Search

This study explores the effect of chemical treatment on the physical, mechanical, and morphological properties of two kinds of sisal geotextiles treated with potassium hydroxide and coated with bitumen emulsion. Physical characteristics like mass per unit area, yarn properties, thickness, water absorption and mechanical properties, including tensile, tearing, and puncture strength, were examined. The findings showed significant enhancements in tensile strength (up to 54.90%), tearing strength (up to 103.81%), and puncture strength (up to 32.2%) of emulsion-coated untreated, emulsion-coated alkali-treated and alkali-treated geotextiles, respectively. Furthermore, the alkali-treated emulsion-coated geotextile had the highest mass per unit area with the least water absorption. Morphological, elemental, and crystallographic analyses complemented these outcomes. [ABSTRACT FROM AUTHOR]

Pile-supported embankments have been recognized as long-standing solutions for construction in compressible soft soils. Instead of improving the physical and mechanical properties of the soft soil, this method emphasizes efforts to transfer the embankment load to a competent layer below the compressible layer. Mortar column inclusion (inklusi kolom mortar or IKM) is recognized as one of the rigid inclusions in a pile-supported embankment. The IKM combined with a load transfer platform (LTP) has been widely utilized to support embankments. Studies on pile-supported embankments have generally focused on the arching mechanisms and geotextile tensile force evaluations; however, most of these investigations were conducted on soft cohesive soils. The application of pile-supported embankment on peat has rarely been studied comprehensively. This study presents a full-scale trial embankment on peat in West Sumatra, Indonesia. The 8-m-high trial embankment was supported by a series of IKM piles and a geotextile-reinforced LTP layer; instruments were then installed in the embankment, ground, LTP, geotextile, and IKM. These instruments included a series of vibrating wire earth pressure cells, vibrating wire strain gages, fiber optic sensors, vibrating wire piezometers, settlement profilers, settlement plates, and inclinometers. The instruments provided observations on the ground movements, IKM displacements, and stresses in the materials. Comprehensive evaluations from field monitoring allowed study of load transfer via the arching mechanism, deformation pattern, and IKM performance in peat. Finite element analyses (FEAs) were also conducted for comparison and verification. The field monitoring results and FEAs showed good agreement, thereby demonstrating the potential of the proposed ground improvement method for embankment construction on peat. [ABSTRACT FROM AUTHOR]

This study investigates the cyclic loading behaviour of a two-layered unpaved road model reinforced with untreated/treated woven and non-woven coir geotextiles over 10,000 cycles. In this study, research efforts were made to develop artificial-neural-network (ANN)-based prediction models for the plastic deformation of untreated/treated coir geotextile-reinforced unpaved road models. Pearson's coefficient of correlation (R2) and the root mean square error (RMSE) was utilized to evaluate the predictive accuracy of the predictive models. Key discoveries include a substantial reduction in plastic deformation for the reinforced two-layered unpaved road models (Types W1, W2, NW1, and NW2), showcasing decreases of 69%, 74%, 58%, and 66%, respectively, compared to the unreinforced model, particularly in unsoaked conditions. The results demonstrated reduction in the plastic deformation in treated coir geotextiles reinforced models. The study reveals an escalation in plastic deformation at 60% cyclic load as opposed to 30%, evident in both unsoaked and soaked conditions. The selected neural network model exhibits high accuracy, with R2 values exceeding 0.95 and RMSE values below 1, indicating precise prediction of plastic deformation of untreated/treated coir geotextile-reinforced unpaved road model. [ABSTRACT FROM AUTHOR]

Geomembranes (GMBs) and geotextiles (GTXs) are the most widely used geosynthetics in landfills and other barrier systems. While various temperature environments may be encountered in practice, the interface shear characteristics of geosynthetics under different temperatures are still not clear. Shear tests of the interface between a high-density polyethylene GMB and nonwoven GTX are performed using a temperature-controlled submerged direct shear apparatus. The testing temperatures range from 10 °C to 70 °C, which covers most of the situations commonly encountered in engineering. The shear behaviors of the textured GMB/GTX interface and smooth GMB/GTX interface are presented, and the mechanism of the temperature influence is analyzed according to the test results and phenomena. Temperature has a significant impact on the GMB/GTX interface peak strength and post-peak strength, and maximum interface shear strength could be obtained when the temperature is approximately 30–40 °C. The influencing mechanisms of temperature on the GMB/GTX interface shear strength are thoroughly discussed. The shear characteristics of the GMB/GTX interface under different temperatures are critical to the stability analysis of geosynthetic slopes in special condition, and this study can also provide a reference for the effect of temperature on the shear behavior of other geosynthetics. • Submerged shear tests of the GMB/GTX interface are conducted at wide temperature ranges covering most of the situations. • Significant weakening of the GMB/GTX interface shear strength has been confirmed to exist at high temperatures. • The influencing mechanism of temperature on interface friction is different from that on asperity interlocking. [ABSTRACT FROM AUTHOR]

