Tests (CFTs) were performed onsite to provide laboratory value for hydraulic conductivity. Throughout their dewatering, the geobags were sampled to determine their rate of dewatering. Influent samples from HSB were also tested to produce a Specific Gravity (Gs), via pycnometer testing and Grain Size Distribution (GSD), via sieve and hydrometer analysis. The dewatering ability of the geobags was high regardless of bag material with a mean total solids percentage of approximately 40% across all samples after only one month of dewatering. The GSD performed on the HPC is gap graded with most particles having a diameter of approximately 0.5-0.05mm. Hydraulic conductivity values for the filter cakes during Column Filtration Testing ranged from 0.5 to 2.5 meters/day. This data will help to guide development of future large-scale HPC dewatering and the parametric design of an REE oxide production plant at the HSB site.

Effect of Woven Geotextile and Geogrid on Mechanical Properties and Deformation Behavior of Kish Carbonate Sand

Effect of Woven Geotextile and Geogrid on Mechanical Properties and Deformation Behavior of Kish Carbonate Sand

Impact of composition and knitting methods of fiberglass grid on the progression of reflective crack in asphalt pavement

In the asphalt pavement with semi-rigid base, the shrinkage cracks initiating from base course often propagate upward to surface course to develops into reflective cracks. The fiberglass grid, as a woven geotextile, is widely used to retard the occurrence of reflective cracks in China, but the impacts of material composition and knitting methods of it on reflective cracks are still not clear. In this paper, two kinds of models, including a two-scale model of fiber bundle-fiberglass grids layer and a coupled thermo-mechanical model of pavement structure, are established. In the two-scale model, the elastic constants (ECs) of fiber bundle and fiberglass grids layer are calculated under different compositions and knitting methods and then assigned to the coupled thermo-mechanical model to estimate the fatigue lives at initiation phase (FL-IP) and propagation phase (FL-PP) of reflective cracks based on an estimation theory. Moreover, this study designs the laboratory tests to validate this estimation method of fatigue life. Then, based on the predicted fatigue life at different phases of crack progression, the sensitivity analysis is implemented to analyze the impacts of composition and knitting methods on the fatigue life. As a result, the recommendations on design and preparation of fiberglass grid are proposed. The results show that, in material composition, the glass fibers with high elastic modulus and volume fraction and the coating materials with high elastic modulus are beneficial to retarding the initiation and propagation of reflective cracks and in knitting methods, increasing density of fiber bundles parallel to the traffic direction and reducing braided angle also has positive effect. These results can be used to optimizing design and preparation of fiberglass grid to reduce the occurrence of reflective cracks in asphalt pavement.

Experimental study on filtration performance of geotextile filter used in emergency rescue of dike piping

Geotextiles, as a type of common filtration material, have broad prospects in emergency rescue of dike backward erosion piping (BEP). To investigate the filtration performance of geotextile in BEP emergency rescue, several experiments were conducted using nonwoven and woven geotextiles to simulate the process of rescuing BEP with geotextiles. The influence of geotextile specifications and types on hydraulic compatibility of the filter system was analyzed, and the clogging mechanism of geotextile during dealing with BEP was revealed at a microscopic level. The results showed that the nonwoven geotextile filter with an equivalent pore size of 0.103 mm had a gradient ratio value of less than 3, and it had a highest flow rate of 260 mL/min. Increasing the thickness and pore size of nonwoven geotextiles within a certain range helped enhance their anti-clogging ability. The main mechanism of clogging in nonwoven geotextiles was the deposition of fine sand particles on their surface, forming a layer of low permeability soil. Plain woven geotextiles experienced severe clogging with a 42% reduction in flow rate, and it was not suitable for rescuing BEP. The clogging mechanism of woven geotextile involved the blocking of horizontal water passages by fine sand particles.

Evaluation of the behaviour of pipes buried in geosynthetic reinforced ground

This paper aims to present an evaluation of the soil-geosynthetic interaction used for protection and reinforcement of a buried flexible pipe inserted in non-reinforced soils and soils reinforced with geosynthetics subjected to the application of a surface overload. Therefore, tests were carried out in models (scale 1:3.5) and numerical simulations using PLAXIS 2D program. In laboratory tests, a 200 mm diameter PVC pipe was used buried in a non-cohesive soil and different types of geosynthetics. The reinforcement used were four geogrids and a woven geotextile, with tensile stiffness varying between 34 kN/m2 and 2000 kN/m2. The results of the experimental tests showed beneficial effects regarding the insertion of the reinforcement in the massif with buried pipe. The efficiency of reinforcement depends on the type of arrangement considered and its physical and mechanical properties. Overall, the numerical simulations showed that the predicted results reproduced the patterns of the experimental results, but some significant deviations between predictions and measurements were observed.

