Performance Of Geotextiles Research Articles

Study on the Performance Evaluation Method and Application of Drainage Nonwoven Geotextile in the Yellow River Sediment Filling Reclamation Area

Technical challenges associated with drainage and filling efficacy confront the Yellow River sediment filling reclamation, a novel approach to reclaiming coal-mined subsided lands. This study proposes an improved geotextile performance evaluation method to address the shortcomings of current geotextile screening methodologies in the drainage of the Yellow River sediment. This method comprehensively considers essential characteristics under working conditions, such as permeability, soil conservation, and blockage prevention properties, including indicators such as the permeability coefficient and sediment retention rate of geotextiles under pressure. Indoor flume filling and drainage experiments were implemented to verify the efficacy of geotextile drainage. The improved method identified thermal-bonded nonwoven geotextiles of 200 and 250 g·m−2 as having the highest comprehensive evaluation scores. The experimental results showed that these geotextiles significantly improved their drainage efficiency and better met the specific requirements of the Yellow River sediment filling reclamation. Traditional screening methods may be unsuitable for sediment drainage conditions, necessitating sediment interception and rapid drainage due to the streaming water–sediment mixture. Therefore, the newly established performance evaluation method is more appropriate for the specific requirements. It is recommended that a simple vibrating device be installed to maintain 20 vibrations per minute to keep drainage channels clear and provide stable drainage performance in engineering applications.

Study on the formation and dewatering process of the surface filter cake of geotextile on the lateral boundary of geotextile tubes under constant flow grouting

In this article, physical model test and numerical simulation are used to study the formation of filter cake and the filtration performance of the geotextile on the lateral boundary of the ultra-fine tailings grouting geotextile tubes from macro and micro levels. At the macro level, the effects of different grouting flow rates and tailings slurry mass concentrations on the surface filter cake formation and the dehydration performance of geotextile on the lateral boundary of the geotextile tubes were analyzed. At the micro level, the use of CFD-DEM method for fluid and particle of two-way coupling numerical simulation research, lateral drainage boundary of superfine tailings in tubes filter cake forming process is analyzed. The research shows that the increase of grouting flow rates and tailings slurry mass concentrations will make the thickness of filter cake great and the structure more compact, which will lead to more serious silting of the surface layer of geotextile and greatly reduce the dehydration performance; The numerical simulation results regularity is consistent with the results regularity of physical model test on the formation of filter cake on geotextile surface of geotextile tubes: the larger the slurry inlet speed and particles concentrations, the more complete the formation of filter cake on geotextile surface, the denser the cake structure, and the less tailings loss. By studying the effects of grouting flow rates and slurry mass concentrations on the surface filter cake formation and tubes dehydration, this article aims to find suitable slurry filling construction conditions and explore the main influencing factors caused by dehydration and consolidation of ultra-fine tailings grouting geotextile tubes, so as to provide some help for the subsequent flocculating of ultra-fine tailings to solve the problem of surface drying and internal wetting of geotextile tubes.

Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios

Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.

Evaluation of Untreated and Treated Coir Geotextile Performance under Cyclic Loading on Unpaved Roads

Evaluation of Untreated and Treated Coir Geotextile Performance under Cyclic Loading on Unpaved Roads

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.

Thermal characteristics and optimization of phase change energy storage subgrade in permafrost regions

In permafrost regions, the thawing of permafrost will cause serious damage to the road structure, and delaying the degradation of permafrost is the key to ensure the road performance. Based on the energy storage characteristics of phase change material (PCM) and the anti-seepage performance of geotextile, a phase change geotextile (PCG) with heat absorption and waterproof functions is prepared in this study. PCG is applied to the subgrade structure, and the phase change energy storage subgrade (PCESS) is proposed. This subgrade structure can effectively reduce the temperature and increases the artificial permafrost table in permafrost regions. In order to study the temperature regulation mechanism of PCESS, the effects of thermal properties of PCM and epoxy resin mixture (PCMERM) and structural parameters of PCG were analyzed by numerical models. The mean absolute errors (MAEs) were 0.88 and 1.08 with experiments conducted to validate numerical model. The analysis of influencing factors showed that the phase change temperature of PCMERM exhibits the best value to improve the regulation effect of PCESS under given conditions. Increasing the heat of fusion and dosage of PCMERM can enhance the regulation effect. When PCG was laid on the top of the subgrade, the regulation effect was the best. Compared with the traditional permafrost subgrade, PCESS showed long-term thermal stability. In addition, the prediction model for the artificial permafrost table change was established. The model predicted the artificial table in three cases, and the MAEs were 0.048, 0.019 and 0.039, respectively. These results suggest that the model can accurately predict the changes of the artificial permafrost table.