In this research, experimental studies and numerical analyses were carried out to investigate how the usage of geotextile and geopolymer coated geotextile as a hybrid method changes the uplift behavior of the screw piles in cohesionless soil. In this context, traditional pile behavior, the effect of different number of helixes and embedment depths on screw piles, the mechanism of geotextile and the effects of geopolymer coating process were investigated. In addition, experimental studies were modeled by using Plaxis 3D and parametric studies were carried out after verification between the results of experimental study and numerical analysis. In the numerical analysis, a segmented helix model consisting of four 90-degree slices was developed instead of the planar helixes commonly used in the literature. For further investigation of the effectiveness of hybrid method, parameters such as improvement ratios and breakout factors were calculated. When the results obtained within the scope of the study were evaluated, the geopolymer coating process increased the bearing capacity of the geotextile by 24 % at 27 % less elongation. It was also seen that uncoated and geopolymer coated geotextile increased the screw pile performance in terms of improvement ratios by 294 % and 364 %, respectively.

This article describes an extensive investigation of the failure mechanisms of a large geotextile mat cofferdam over a deep soft clay layer, where the large geotextile mat was filled with sand. Finite element (FE) analysis was conducted to provide insight into the behaviour of large geotextile mats. The FE results were validated against 1 g model test data and centrifuge test data prior to undertaking a detailed parametric study. It is found that large geotextile mat cofferdam over deep soft clay has two distinctive types of failure mechanisms – global and local failure mechanisms. The global failure mechanism showed the whole dam sank downwards together, and the local failure mechanism included a central standing ridge with two dam sides sliding downwards. A formula, based on the results of the parametric study, was proposed to distinguish the potential failure mechanism of the dam and the foundation soil. For these two different failure mechanisms, both limiting fill height and safety factor of the dam could be predicted using the equations obtained from this study. Finally, a design framework was proposed to provide guidance for designing the large geotextile mat cofferdam over deep soft clay under construction. [ABSTRACT FROM AUTHOR]

More than one-third of highway retaining wall failures around the world occurred due to missing or inadequate drainage systems. A research study was conducted to determine the performance of a recently developed pore pressure mitigation system through the usage of conical geotextile units filtering retaining wall backfill soils used in highway environment. A numerical model based on a computational fluid dynamics and discrete element method (CFD-DEM) coupled approach was developed to simulate particle movement in the soil and piping through the geotextiles. The model was used for conventional as well as conical geotextile filter systems that use woven and nonwoven geotextiles filtering marginal backfill soils with high fines contents and a common gravel backfill material. Both soil-geotextile contact zone and system permeabilities were influenced by varying fines content in the backfill material. Conical filter usage increased the system permeability up to 2.6 times, while piping rates increased up to almost 10 times as result of conical filter usage. A retention ratio successfully predicted piping rates for different types of woven and nonwoven geotextiles with a percent error range of 13–30%, and was used to develop simple performance charts. The developed charts can be useful for practitioners, and the developed methodology can be adopted to extend these chart solutions to other types of soils and geotextiles. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study investigating the effect of particle shape of granular soils on the shear strength characteristics via direct shear tests. Thirty direct shear tests were conducted on spherical and crushed sand mixtures with different proportions (i.e. 0%, 25%, 50%, 75% and 100%). The overall regularity (OR) parameter of sand particles varies between 0.788 and 0.909, fairly reflecting the particle shape of sand mixture. A particular relation between OR and maximum shear strength was found, namely that maximum shear strength increases with a decrease in OR. Furthermore, a gradual increase was observed in the improvement factor (If) due to geotextile reinforcement with an increase in OR except for S25C75, representing 25% spherical and 75% crushed sand, at high and low normal stress levels (i.e. 29 kPa and 116 kPa). The interfacial friction angle (ϕ) of sand mixtures is improved by geotextile reinforcement. Additionally, geotextile reinforcement caused an apparent increase in ϕ with decreasing OR values. [ABSTRACT FROM AUTHOR]

