High-strength Geotextile Research Articles

Geogrid-type geotextile made from Typha domingensis fibers with high tensile strength for erosion control

The present invention relates to a geotextile of the geogrid type manufactured with fibers from the Typha domingensis plant, known as cumbungi, recognized for its remarkable tensile strength. This geotextile is developed to mitigate erosive processes and is produced from natural fibers arranged in a mat configuration. This product fit in with the technical fields of civil engineering and textile materials. The central innovation of this geotextile lies in the provision of a natural alternative featuring biodegradable fibers and high tensile strength. Its applications in environmental engineering include erosion prevention, slope stabilization, and reinforcement of road structures, with the fundamental goal of preserving the soil against degradation and erosion. This high-strength geotextile is composed of Typha domingensis fibers skillfully interwoven and connected to form a grid structure, with each unit covering approximately 0.25 m2s. Furthermore, a double layer of waterproofing material is incorporated to provide greater cohesion, environmental durability, and tensile strength. In practical applications, this geotextile demonstrates a remarkable ability to withstand mass movements even before local vegetation develops. This makes it a technological alternative that synergistically combines technological and ecological processes, incorporating the principles of soil bioengineering while offering a sustainable alternative to synthetic geotextiles. The use of this geotextile in the field is preferably combined with living components such as seeds, plant stakes, wood, or rocks for slope or embankment stabilization, with a primary focus on effective erosion control and the promotion of environmental sustainability.

Исследование конструкции земляного полотна на свайном основании с гибким ростверком

Purpose: To investigate the roadbed in the construction of pile foundation united by flexible grillage made of geosynthetic material. To investigate how geosynthetic material will work in such a grillage. To create analytical model of pile foundation with flexible grillage. To determine the strength of such textile material used in the construction. To analyze the advantages and flaws of existing methods for calculating pile foundation structure united by flexible grillage made of geosynthetic material. Methods: Structure parameters of flexible grillage reinforced with geosynthetic material, were calculated using three methodologies: British standard BS 8006-2010, German EBGEO methods, flexible thread calculating method. Results: Arched effect arising in mound body has been studied. Deflections in geosynthetic material were calculated at different loading levels of the structure by soil. Experimental values of forces in geosynthetic material are obtained. "Critical height" is set - the distance from pile top which within, arched effect is formed. Numerical value of uniform emptying has been established which at, pile foundation different rigidity is not revealed on surface. The strength of geosynthetic material of flexible grillage of highway mound foundation is estimated. Existing calculation methods for compliance with experiment results are analyzed. Practical importance: Technical solutions have been developed for two types of flexible grillage structures, both, combined and flexible ones with the use of one or more layers of high-strength geotextile with sand in the form of geo-confining. The developed technical solutions meet all requirements of existing regulatory documents and obtained calculated indicators as well as the requirements for strength, reliability and structure durability. The proposed constructions can be recommended for practical use.

Effect of Sustained Loading on the Direct Shear Behaviour of Recycled C&D Material–Geosynthetic Interfaces

Recycled construction and demolition (C&D) wastes have been pointed out as a feasible alternative to traditional backfill materials of geosynthetic-reinforced structures, but the current knowledge about the interface behaviour between these unconventional (recycled) materials and the reinforcement is still limited, particularly as far as the time-dependent response is concerned. In this study, a series of large-scale direct shear tests was conducted using an innovative multistage method to evaluate the influence of shear creep loading on the direct shear response of the interfaces between a fine-grained C&D material and two different geosynthetic reinforcements (high-strength geotextile and geogrid). The peak and large-displacement interface shear strength parameters obtained from tests involving sustained loading were compared with those from conventional interface tests. Test results have shown that the shear creep deformation of the interfaces increased with the magnitude of sustained loading. The test specimens experienced additional vertical contraction during the creep stage, which tended to increase with the applied normal stress. For the recycled C&D material-geotextile interface, the sustained loading induced a reduction in the apparent cohesion and a slight increase in the friction angle, when compared to the values estimated from conventional tests. In turn, for the geogrid interface, the apparent cohesion values increased, whereas the friction angle did not significantly change upon shear creep loading.

Long-Term Tensile Behavior of a High-Strength Geotextile after Exposure to Recycled Construction and Demolition Materials

Long-Term Tensile Behavior of a High-Strength Geotextile after Exposure to Recycled Construction and Demolition Materials

Time-Dependent Response of a Recycled C&D Material-Geotextile Interface under Direct Shear Mode.

