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... A limited right-of-way (ROW) available in the case of existing roadways and scarcity of the land and existing site conditions available for the construction of new roadways have complicated the construction of earth retaining structures. Ever since the conceptualization of reinforced earth by Vidal [1], reinforced earth structures have become an integral part of the transportation infrastructure facilities. Over the past four decades, mechanically stabilized earth (MSE) walls have been used to minimize the required ROW for embankments and used in the construction of new roads. ...
... Modern concepts of the MSE walls were conceptualized and popularized by Vidal [1]. Initially, these walls were constructed using galvanized steel strips to provide resistance against lateral earth pressure. ...
... It may be possible to use reinforcement lengths as low as 50% of the wall height, instead of the 70% required by many agencies worldwide. For instance, Hong Kong guidelines suggest 0.5H as the minimum reinforcement length, while Brazilian guidelines recommend a minimum of 0.8H [1]. The Federal Highway Administration (FHWA) guidelines [2] recommend a minimum ratio of 0.7 and acknowledge that longer reinforcement lengths are necessary for structures subject to surcharge loads, while shorter lengths may be used in special conditions [3]. ...
This paper reviews the previous studies on mechanically stabilized earth (MSE) wall, soil nail (SN) wall, and hybrid earth retaining structures (HERS) to provide a critical appraisal and state-of-the-art review followed by way forward regarding recommendations on the analysis, design, and practice. The first part of the paper deals with the brief review of the deterministic and reliability analyses of the MSE and SN walls. The second part presents the review of the literature related to the HERS, which consists of MSE over SN wall and shored MSE and narrow MSE walls. Even though the HERS are alternative to the MSE and SN walls and are especially effective in hilly terrains, they are not yet that popular owing to the lack of well-established design guidelines and construction procedures. A limited number of studies have been available in the literature on the HERS from the deterministic and probabilistic perspectives and are not available in the main-stream publications. Due to uncertainties of the material parameters of the soil and geo-synthetics, realistic and accurate prediction of the behavior of the reinforced earth retaining structures is very necessary and accordingly the studies reported on reliability studies are reviewed and presented. In the current design practice, the HERS are conservatively designed using guidelines developed for the MSE and SN walls. Therefore, there is a need to develop comprehensive analysis and design procedures for the safe and economical design of HERS.
... The reinforcements have different types such as strips, nets, rods, fibers, and sheets that provide the soil texture with tensile strength upon loading. The reinforced soil was introduced for the first time by Vidal in 1969(Vidal 1969. At the beginning of the 1970s, the researchers found a potential in developing a new reinforcing method used for the wea k so il la yer s. ...
... The reinforcements have different types such as strips, nets, rods, fibers, and sheets that provide the soil texture with tensile strength upon loading. The reinforced soil was introduced for the first time by Vidal in 1969(Vidal 1969. At the beginning of the 1970s, the researchers found a potential in developing a new reinforcing method used for the wea k so il la yer s. ...
... The difference between the influences of inextensible and extensible reinforcements is significant in terms of the load-settlement behaviour of the reinforced soil system (Figure 1.25). The soil reinforced with an extensible reinforcement (termed ply-soil by McGown and Andrawes, 1977) has greater extensibility and smaller losses of post-peak strength compared to soil alone or soil reinforced with inextensible reinforcement (termed reinforced earth by Vidal, 1969). However, some similarity between the ply-soil and the reinforced earth exists in that they inhibit the development of internal tensile strains in the soil and develop tensile strengths. ...
... Straw belongs to biomass fibers and can serve as a reinforcing material for soils. Reinforced soil-related research has a long history, with the French engineer Vidal H [5] being the first to introduce the concept of modern soil reinforcement in the early 1960s. This concept involves incorporating strips into the soil. ...
Straw reinforcement improves the mechanical properties of soil matrices by uniformly incorporating dispersed straw materials, demonstrating advantages in strength enhancement, toughness improvement, and deformation control. This study aims to compare the reinforcement effects of different types of straw on soil and clarify the optimal method for straw-based soil stabilization. For wheat straw-reinforced soil using different processing methods (straw segment, straw powder, and straw ash) and mass contents, the basic geotechnical properties of each mixture were first determined. Triaxial tests were then performed under varying confining pressures and compaction conditions to assess the strength and modulus characteristics of the different reinforced soil specimens, and the microstructural characteristics of fiber-reinforced soil were investigated using scanning electron microscopy (SEM) analysis. The experimental results indicated that the strength and ductility of soils increased significantly with the addition of straw. The optimal performance of straw-reinforced soils occurred at 0.3% content. The elastic modulus increased by 85%, 64%, and 57% under confining pressures of 50 kPa, 100 kPa, and 200 kPa, respectively. At 200 kPa, straw segments provided the highest modulus increase of 57%, while straw ash achieved the greatest strength improvement of 97%. Furthermore, considering both compaction effects and cost efficiency, a compaction degree of 95% is recommended for straw-reinforced soil in engineering applications. Based on scanning electron microscopy, it was observed that the distribution characteristics of different straw types within the soil exhibit distinct patterns. This study aims to provide data to support the efficient utilization of straw materials in engineering applications.
... The French Road Study Laboratory has conducted considerable research on the practicality and benefits of using reinforced earth as a construction material. H. Vidal and DERRICK I. PRICE published an extensive document on reinforced earth in 1969 and1975 [4][5]. In 1972, the first reinforced-earth retaining wall with metal strips as reinforcement was built in southern California. ...
The use of non-biodegradable and reinforcing materials in soil mass enhances safety with a highly cost-effective and dependable method. In this study, we used the limit equilibrium analytical technique to numerically determine the total internal and external stability performance of retaining walls using seven different height models. The reinforcement allows the soil mass to withstand strain in ways that the earth could not alone. Because stresses formed within the mass are transmitted from the soil to the reinforcing strips through friction, the internal friction of the soil is the source of this tension resistance. The parametric and comparative investigations yielded a wealth of information concerning the internal and exterior stability of reinforced earth-retaining walls. In this study, galvanized steel strips and geotextiles are engaged as reinforced elements in the reinforced soil. We demonstrated the energy difference between these two sorts of components. In this paper, we look at serviceability through internal stability to enhance the wall's service life and factor of safety against overturning, sliding and bearing capacity failure. The major goal of this study is to compare the factor of safety against failure (pullout, strip breaking, bearing capacity, overturning, sliding, and so on) between reinforced and unreinforced models generated using numerical analysis to see which is more constructive. After numerical analysis, we found that the value of the factor of safety increased significantly in all types of failures. Not only that, but we also find out which is more reliable between strips and fabrics.