Multiphysics analysis of tramway geotechnical infrastructure: numerical modelling

Under realistic field conditions, geotechnical infrastructures are usually influenced by complex interactions of mechanical behaviour under the action of an internal water flow. This mechanism could be the main origin of damage to embankments. This study develops a new hydro-mechanical (HM) approach based on Darcy's law model and Biot's poroelastic concept to investigate the behaviour of soil with and without geotextile under realistic conditions. The problem's numerical solution is carried out using a finite-element method. The proposed two-dimensional model was implemented in Comsol Multiphysics Software. Under coupled HM behaviour, the stress in porous materials causes a volumetric change in strain, which causes fluid diffusion. Consequently, pore pressure dissipates through the pores. To discuss the advantages of coupled HM modelling and evaluate the geotextile performance, volumetric strain, pore-water pressure, storage and displacement are compared for a mechanical, hydraulic and HM model. These analyses were undertaken in connection with a tramway embankment project in a marshy area in Sidi Bel Abbes. The simulation results show better results for geotextile and embankment in HM coupled modelling.

Geotextile performance of fabrics woven by polyethylene terephthalate yarns prepared directly from drinking bottles

This research article describes the preparation and characterization of geotextile-reinforced embankment made from yarns produced from polyethylene terephthalate bottles by the bottle cutter and stretching yarn prototype. The yarns produced from plastic bottles were weaved to obtain fabrics with different pattern structures. Yarns and fabrics samples were characterized including yarn number, yarn tensile, fabric thread density, fabric weight, fabric thickness, fabric breaking strength, and fabric bursting strength. The performance of the fabric samples as a geotextile was evaluated by direct shear test, California bearing ratio, and water permeability. The results show that the fabric pattern structure plausibly was the main factor for geotextile performance. The fabric samples with low thread density could develop both interlocking and interbedding mechanisms resulting in higher shear stress and California bearing ratio. Lastly, PLAXIS 2D program simulation with finite element method was used to estimate the possibility of the use of fabric samples as geotextile-reinforced embankment. It was found that the predicted safety factor of soil erosion with fabric sample could reach the value of one which is higher than the safety factor of the soil erosion without fabric sample.

Change pattern of geomembrane surface roughness for geotextile/textured geomembrane interfaces

Applying textured geomembrane improves the frictional performance of geotextile and geomembrane interfaces. However, very limited research has been conducted to analyze the variation in textured geomembrane roughness during geotextile/geomembrane interface shear processes. In this study, a geomembrane surface roughness measurement method for measuring asperity height data with fixed intervals was presented. Normalized profile length and fractal dimension were used to quantitatively describe the geomembrane surface deformation during the geotextile/textured geomembrane interface shear process. It was found that applying normal stress led to a reduction of the roughness parameters. After the mobilization of the peak shear stress during the shear process, the chosen roughness parameters decreased with the shear displacement. And, increasing the normal stress made the shear-induced reduction of roughness parameters more obvious. The hyperbolic model can be used to describe the quantitative relationship between the geomembrane roughness parameters and the shear displacement. This study can help explain the displacement-softening post-peak behavior of the geotextile/textured geomembrane interfaces.

Effect of warp and weft uniaxial tension on the permeability of sand covered with geotextile

The permeability of sand covered with geotextile is affected by the permeability of geotextile, which is related to the tensile state of the geotextile. Considering the weaving mode of geotextile, the effects of warp tension and weft tension on the permeability of sand covered with geotextile were studied by experiment. Four different specifications of geotextiles were selected for warp and weft tension respectively. The changes of permeability parameters of sand covered with geotextile under non tension, warp and weft tension were measured by vertical permeability instrument, and the effects of warp and weft tension on permeability parameters such as seepage velocity, sand loss and gradient ratio were analyzed. The test results show that the water permeability and anti silting performance of the geotextile increase with the increase of tensile strain, and the soil conservation performance decreases with the tensile strain increasing. Meanwhile, the relationship between permeability and warp tensile strain is not monotonic. When the warp tensile strain 3%, the water permeability and anti silting performance of geotextile are the weakest, and the soil conservation performance is the strongest.

