Geotextile Reinforcement Research Articles

Investigation of the Bearing Capacity and Collapsibility of Gypseous Soil Using Geotextile Reinforcement

This study aims to increase the bearing capacity of the soil by using geosynthetics in a single, double, or triple distribution pattern. The gypseous soil samples were brought from a site near Sawa Lake in Al-Muthanna Governorate with a gypsum content of about (37%), the Soil-Model apparatus of dimensions (60 × 60 × 50) cm with the proposed square footing of dimensions (10 × 10) cm are used in the experimental program of this study. To achieve this goal, a series of (48) different model tests were used on gypseous soil subjected to vertical stress in both dry and wet (saturation) conditions. Depending on the results of load-settlement curves relationships, the ultimate bearing capacity of dry and wet gypseous soil models was determined using the Two Tangent Intersection technique. The results also showed that the number of geotextile layers and the relative density of the gypseous soil samples significantly impact the improvement of the bearing capacity of gypseous soil models. Furthermore, the results showed that the improvement ratio in bearing capacity (BCR%) for gypseous soil models tested after being reinforced with geotextile layer for dry and wet (saturation) at relative density (RD) of 30% and 60% in single, double and triple distribution pattern. The percentage of the improvement in the wet case was higher than in the dry case. It was 143 % in the wet case when using triple-layer geotextile at different depths of reinforcement, while it was 96 % in the dry case.

Characteristics of Shallow Foundation Carrying Capacity Geotextile Reinforcement Interaction and Soil Density Level

Characteristics of Shallow Foundation Carrying Capacity Geotextile Reinforcement Interaction and Soil Density Level

Prospect of using geotextile reinforcement within flexible pavement layers to reduce the effects of rutting in the middle and southern parts of Iraq

Abstract Geotextile reinforcement techniques have been widely used in paving works around the world and have proven to be effective in improving pavement performance. This study has focused on using different positions and numbers of geotextile reinforcement sheets between the layers of flexible pavement for rutting reduction. Fitting depth was measured in the field at seven constructed sections of the pavement of the road model. Each section has been strengthened with different reinforcement approaches. All road sections were subjected to a maximum load repetition of 10,000 cycles. The results indicate that using three layers of geotextile beneath each course of the designed road pavement sections (surface, binder, and base) reduced rutting by 96%. Traffic benefit ratio (TBR) has been employed in this study to reveal the behavior of geotextile reinforcement in increasing the service life of the road. TBR values are the load cycling ratio between the reinforced and unreinforced section for the exact recorded rut depth, it has been found to be minimally equal to 4 for the case of using one layer of reinforcement at interface I, and that value keeps growing up for other reinforcement cases.

Strengthening of high plastic clays by geotextile reinforcement

Strengthening of high plastic clays by geotextile reinforcement

Mechanical and hydraulic compatibility of RAP with geosynthetics used in MSE walls

Mechanical and hydraulic properties of recycled asphalt pavement (RAP) as backfill in mechanically stabilized earth (MSE) walls were evaluated. Woven and nonwoven geotextiles and uniaxial and biaxial geogrids were used as reinforcements. Results of interface direct shear tests showed that the interface friction angle (δ) of RAP-geogrid was higher than that of RAP-geotextile. On average, the δ for RAP-biaxial geogrid was 15% higher than δ for RAP-uniaxial geogrid. For geotextile reinforcement, the δ for RAP-woven geotextile was 20% higher than δ for RAP-nonwoven geotextile. Compaction of RAP at elevated temperatures only slightly affected δ. Pullout capacities of RAP-uniaxial geogrid and RAP-woven geotextile are comparable to those of sand-uniaxial geogrid at different overburden pressures. The compacted RAP reinforced with uniaxial geogrid, however, exhibited significant creep strains at a range of sustained pullout forces that led to failure of the RAP-uniaxial geogrid. Reducing the pullout capacity by 40% is recommended for design to reduce the potential of creep failure. Long-term filtration tests showed that in all cases RAP-geosynthetic systems were able to drain freely and this behavior could be predicted with the existing clogging criteria that have been previously developed for sands and gravels.