Subsurface drainage pipes covered with filters and geotextiles are the key to preventing clogging and ensuring efficient drainage. To improve the salt discharge efficiency of these subsurface drainage pipes, different layers of geotextiles were set outside the pipes with the aid of uniform gravel filters. This paper reports our findings from laboratory simulation of subsurface drainage pipes and experiments. The study examined the influence of different layers of geotextiles on the drainage efficiency, salt discharge effects of subsurface drainage pipes, and the effect of superimposed geotextiles on the salt drainage efficiency as well as the anti-clogging effect of subsurface drainage pipes. The results are as follows: (1) The geotextile and filter material wrapped around the subsurface pipe facilitated the movement of water towards the subsurface pipe, which could promote the salt discharge of the subsurface pipe. However, in the single leaching experiment, the reduction in soil pH was not significant for different scenarios. (2) The salt removal rate of the geotextile-wrapped subsurface pipes was more than 95%. The salt removal rate of the double-layer geotextile scenario was the highest (96.7%), and the total salt content of soil profiles was 8.3% and 31.3% lower than those of the single-layer and triple-layer geotextile scenarios, respectively. The drainage efficiency of the double-layer geotextile scenario was the highest, and the salt distribution in the 0–60 cm profile was relatively uniform, ranging from 2.3 to 3.0 g∙kg−1. (3) The clogging in the triple-layer geotextile scenario was caused by the geotextile, i.e., a dense filter cake layer formed on the surface of the geotextile. The clogging in the single-layer and double-layer geotextile scenarios was the clogging of the geotextile itself, i.e., soil particles retained in the fiber structure of geotextiles. (4) In the case of the single-layer and double-layer geotextile scenarios, the soil particles failed to completely clog the selected geotextiles, and there were still a large number of pores retained. The double-layer geotextiles integrate filtration, clogging prevention, and drainage promotion to provide the best salt drainage with the subsurface pipe. This study reveals the influence of the filter on soil water salt and salt discharge and provides a theoretical explanation and technical justification for the application of the subsurface pipes salt discharge technology in saline soil ameliorate. [ABSTRACT FROM AUTHOR]

Many design guidelines have been proposed for piled embankments, most of which consider piles or columns as rigid inclusions. In this study, a small-scale physical model test was performed to investigate the load transfer mechanism of a geotextile-reinforced sand layer over a soft subsoil improved by semirigid columns. A multi-stage load was applied at the top of the sand layer until the columns started to yield. When the columns yielded, a reverse load transfer was observed. Vertical stresses were measured and analyzed in terms of efficacy and stress reduction ratio (SRR) with a comparison of existing design guidelines for assessing soil arching. Among the reviewed guidelines, the approach recommended by the Dutch guidelines provided the closest results to the experimental data, whereas the one adopted by the American guidelines predicted well the change in efficacy and SRR under different surcharge loads. However, the load transfer mechanism after the yielding of columns is beyond the scope of the existing design guidelines. In addition, it was found through regression analysis that the increment of vertical stresses on columns and surrounding soil followed an inclined line under partially undrained conditions during loading stages and a curve during consolidation. [ABSTRACT FROM AUTHOR]

Treating the high water-content sludge with vacuum-assisted prefabricated horizontal drains (PHDs) placed inside, geotextile tubes have the advantage of multiple drainage paths, and geomembrane tubes have the superiority of high vacuum maintenance. Therefore, converting the geotextile tube into a geomembrane tube during slurry dewatering is an effective measure for greater dewatering efficiency and better dehydration effect. In this study, a profound plane-strain consolidation model considering two-dimensional seepage is developed for explaining the dewatering mechanism of sludge in the geo-tubes. Analytical solutions are given and validated by the experiment. The impact of major variables on tube efficiency is further discussed to reference the practice design. Parametric analyses reveal the critical time corresponding to the optimal efficiency of the geotextile tube, after which its consolidation efficiency decreases significantly. However, the consolidation efficiency of a geomembrane tube increases throughout the duration. Consequently, a switching point corresponding to the iso-efficiency state of the geotextile tube and geomembrane tube can be determined for the tube conversion. [ABSTRACT FROM AUTHOR]

Pile-supported embankments have been recognized as long-standing solutions for construction in compressible soft soils. Instead of improving the physical and mechanical properties of the soft soil, this method emphasizes efforts to transfer the embankment load to a competent layer below the compressible layer. Mortar column inclusion (inklusi kolom mortar or IKM) is recognized as one of the rigid inclusions in a pile-supported embankment. The IKM combined with a load transfer platform (LTP) has been widely utilized to support embankments. Studies on pile-supported embankments have generally focused on the arching mechanisms and geotextile tensile force evaluations; however, most of these investigations were conducted on soft cohesive soils. The application of pile-supported embankment on peat has rarely been studied comprehensively. This study presents a full-scale trial embankment on peat in West Sumatra, Indonesia. The 8-m-high trial embankment was supported by a series of IKM piles and a geotextile-reinforced LTP layer; instruments were then installed in the embankment, ground, LTP, geotextile, and IKM. These instruments included a series of vibrating wire earth pressure cells, vibrating wire strain gages, fiber optic sensors, vibrating wire piezometers, settlement profilers, settlement plates, and inclinometers. The instruments provided observations on the ground movements, IKM displacements, and stresses in the materials. Comprehensive evaluations from field monitoring allowed study of load transfer via the arching mechanism, deformation pattern, and IKM performance in peat. Finite element analyses (FEAs) were also conducted for comparison and verification. The field monitoring results and FEAs showed good agreement, thereby demonstrating the potential of the proposed ground improvement method for embankment construction on peat.