... The use of these materials has expanded as a viable and dependable method in geotechnical application projects with the development of natural and synthetic fibers. Vidal [67] introduced the idea and logic of fiber inclusions for the first time in the modern history of soil improvement. His technique involved inserting a strip or bar into the ground at a predetermined spot. ...
One well-known technique for treating problematic soils is soil stabilization. Its quick and inexpensive deployment provide it an advantage over replacing soil. The chemical stabilization of soil using an alkali-activated binder is referred to as a method to enhance the engineering properties of soil. Alkali-activated binders often have a high peak compressive strength, but they also have a propensity for post-peak brittleness, which is crucial in geotechnical applications. It is understood that shear stress, which is produced when relatively high tensile strength discrete fibers reinforcement are implanted in a treated soil matrix, is transferred to the fibers as tensile strength, increasing the overall soil strength and accelerating the transition from brittle to ductile post-peak behavior. Two different types of fibers—natural and synthetic—are typically used to enhance soil. The major goal of this work is to review, with reference to existing scientific data, the history, advantages, and uses of using various kinds of natural and/or synthetic fibers in alkali-activated soil reinforcement.
... Rao 1996). Vidal was the first to propose the notion of enhancing soil mechanical qualities (Vidal 1969). Plant roots improved the overall strength of soils as well as the stability of natural slopes (Wu, McKinnell, and Swanston 1979). ...
This study examines the effects of fibre (0-3%) and cement (0-3%) additives on poorly graded Toyoura sand under consolidated undrained (CIU) compression and extension conditions. Compression tests revealed that dense sands exhibit increased peak strength, stiffness, and a steady decline from peak to post-peak strength. Cemented and fibre-cemented specimens demonstrated stiffer responses and strain-hardening post-peak behavior compared to pure sand. Adding fibres and cement significantly enhanced peak deviatoric stresses, while their impact under extension loading was less pronounced. Fibre and cement combinations, particularly at higher percentages, improved the strength of pure sand under extension conditions. Randomly oriented fibres increased friction angle, cohesion, and compressive strength, while cemented and fibre-cemented specimens exhibited higher secant moduli. The additives enhanced strength parameters, the slope of the critical state line, and the state parameter, with the stress ratio (q/p') rising for both peak and critical states.
... Soil reinforcement has been widely practiced in engineering applications to improve mechanical properties of soil to enhance embankments, slopes, subgrades, pavements, etc. According to Vidal [1], the strength improvement mechanism of reinforced soil is simultaneously contributed by the properties of fiber and the host soil-fiber interaction. Consequently, the increasing interest in soil reinforcement techniques has consistently spurred the identification of newer materials to use as reinforcements. ...
Millions of tonnes of bagasse are annually generated as waste from the sugar industry, the disposal of which poses a critical global challenge. To address this, the study explores the potential utilization of sugarcane bagasse fibers as a reinforcing material to sand, aiming to enhance its mechanical properties through laboratory investigations. Initially, the primary physical characteristics of both sand and bagasse fibers are examined using laboratory tests and scanning electron microscopy. Further, consolidated drained triaxial compression tests were carried out on sand specimens, with fiber contents varying from 0 to 2%. The investigations encompass the influence of fiber content, fiber length, and effective confining pressures on the strength parameters, dilation, and stiffness of reinforced sand. Upon shearing, the bagasse reinforced sands exhibited a strain-softening behavior at low fiber contents and a strain hardening behavior at higher fiber contents. Results indicate the beneficial utilization of bagasse fiber in enhancing the strength parameters, and reducing the residual strength loss of sand, sensitive to the effective confining stress. With increase in percentage of bagasse fiber, the dilation of sand was found to be decreasing. The inclusion of bagasse fibers also leads to a reduction in the initial and secant stiffness of the sand. Furthermore, as the length of fiber shortens at same percentage of fiber, the peak and critical angle of friction reduces. Based on the test results, a normalized model of the reinforced sand has been developed to capture the peak and residual states of the sand in correlation with different critical parameters.
... O conceito de reforço de solo foi inicialmente introduzido por Vidal (1969) e se consolidou no pioneiro trabalho de Binquet e Lee (1975a, 1975b com uma avaliação do comportamento de maciço arenoso reforçado com tiras de metal. No decorrer do tempo, com novas exigências e tecnologias em relação ao material, formas e tamanhos, as tiras metálicas foram substituídas por geotêxteis, geocélulas e geogrelhas. ...
... The concept of soil reinforcement was initially published by Vidal (1969) and was consolidated in the pioneering work of Lee (1975a, 1975b) with an evaluation of the behavior of sand mass reinforced with metal strips. Over time, with new requirements and technologies in relation to material, shapes and sizes, metallic strips were replaced by geosynthetics. ...
... The Ziggurat of the ancient city of Agar-Quf represents the oldest known instance of soil reinforcement. The approach of reinforced earth was pioneered by Vidal [4]. Initially, the focus of the study was on the examination and creation of retaining walls. ...
