Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 8
Use of Rigid Inclusions, Retaining Structures, and Geosynthetics for Enhanced Stability
- 2025
- Book
- Editors
- Cholachat Rujikiatkamjorn
- Jianfeng Xue
- Buddhima Indraratna
- Book Series
- Lecture Notes in Civil Engineering
- Publisher
- Springer Nature Singapore
About this book
This book presents select proceedings of the 5th International Conference on Transportation Geotechnics (ICTG 2024). It includes papers on ground improvement methodologies, dynamics of transportation infrastructure, and geotechnical intricacies of mega projects. It covers topics such as underground transportation systems and heights of airfields and pavements. This book discusses diverse thematic landscapes, offering profound explorations into sensor technologies, data analytics, and machine learning applications. The publication highlights advanced practices, latest developments, and efforts to foster collaboration, innovation, and sustainable solutions for transportation infrastructure worldwide. The book can be a valuable reference for researchers and professionals interested in transportation geotechnics.
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Table of Contents
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Frontmatter
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Finite Element Study of Unreinforced and Reinforced Unpaved Roads Subjected to Repetitive Vehicular Loading
Nayan Jyoti Sarma, Arindam DeyThe chapter delves into the finite element study of unpaved roads subjected to repetitive vehicular loading, focusing on both unreinforced and reinforced structures. It begins by introducing the prevalence and characteristics of unpaved roads, which comprise a substantial portion of the global road network. The study then explores the rutting behavior of unpaved roads under varying numbers of vehicular load repetitions and axle loads, illustrating how deformation increases with repeated loading. The chapter also discusses the application of geosynthetics as a sustainable and economical solution to mitigate rutting. By incorporating geotextiles with different axial stiffnesses, the analysis demonstrates a significant reduction in rutting, with higher stiffness geotextiles showing greater effectiveness. The use of finite element modeling in PLAXIS 2D allows for a detailed examination of stress distribution and deformation patterns, providing valuable insights into the behavior of unpaved roads under real-world conditions.AI Generated
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AbstractAn unpaved road system is frequently subjected to distresses arising especially from rutting. This phenomenon is mostly imbibed by the repeated vehicular loading acting on the aggregate layer. Traditional design undrained analysis of unpaved road design leads to overestimated aggregate thickness, which has an eventual toll on the project cost. Hence, it becomes imperative to comprehend the behaviour of the unpaved road system subjected to repetitive vehicular loading and its consequent effects on rutting. This paper reports, the detailed outcome of Finite Element (FE) based analyses of unreinforced unpaved road system comprising a soil subgrade represented by generalized shear strength parameters. The aggregate layer is subjected to repetitive vehicular loading arising from different axle loads, and their influence on the rutting behaviour is illustrated. Further, to counteract rutting originating from higher axle loading, a planar geotextile with different stiffnesses is introduced at the aggregate-subgrade interface. The study successfully shows that even a single layer of high tensile strength geotextile can completely arrest the accumulation of deformation beyond certain number of loading cycles. -
Evaluation of Pavement Performance for Three Different Designs on the Expansive Subgrade: Three Case Studies
Sagun Shrestha, Md Mizanur Rahman, Md Rajibul Karim, Hoang Bao Khoi NguyenThe chapter focuses on the evaluation of pavement performance for three different designs constructed over expansive subgrades. It presents case studies from three trial roads in Adelaide, Australia, where geosynthetics were used to stabilise pavements. The study compares the performance of pavements with geogrid, geocomposite, and no geosynthetics, using crack and defect mapping surveys and soil reactivity measurements. The results indicate that geosynthetics, particularly geogrid, significantly improve pavement performance by reducing crack formation. The chapter also highlights the impact of environmental factors, such as seasonal changes and soil reactivity, on pavement deterioration. The findings contribute to the understanding of geosynthetic applications in pavement construction and their long-term benefits.AI Generated
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AbstractThe expansive/reactive subgrade issue has been prevalent in pavement construction throughout Australia, with an estimated 30% of the country’s land surface covered by expansive soil. The shrink-swell problem caused by subgrade movement poses a significant challenge, damaging constructed pavements. Various approaches have been implemented to address this issue, mitigate the detrimental effects, and combat the damage caused by expansive soil. A minimum non-reactive or stabilised cover depth is recommended for low to moderately reactive subgrades. However, in the case of highly reactive subgrades, Austroads and state road agencies advise conducting a comprehensive geotechnical assessment to explore alternative solutions. This article evaluates the potential of geogrid and geotextile in resisting movement caused by reactive soil and assesses their effectiveness