Determining Geotextile Effects on Bearing Capacity Ratio and Cost of Pavement Layers by Conducting CBR Tests

ABSTRACT In this study, California Bearing Ratio (CBR) tests in a laboratory were performed to observe the effects of geotextiles on bearing capacity ratio, pavement layer thickness, and cost for geotextile reinforced soils. Fourteen geotextile samples, most of which were produced from recycled materials, were used in the experiments. Therefore, physical properties of geotextiles were compared to each other in order to find the most effective type of geotextiles by CBR tests. Then, relationship and adaptation between soil particles and geotextile types were researched by using microscope analyses. Additionally, AASTHO pavement thickness calculations were conducted and cost analysis according to reinforced pavement design were investigated either for reinforced base and for reinforced subbase layers. As a result of the study, it was found that using geotextile can increase CBR behavior, and the bearing capacity ratio values can be more almost 3.5 times than unreinforced models. Each geotextile reinforcement type has a characteristic behavior on the pavement layer and generally, they decrease the pavement thickness and as for long span they can be more economical.

Rainfall Induced Geotextile Reinforced Model Slope Embankment Subjected to Surcharge Loading: A Review Study

Rainfall Induced Geotextile Reinforced Model Slope Embankment Subjected to Surcharge Loading: A Review Study

Comparison of safety factor and geosyntetic reinforcement requirement for slope stability using 2-D and 3-D analysis method

The analysis of landslide slope stability since 1960s is the development of a 2-D structure proposed by various experts, through the 3-D method. Most of these previous studies stated that the ratio of 3-D and 2-D safety factors was more than one for cohesive and less than one for non-cohesive soils. These were because several required slope reinforcements were affected by the safety factors, with the analytical differences of the 2-D and 3-D methods causing a distinction in the requirements. These differences further cause problems by underestimating or overestimating the design. Therefore, this study aims to determine a comparative analysis of 2-D and 3-D slope stability on several required reinforcements. The analyses of the 2-D and 3-D structures were carried out using the LEM proposed by Fellenius and Hovland, respectively. The comparison of the several required reinforcements was also conducted using geotextile with Tult = 200 kN/m. The results showed that the reinforcements required with geotextile between 2-D and 3-D analysis were relatively similar on homogeneous soils. Meanwhile, the geotextile reinforcement needs were different for heterogeneous soils. Under different certain conditions, the need for 2-D reinforcement was greater and lesser than 3-D. In addition, the difference in the reinforcement required for the analysis of these structures was between 1-8 layers of geotextile, depending on soil parameters, slope, and length of the landslide field.

Reducing Settlement and Collapse of Gypseous Soil Using Geotextile Reinforcement

Collapsible soils are problematic soils that have substantial strength while dry but lose strength when wet, resulting in excessive settlements. Soil collapse occurs when increasing moisture weakens chemical or physical connections between soil particles, allowing the soil structure to collapse. The existence of these soils, often with significant gypsum concentration, created serious challenges for structures and major projects. The primary goal of this study is to conduct a series of model tests subjected to static vertical stress to assess the ability of soil stabilization using geosynthetics material by employing single, double, and triple geotextile layers put at various places. A unique model test configuration was employed for this testing. The gypseous soil used was brought from near Sawa Lake by coordinates (31◦18′42.83″N, 45◦00′49.36″E) in Al-Muthanna Governorate. The gypsum content was more than (37%). It was found that, the ultimate bearing capacity of dry and wet gypseous soil models had been determined by using Two Tangent Intersection technique. The results show the Settlement Reduction Factor (SRF) % and the ratio of decreasing the collapse magnitude (Δed )

Mitigation of track buckling in transition zones of steel bridges by geotextile reinforcement of the ballast layer

Track thermal buckling is one of the primary safety issues of continuously welded rail tracks. It has been shown that transition zones of open deck steel bridges are more prone to track buckling, as the thermal loads from the bridge and lower track lateral resistance in this region can destabilize the track in the lateral plane. The aim of this paper is to assess the possibility of reinforcing the ballast layer with geotextiles to mitigate the track buckling problem in the transition zones. To do so, a number of laboratory experiments are performed using one and two layers of geogrids and various depths of ballast layer. Single tie push tests are performed on the track and force-displacement curves are derived for the sleepers. It is shown that adding the geotextile layer to the ballast layer can increase its lateral resistance by up to 41%. The results are then introduced in the numerical model of a track developed in Abaqus finite element software for track buckling analysis. It is shown that adding the geogrid layer can increase the track buckling temperature by up to 11.33 °C, an increase of almost 21%, compared to that of an unreinforced track.