Geosynthetic-reinforced soil structures have been used extensively in recent decades due to their significant advantages over more conventional earth retaining structures, including the cost-effectiveness, reduced construction time, and possibility of using locally-available lower quality soils and/or waste materials, such as recycled construction and demolition (C&D) wastes. The time-dependent shear behaviour at the interfaces between the geosynthetic and the backfill is an important factor affecting the overall long-term performance of such structures, and thereby should be properly understood. In this study, an innovative multistage direct shear test procedure is introduced to characterise the time-dependent response of the interface between a high-strength geotextile and a recycled C&D material. After a prescribed shear displacement is reached, the shear box is kept stationary for a specific period of time, after which the test proceeds again, at a constant displacement rate, until the peak and large-displacement shear strengths are mobilised. The shear stress-shear displacement curves from the proposed multistage tests exhibited a progressive decrease in shear stress with time (stress relaxation) during the period in which the shear box was restrained from any movement, which was more pronounced under lower normal stress values. Regardless of the prior interface shear displacement and duration of the stress relaxation stage, the peak and residual shear strength parameters of the C&D material-geotextile interface remained similar to those obtained from the conventional (benchmark) tests carried out under constant displacement rate.

Short-term tensile behaviour of three geosynthetics after exposure to Recycled Construction and Demolition materials

Designing and building structures and infrastructures with alternative and environmentally friendly materials is, nowadays, an important step towards a more sustainable society. Recycled Construction and Demolition (C&D) materials have been considered as alternative materials in different civil engineering applications, such as unbound pavement layers and structural embankments, in which geosynthetics are also frequently applied. If the durability of geosynthetics is an important issue when conventional materials are used, it becomes more relevant when utilising alternative materials. This paper presents and discusses the chemical and environmental degradation induced by a recycled C&D material on the short-term tensile behaviour of three geosynthetics used typically as reinforcement material (two geogrids and a high-strength geotextile), after 24 months of exposure. For comparison purposes, geosynthetics samples were also exposed to a natural soil. The physical and environmental characterization of the recycled C&D material are presented and the tensile behaviour of intact (as-received) samples, immediately exhumed samples and exhumed samples after 24 months of exposure are characterized and discussed. To evaluate the potential damage in more detail, Scanning Electron Microscope (SEM) analyses were carried out. Regardless of the geosynthetic type and exposure condition, the geosynthetic’s tensile strength decreased after 24-month exposure. This loss of tensile strength was insignificant for the high density polyethylene geogrid and higher for the geotextile. The effect of exposing the geosynthetics to the recycled C&D material for 24 months had some relevance only for geotextile. For both geogrids, the loss of strength for the specimens immediately exhumed and exposed through 24 months is comparable. In general, the exposure to the recycled C&D material or to the soil induced similar effects.

Pullout behaviour of geosynthetics in a recycled construction and demolition material – Effects of cyclic loading

Abstract In recent years, the use of construction and demolition (C&D) materials as alternative aggregates in geotechnical engineering applications, such as embankments, pavement subbase layers and geosynthetic-reinforced structures has raised increasing attention from researchers and practitioners worldwide. On the other hand, geosynthetics, particularly geogrids and high strength geotextiles, are used as a reinforcement material in some of those applications. When these infrastructures are subjected to repeated loadings (e.g. traffic, wave and seismic loads), the understanding of the interaction properties at the backfill-geosynthetic interfaces under cyclic loading conditions is of primary interest. This paper describes an experimental study carried out using a large-scale pullout test apparatus to assess the load-strain-displacement behaviour of two geosynthetics embedded in a recycled C&D material under cyclic and post-cyclic loading conditions. Test results show that cyclic loading can measurably reduce the post-cyclic pullout resistance of the geotextile (up to 15%), when compared to that obtained from the benchmark monotonic test. Conversely, the cyclic loading did not significantly influence the pullout resistance of the geogrid. The cumulative cyclic displacements over the length of the geosynthetics were found to increase with the load amplitude and the pre-cyclic pullout load level. Moreover, under identical test conditions, the accumulated cyclic deformations along the geotextile length consistently exceeded those for the geogrid, possibly due to the lower tensile stiffness of the geotextile at low strains.