The soft soil's poor tensile strength requires reinforcing to increase bearing capacity, improve stability, and reduce settlements. This study assessed the efficacy of using geogrid layers to enhance and secure the soil surrounding tunnels. enabling the tunnel to endure pressure, particularly during excavation. The utilization of geogrids in soil reinforcement has experienced a substantial rise as a result of their consistent dimensions and exceptional tensile strength. To quantify the exerted force transferred to the tunnel, during this study utilized various testing tools, including a soil container, a steel loading frame, data loggers, a 0.5-ton load cell, and a miniature pressure cell. The vertical loads are applied by utilizing a hydraulic jack. A series of eleven tests were conducted on the tunnel at two depths of 1.5D and 2.5D, where D is the tunnel's diameter. The different models of geogrid layers showed that using two layers of geogrid at the first dimension, 0.5B and 1B from the base, led to a significant increase in tunnel stability. Two layers of reinforcement were used in both directions, giving the soil a high bearing capacity for the loads applied to the tunnel. This resulted in an improvement, a 1.65 in 1.5D and a 1.82 in 2.5D. The pressure above the pipe decreased by approximately 7.1kPa at the first tunnel depth and about 3.5kpa at the second depth. In conclusion, the study found the geogrid improves the stability of the tunnel by equally distributing loads and minimizing stress concentrations, hence decreasing the chances of collapses or deformations. Doi: 10.28991/CEJ-2024-010-08-04 Full Text: PDF
... Reinforced earth structures have become an integral part of transportation infrastructure ever since Henri Vidal (1969) presented the concept of reinforced earth in 1969. Over the past four decades, mechanically stabilized earth (MSE) walls have been used to minimize the required right-of-way for embankments and to construct the new roads (Abbas Samee, Yazdandoust, and Ghalandarzadeh 2022;Divya and S 2022;Jamnani, Yazdandoust, and Sabermahani 2023;Rahmouni et al. 2016;Shukla, Sivakugan, and Das 2011;Wu and Pham 2010). ...
... The reinforcing soil concept, initially introduced by Vidal [1], has undergone significant transformations to meet the geotechnical requirements. The evolution began with metallic strip reinforcements, later transitioning to polymeric sheet-type reinforcements. ...
In the last decades, geosynthetics have established their efficacy in enhancing bearing capacity and reducing settlement in various applications. Despite these advantages, researchers have identified minimal benefits associated with conventional geosynthetic reinforcement at low deformation levels. Consequently, the concept of geosynthetic prestress has gained recognition as a promising solution, aiming to enhance performance and expand its applicability across all deformation levels. While existing studies focus on prestressed geotextile or prestressed geogrid, this research uniquely delves into the behavior of prestressed geocell-reinforced sand. The study experimentally investigates various parameters, including geocell placement depth, cell height, geocell layer length, prestress magnitude, and the stage of tension release, under a strip footing vertically loaded, offering a comprehensive comparison with the un-reinforced or un-prestressed cases. The findings emphasize the superior effectiveness of the geocell prestressing process, capitalizing on its distinctive advantage of tension release- a feature not shared by prestressed geotextiles or geogrids. Furthermore, the research identifies critical design parameters, highlighting that the optimal geocell placement depth and layer length correspond to 0.2 and 7.5 times the footing width, respectively. Additionally, the study establishes that the optimal prestress magnitude is 45% of the geocell ultimate tensile strength, with the most effective tension release occurring at 30% of the ultimate capacity of the un-reinforced case.
... However, not only is it beneficial to improve the 'weak' soil, but it is also advantageous to strengthen the comparatively stable but inadequate ground(in terms of 'complexity of requirements'). It started with Vidal (Vidal 1969) and progressed through the pioneering work of Binquet and Lee (Binquet and Lee 1975). Strip-metallic reinforcements were initially taken over by geosynthetics in various forms, including geocells (three dimensional) geotextiles and geogrids (planar type). ...
Extensive research has been conducted on the performance of footings on both uniform and layered soil strata, focusing on conventional footing designs. Ring footings, on the other hand, have not undergone thorough field and laboratory evaluations, particularly for multi layered soil strata. A series of laboratory tests were performed with ring and circular footings resting on different homogeneous and layered soil strata. The study considered multiple unreinforced and reinforced foundation configurations by altering the thicknesses (H) of the top layer, in the range of 0.66–2.66D, overlying the subgrades of varying relative density, ranging from very loose (DrB = 30%) to stiff (DrB = 50%, 80%). The findings of the study suggest that the performance of foundations is significantly affected by the placement of geogrid at the interface between the layers. A profound improvement in the performance with respect to the load bearing capacity and reduction in footing settlements was observed due to the introduction of geogrid. However, the extent of improvements was influenced by the relative density of the subgrade, the level of settlement experienced by the footing, and the thickness of the top layer. The effectiveness of reinforcement was reduced as the lower layer stiffness and the top layer thickness increased. The study observed the highest improvement of 2.3 in terms of bearing pressure ratio for H = 0.66D and DrB = 30%. In both the unreinforced and reinforced cases, it was observed that the ring foundation with the optimal diameter ratio exhibited higher bearing pressures than the circular foundation with the same outer diameter.
... The design of the Mumbai-Ahmedabad high-speed rail (HSR) corridor was adopted from Japan's Shinkansen HSR tracks (Tatsuoka et al., 2014), which uses geosynthetically reinforced earth (GRE) foundations. The design of GRE structures in Japan was inspired by the Terre Armee method developed by Vidal (1969) in France. The method requires reinforcement layers to be placed in an alternate arrangement with the soil layers to strengthen the whole structure. ...
A high-quality railway track resting on an excellent foundation is required to support high-speed railway transportation. The foundations of high-speed railway tracks are generally constructed on the lifted embankment with the improved ground using different reinforcement agents like geosynthetics and rigid lateral support. The present study performed dynamic finite element simulations on a ballasted rail track laid over a geosynthetically reinforced embankment with and without facing wall support. Three foundation geometries were analyzed to examine the effect of facing wall support and geosynthetics on the lateral resistance of the foundation. An area loaded with a constant pressure was moved at a constant speed, causing the load motion at different speeds in the 90–360 km/h range. Different parameters were calculated at node paths to help understand the lateral effect of moving load. The results showed that the lateral resistance based on nodal acceleration and velocity increased with facing wall support in the range of 40%–57%. Any increment over the minimum facing wall thickness of 300 mm does not significantly increase lateral resistance. Geosynthetics provided a vital function in the foundations with a less bulk volume of soil and increased the lateral resistance by 10%.