Introduction/purpose: Geosynthetic materials have been successfully used for soil reinforcement to improve bearing capacity. In this article, geotextiles are used as tension material for the reinforcement of a mixture based on dredged sediment from the Cheurfas dam (Mascara) and quarry sand. Methods: Immediate bearing index tests were carried out in the laboratory to study the mixing behaviour, and the three-point bending flexural test was carried out on prismatic specimens to study the traction capacity of the mixture. Mixture samples are selected and tested without reinforcement. Then, by placing one, two and three layers of geotextile at a certain depth of the sample, the effects of a number of layers and type of geotextile and geogrid on increasing the bearing capacity of the mixture are discussed. Results: The results of these tests show that the bearing capacity of the samples reinforced by geotextile and geogrid is increased compared to that of the unreinforced samples. Based on the results obtained from ProctorIPI, their values do not permit the movement of construction machinery during the construction of pavement layers. The Immediate Bearing Index values are found sufficient for pavement layers. Geotextile introduction increases traction strength and improves stress distribution on soil samples, with the effect being significant for woven geotextile blends. Conclusion: All things considered, the results point to the possibility of using reinforced local soils as an affordable and practical option for building pavements. To guarantee long-term performance and optimise building methods, more research is advised.

Utilizing one of the most effective new technologies is the primary goal of this research, which uses a combination of bituminous surfacing materials with geotextile reinforcement sheets, to improve the behavior of asphalt mixes and fatigue reduction. The aim of this research is to analyze the impact of woven geotextile upon fatigue characteristics of hot mix asphalt mixtures. In order to improve the tensile qualities of the asphalt pavement, the experimental program for this study includes the application of geotextile within the wearing layer. Marshall fatigue and stability tests were carried out. Four-point bending test in a strain-controlled mode was adopted in this study. Three micro strain levels (250, 400, 750) at a frequency of 5 Hz were used. The findings demonstrated that unreinforced mixtures have a shorter fatigue life than wearing layers reinforced with geotextile. Additionally, exposure to different temperatures (5, 20, 30°C) showed that the performance of the geotextile interlayer system in cold environments is inferior to that of those in warm and moderate climates. The analyzed geotextile has a positive impact on the performance of the pavement and a large potential to extend the life of the pavement as a whole, according to the obtained results of fatigue life.

This paper is mainly concerned with studying the stability of a marine causeway in the case of using two different reinforcement systems. The first system is a geotextile layers reinforcement system (GLRS), and the other system is a geotextile mats reinforcement system (GMRS). Another purpose of this study is to have a more comprehensive view of the behavior of these systems in three different soils. To achieve the purposes mentioned above, a numerical study was conducted utilizing ABAQUS V6.14. The research expanded to include the parametric analysis phase in sequential models to examine various parameters. The results are compared with those obtained from a reference scenario. The parametric study for the (GLRS) shows that geotextile thickness is the most sounding parameter on the stability of the causeway. also, the results confirm that less vertical spacing between layers gives higher stability. Furthermore, the relative length of the geotextile layer does not always need to achieve the maximum value to have an evident effect. Also, it can be concluded from the obtained results that the effect of the same parameters behaves in a similar trend for the other system. Lastly, The results generally show that (GMRS) is the more effective system to enhance the stability of the silty sand marine causeway. While the (GLRS) sounds to be more effective for dense sand and stiff clay soils.

Geotextile is a geosynthetic-based soil stabilization technique recently used to reinforce the soil and stabilize the canal slopes. In this study, the effect of using different nonwoven geotextile configurations on soil reinforcement and slope stability for irrigation canals subjected to loads on a canal berm was experimentally and numerically investigated. First, a laboratory model was constructed, the materials were prepared, and testing procedures were performed. The experiments were conducted to investigate settlement due to footing loads of width B acting on a canal berm in a dry case under different scenarios of geotextile soil reinforcement. Different lengths (l = 1.5, 2.0, and 4.0 B) and depths (d = 0.5, 1.0, and 2.0 B) of geotextile layers were used. Second, the experimental data were used to calibrate and validate the PLAXIS-3D model. Third, a series of simulation scenarios were conducted to investigate the joint effect of geotextile configurations on settlement. After that, the PLAXIS-3D model was used to determine the factor of safety (FoS) of the Ismailia Canal (i.e., real case study) side slope under different loading conditions with and without geotextile reinforcement. Finally, a cost analysis was conducted for Ismailia Canal under different geotextile configurations. Results showed a close agreement between experimental and PLAXIS-3D simulation results. Results also showed that geotextile reinforcement enhances bearing capacity ratio (BCR) and reduces settlement. As the length of the geotextile layer increases, the BCR increases and the settlement decreases. Among the investigated geotextile configurations, the optimum configuration was found when l = 4 B and d = B. In addition, soil reinforcement by geotextile for Ismailia Canal under an excavator load of 40 tons lowered the settlement values by about 10%, whereas its effect on the slope stability FoS was almost inconsiderable. Therefore, geotextile reinforcement can be used to relatively reduce settlement near canals' embankments. [ABSTRACT FROM AUTHOR]