Geosynthetic solutions for road stabilization and railway ballast optimization over frost susceptible and expansive clays: A case study of the Cargill Canola processing facility

The Cargill Canola processing facility, a $350 million project, began construction in July 2022 and is set to be operational in 2025. The site's geology primarily consists of fine-grained glaciolacustrine sediments, mainly silts and clays. A significant geotechnical challenge was the presence of a weak upper silty clay soil layer, approximately 10 metres thick, which was susceptible to frost heave during freezing temperatures and volumetric changes due to water exposure. Spring melt also raised concerns about excess water accumulation weakening the subgrade, leading to structural damage. The high plasticity index of the subgrade increased the potential for swelling in warmer conditions, complicating the design challenges during seasonal transitions. To address these issues, geosynthetics were employed. Three types were used: a moisture management woven geotextile to provide hydraulic and mechanical stabilization in the rail and road structures, an integrated high-modulus woven geotextile to provide ballast reinforcement, and a biaxial geogrid for base reinforcement in the access roads. The integrated high-modulus woven geotextile was also used in staging areas and gravel pavements to reduce the amount of granular base material required. This case study offers valuable insights for geosynthetic solutions in stabilizing roads and optimizing railway ballast over frost-susceptible and expansive clays. It demonstrates the effectiveness of geosynthetics in mitigating challenges posed by weak soils, frost susceptibility, and expansive clays, contributing to more resilient infrastructure designs.

Tensile and puncture behaviour of a woven geotextile submitted to laboratory mechanical damage tests with incinerator bottom ash

Incinerator bottom ash can be used as recycled aggregate in some engineering applications, where it may be in contact with geotextiles. In this work, a woven geotextile (made of high-density polyethylene filaments) was submitted to mechanical damage under repeated loading tests with different aggregates, namely: incinerator bottom ash, two aggregates of natural origin (tout-venant and gravel 4/8) and a synthetic aggregate (corundum). The damage suffered by the geotextile was assessed by monitoring changes on its tensile and puncture behaviour. The mechanical damage under repeated loading tests induced some reductions in the tensile and puncture properties of the geotextile. The impact of IBA was not exaggeratedly pronounced, and did not differ greatly from that of tout-venant, which was the least damaging aggregate. Gravel 4/8 had a slightly higher impact than incinerator bottom ash, with corundum being the aggregate that induced the most pronounced reductions in the tensile and puncture properties of the geotextile. The use of incinerator bottom ash as recycled aggregate in contact with geotextiles may be a viable option, promoting its valorisation and contributing to more sustainable geotechnical engineering.

Use of geosynthetics and reduction of environmental impacts in the construction of a new parking apron at Ostend airport in Belgium

The theme of microplastics (MP) emissions is one of the focuses of possible environmental concerns when using geosynthetic products in the civil engineering applications. For the construction of a new aircraft parking apron at the Ostend airport in Belgium, a relevant amount of gravel has been substituted with an appropriate woven geotextile for stabilizing the ground. The initial consideration for this decision was essentially due to the important economic and ecological advantages in terms of material savings, time needed for their installation and the overall construction costs. This paper reports the successive analyses showing a very relevant saving in CO2 emissions (more than 77%), which would justify by itself the solution with geosynthetics, if compared with the use of gravel. The specificity and precision of the data available allowed the calculation of a dramatic saving (more than 97%) also in terms of MP emissions, due to the spare of trucks for the transport of materials, preventing also the MP formation connected to the truck’s tires wearing.

Innovative woven geotextiles and geo fibres leading the sustainability path

The Beaulieu International Group has established a transparent way to communicate the environmental impact of their products. Via Environmental Product Declarations (EPDs), third party verified certifications and by following ISO 14025, the impact of the commercialized geotextile engineered solutions are calculated and presented to users. These show a clear advantage of using innovative products such as UltraForce staple fibers for non-woven geotextile fabrics or Beaulieu’s woven technical fabrics, evidenced by a reduced global warming potential (GWP), dematerialisation and increased product longevity.