Influence of physical clogging on filtration performance of soil-geotextile interaction

During the past four decades the use of nonwoven geotextiles as filter materials in geotechnical works has experienced a marked increase. In this study, the water permeability coefficient of nonwoven geotextiles after 23 years of exploitation in drainage system was determined to evaluate the influence of physical clogging on filtration performance of geotextiles. The obtained results showed that the geotextiles were clogged by soil particles. What is more, the objective in this study was to establish a gradient ratio test method for estimating a clogging phenomenon of geotextile filter adequately. A series of gradient ratio tests on three kinds of needle-punched nonwoven geotextile filters whose number of constrictions differs was performed. A geotextile filter was put under a silty sand layer. Based on the test results, it was confirmed that the water permeability coefficient became small as gradient ratio increased depending on the number of constrictions of the geotextile. It was also found that the modified gradient ratio GR4 is more sensitive than GR8 and GR25. Based on interpretation of the experimental results, the authors recommend the acceptance limit of GR8 equal to 3.7 and of GR4 equal to 4.8.

Weathering of geotextiles under ultraviolet exposure: A neglected source of microfibers from coastal reclamation

Geotextiles are a group of polymeric materials widely used in coastal reclamation projects. However, long-term exposure to solar illumination deteriorates the performance of geotextiles, resulting in physicochemical changes and high risks of releasing microfibers. This study investigated the photoaging behavior of geotextiles and evaluated the capacity of geotextiles to release microfibers in coastal reclamation areas through a combination of field research and laboratory experiments. A field survey in the coastal reclamation area of Yancheng (China) confirmed that many geotextiles made from polyethylene terephthalate (PET) existed on the beach, which was accompanied by a high value of carbonyl index of 0.70–0.93. The results from laboratory experiments revealed that ultraviolet exposure activated the photooxidative process and promoted the breakdown of PET geotextiles. Data of scanning electron microscope and laser particle analyzer showed that, initially, particles with the size of less than 1 μm were generated on the surface of geotextiles, followed by fragments with sizes of 1–100 μm falling off with the passage of time. The number of particles on the surface was calculated using Image-Pro Plus software and the maximum particle density was found to be around 2.52 million particles·mm−2. In addition, based upon the conversion of irradiance between the simulated solar and natural solar, it was roughly estimated that the annual emissions of PET geotextile fibers in coastal reclamation areas were 0.24–0.79 million tons all over the world. It is inferred that polymer-made geotextile is a significant source of microplastic pollution in reclamation zones of coastal areas.

Spunbonded needle-punched nonwoven geotextiles for filtration and drainage applications: Manufacturing and structural design

Recently, geotextiles have gained widespread popularity as porous materials in the fields of geotechnical and geoenvironmental engineering. Spunbonded needle-punched nonwoven geotextiles are an important part of the nonwoven geotextile family. In these geotextiles, filaments are mechanically entangled to form a complex three-dimensional structure, which provides the geotextile a bulky nature. Additionally, this unique fabrication process ensures provision of a variety of widely distributed pores which are essential for the targeted functions of filtration and drainage. This review summarizes manufacturing process of spunbonded needle-punched nonwoven geotextiles and highlights the relationship among process parameters, fabric structure and hydraulic properties. At last, the paper reviews the failure mechanism and design principle of the filtration and drainage performance of geotextile.

Soil Stabilization For Pavements Using Geofabrics Based On California Bearing Ratio

India has the largest road network however the prevailing roads ar structurally inadequate to accommodate the current volume of traffic. Use of geosynthetics is compatible and conjointly effective within the method of up soil properties. the current study conducts experiment on the performance of geotextile (woven and non-woven) as soft subgrade and unbound gravel in unpaved versatile pavement system victimization CA Bearing magnitude relation (CBR) take a look at. Reinforcement magnitude relation comparison of woven and non-woven geotextile reinforcenment supported CMB load penetration take a look at indicates that the performance is improved with the inclusion of geotextile.

The Behaviour and Performance of Geo-Textiles with Reference to CBR Value on Clay Soil

Geo-textiles are polymers of high tensile strength, and they are flexible in nature. They are widely used in a variety of engineering applications including soil reinforcement. Hence, it was necessary to make an in depth study on the use of geo-textiles and their relative advantages. This work focuses on a comparative study on the load carrying capacities using geo-textiles. A series of California Bearing Ratio (CBR) tests were performed on soil reinforced with geo-textiles, placed in single and double layers at different depths. The CBR value and stress-strain results of this study provided a better understanding on the comparative changes in load carrying capacities of the soil. The information will help in better decision making in the field of soil reinforcement.