Soil water loss is an important component of the water balance in irrigated agriculture. This study investigated the effects of geotextiles on water loss during soil drying and cracking. The results indicate that the residual water content of soil samples increased by 98.5%, 145.5%, and 164.7% with geotextile masses per unit area of 100, 300, and 400 g/m2, compared that of soil without geotextiles. There are two water loss stages of soil, the "rapid loss" and the "residual loss," under the condition of bottom water loss, which is different from the evaporation stage of normal soil without bottom water loss. When a geotextile is added to the soil, the stages of bottom water loss will become "rapid loss, deceleration loss, and residual loss." When the mass per unit area of 400 g/m2 geotextile was used, the crack ratio, probability entropy, and fractal dimensions decreased by 15.19%, 6.47%, and 5.81%, respectively. The geotextile mass per unit area increased the specific surface area of the soil, and water retention was improved. When the mass per unit area of the geotextile increased, the interface friction between the soil and geotextile increased, and the cracking of the soil was effectively inhibited. • With the increase of the density of geotextile, the water retention and crack resistance of soil can be improved. • The increase of geotextile aggregates results in the reduction of soil cracks. • The geotextile can increase the surface area and pore volume of geotextile, enhance water retention of soil. [ABSTRACT FROM AUTHOR]

Introduction/purpose: Geosynthetic materials have been successfully used for soil reinforcement to improve bearing capacity. In this article, geotextiles are used as tension material for the reinforcement of a mixture based on dredged sediment from the Cheurfas dam (Mascara) and quarry sand. Methods: Immediate bearing index tests were carried out in the laboratory to study the mixing behaviour, and the three-point bending flexural test was carried out on prismatic specimens to study the traction capacity of the mixture. Mixture samples are selected and tested without reinforcement. Then, by placing one, two and three layers of geotextile at a certain depth of the sample, the effects of a number of layers and type of geotextile and geogrid on increasing the bearing capacity of the mixture are discussed. Results: The results of these tests show that the bearing capacity of the samples reinforced by geotextile and geogrid is increased compared to that of the unreinforced samples. Based on the results obtained from ProctorIPI, their values do not permit the movement of construction machinery during the construction of pavement layers. The Immediate Bearing Index values are found sufficient for pavement layers. Geotextile introduction increases traction strength and improves stress distribution on soil samples, with the effect being significant for woven geotextile blends. Conclusion: All things considered, the results point to the possibility of using reinforced local soils as an affordable and practical option for building pavements. To guarantee long-term performance and optimise building methods, more research is advised. [ABSTRACT FROM AUTHOR]

Soft peat soils are located in many zones and at a given depth all over the world and are characterized by their low shear strength and high settlement. It can also cause progressive failure of roads, embankments, and foundations. Sand cushioning is the most beneficial technique used to relieve the stress transmitted to the peat layer to mitigate any deformation and shear failure. In this research, a field study of a road with a soft peat layer located at a depth 4m below the ground surface is carried out. The plate load test is conducted on three cases over the peat layer using sand cushions with and without reinforcement. The results were compared with plate footing on the surface of the road without stabilization. The field tests of the improved technique were verified and deeply analyzed using the numerical program Plaxis. The finite element analysis mainly sheds light on the simulation of the dynamic response that represents the compaction of the sand cushion over the peat layer. A series of numerical models has been done considering the effect of repeated load compaction on the adopted sand cushions with and without reinforcement. The numerical analysis is directed to show the effect of repeated loads of compaction equipment that were used on decreasing the stress over the peat layer. The results showed that the composite compacted cushion with both a higher number of cycles and stress has a great effect on relieving the stresses transmitted to the face of the peat. As a result, the footing capacity is increased with less deformation. [ABSTRACT FROM AUTHOR]

Wicking geotextiles have proven effective in reducing water content in road bases under both saturated and unsaturated conditions, thereby increasing granular base strength and mitigating moisture-related damage to the pavement. Despite their effectiveness in paved roads, the use of wicking geotextiles in permeable road and sidewalk, particularly in areas requiring robust drainage such as sponge cities, is not well explored. In "sponge city" roads, moisture content fluctuations and subsequent damage to the structure often cause concern, and the wicking geotextile's drainage could be a potential solution. Therefore, this study aims to investigate and quantify the effectiveness of wicking geotextiles in reducing the moisture content and improving the resilient modulus of permeable sidewalk base layers. The moisture contents of unstabilized and one-directional wicking geotextile- and two-directional wicking geotextile-stabilized bases under permeable paving bricks were monitored with an interval of 7-10 days for over a year. An analytical approach to reconstruct daily moisture content in the base layerwas proposed based on the simulated rainfall saturation test. This approach further assesses the enhancements in resilient modulus due to the drainage capabilities of wicking geotextiles. The experimental results indicated that the two-directional wicking geotextile outperforms its one-directional counterpart and both wicking geotextiles outperformed the control condition in terms of drainage efficiency. By reconstructing the daily moisture content and utilizing the relative damage model, the two-directional wicking geotextile significantly improved the annual equivalent resilient modulus of the base layer under permeable paving bricks. [ABSTRACT FROM AUTHOR]