A study on GCCM (geosynthetic cementitious composite mat) performance improvement by structural composition of woven geotextiles

By applying ‘yarn inlay’ technology using reinforcing fibers, a double raschel GCCM that improved the structural elongation control and reinforcement ability of knitted fabrics was manufactured. In order to improve the cross-sectional reduction of GCCM due to curing shrinkage of concrete, the effects of blowing agent content and concrete filling rate were analysed as a result of the bending strength test, Double raschel GCCM showed the improved brittleness compared to that of general concrete. In addition, it was confirmed that the durability of Double Cell GCCM did not decrease significantly even after 10 days of concrete curing. Finally, the bending strength in special environments such as seawater, freeze-thaw, acidic and alkaline solutions was analysed, and the durability of double raschel GCCM in application environments was confirmed.

Sediment Barriers’ Performance in the Laboratory: Evaluation of Clogging and Filtration Characteristics in Geotextiles Subjected to Discharge Cycles

This research aims to assess the clogging process of geotextiles within silt fences. For that purpose, the filtering efficiency, flow rate, and clogging of three geotextiles (GTX-1, GTX-2, and GTX-3) employing two distinct soils and under three sediment discharge cycles were investigated. The analysis adhered to the American standard D5141-11 and, as further analyses, qualitative and quantitative inspections were conducted through microscopic images of the materials. The results showed greater clogging of the nonwoven geotextile, GTX-1, with higher retention efficiency (approximately 100%) and better turbidity removal for both soils, equal to a reduction of around 94%. For GTX-2, a woven geotextile with a larger pore opening, less intense clogging and lower retention efficiency were observed after the third discharge; the average was 96% for both soils. GTX-3, a woven geotextile with a smaller apparent opening, exhibited a behavior similar to GTX-1: as the number of cycles increased, the material experienced more clogging and higher retention efficiency for soil 1 (approximately 98.5%). Based on these findings, it can be inferred that the discharge cycles impact the tested geotextiles in diverse ways and, therefore, the selection of the material should be contingent on project requirements.

Sedimentation Behavior of Flocculant-Treated Dredged Slurry under Filtration of Woven Geotextiles

Geotextile tubes have offered a cost-effective and convenient solution for the treatment of dredged slurry in recent years. Despite their benefits, the dewatering process of this method remains cumbersome and time-consuming. The incorporation of flocculants into dredged slurries has been shown to mitigate the clogging of geotextile tubes, thereby enhancing the efficiency of the dewatering process. To quantify the impact of flocculant addition on the dewatering performance, a series of laboratory tests were conducted to investigate the sedimentation behavior of flocculant-treated river-dredged slurries under filtration of woven geotextiles. The impact of different flocculants is evaluated with the sedimentation rates of dredged slurries, specifically nonionic polyacrylamide (NPAM) and cationic polyacrylamide (CPAM). Results demonstrated that both NPAM and CPAM, at an optimal concentration of around 250 mg/L, could substantially increase the settling rates of slurries when filtered through geotextiles. At equivalent flocculant concentration, NPAM outperforms CPAM in accelerating sedimentation rates. It is also evidenced that adding flocculants can significantly augment the particle size and permeability of slurries. After adding flocculants, the water content and dry density of the final sediments exhibit a more uniform distribution in the vertical direction compared to the original slurry. Furthermore, scanning electron microscopy was employed to analyze the micromorphology of the final sediments treated with different NPAM concentrations. The results showed that the slurries exhibited significant void structure under treatment with the optimal concentration of NPAM, demonstrating the flocculants’ effectiveness in enhancing the dewatering process of river-dredged slurries when filtered with geotextiles.