... To investigate the stress state of reinforced soil in actual conditions, scholars both domestically and internationally have employed triaxial tests to analyze the strength and deformative properties of reinforced soil. The shear strength characteristics of reinforced soils were investigated through triaxial tests by Vidal et al. (Vidal, 1969;Lei, 2000;Zhang et al., 2023); the results of the tests revealed that the reinforcement primarily improves soil shear strength by increasing the cohesive force. Furthermore, the shear strength also varies non-linearly with an increase in the number of reinforced layers. ...
Introduction: The soil in geogrid-reinforced structures is typically unsaturated, with the shear strength provided by both the matrix suction and the reinforced body. Traditional structural designs for saturated soils only consider the shear strength provided by the reinforced body, neglecting the part provided by matrix suction. As a result, the design for reinforced structures is biased toward conservatism.
Method: The study examined the matrix suction-provided shear strength in reinforced soils through strain-controlled triaxial and soil-water characteristic curve (SWCC) pressure plate instrumentation. The feasibility of the Schrefler and Khalili unsaturated soil shear strength formulas for predicting shear strength based on matrix suction forces was verified.
Results: The study revealed that the cohesion of saturated reinforced soil exhibits a significant decrease in contrast with unsaturated reinforced soil, with matrix suction serving as a crucial consideration for reinforced structure design.
Discussion: The experimental results confirm the suitability of applying the quasi-cohesion increment theory to reinforced clays. The Khalili formula can be utilized to predict the quasi cohesion of unsaturated reinforced soils with greater accuracy under diverse dry density conditions. The results obtained using post-shear moisture content were closer to the measured values than those using initial moisture content.
... Η ενίσχυση των εδαφών επιτυγχάνεται με διάφορες μεθόδους, όπως η χρήση γεωσυνθετικών, μεταλλικών λωρίδων, ινών. Σημειώνεται ότι η σύλληψη της ιδέας ενίσχυσης του εδάφους με ίνες πραγματοποιήθηκε από τον Vidal (Vidal, 1966;Vidal, 1969). ...
The purpose of this research effort is to develop mathematical tools for
estimating the strength under undrained loading conditions of various soils reinforced with circular fibers. In this process, a database was created including experimental data from unconsolidated – undrained triaxial compression tests collected from various publications. In the development of the models, the multivariable ordinary linear regression method was used. The prediction efficiency of the proposed models is satisfactory based on the experimental data used for their validation.
... Therefore, tensile elements are often used to compensate this weakness. The concept of soil reinforcement was initially expressed by Vidal (1969). Reinforced soils are used in the construction of many geotechnical structures such as retaining walls, embankments, slopes and shallow foundations. ...
Back-to-Back Mechanically Stabilized Earth (MSE) walls can sustain significant loadings and deformations due to the interaction mechanisms which occur between the backfill material and the reinforcement elements. These walls are commonly used in embankments approaching bridges, ramps, and railways. The performance of a reinforced wall depends on numerous parameters, including the ones defining the soil, the reinforcement, and the soil/reinforcement interaction behavior. The focus of this study is to investigate numerically the behaviour of back-to-back mechanically stabilized earth walls, considering synthetic and metallic strips. A two-dimensional finite difference numerical modeling is considered. The role of the soil friction angle, the soil material quality, and the wall width to the height ratio are investigated in a parametric study. Their effects on the soil/strip shear displacements and tensile forces on the reinforcements are presented. The behaviour of the reinforcement strips in back-to-back reinforced walls strongly depends on the distance between walls and on the soil parameters.
... The concept and principle of soil reinforcement were first developed by Vidal in 1969 when he found that adding reinforcements to a soil mass increases the shear strength of soil [1]. The reinforcing effect of fibers in soil reinforcement was first noticed by Waldron in 1977, when he observed that natural root fibers contribute to the improvement in soil strength due to their reinforcing effect [2]. ...
The aim of this study is to investigate the bearing capacity-settlement behavior of strip footing settling on sand soil randomly reinforced with glass fiber, basalt fiber, macromesh fiber, and four different hybrid fiber additives in which these fibers are used together. Model tests were carried out in the laboratory on the strip footing and placed on the unreinforced and reinforced sand with different fibers. In the study, model tests were carried out on seven types of randomly reinforced soils by using glass, basalt, macrame, and mixtures of these fibers as reinforcement. In the model tests, two different fiber contents, 1% and 2%, and two different fiber lengths, 24 mm and 48 mm, were used. Tests were carried out with Dr = 30% and 50% relative density, and reinforcement depths 1B, 2B, and 3B were selected. In addition, the photographs taken during the test were analyzed with the particle image velocimetry (PIV) method and the displacements on the soil were examined. As a result of the reinforced and unreinforced model tests, the highest ultimate bearing capacity was measured as 680 kPa from the tests with Dr = 50% relative density, 48 mm length, 2% contents, and 3B depth macromesh fiber reinforced. In hybrid fibers, the highest ultimate bearing capacity was measured as 495 kPa, with Dr = 50% relative density, 48 mm length, 2% contents, and 2D depth micromesh and basalt fiber-reinforced tests. In the reinforced tests, it was concluded that the most effective fiber on bearing capacity is macromesh fiber. It can be seen that in the PIV analysis, as the fiber additive increased, the settlements made by the foundation decreased under the same pressure. It has also been observed that adding reinforcement to the soil transfers the stresses occurring in the soil to a wider area.
... INTRODUCTION Vidal (1969) demonstrated that the introduction of reinforcing elements in a soil mass increases shear resistance of the medium. The mechanical interlock effect of the fibres provides increased tensile strength and cohesion to the soil matrix. ...
... In the last few decades, various studies have been performed which have proven the efficiency of geosynthetics to improve the ultimate loadbearing capacity (ULBC) and decrease the footing's settlement. The very first concept of soil reinforcement was put forward by (Vidal, 1969), and (Binquet & Lee, 1975) performed the first systematic study of shallow foundations resting on reinforced soil. Since then, various experimental studies have been performed to investigate the ULBC and settlement of the footing (Khing et al., 1993;Adams & Collin, 1997;Dash et al., 2004;Azzam & Farouk, 2010;Aria et al., 2021). ...