Performance of nonwoven geotextiles on soil drainage and filtration

The selection of a geotextile to prevent the soil suffusion in a civil engineering work is a classical problem. The internal erosion is a key factor as the migration of fine particles damages the integrity of the soil structure. This work deals with the problem of using a draining system consisting of a layer of soil and a geotextile sheet in order to prevent soil suffusion. It proposes a methodology which allows ordering the performance of nonwoven geotextiles. A range of experimental approaches were implemented including seepage flow tests under controlled flow rates. A detailed analysis of the data shows that intrinsic properties of geotextiles are not sufficient to predict their behaviour in a draining system. Moreover, the classical flow tests of the draining systems are not sufficient to adequately discriminate the three geotextile specimen used here. On the other hand, it seems important to use the history of the hydraulic gradient with respect to the flow rate variation. Thus, the present data of normalised relative pressure drop and normalised relative variation of flow rate are arranged in terms of a dimensionless criterion. This methodology enables evaluating and discriminating the performances of the geotextiles used here in terms of filtration and drainage functions.

Design graphs to estimate reduction factor of nonwoven geotextiles due to installation process

It seems that performance of geotextiles is directly related to their survivability, which affects design economy. This paper aims to present design graphs in order to estimate the tensile strength reduction factors of nonwoven geotextiles due to the installation process in the soil embankment. The design graphs have been established based on a series of full-scale field tests and analytical procedures. The variables include medium grain size of backfill materials, subgrade CBR, relative density of backfills, as-received geotextile tensile strength and the transferred stress over the geotextiles level, during installation. It is concluded that tensile strengths of the geotextile got decreased in the aftermath of compaction process under higher relative density, larger particle size of the backfill, lower as-received grab tensile strength (decreasing the AASHTO’s geotextiles class from 1 to 3) and finally, being in the neighbourhood of weaker subgrades. These intensifying conditions necessitate designers using high-survivability geotextiles.

Impact resistance and evaluation of retained strength on geotextiles

Over the last few decades, geotextiles have progressively been incorporated into geotechnical applications, especially in the field of coastal engineering. Geotextile materials often act as separator and a filter layer between rocks laid above and subgrade beneath. This versatile material has gradually substituted traditional granular materials because of its ease of installation, consistent quality and labour cost-efficiency. However, geotextiles often suffer damage during installation due to high dynamic bulk loading of rock placement. This can degrade geotextiles' mechanical strength. The properties considered in this paper include the impact resistance and retained strength of geotextiles. In general, the greater the impact energy applied to geotextiles, the greater the potential for damage. Results highlight the inadequacy of using index derived values as an indicator to determine geotextile performance on site because test results shows that geotextiles (staple fibre (SF) and continuous filament (CF)) with better mechanical properties did not outperform lower mechanical strength materials. The toughest CF product with a CBR index value of 9696N shows inferior impact resistance compared to SF product with the least CBR strength (2719N) given the same impact energy of 9.02 kJ. Test results also indicated that the reduction of strength for CF materials were much greater (between 20 and 50%) compared to SF materials (between 0 and 5%) when subjected to the same impact energy of 4.52 kJ.

Water Quality Improvement Performance of Geotextiles Within Permeable Pavement Systems: A Critical Review

Sustainable drainage systems (SuDS; or best management practices) are increasingly being used as ecological engineering techniques to prevent the contamination of receiving watercourses and groundwater. Permeable paving is a SuDS technique, which is commonplace in car parks, driveways and minor roads where one of their functions is to improve the quality of urban runoff. However, little is known about the water quality benefits of incorporating an upper geotextile within the paving structure. The review focuses on five different categories of pollutants: organic matter, nutrients, heavy metals, motor oils, suspended solids originating from street dust, and chloride. The paper critically assesses results from previous international tests and draws conclusions on the scientific rigour and significance of the data. Findings indicate that only very few studies have been undertaken to address the role of geotextiles directly. All indications are that the presence of a geotextile leads only to minor water quality improvements. For example, suspended solids are being held back by the geotextile and these solids sometimes contain organic matter, nutrients and heavy metals. However, most studies were inconclusive and data were often unsuitable for further statistical analysis. Further long-term research on industry-relevant, and statistically and scientifically sound, experimental set-ups is recommended.

Development of a methodology for the evaluation of geomembrane strain and relative performance of cushion geotextiles

The protection of liners in landfill sites is of the utmost importance in the calculation of the usable design life of a landfill system. This research presents the establishment of an improved method for analysing the strain induced on a geomembrane using laser scanning technology to better determine the design life of the geomembrane. The ability to reproduce results with a high degree of accuracy under a range of test conditions was investigated. The results of this research showed that the use of high-definition laser scanning techniques produces repeatable and highly accurate results allowing precise indication of potential stress crack failure while providing a realistic comparison of cushion geotextile performance.