The usage of geosynthetics can be employed widely in the field and geotechnical engineering. The ground improvement approaches using geosynthetics as reinforcing materials are widely used to overcome the limitations of other methods. Considering these aspects, a sequence of model load versus settlement experiments with variance in the position of geotextile and percentage of lime was executed to observe the toughness as well as settlement properties of the silty sand with single layer of geotextile. There are several aspects of this paper like the computational techniques such as artificial neural network (ANN) and extreme learning machine (ELM). The implementation of computational models gives an advanced resolution for forecasting the load sustaining capability of the rectangular footing in a simple and economic way. These computational models could be judged by employing several well-approved statistical indices. It could also be verified through the experimental results achieved from the studies. The upshot shows that the developed ELM model has a remarkable potential to evaluate the ultimate bearing capacity (UBC) of the rectangular footing. It can be set forth as a predictive tool for the initial designing process. [ABSTRACT FROM AUTHOR]

The study investigates the influence of geonet and non-woven geotextile reinforcement on the strength performance of municipal solid waste (MSW fines). A set of unconsolidated undrained static and dynamic triaxial tests was conducted on the reinforced MSW fines samples by a varying number of reinforcement layers (0, 1, 2 and 3) to investigate the stress-strain and strength behaviour of the composite material. The MSW fines (particle size < 4.75 mm) inherently exhibit limited mechanical strength and required the use of additional ground improvement procedures to make them suitable for practical field applications. Although laboratory tests have shown improvements in the static strength of the investigated MSW fines when reinforced, due to the lack of any observed improvements in its dynamic strength characteristics, concerns continue regarding the viability of using this composite material in high seismic zones. [ABSTRACT FROM AUTHOR]

Applying stone columns (SCs) is an economical method to improve loose soil. This laboratory study is conducted on the effects of simultaneous use of crumb tire (CT) and fly ash (FA) on the shear behavior of SCs encased with geotextile and fiber-reinforced polymer (FRP) in soft clay. A large-scale direct shear device was utilized to do the desired tests. The samples were exposed to normal stress values of 20, 40, and 70 kPa. First, optimal percentages of CT and FA were determined to be used with granular materials in the SCs. The impact of installing ordinary reinforced and unreinforced SCs on the shear behavior of the assembly was examined. Installing the SCs in soft clay bed and adding the CT-FA composite to the SC materials increased the shear strength. Supplementing the CT-FA composite to the SC materials increased shear strength of the assembly to 4.6%-10%. The shear strength rose more than twice when the normal stress increased from 20 kPa to 70 kPa and it was mobilized more since CT-FA composite is present. It increased due to a rise in the replacement ratio of the SCs in the assembly. By installing the ordinary composite SCs in clay bed under the normal stresses of 20 kPa and 70 kPa, the shear strength increased to 34% and 41.7% and it would rise in the encased mode more than in the ordinary mode. Furthermore, the FRPbased reinforcement enhanced the shear strength more than the geotextile reinforcement did. [ABSTRACT FROM AUTHOR]

The effects of test method and strain calculation method on strains from nominal 25 mm coarse gravel indentations are examined for a 1.5 mm thick HDPE geomembrane with full-scale physical modeling. Maximum principal strains were calculated using thin plate theory that considers lateral displacement effects and bending strain. Strains from index tests with no subgrade were found to be twice as large as those from performance tests with clay, while strains from index tests with rubber as the subgrade were only 40% of those with clay; neither index test is suitable for selecting protection layers to limit geomembrane strain. Strains from past index tests with idealized single-point loading need to be multiplied by a factor of at least 1.8 to reproduce the maximum strain from performance tests with coarse gravel. Limiting the average membrane strain to 0.25% was found to limit the maximum principal strain to less than 6%, but not to 3% as originally intended by the German standard. The maximum result of membrane plus bending strain of 3% was shown to be closer to a maximum principal strain of 4–6% because of large-displacement and three-dimensional effects. The geotextile protection layers tested (nonwoven, needle-punched, 1500 and 1800 g/m2) were only able to limit the strain to 6% at a vertical pressure of 250 kPa and were unable to limit strain below 3%. • Strains from coarse gravel are compared to quantify the effects of test method subgrade and strain calculation method. • Strain from index tests with no subgrade was 1.9 times greater than that from performance tests with the clay subgrade. • Strain with clay was 2.4 times than index tests with rubber subgrade. • Limiting the average membrane strain to 0.25% limits the maximum principal strain to less than 6%. • 3% membrane plus bending strain is closer to 4 to 6% strain because of large-displacement and three-dimensional effects. [ABSTRACT FROM AUTHOR]