The present study aims to generate generalized equations for the determination of ultimate load-bearing capacity (ULBC) of geogrid reinforced foundation (GRF) soil using the wraparound ends technique. Firstly, the ULBC of the reinforced soil is investigated by employing the two-dimensional FEM tool, and then a multiple linear regression (MLR) analysis is performed to obtain the generalized equations for the determination of the same. A series of solutions have been generated by performing a parametric study on the geometrical configuration of the wraparound ends configuration along with the geogrid’s axial elastic stiffness (EA). The results recommend that the generated equations are reliable as the coefficient of determination (R2) ranges nearly 1 for EA up to 2000 kN/m. However, beyond certain values of stiffness parameters, some qualitative intervention is needed to interpret the ULBC.
... Soil reinforcement by adding fibers was used first in antiquity, around 5000 years ago, using straw and hay to reinforce mud blocks [73]. In modern history, French engineer Vidal was the first to stablish the soil reinforcement concept [74]. He showed that the addition of elements into a mass of soil improves the strength of the medium [75]. ...
A frequent problem in geotechnics is soils with inadequate physical–mechanical properties to withstand construction work, incurring cost overruns caused by their engineering improvement. The need to improve the engineering properties of soils is not recent. The most common current alternatives are binders such as cement and lime. The climate change observed in recent decades and the uncontrolled emission of greenhouse gases have motivated geotechnical and geoenvironmental researchers to seek mechanisms for soil reinforcement from a more sustainable and environmentally friendly approach by proposing the use of recycled and waste materials. An alternative is natural fibers, which can be obtained as waste from many agro-industrial processes, due to their high availability and low cost. Sawdust, as a by-product of wood processing, has a rough texture that can generate high friction between the fiber and the matrix of the soils, leading to a significant increase in its shearing strength and bearing capacity. This concept of improving the properties of soils using natural fibers distributed randomly is inspired by the natural phenomenon of grass and/or plants that, when growing on a slope, can effectively stabilize the said slope.
... The technique used depends on factors such as the type of soil and construction requirements. Among the various soil improvement techniques, soil reinforcement is the most popular worldwide due to its easy installation, cost-effectiveness, and multiple applications (Vidal 1969;Binquet and Lee 1975;Saran 2005;Shukla 2012). Soil reinforcement has been modified over time based on the requirements and new ideas in terms of the materials used, shapes, and sizes. ...
... Casagrande was the initial proposer of earth reinforcement concept to stabilize weak soils providing high-strength membranes placed in horizontal layers (Westergaard 1938). Later, the concept of modern form of earth reinforcement was introduced by Vidal (1969) where the reinforcing elements, such as metallic strips or polymeric geotextiles or geogrids are placed in horizontal layers. As a result of this placement, the lateral pressure arising from each section is counterbalanced by local reinforcing elements. ...
Similar to geosynthetics, Jute Geotextiles (JGTs) also show different load-strain–time responses under different loading regime at isothermal conditions. For JGTs strain envelope approach through isochronous curves is adopted, which is already being implemented for geosynthetics. The required parameters of JGTs for ultimate strength design approaches are rarely reported in literature. JGTs shows significant amount of strain difference at the very beginning and has small fluctuation over time compare to synthetic geotextiles. From isochronous curves of selected JGTs, the possible design life for a particular load or the load carrying capacity at the End of Design Life can be predicted for a specific strain. Strain envelops show that locked strain (ƐL) increases from 7.1 to 8% for time period of 0.1 h to 100000 h and the recoverable strain (ƐR) decreases with the increase in loading time. Results indicate that when a particular strain is developed within a shorter duration, larger value of ƐR and smaller value of ƐL are found. In case of longer duration, it vice versa. The available strain (εR = εT—εL) indicates the capability to withstand additional short-term loads e.g. earth quake, which decrease proportionally with the increment of ƐL. With this understanding it can be said that the overall system became vulnerable against additional loading over ages whereas the total strain remains same. It is expected that the findings and observations of the study will be useful for the application of JGTs in various civil engineering works, as well as for the standardization of JGTs.
... Construction of road embankments over weaker subgrades is challenging work for geotechnical engineers because of the high compressibility, poor bearing capacity of the embankment, and the low shear strength of subgrade soil, which lead to excessive differential settlements and even embankment failure [1,2]. Thus, various evolutional techniques have been developed to improve the performance of soil on the embankment and solve the above problem eventually. ...
In this work, a new type of geocell with high-strength characteristics was applied to support the embankment to improve its performance. To evaluate the performance of an Embankment Reinforced by a New-style geocell, the geocell-reinforced embankment was designed to obtain optimal design parameters by using Abaqus Finite Element program. The parameters, including the aperture size of the geocell, reinforcement spacing, reinforcement length, slope rate, and slope step, were determined by analyzing the mechanical behavior of the embankment reinforced by a new-style geocell based on the safety factor, lateral displacement, and tensile stress on the geocell-reinforced embankment. Then a numerical simulation, where the performance of geocell-reinforced embankment was evaluated in terms of horizontal displacement, vertical displacement, tensile stress, shear stress, and plastic zone compared with unreinforced embankment, was conducted to evaluate the improvement effects of the new-style geocell on the embankment performance. The results revealed that the concentration area of horizontal displacement for the geocell-reinforced embankment, mainly located near the bottom of the embankment, was significantly reduced. The vertical displacement and differential settlement of the embankment were reduced by 13% and 79.6% after reinforcing, respectively. Moreover, the provision of geocell reinforcement greatly influenced the internal stress of the embankment, resulting in a 40% reduction in the distribution area of tensile stress. The comparison between the geocell-reinforced and unreinforced embankment on the plastic zone indicated that the slope toe of the embankment was the weakest position for shear failure, regardless of whether it was reinforced or not.
... Among them, the application of steel fibres is very common in concretes [35]. Using fibres in soils is much earlier than their use in concrete, which acted as reinforcing components in a soil mass and led to increased shear resistance [38]. Various natural or synthetic fibres are also used to reinforce other earth materials, blocks, and bricks [39]. ...