Case Histories on the Application of Vacuum Preloading and Geosynthetic-Reinforced Soil Structures in Indonesia

Geosynthetics technology has been applied in Indonesia as early as 1983 where a high strength geotextile of 200 kN/m was laid to help stabilize the highway built on swampy land toward Jakarta International Airport. Since then, geosynthetics have been gaining popularity in solving various geotechnical problems, e.g., slope stabilization, construction of retaining walls, acceleration of consolidation, lining of ponds, construction of breakwaters and shore protection works, etc. Six case histories on the application of geosynthetics technology are presented in this paper. Three case histories on the application of prefabricated vertical drain with vacuum preloading to accelerate consolidation process of very soft clay are discussed. The first case is a vacuum preloading on lowland area, just a few km from seashore. The second case was vacuum preloading on high ground of about 700 m from sea level. The third case was vacuum preloading combined with surcharging. Another three case histories discussed the application of geosynthetic-reinforced soils in slope stabilization where, instead of granular material, cohesive materials were utilized as backfill. The first was its application for river embankment stabilization. The second was a back-to-back 13-m-high reinforced soil to support a railway on top of it. The third was a 25–37 m high retaining structure developed on a problematic clay shale for a runway support. Despite the difficulties encountered, each of the projects was finally executed safely and successfully.

Performance evaluation of full-scale geosynthetic reinforced flexible pavement

An accelerated wheel load testing program was conducted to evaluate the benefits of using geosynthetics to enhance the performance of pavement constructed over soft subgrade. Six full-scale test sections were constructed, among which two sections were reinforced by one or two layers of triaxial geogrids, and two sections were reinforced by one layer of high strength geotextile with different base layer thickness. The test sections were instrumented by a variety of sensors to measure the load- and environment-associated pavement response and performance. The results of full-scale accelerated load testing demonstrate the benefits of using geosynthetics in terms of reducing the permanent deformation in the pavement structure. The geosynthetics benefit to reducing the maximum stress on top of subgrade is more distinguishable at a higher load level. It was also found that the geosynthetic placed at the base-subgrade interface was able to improve the performance of both subgrade and base layers. By placing an additional layer of geogrid at the upper one-third of the base layer, the performance of the base layer was further enhanced. While the geosynthetic showed appreciable benefit to reducing the permanent deformation of subgrade in this study, it showed little effect on the resilient properties of subgrade.

Geotextile Tube Assessment Using Hanging Bag Test Results of Dairy Sludge

Geotextile tube is an innovative product developed by sewing permeable high strength geotextiles to form large tubes. The main application of geotextile tube is dewatering of dredged materials sediments and industrial waste slurry. The present study describes the performance of dairy sludge dewatering using hanging bag test. The effect of the addition of coagulant has been studied. Alum was used as a coagulant. Dewatering was carried out for dairy sludge without the addition of alum and dairy sludge mixed with alum. The environmental analysis was carried out of the sludge before and after hanging bag test to study the quality of filtrate. Also, analysis of filter cake was done to check its suitability for reuse thus proving zero waste condition. It was found that geotextile tube was efficient in dewatering the sludge and its efficiency increases with the addition of a coagulant. Dairy sludge dewatering without the addition of alum showed the maximum flow rate of 4.95 cm3/sec and dewatering time of 2280 min as compared to dairy sludge dewatering with the addition of alum which showed the maximum flow rate of 7.66 cm3/sec and dewatering time of 2160 min.

Use of Mixed Construction and Demolition Recycled Materials in Geosynthetic Reinforced Embankments

The use of construction and demolition (C&D) recycled materials in the construction industry represents an important step towards a more sustainable future and, simultaneously, represents a new market opportunity to be explored. In the last years, several case studies relating to the application of C&D recycled materials have emerged, mainly, in base and sub-base layers of the roadway infrastructures and in concrete production. This papers deals with the use of fine mixed recycled aggregates as filling material of geosynthetic reinforced embankments. The physical, mechanical and environmental characterization of C&D recycled materials is presented and discussed, as well as, the direct shear behaviour of two C&D materials/geosynthetic interfaces. The C&D recycled material was collected from a Portuguese recycling plant and comes from non-selected C&D wastes. One geogrid and one high strength geotextile were used to assess the interfaces behaviour. The environmental characterization of the C&D recycled material, carried out through laboratory leaching tests, has not shown any environmental concerns. Direct shear test results have revealed that the increase in C&D recycled material moisture content can measurably reduce the interface shear strength. The shear strength of the C&D material/geosynthetic interface has improved with the degree of compaction increase. The coefficients of interaction reached for C&D material/geosynthetic interfaces, a key factor in the design of geosynthetic reinforced structures, compare well with those found in the literature for soil/geosynthetic interfaces.