Various researchers have highlighted that geosynthetic-encased stone columns could be used in place of stone columns (SCs) in very soft soil. In this study, field load tests are performed on individual partially geotextile-encased stone columns (pESCs), individual stone columns (SCs), and a field embankment reinforced with pESCs and SCs in silty clay. Although the material cost of pESCs is designed to be comparable to that of SCs, the tests reveal that pESCs display a higher allowable bearing capacity and stress concentration ratio and less residual settlement than SCs. The embankment reinforced by pESCs is found to incur fewer lateral displacements, while there is no improvement in the drainage performance during the construction period compared to the SCs. For the pESCs, 51–66% of the pressure acting on the top of the column propagates to a depth of z = 1.2 m, wheras, for the SCs, it is only 21–55%. Furthermore, to estimate group behaviour, the ultimate bearing capacity of an individual pile composite ground can be extrapolated. However, individual pESCs achieve much higher stress concentration ratios than the pESC group. • The paper reports large scale field data of partially geotextile-encased stone columns (pESCs) and stone columns (SCs) supporting embankment. • Although the material cost for pESCs was designed to be comparable to that of SCs in these tests, the pESCs had a higher allowable bearing capacity and less residual settlement. • The ultimate bearing capacity of an individual pile composite ground could be extrapolated to estimate group behaviour. • The individual pESCs achieved much higher stress concentration ratios than the pESC group. [ABSTRACT FROM AUTHOR]

The rehabilitation of deteriorated pavements using Asphalt Concrete (AC) overlays consistently confronts the reflection cracking challenge, where inherent cracks and joints from an existing pavement layer are mirrored in the new overlay. To address this issue, the current study evaluates the effectiveness of Engineered Cementitious Composite (ECC) and geotextile fabric as mitigation strategies. ECC, characterized by its tensile ductility, fracture resistance, and high deformation capacity, was examined in interlayer thicknesses of 7, 12, and 17 mm. Additionally, the impact of geotextile fabric positioning at the base and at 1/3 depth of the AC specimen was explored. Utilizing the Overlay Testing Machine (OTM) for evaluations, the research demonstrated that ECC17 significantly mitigated reflection cracking, showing a notable 764% increase in the number of load cycles to failure (Nf) compared to the Geotextile Base (GB) specimen. Against the Reference Specimen (RS), ECC17 exhibited a remarkable 1307% enhancement in Nf values, underscoring its effectiveness. Geotextile fabric, particularly at 1/3 depth, demonstrated notable resistance but was overshadowed by the performance of ECC interlayers. The results clearly indicate that ECC, especially ECC17, stands out as an effective solution for mitigating reflection cracking, including joints, in AC overlays. [ABSTRACT FROM AUTHOR]

Underground pipes used to transport various goods and materials can face many damage-inducing incidents, such as landslides, extra traffic loading, and rockfall impacts during their service lives. This study investigated the level of protection provided to buried pipes by geosynthetics, focusing on their types and layout arrangements. Therefore, the performance of pipes protected with a single or double horizontal layer of geosynthetics and the efficiency of reinforcement arrangements, which involve single or four layers of geosynthetics wrapped around the pipes, were comparatively investigated using a free-fall test apparatus. Compared with the case without protection, adding a single horizontal layer of reinforcement reduced the maximum acceleration values measured on the buried pipe by 70–73% in geotextile, geonet 2D, and geonet 3D applications. It was determined that the protection layer contributed more to the protection against impact as the number of layers increased, and the placement approached the surface. Double-layer systems performed significantly better in absorbing energy than single-layered systems. The geonet 3D + geotextile layer combination provided the best performance under impact loading and was further improved by shallower placement. [ABSTRACT FROM AUTHOR]

Geopolymers assume an irreplaceable position in the engineering field on account of their numerous merits, such as durability and high temperature resistance. Nevertheless, geopolymers also demonstrate brittleness. In this study, geotextiles with different layers were added to geopolymer to study its compressive strength and stability. Laboratory materials such as alkali activators, geotextiles and granite residual soil (GRS) were utilized. The samples were characterized via XRD, TG-DTG, SEM-EDS and FT-IR. The results indicate that the toughness of geopolymer is significantly enhanced by adding geotextiles, and the strength increase is most obvious when adding one layer of geotextile: the strength increased from 2.57 Mpa to 3.26 Mpa on the 14th day, an increase of 27%. Additionally, the D-W cycle has a great influence on geotextile polymers. On the 14th day, the average strength of the D-W cyclic sample (1.935 Mpa) was 1.305 Mpa smaller than that of the naturally cured sample (3.24 Mpa), and the strength decreased by 40%. These discoveries offer a novel approach for further promoting the application of geopolymers, especially in the field of foundation reinforcement.