... The concept of reinforcing soils by adding fibers was developed in antiquity, more than 5,000 years ago, when ancient civilizations used straw and hay to reinforce mud blocks [73]. In modern history, the concept and principle of soil reinforcement were developed first by the French engineer Vidal [74], who showed that the introduction of reinforcing elements into a mass of soil caused an increase in the shearing strength of the medium [75]. Consequently, after these results, there has been an increase in the use of fibrous materials for the improvement of the engineering properties of soils, as an imitation of the past [73]. ...
A frequent problem in Geotechnics is the soils with inadequate physical-mechanical properties before the efforts to which they will be subjected by the constructions, incurring cost overruns caused by their engineering improvement. The need to improve the engineering properties of soils is not recent, currently observing that the most common alternatives are binders such as cement and lime. The climate change observed in recent decades and the uncontrolled emission of greenhouse gases have motivated Geotechnical and Geoenvironmental researchers to seek mechanisms for soil reinforcement from a more sustainable and environmentally friendly approach by proposing the use of recycled and waste materials. An alternative is natural fibers, which can be obtained as waste from many agro-industrial processes, implying their high availability and low cost. Sawdust as a by-product of wood processing has a rough texture that can generate high friction between the fiber and the matrix of the soils, leading to a significant increase in its shearing strength and bearing capacity. This concept of improving the properties of soils using natural fibers distributed randomly is inspired by the natural phenomenon of grass and/or plants that when growing on a slope can effectively stabilize a said slope.
... The researchers' journey began with the notion of reinforcement by putting metal tapes into the soil mass and evaluating them inside laboratory model tests [20][21][22][23], therefore the concept of soil reinforcement is regarded as old and not a creation of recent decades. As there was a notable improvement in the carrying capacity of the soil, the pace of these studies intensified, thus it expanded to the inclusion of the ground reinforcement materials (geosynthetics) [24][25][26][27], and predominantly sand was employed as a foundation soil because of the possibility of interlocking its grains with these materials [23][24][25][26], where researchers investigated several important variables of this inclusion that directly affect the desired improvement results, such as the shape of the studied foundation, the relative density of the foundation soil, the number of layers of reinforcing material, the spacing between them, the depth of the first layer, and many other parameters that researchers seek to study and provide reliable results about them [27][28][29][30][31][32][33]. ...
The rapid growth in all sectors puts great pressure on natural resources, making them vulnerable to depletion, not to mention the huge volume of waste, which is an inevitable result of this growth, especially industrial ones. These challenges drove researchers to seek sustainable alternatives with the least dependence on natural resources and invest in industrial wastes simultaneously. In the last decade, ferrochrome slag was able to draw the attention of researchers to use it in the construction sector, but it did not have an opportunity to prove its worth as a foundation material despite its outstanding physical and mechanical properties. In the current research, and after verifying the environmental acceptance of ferrochrome slag through the leaching test to determine the toxicity of waste seeping into the ground, an experimental investigation was carried out through a series of laboratory model footing tests using a bed of ferrochrome slag with a medium relative density of 65%, the bearing capacity of each square and rectangular foundation that laying on the slag bed was evaluated in unrein-forced and reinforced conditions with two different types of geosynthetic materials, geogrid and geotextile (non-woven), the variable parameters included the type of footing, the sort of reinforcement and the number of reinforcement layers. The findings showed a good response to the inclusion of the geosynthetic layers, adding a layer of geogrid, two and three layers increased the bearing capacity of square footing by 7%, 32%, and 52%, respectively. The bearing capacity ratio (BCR) with adding three layers of geotextile for rectangular footing (1.95) was found to be better than that of square footing (1.64), however, for three layers of the geogrid, the BCR value of square footing (1.52) was slightly more than that of rectangular footing (1.48). The environmental acceptance and the good response to the geosyn-thetics open up the chance for the ferrochrome slag to stand out as a sustainable alternative to granular footing materials, with geotextiles outperforming their geogrid counterparts in improving the bearing capacity of both types of foundations studied. © 2022, Sustainable Building Research Center. All rights reserved.
... Many experimental researches conducted on fiber reinforced materials have demonstrated, mostly by means of laboratory tests. The concept of reinforced soil was first given by Vidal [1]. Park and Tan studied the effects of short fiber reinforcement on the performance of soil wall [2]. ...
Solid waste management, especially the huge quantity of waste plastics, is one of the major environmental concerns nowadays and recycling plastic waste from water bottles has become one of the major challenges worldwide. In this paper we describe an experimental study of the utilization of waste plastic bottle chips in the reinforcement of silty soil. The experimental program includes the study of the effect of waste plastic fibers on maximum dry density (MDD), optimum moisture content (OMC) with different sizes and contents and one dimensional consolidation tests, to evaluate the benefit of utilizing randomly distributed waste plastics fiber to improve the engineering behavior of a tested soil. Silty soil specimens were prepared and tested at five different percentage of plastic waste content (i.e. 0.25%, 0.50%, 0.75%, 1% and 1.25% by weight of the parent soil). The size of plastic chips used, are 4mm, 8mm and 12mm long and 4mm in width. The results show that maximum dry density (MDD) and optimum moisture content (OMC) of the soil decreases with the addition of waste plastic fibers, also reduced the compressibility of soil significantly.
... Since the inception of the concept of MSE walls by Vidal (1969), researchers worldwide 32 have been trying to explore the possibility of economizing the system of MSE walls by using 33 varied types of reinforcements and fill materials. In recent years, due to the exponential growth in 34 road infrastructure around the globe, the demand for MSE walls has been rising. ...
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This study investigates the use of coconut shells as a sustainable reinforcement material to enhance the bearing capacity of sandy soil. Laboratory model tests were conducted to assess the performance of coconut shell-reinforced sand as a foundation medium. Different shell arrangement patterns were analyzed and compared with the performance of HDPE geocells. The results indicate that coconut shell reinforcement substantially increases soil bearing capacity, from 218 kPa in unreinforced sand beds to 414.5 kPa with coconut shell mat reinforcement. Coconut shell mats present a cost-effective and environmentally friendly alternative to commercial geocells. However, their limited durability in untreated form confines their application to short-term uses, emphasizing the necessity for proper treatment to support long-term applications.