ALTERNATIVE IMPROVEMENT OF SUBGRADE AND REINFORCEMENT OF EMBANKMENT ON PELABUHAN KUALA TANJUNG TOLL ROAD, INDERAPURA - KUALA TANJUNG SECTION IN NORTH SUMATRA (STA 0+000 S/D STA 3+500)

Planning the Kuala Tanjung Ruas Port of Inderapura - Kuala Tanjung Toll Road is one of the efforts to support economic growth in North Sumatra. The toll road will be built on a pile with a height of 2 ms / 9 m at STA 0 + 000 to STA 3 + 500. Due to limited land, the toll road section must be built on the poor subgrade. Based on the N-SPT test results, it is known that the subsoil consists of a clay layer with a thickness reaching 36 meters and a layer of sand at the top and bottom with a low N-SPT value. If the soft subgrade is burdened with a high heap, it is estimated that the subgrade will experience landslides, so it is necessary to plan the improvement of the subgrade and reinforcement of the pile.The soil improvement method chosen is the pre-loading method with a combination of the prefabricated vertical drain (PVD). Pre-loading method aims to spend the compression that occurs on the subgrade so that there is no compression during the service life of the road. The combination with PVD is intended to speed up the compression time in thick clay layers. The stability of the embankment will be calculated using a computer-assisted program, and geotextile reinforcement planning will be carried out if the value of the safety factor does not meet the requirements.Based on the analysis of compression computation will be divided into five zones. The amount of compression obtained under various piles of 2 ms / d 9 m was 2.25 m, 1.49 m, 1.75 m, 2.57 m, 3.65 m, 4.3 m, 4.69 m, and 5.06 m with an initial heap height of 5.02 m, 5.26 m, 6.51 m, 8.34 m, 10.41 m, 12.07 m, 13.46 m, and 14.83 m. Compression time required for subgrade is relatively long with a period of more than five years so that the planned acceleration with PVD. To accelerate the compression time to 5-6 weeks, a triangular PVD installation pattern is used with a spacing between PVD of 1.5 m and a depth of PVD installation as thick as a soft soil layer. From the results of the pile stability control, it is predicted that the pile will experience slides so that the reinforcement is installed with geotextile.Rp1.598,213,522,582.08.

Triaxial behaviour of geotextile reinforced sand

ABSTRACT In order to study the behaviour of reinforced sand, a series of monotonic consolidated drained and consolidated undrained triaxial tests was conducted on Chlef sand samples and, respectively, sand samples reinforced with one layer and two layers of geotextile reinforcement. Considering both the relatives densites of samples (Dr = 30% and 80%) and the different levels of confining pressure (p’c) of 50, 100, and 200 kPa. It is noticed from the obtained results that reinforcement contribution was evident in the drained condition than for the undrained one. Results have shown under low confining pressure that adding two layers of geotextile reinforcement to loose sample leads to an increase in the value of maximum shear strength significantly for undrained sample of about 97%, then it will be less important by increasing confining pressure up to 200 kPa; at this level, the maximum shear strength has become more pronounced for the drained reinforced sample. It was also observed that the dilation of dense samples has clearly affected by the confining pressure, and this should be mainly attributed to the low dilatancy property of Chlef sand.

An Experimental Comparison of Simple Measurements Used for the Characterization of Sand Equestrian Surfaces.