Recycled Construction and Demolition Wastes as filling material for geosynthetic reinforced structures. Interface properties

Construction and Demolition Wastes (C&DW) are increasingly being reused in civil engineering applications, mainly in concrete production and base layers of roadway infrastructures. However, frequently the fine grain portion of these recycled aggregates is not considered suitable for those applications being landfilled instead of recycled. Moreover, the value-added utilisation of recycled C&DW in the construction of geosynthetic reinforced structures (steep slopes and retaining walls) is almost an unexplored field. This research assesses the feasibility of using fine-grain recycled C&DW as filling material of geosynthetic reinforced structures (GRS), appraising the physical, mechanical and environmental characterization of the construction and demolition material (C&DM), as well as, the direct shear and pullout behaviour of the interfaces between this material and three distinct geosynthetics (two geogrids and one geocomposite reinforcement or high strength geotextile). Direct shear tests results have shown that fine-grain recycled C&DW, properly compacted, exhibit similar shear strength to natural soils used commonly in the construction of GRS. The potential contamination of groundwater by these recycled C&DW was evaluated through laboratory leaching tests and, excepting the values of sulphate and total dissolved solids (TDS), this recycled C&DW complies with the provisions of European Council Decision 2003/33/EC for inert materials. High values of coefficients of interaction for C&DW/geosynthetic interfaces, a parameter of utmost importance in the design and performance of GRS, were achieved. The results herein presented support the viability of using these recycled C&DW as filling material for GRS construction.

Damage Induced by Recycled Aggregates on the Short-Term Tensile Behaviour of a High-Strength Geotextile

This paper presents the mechanical, chemical and environmental degradation induced by recycled Construction and Demolition Wastes (C&DW) on the short-term tensile behaviour of a nonwoven polypropylene (PP) geotextile reinforced with polyester (PET) yarns. In order to study the chemical and environmental degradation a damage trial embankment (2m x 3m in plant) was constructed using recycled C&DW as filling material. The damage caused by the mechanical actions during installation was also simulated by installation damage laboratory tests. Wide width tensile tests were performed on geotextile samples exhumed from the trial embankment after 12 months, on laboratory damaged samples and on intact (as-received) samples. Their short-term tensile behaviour is compared. Scanning electron microscope (SEM) images of intact and exhumed specimens are also presented.

Experimental investigation on the pullout behaviour of geosynthetics embedded in a granite residual soil

Geosynthetics, including geogrids and geotextiles, have been extensively used for stabilisation and soil reinforcement in several geotechnical structures, such as foundations, abutments, walls and slopes. In these applications, soil–geosynthetic interaction plays a determinant role. This paper describes an experimental study carried out using a large-scale pullout test apparatus, aiming to investigate the pullout behaviour of different geosynthetics embedded in a granite residual soil. The study involved two geogrids (one biaxial and the other uniaxial), one geocomposite reinforcement (high-strength geotextile) and one geotextile. The soil was compacted to different relative densities. Test results have revealed that soil–geosynthetic interaction under pullout loading conditions is highly influenced by the geosynthetic properties and soil density. Regardless of soil density, the biaxial geogrid exhibited higher pullout resistance than the other geosynthetics. At maximum pullout force, the deformation along the length of the geotextiles was considerably more pronounced than that along the geogrids. For the conditions adopted in this study, the soil–geosynthetic pullout interaction coefficients ranged from .25 to .52. In general, the values of the scale effect correction factor obtained for the geotextiles were slightly lower than the value recommended by the Federal Highway Administration in the absence of test data.

Direct shear behaviour of residual soil–geosynthetic interfaces – influence of soil moisture content, soil density and geosynthetic type

ABSTRACT: Soil–geosynthetic interface shear strength is an essential parameter for the design and stability analysis of geosynthetic-reinforced soil structures. Economic and environmental reasons have led to increasing use of locally available residual soils with a significant percentage of fines and lower draining capacity, when compared with the traditional good-quality backfill materials. This paper describes an extensive laboratory study carried out using a large-scale direct shear test device, in which the influence of soil moisture content, soil density and geosynthetic type on the direct shear behaviour of the soil–geosynthetic interface was evaluated. The study involved a locally available granite residual soil and four geosynthetics: two geogrids (one uniaxial and the other biaxial), one geocomposite reinforcement (high-strength geotextile) and one geotextile. Test results have revealed that the increase in soil moisture content can measurably reduce the soil–geosynthetic interface shear strength. Regardless of soil moisture content, soil density proved to have a remarkable influence on interface shear strength, particularly when geogrids were used. Among the different geosynthetics tested, the biaxial geogrid was found to be the most effective reinforcement for this particular type of soil, concerning the direct shear mechanism. For soil–geogrid interfaces, the coefficients of interaction ranged from 0.71 to 0.99. For soil–geotextile interfaces, the coefficients of interaction varied from 0.54 to 0.85.