Between retaining structures, widely used in road infrastructure, there is a wide range of possibilities: conventional gravity structures (gabions, screens, etc.), reinforced, embedded, anchors, mechanically stabilized soil, among others. Among them, there is also the giant geotextile bags, which work by gravity using fill material from the site and demonstrating good performance against fluvial and maritime erosion, and road protection or containment. This article presents the versatility of giant geotextile bags in road infrastructure, embankment or slope stabilization; and river and coastal erosion control. As a case study, the Bengala (kilometer 21 of the Garzón - Neiva road) and Crespo Tunnel (Cartagena - Colombia) are presented. The methodology used to evaluate the evolution of the improvement with the intervention of giant geotextile bags is done through the report of design, execution, follow-up and control of the geometry of the intervened site. The areas intervened with giant geotextile bags show an effective behavior in soil stability, erosion control and geometric recovery. At a qualitative level, the process of restoration and stabilization of the affected coast and slope is evident, thanks to the intervention with giant geotextile bags. At a quantitative level, the long-term stability and geometric recovery of the intervened areas can be appreciated. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The elastic cushion is mostly used between the layers of ballastless tracks laid on a large-span cable-stayed bridge with a main span of more than 300 m. The rubber material is easy to harden and age, the geotextile has good acid-alkali resistance and antiwear performance, and the feasibility of geotextile application on the large-span cable-stayed bridge can be explored. The coupling model of a long-span cable-stayed bridge and the ballastless track was established to analyze the longitudinal mechanical characteristics of the seamless line, the deformation of the track structure, and the separation of the track plate and base plate under different loads. The results show that the application of geotextile or elastic cushion has little effect on the longitudinal mechanical properties of seamless lines. Compared to the elastic cushion, laying the geotextile increases the longitudinal stress of the slab by 0.13 Mpa, 0.025 Mpa, and 0.06 Mpa under different types of loads. The strength calculation of the seamless track is within the safety range. Laying elastic cushion can restrain the generation of separation under vertical loads, but there is no effect laying elastic cushion under temperature loads and braking loads, and the height of separation was less than 0.4 mm. The stress and deformation of the ballastless track do not exceed the standard when applying geotextile; it is feasible to apply geotextile on ballastless tracks on a large-span cable-stayed bridge. The next step is to study the vehicle–bridge–track dynamic response when elastic cushion and geotextile are laid. [ABSTRACT FROM AUTHOR]

Weathering agents can significantly affect the mechanical response of geotextiles, particularly when long exposure periods are involved. Usually, in design, changes in the mechanical behavior of geotextiles are represented by reduction factors for their tensile strength. However, their full tensile force versus elongation response can be affected. The main aim of this work was to contribute to defining simple procedures to estimate tensile force versus elongation curves for weathered samples of geotextiles. The tensile response of two thermally bonded polypropylene geotextiles, before and after natural and artificial weathering, was assessed experimentally and analyzed using different constitutive models: polynomial (Orders 4 and 6) and hyperbolic. The influence of weathering on the mechanical response of the geotextiles was analyzed, polynomial and hyperbolic models for representing the tensile force versus elongation response were adopted and their parameters derived, and simple relations were implemented to estimate model parameters for weathered samples. Results revealed the occurrence of changes in the tensile behavior of the geotextiles, both under natural and artificial weathering conditions. Both groups of models fitted the experimental data properly. The Order 4 and 6 polynomial models are shown to have limited application, as the model parameters had no link to the tensile properties of the geotextiles. By contrast, the parameters of the hyperbolic model were linked to the tensile properties, particularly if affected by correction factors. The hyperbolic model parameters of the weathered samples were estimated using the model parameters of the reference samples and the reduction factors to allow for weathering (initial stiffness and tensile strength). These estimates proved to be adequate for representing the tensile response of weathered samples, particularly for low ranges of elongation. Finally, a simple procedure to represent the tensile response of weathered geotextiles was proposed. This procedure has shown promise in generating realistic tensile versus elongation curves. [ABSTRACT FROM AUTHOR]

Merauke Regency is a lowland area that has soft soil which predominates. One of the methods to overcome the subsidence in silt soil, it is necessary to strengthen it by using geotextiles. The function of the geotextile is to hold the soil surface so that there is no subsidence in the soil. This study aims to determine the carrying capacity of silt soil before and after being given geotextile reinforcement.The study used an experimental method using the addition of Geotextile (non-woven type TS600) to strengthen the carrying capacity of silt soil. The silt soil carrying capacity test was divided into several variations, namely without using geotextile reinforcement and reinforced with 1 layer, 2 layers, and 3 layers of geotextile at a depth of 10 cm, 20 cm and 30 cm.The results of research conducted in the laboratory, the use of geotextile materials to increase the carrying capacity of silt soil has increased compared to the initial conditions. Soil without using geotextiles has a greater decrease, namely at a load of 5 kN there is a settlement of 20.3 mm. By using a single layer geotextile reinforcement material at a load of 5 kN there was a decrease of 10.97 mm, while using a two layer geotextile reinforcement material at a load of 5 kN there was a decrease of 8.09 mm, and using a three layer geotextile reinforcement material with a load of 5 kN there was a decrease of 6.01 mm. It can be concluded that the use of geotextile reinforcement can reduce the settlement of silt soil. [ABSTRACT FROM AUTHOR]