An attempt was made to investigate the feasibility of cement bags obtained from construction sites to be used as planner reinforcement in sands by conducting laboratory load-settlement tests. The cement bag strip has been placed at different depths in single and multiple layers within a model tank’s sand bed of 65% relative density. The load settlement response of reinforced and unreinforced sand beds was compared after the compression load test. The influence of the number of reinforcement layers and reinforcement depth from footing on the load-settlement behavior has been examined and critically appraised for their practical significance. It has been found that the ultimate bearing capacity of the foundation increases with the increase in the number of reinforcement layers, and the footing settlement is noted to reduce with the presence of the cement bag. Maximum improvement in load-bearing capacity was 3.5 times for four layers of reinforcement and 2.5 times for single-layer reinforcement placed at a depth of 0.5 B.
This paper discusses to develop a three dimensional (3D) numerical model which can effectively simulate the behavior of geocell reinforced soils using a commercial finite element program. In the usual instance, numerical modeling of geocell is difficult due to their curved geometry and complex material surfaces. It is therefore not surprising that much of the previous studies on geocell have eluded this approach and have otherwise used an equivalent composite method. It treats the geocell–soil composites as a new soil layer with improved strength and stiffness properties. Unfortunately, despite its simplicity, this method can often be incorrect as it does not properly account for the state of in situ stress in the soils. Plane stress conditions are also violated especially when the geocell are placed close to the ground surface. Likewise, the shape of the geocells also affect the working of geocell. In the present study, the reinforced soil layer considers the interaction between the geocell and its nodes at connections. Geocell are modelled using poly-curves available in the software. Three types of simulations are then made, they are: reinforced soil with geocell and unreinforced soil, rectangular geocell with curvilinear geocell, and geocell with different axial stiffness. It was seen that the secant modulus of the reinforced soils increases with the increase in the curvature of the geocell. And as the axial stiffness of the geocell material increases, the secant modulus of the reinforced soil also improves.
The substantial annual consumption of natural resources by the building sector raises concerns about future depletion. Conversely, the accumulation of industrial waste in substantial volumes presents crucial environmental hazards. This study explores the utilization of granulated ferrochrome slag (GFS) as a sustainable alternative to sand for shallow foundations which has been little explored for this purpose. The model test is conducted on GFS with a relative density of 30% in a test tank of 1.6 m (L) × 1.0 m (W) × 1.2 m (D) with and without reinforcement to find the ultimate bearing capacity of surface square footing. Two reinforcement geogrid and geotextile types were contemplated in a GFS bed with three layers of conditions at various depths. Bearing capacity ratios (BCR) of 1.29, 1.45, and 1.56 were observed for single, double, and triple layers of geogrid; geotextile outperformed geogrid with BCR of 1.46, 1.92, and 2.28 consecutively. A numerical simulation using PLAXIS-3D has been carried out to validate the model test data. The outcomes of the numerical and experimental results showed a good agreement among themselves. Angular particles with high specific gravity and higher friction angle make GFS a better loading-bearing geomaterial than other granular materials. The chemical examination of GFS found acceptability regarding its leachability within allowable limits. All these factors make GFS satisfactory to use as a reinforced foundation bed material.
Retaining walls, which are used to promote deep excavations, deep embankments, basements, etc., is one of the essential components of different infrastructural projects. Retaining walls are frequently built for a variety of applications, most common being a highway or railway construction, bridge abutments, and deep embankments. In many civil infrastructures, these structures are being used and are often being subjected to different surcharge loading conditions. In deciding the cross-sectional dimensions of the retaining walls, the earth pressure has an important role. On the other hand, backfill materials and their properties effect on the lateral earth pressure. Normally, cohesionless soils are used in the backfill, for the better performance of earth pressure different type of reinforcement is used on the backfill soil of the retaining wall. However, geosynthetics reinforcement and new lightweight fill materials like tire chips are being explored and suggested as alternative backfill materials due to safety, environmental, and economic causes. For the purpose of this research, a new experimental model setup due to RB-T (which is able to rotate about the base and translates) mode of wall movement was developed in the laboratory to investigate the lateral earth pressure against retaining wall due to the influence of surcharge load and backfill reinforcement. For the influence of surcharge load on the backfill surface, the surcharge load was applied in three different locations from the retaining wall. However, the influence of backfill reinforcement. Geogrid and tire chips due to their high shear strenght and unique properties were used as reinforced backfill. According to the findings of this research, the following conclusions can be drawn: Increasing the location [distance from the wall edge] of the surcharge load has significantly decreased the active earth pressure especially for the top soil layers. Also, the maximum point of the peak earth pressure moves toward the lower part of the retaining wall as the surcharge load locations from the retaining wall increases. In case of reinforced backfill, it was observed that the lateral earth pressure efficiently decreases compared to the unreinforced backfill. However, the total thrust and its point of application are varied due to the variation of earth pressure distribution.
Sustainability has garnered significant attention from the global engineering community in recent years. Explorations into the utilization of sustainable materials for enhancing soil strength and mitigating soil failures have been underway for several decades. This paper offers a detailed review of application of waste materials to counter soil liquefaction. Even though conventional materials and methods of liquefaction mitigation offer substantial resistance to liquefaction, these approaches raise concerns related to sustainability, environmental impact, and economic implications. In this context, utilization of unconventional waste materials to enhance liquefaction resistance stands out, owing to its emphasis on sustainability, cost-effectiveness, and environment-friendly practices. Different waste materials used for the liquefaction mitigation are discussed and compared in terms of their underlying mechanism of improvement. The paper also discusses the issues, challenges, and potential benefits of the utilization of these waste materials, to promote their use in the most efficient and best possible way. The discussion concludes that the utilization of waste materials in liquefaction mitigation outperforms the other methods and materials across different dimensions such as material availability, cost, and sustainability, providing a promising avenue for addressing liquefaction challenges in the present and the future.