Simple SummaryConsistency of equestrian surfaces can contribute to safety and performance. An optimal surface is influenced by the design and material selection as well as maintenance and climate. To improve surfaces the quantitative testing of functional surface properties must expand beyond the current testing at the highest levels of competition. More widespread quantitative measurements would have a positive influence on animal welfare and rider safety. To expand beyond the current top levels of the sport, simple tools are required that can be shown to detect relevant changes in construction and maintenance. Our work suggests that the appropriate use of simple devices can help with both quality control of new surfaces and the monitoring of existing surfaces. Performance modifications to the layered surface design and addition of Geotextile were detected using the Going Stick and a simple impact test. These measured results are also influenced by other factors related to the surface condition such as moisture. Caution must be exercised in the interpretation of the results since these tools have not been demonstrated to correlate to either performance or safety of the surface. However, these results are encouraging and provide a justification for future development of this type of equipment.Quantitative measurements of performance parameters have the potential to increase consistency and enhance performance of the surfaces as well as to contribute to the safety of horses and riders. This study investigates how factors known to influence the performance of the surface, incorporation of a drainage package, control of the moisture control, and introduction of a geotextile reinforcement, affect quantitative measurements of arena materials. The measurements are made by using affordable lightweight testing tools which are readily available or easily constructed. Sixteen boxes with arena materials at a consistent depth were tested with the Going Stick (GS), both penetration resistance and shear, the impact test device (ITD), and the rotational peak shear device (RPS). Volumetric moisture content (VMC %) was also tested with time–domain reflectometry (TDR). Results obtained using GS, RPS, ITD, and TDR indicate that the presence of the drainage package, moisture content, and geotextile addition were detected. Alterations due to combinations of treatments could also be detected by GS, ITD, and TDR. While the testing showed some limitations of these devices, the potential exists to utilize them for quality control of new installations as well as for the monitoring of maintenance of the surfaces.

Mechanically Stabilized Earth MSE Walls Applications: Review

Internally stabilized walls have entirely transformed the soil preservation mechanism. While such walls have achieved widespread recognition in many areas of the world, such a structure is widely adopted recently. The key explanation might be that such walls are likely to be more costly than traditional externally reinforced walls and that the construction processes included could be too time-consuming. This article provides an overview of the background, styles, advantages, and disadvantages of Mechanically stabilized earth (MSE) wall requirements. For contrast, traditional construction samples of externally and internally supported walls have been given, including metal strip reinforcement walls, reinforcement concrete cantilever retaining wall, geotextile reinforcement walls, and grounded earth walls of various heights.

Pull-Out Resistance of Sand-Geosynthetics Reinforcement

Geosynthetics are widely used in earth retaining structures such as steep slope and earth retaining wall. The stability of the earth retaining structures depends on the interaction between geosynthetics and soil at the reinforced area known as reinforcement mechanism. The reinforcement mechanism of the soil reinforced structure usually difficult to be analysed thoroughly. It is because the preliminary study on the pull-out resistance and durability of the reinforcement material is not taking into account before it has been used to the site location especially in Malaysian practises. Less supervision and the assessment after the installation of the reinforcement materials also contributed to the failure of the soil reinforcement. In this paper, the laboratory model was used to imply the real condition of the soil reinforced structure using pull-out test. A standard pull-out test was carried out by using geotextile and geogrid reinforcing elements embedded into silica sand of size D50=1.357 mm and D50=0.571 mm subjected to normal pressures of 100 kPa, 150 kPa and 200 kPa. Comparative result and analysis showed that the geotextile reinforcement give more resistance rather than geogrid reinforcement under high normal pressure.

Experimental and numerical prediction of California bearing ratio of expansive soil stabilized by bagasse ash and geotextile reinforcement

The target of this paper is to predict the CBR value by correlating the optimum moisture content, maximum dry density, Plasticity Index, proportion of sugarcane bagasse ash and also the variety of Geotextile layers. The linear relationships between the higher than mentioned properties and CBR worth exploitation Multiple rectilinear regression Analysis resulted during a sturdy correlation between the parameters. ANN model is developed exploitation ANN tool of MATLAB R2014a software. A multilayer perceptron network with feed forward back propagation is used to model variable the number of hidden layers. The graph aforethought between the predicted and experimental values shows that everyone the values are getting ready to equality line, indicating foreseen values are regarding the discovered values.

A Bioinspired Technique for Improving the Interaction Between Cohesive Soil and Geotextile Reinforcements