PREDICTION OF THE VERTICAL PERMEABILITY COEFFICIENT BASED ON FRACTAL THEORY FOR WOVEN SLIT-FILM GEOTEXTILES

The coefficient of vertical permeability is a common filter design criterion for woven slit-film geotextiles. According to the pipe flow theory, a permeability coefficient model has been proposed for predicting the permeability coefficient of woven geotextiles, in which the pore characteristics were described by the Sierpiński carpet fractal theory. The verification of models is performed in 12 woven geotextiles of two types using a digital image method and a vertical water permeability test of the geotextile. The influence of the pore characteristics on the permeability coefficient is further explored using univariate and multivariate analyses. The results show that the porosity model can accurately predict the total percent pore area (POA) and the POA distribution of the woven geotextiles, and the permeability model can accurately predict the permeability coefficient of the geotextiles. The permeability coefficient of geotextiles decreases with the pore area fractal dimension and the minimum pore size under the action of a single factor. The permeability coefficient increases as the maximum pore size increases. POA and maximum pore size are the most significant independent variables affecting the permeability coefficients of geotextile under the action of multifactor.

Soil strength improvement by reinforcing soil with geotextiles

In recent times, geosynthetic products are widely utilized in the construction sector and particularly in the field of Geotechnical Engineering. Geosynthetics are the synthetic products used mainly within the soil to perform various functions. In this paper, an attempt has been made to utilize Woven geotextiles (WG) and Non-woven geotextiles (NWG) as reinforcement within soil to enhance the strength of subgrade soil. 2 types of coarse-grained soil, soil with high fines content and soil with low fines content were utilized in the experimental work. WG and NWG were placed at varying depths of H/5, 2H/5, 3H/5 and 4H/5 from top of the soil specimen (where H is the height of soil specimen), to find the enhancement in soaked & unsoaked California Bearing Ratio (CBR) strength of soil with respect to that of unreinforced soil. Based on the experimental results, improvement in CBR strength of soil reinforced with geotextile and the ideal location of placement of geotextile within the soil thickness varied according to the soil type and this may be attributed to the presence of varied percentages of fines within soil. Also, the soil reinforced with WG was observed to be more effective in terms of strength gain as compared to that of soil reinforced with NWG. Improvement in CBR strength of subgrade soil reinforced with geotextiles leads to reduced pavement thickness thus resulting in a cost-effective construction.

Internal erosion and permeability of Na CMC-treated and PAM-treated geosynthetic clay liners

This paper investigates the occurrence of internal erosion and the variation of the permeability of geosynthetic clay liner (GCL) with respect to its geotextile component, polymer type and polymer amount added to its bentonite component, hydraulic head, and subgrade material by performing extensive triaxial permeability tests on the GCL specimens. To do this, Na carboxymethyl cellulose (CMC) and polyacrylamide (PAM) were treated with the bentonite component of the GCLs. Then, the GCLs were placed over poorly graded gravel (GP) and poorly graded sand (SP). Consequently, they were tested with two different woven geotextile components under the hydraulics heads of 0.3 m and 10 m. Results showed that only GCLs tested with woven geotextile, having lower tensile strength, lower mass/area and lower thickness over the gravel at a hydraulic head of 10 m, experienced internal erosion. Critically, Na CMC and PAM treatment caused 2–2.5 orders of magnitude decrease in the permeability. Actually, 2% Na CMC and 1% PAM treatment by dry mass were found to be the optimum polymer contents. Both the environmentally friendly biopolymer Na CMC and the synthetic polymer PAM can effectively be treated with Ca bentonite to enhance the hydraulic performance of the GCLs.

Mechanical damage of geotextiles induced by recycled construction and demolition waste

Construction and demolition waste is one of the most impactful waste streams worldwide, so efforts should be made to find applications that promote its recovery. The use of recycled aggregates from construction and demolition waste as filling materials in geotechnical works, where they may come into contact with geosynthetics, is one of those applications. This work evaluates the mechanical damage induced to five geotextiles with different structures (non-woven and woven) by three recycled aggregates from construction and demolition waste. The damage suffered by the geotextiles was evaluated qualitatively by visual inspection and quantitatively by monitoring changes in their tensile and static puncture behaviour. The results showed that in some cases, the recycled aggregates from construction and demolition waste induced damage to the geotextiles, affecting their properties. The impact of the aggregates depended on (a) their particle characteristics and (b) the physical properties of the geotextiles. For both non-woven and woven geotextiles, the increase in mass per unit area and thickness resulted in better resistance to degradation. The damage caused by the recycled aggregates to 251 and 495 g/m2 non-woven geotextiles was small to negligible. Corundum (standard aggregate) had a more harmful impact on the geotextiles than the recycled aggregates.