Utilization of Geosynthetic Material Interfaces for Reduction of Cyclic Motion Induced Accelerations

The geosynthetic materials are extensively used in a wide range of applications in civil engineering. In this study, a nonwoven high strength geotextile which is generally utilized as a reinforcing material for earth structures and a ultrahigh molecular weight polyethylene (UHMWPE) geomembrane (generally used to seal the inner face of toxic liquid tanks against leakage) are used together beneath structures for seismic isolation purposes. The dynamic interface properties of the surface formed between these two materials have been tested on small scale models by shaking table tests. The results were impressive such that the accelerations transferred to the superstructure were significantly reduced. Also, it was observed that the materials used during the research had almost no abrasion at the end of a series of experiments which revealed that the tested materials could be used for repetitive dynamic loadings.

Performance of Reinforced–Stabilized Unpaved Test Sections Built over Native Soft Soil under Full-Scale Moving Wheel Loads

This paper presents the findings from an ongoing research study that evaluated two recently developed geosynthetic products: a triaxial geogrid and a high-strength woven geotextile for reinforcing or stabilizing roads constructed over native soft soil in the state of Louisiana. Six full-scale test lane sections were constructed: two were reinforced by one and two layers of triaxial geogrids, respectively, while high-strength geotextile was used to reinforce two of the other sections with aggregate layers of different thicknesses. The remaining two sections were left as controls: one was constructed over a sand embankment 30 cm thick representing the common practice in southern Louisiana. The unpaved test sections were subjected to a full-scale moving wheel load applied by the accelerated loading facility. A variety of instrumentation was used to measure the load-associated and the environment-associated pavement responses and performance. Results of the full-scale testing on the unpaved test sections demonstrated the benefits of geosynthetic reinforcement–stabilization in reducing the permanent deformation in the pavement structure. The test sections’ resilient behavior did not seem to be influenced by the presence of geosynthetics. In addition, instead of the soft soil subgrade, the aggregate layer was the primary contributor to the total permanent deformation–surface rutting of the unpaved sections under the testing conditions in this study. Geosynthetics were mobilized and generally exhibited a strain around 0.2%.

High-Strength Geotextiles in Ultraheavy-Load Haul Roads

The heaviest trucks serving shovel-and-truck mining operations have tripled in weight to more than 600 tonnes gross weight over the past 30 years. The design of haul roads to support these trucks is becoming ever more challenging. An additional problem is the huge demand for aggregates with which to construct these thick, wide roads. In this study of the problem, a numerical modeling investigation was performed for a 300-tonne-design axle on a granular pavement consisting of a capping layer, base, and subbase (0.5, 1.0, and 1.5 m thick, respectively). Conventional linearly elastic analyses and analyses not permitting tension were carried out. While the results of the conventional elastic analysis permitting tension had indicated that there was no reinforcing effect with these geotextiles, the results of the no-tension analysis indicated a significant reinforcement effect attributable to the inclusion of high-strength geotextiles in the cross section. The results bring into question the use of analyses permitting tension in the granular pavement materials.

Three Decades of Geosynthetics in India

With the recent emphasis on infrastructure development, geosynthetics in India have received a tremendous boost. Apart from the consistent use in pavements of the east-west and north-south corridors and golden quadrilateral of the NHDP projects being executed by the NHAI, reinforced soil walls in urban flyover approaches have become common, due to their distinct advantages over conventional reinforced concrete walls. These apart, the use of high strength geotextiles and geocell mattresses for foundation of high embankments on soft soils has also proven to be feasible even in black cotton soil areas. Increasing emphasis is being given to the development and use of natural fibre (particularly, jute and coir) geotextiles for civil engineering applications. The paper traces many of these developments and summarizes the key issues to be taken note of for utilizing the vast potential geosynthetics offer, in India's march to development.

Performance Assessment of Geosynthetics and Cement as Subgrade Stabilization Measures

Abstract Work in this paper presents the results of field testing on four instrumented roadway sections constructed on poor subgrade soils and stabilized with select fill, geosynthetics, or cement. Loading was applied using 1000 consecutive truck passes and profile surveying was performed to provide permanent deformation (rutting) data. Peak vertical stresses at the subgrade as well as moisture conditions were also monitored during testing. Results indicated that the deep undercut (31 in./790 mm) with select material backfill section produced the largest cumulative rut depths due to shallow incremental plastic strains induced during each axle pass. The use of a thin Aggregate Base Course (ABC) surface layer (3 in./75 mm) over the select material reduced the rate of rutting. The biaxial geogrid and the high strength geotextile showed a relatively equal performance in all aspects of the study. The cement stabilized section produced a slightly larger average rut depth than the geosynthetically-reinforced sections due to localized areas of pronounced cumulative rutting. However, there were several areas of the soil-cement test section that performed as well as the geosynthetically-reinforced sections.