Reinforced soil structures often cannot perform properly when there is a weak interface which is not capable of mobilizing the required shear strength between fine-grained soils and the reinforcing elements. The calcium carbonate precipitation (CCP) technique adopted in this research has proved to be extremely useful in removing this deficiency. In this study, plant-derived urease-induced calcium carbonate precipitation (PDUICCP) was used as a novel method to improve the performance of the interface. Instead of using commercial-grade purified urease, the extract of soybean seeds was mixed with calcium chloride and urea to prepare a precipitating solution to reduce the costs. In addition, xanthan gum was used as a benchmark to examine the efficiency of the calcium carbonate precipitation process. Modified direct shear tests were performed on the kaolin clay specimens with two different relative compactions, three concentrations of the precipitating solution, and three different geotextiles to assess the performance of the proposed method. The results revealed that the application of the proposed method improved the interfacial shear strength considerably with the interface efficiency increasing from 12 to 270% depending on the geotextile texture and roughness, the relative soil compaction, and the concentration of the precipitation solutions. The highest increase in the interfacial shear strength for all the concentrations of the precipitating solutions was obtained when the polypropylene nonwoven geotextile was used. In all the cases, increasing the relative soil compaction enhanced the interfacial shear strength and interface efficiency. The optimal concentration of the constituents in the precipitating solution was obtained when 0.64 molar (M) calcium chloride and 1 M urea were used. The results of this study can mark the beginning of a new type of geosynthetics with multiphase strength parameters after the addition of environmentally friendly materials. Moreover, they pave the way for using fine-grained soils as the bulk backfill material in reinforced soil structures where coarse-grained soil is not readily available.

Load Bearing Capacity of Cohesive-Frictional Soils Reinforced with Full-Wraparound Geotextiles: Experimental and Numerical Investigation

This research investigated the effects of types of cohesive-frictional soil and geotextile reinforcement configurations on the bearing capacity of reinforced soil foundation (RSF) structures, via laboratory test and numerical simulation. The four reinforcement configurations studied for the RSF included: (i) horizontal planar form of geotextile, (ii) full-wraparound ends of geotextile, (iii) full-wraparound ends of geotextile with filled-in sand, and (iv) full-wraparound ends of geotextile with filled-in sand and sand backfill. The foundation soils studied were mixtures of fine sand and sodium bentonite at replacement ratios of 0, 20, 40, 60, 80, and 100% by dry weight of sand to have various values of plasticity index (PI). The numerical analysis of RSF structures was performed using PLAXIS 2D software. Several factors were studied, which included: embedment depth of the top reinforcement layer (U), width of horizontal planar form of the reinforcement (W), and spacing between geotextile reinforcement layers (H). Number of reinforcement layers (N) was varied to determine the optimum parameters of U/B, W/B, H/B, and N, where B is the footing width. The most effective improvement technique was found for the full wraparound ends of geotextile with filled-in sand and sand backfill. The outcome of this research will provide a preliminary guideline in a design of RSF structure with different ground soils and other RSF structures with different geosynthetic types.

Behaviour of sandy soil reinforced with geotextile having partially and fully wrapped ends

The wraparound reinforcement technique has been studied recently by researchers as a way of improving the bearing capacity and load−settlement characteristics of a sand bed supporting a strip footing with a constant land width for foundation, but with the use of varying width of geotextile reinforcement. This research study presents an experimental evaluation of geotextile-reinforced sand bed enhanced with a wraparound reinforcement technique having partially and fully wrapped ends with the use of constant width of the geotextile reinforcement, but with varying land width of the foundation. Laboratory model tests were conducted to investigate the influence of the lap length coverage of wraparound ends on the load−settlement behaviour of reinforced sand. Additionally, an instrumentation programme with pressure cells was designed to study the pressure distribution in foundation sand beneath the geotextile layer. The test results reveal that fully wrapped models possess the most improved behaviour, with about 50% improvement in the bearing capacity and 50% reduction in the land width occupied by the reinforcement compared with a reinforced model without wraparound ends.

Experimental and Numerical Investigation of Load Carrying Capacity of Vertically and Horizontally Reinforced Floating Stone Column Group

The present work investigates the load carrying capacity of vertically and horizontally reinforced floating stone column group through model testing. Two group arrangements using three and four stone columns for both unreinforced and reinforced conditions are testing under compressive loading. The geotextile reinforcement is provided throughout the stone column length (300 mm) in vertical direction and in form of circular discs at spacing of 30 mm along column length for reinforcing horizontally. The results of load-settlement behavior and failure mechanism of both unreinforced and reinforced group is studied. The testing results indicated reduced lateral bulging and higher stone column load capacity for horizontally reinforced columns in comparison to vertically reinforced. For validation of experimental results, numerical modeling using finite element (FE) code Plaxis 2D has also been conducted. The FE results depict lower load capacity as compared to model testing for settlement of 30 mm. However, the failure mode for both model tests and FE analysis was marked by bulging near the top of stone column and punching. Furthermore, load capacity is also check using empirical relations as given by IS code and previous literature. It is observed that experimental and analytical results are found in good agreement.