Mermer kullanımının artmasına bağlı olarak, ortaya çıkan mermer atıkları dünya çapında önemli bir çevre sorunu haline gelmiştir. Sürdürülebilirliğin önemli olduğu günümüzde bu tür atıklar inşaat işlerinde çeşitli amaçlar için kullanılmaktadır. Sürdürülebilirliğe en büyük katkı, atık maddelerin yeniden kullanımıdır. Yapılan deneysel ve hesaplamalı çalışmada, üç farklı atık mermer tozunun zemin stabilizasyon malzemesi olarak kullanılabilirliği araştırılmıştır. Çalışmanın deneysel kısmında atık mermer tozları % 0-10-20-30 ve 40 oranlarında iki farklı CL sınıfı killi zemine eklenmiş ve zeminlerin mukavemet özelliklerindeki değişiklikler Atterberg limitleri, standart Proctor sıkıştırma, kesme kutusu, ve Kaliforniya taşıma oranı (CBR) testleri ile izlenmiştir. Hesaplamalı kısımda ise CBR ve AASHTO-93yöntemleri kullanılarak yapılan stabilizasyonun üstyapı kalınlığına etkileri belirlenirken, KENPAVE yazılımı ile Mekanistik-Amprik tasarım metoduna uygun olarak mermer tozu iyileştirmesinin üstyapının yorulma ömrüne olan katkısı araştırılmıştır. Elde edilen test sonuçları mermer toz atıklarıyla stabilize edilen düşük plastisiteli killerin dayanım özelliklerinin iyileştiğini göstermiştir. CBR ve AASHTO-93 metotları ile bu iyileştirmenin gereken üstyapı kalınlığını azaltabileceği, SN sayısındaki azalma ile karayolu imalatında yüzlerce metreküp malzeme kazancı sağlanabileceği hesaplanmıştır. Mekanistik-Amprik yöntem ile yapılan hesaplar da atık mermer tozu stabilizasyonu ile üstyapının kritik tekerlek izi oturması ömrünün ortalama %86’ya kadar artabileceğini öngörmektedir.
Population expansion and the development of technology have led to an increase in construction activities. In many cases, foundation grounds do not have a high enough bearing capacity and are not capable of ensuring the safe exploitation of the construction. A soil with poor mechanical characteristics must be improved using various methods, such as adding hydraulic binders (lime and cement), natural fibres, or more recently, plastic waste materials. This work aims to study the behaviour of plastic waste materials made from polyethylene terephthalate (PET) in soil improvement. Thus, the mechanical characteristics of a clay improved with shredded PET were studied. PET was added in relation to the dry mass of the clay, in percentages of 2%, 4% and 6%. The studied clay was collected from a construction site around Cluj-Napoca, Romania, from a depth of 1 ÷ 10 m. PET was provided by a local plastic waste repository. It comes from recycled water, beer and soda bottles and was cleaned using specific methods for cleaning and recycling plastic waste. PET was shredded into irregular shapes with sizes ranging from 3 mm to 12 mm and was randomly distributed in the test specimens. Compression and direct shear tests were carried out to study the compressibility and shear parameters of the improved soil (internal friction angle and cohesion). The experimental results showed an improvement in the mechanical characteristics of the clay even at a low PET addition of 2% and 4%. This method can contribute to solving two current problems of the modern world: reducing pollution by recycling plastic waste materials and using them to improve the mechanical characteristics of soil.
The use of natural fibers for soil reinforcement has been popular for over 5000 years. In this study, Coconut midrib fiber extracted from fallen coconut leaves was utilized as a reinforcing material to examine its suitability as a new sustainable product. A series of large-scale plate load tests were conducted to evaluate the bearing capacity of the reinforced soil. The tests were performed on soil compacted at two different relative densities. The results showed that parameters such as relative density of sand, distance from the footing base to the first layer of reinforcement, distance between consecutive layers of reinforcement, and the number of reinforcement layers are important factors that affect the bearing capacity improvement factor of reinforced soil. To understand the surface roughness, SEM and FTIR analyses were conducted. Numerical analysis was performed to validate the experimental results.
Mechanically stabilized earth (MSE) retaining walls are used extensively in the U.S.A. However, some of these walls are experiencing excessive movements. There is currently no clear numerical assessment or in situ procedure to monitor and evaluate such walls. The current study developed a procedure involving field and experimental measures on two MSE walls in Hurst, TX. The facia panels were monitored using a 3-D robotic laser scanner. The backfill soil testing involved in situ resistivity imaging and laboratory soil testing following applicable specifications. Also, a regression analysis was conducted to assess the effect of different wall parameters on MSE wall performance. Laser scanning showed both walls exhibited lateral and settlements in the ranges of 4–5 mm and 4–8 mm, respectively, relative to the scan initiation time. The movements varied with seasonal rainfall changes with peaks and valleys. Soil tests showed the backfill soil for both walls was not acceptable in regard to fines content, friction angle, and optimum dry density. Resistivity imaging scans indicated backfills have poor permeability characteristics. The techniques proved to be efficient in assessing MSE walls are laser scanning, resistivity imaging, and soil testing. The radar scanning approach in this study was unsuccessful in effectively locating such failed straps due to dense steel rebar cage obstruction to radar waves in the shoulder concrete pavements. The developed regression model shows that wall lateral movement is affected the most by pore pressure, increases considerably with increasing reinforcement ductility, and decreases with increasing reinforcement length and soil cohesiveness.
Reinforced earth walls have been widely used for retaining soils due to their lower construction cost and flexibility. The fill materials used in reinforced earth walls such as moorum (silty gravel) and river sand are getting scanty day by day as they are also the major building materials. In order to overcome this scenario, alternate fill materials for use in reinforced soil structures are need to be explored. The studies carried out by various researchers enabled the use of copper slag as fill material in reinforced earth walls. In the present study reinforced earth walls for retaining backfill heights of 4–10 m are designed according to BS 8006–1:2010 and are compared with reinforced earth walls designed for the same heights using conventional fill material in non-seismic and seismic conditions. Copper slag has high angle of shearing resistance of about 41° at OMC and MDD conditions and 38° in saturated condition due to presence of rough textured angular particles. Though copper slag induced relatively more bearing pressures due to its relative high unit weight, the induced tensile forces are observed to reduce by about 10–13% when compared to the conventional fill material moorum in both non-seismic and seismic conditions.
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