in minimising pavement damage. Three road sections were constructed using different configurations. One road section utilised only geogrid, another combined geogrid and geotextile, while the control section had no geogrid or geotextile. The geogrid and geotextile were placed over the expansive subgrade. The design traffic, subgrade CBR (California Bearing Ratio), and reactivity index of the subgrade were consistent across all three road sections to evaluate the performance of pavement configurations. Similar road sections were constructed on three different reactive soils in Adelaide. Over a period of time, road performance surveys were conducted following the guidelines provided by Austroads. The findings revealed that both the geogrid section and the geogrid with geotextile section outperformed the control section in all three locations. This indicates that the inclusion of geogrid and geotextile significantly improved the performance and durability of the road sections constructed on reactive soils. -
Improved Liquefaction Resilience of Transportation Infrastructure with Geofoam Buffers
Balaji Lakkimsetti, Gali Madhavi LathaThe chapter delves into the critical issue of soil liquefaction during seismic events and its implications for infrastructure stability. It introduces the innovative use of expanded polystyrene (EPS) geofoam buffers as a cost-effective solution to enhance liquefaction resilience. Through a series of simple shear tests, the study examines the impact of geofoam density and layer thickness on pre-liquefaction shear strength, liquefaction resistance, and post-liquefaction shear strength. The findings highlight the significant benefits of using geofoam buffers, particularly thick, lightweight layers, in improving soil performance during earthquakes. However, the study also underscores the need for careful selection of geofoam properties to maintain an optimal balance between shear strength and liquefaction resistance.AI Generated
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AbstractThe efficacy of geofoam buffers in enhancing the seismic performance and dynamic load response of retaining walls and road embankments is well-established. However, limited research has been conducted to comprehend their role in mitigating soil liquefaction. This study investigates the shearing behavior of sands with Expanded Polystyrene (EPS) geofoam buffers, both before and after liquefaction, through a set of monotonic and cyclic simple shear tests. The investigation considers variations in layer thickness and geofoam density, employing two different thicknesses and three different densities in the tests. The results indicate that geofoam buffers reduce both pre-liquefaction and post-liquefaction shear strength of sand. However, they demonstrate a significant improvement in liquefaction resistance, with better outcomes observed at increased layer thickness and lower geofoam density. This enhancement is attributed to the exceptional energy absorption quality and compressibility of geofoam buffers. Nonetheless, this has a converse impact on the shear strength of sand. Consequently, it is imperative to carefully select the appropriate density and thickness of the geofoam layer to strike a balance between shear strength and liquefaction resistance. -
Direct Shear Testing of Recycled Construction and Demolition Waste-Geosynthetic Interfaces Under Cyclic Normal Loading
Fernanda Bessa Ferreira, Pedro Valente Pereira, Castorina Silva Vieira, Maria Lurdes Lopes, Amir ShahkolahiThe chapter focuses on the direct shear testing of recycled construction and demolition waste-geosynthetic interfaces under both static and cyclic normal loading conditions. It delves into the effects of cyclic loading on the interface shear strength and dilation behaviour, demonstrating that cyclic loading can reduce peak shear strength and alter dilation patterns. The study also evaluates the impact of loading amplitude and frequency on the shear behaviour of these interfaces, revealing significant variations that are critical for designing resilient and sustainable infrastructure. The experimental results provide valuable insights into the performance of geosynthetics in recycled waste applications, contributing to the broader goal of sustainable waste management and infrastructure development.AI Generated
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AbstractGeosynthetics have increasingly been used in geotechnical engineering applications due to their numerous benefits, including the cost-effectiveness, reliability and contribution to sustainability. When employed in transport infrastructure projects, geosynthetics may perform a variety of functions, leading to increased stability and longevity of the system. This paper describes a laboratory study carried out using a large-scale direct shear test apparatus to characterise the direct shear behaviour of the interfaces between a recycled construction and demolition (C&D) material and two geosynthetics (a geogrid and a geocomposite) subjected to cyclic normal loading. The direct shear tests were performed under a constant shear displacement rate, while the normal loading varied cyclically at predefined frequency and amplitude values. Direct shear tests under static normal loading were also performed for comparison purposes. Test results have shown that the interface shear strength and dilation behaviour tend to decrease under cyclic normal loading and are influenced by the applied frequency and amplitude. The peak and large displacement shear strengths of the interface with the geogrid exceeded those reached when the geocomposite was used, which may be attributed to more effective interlocking of the aggregates within the geogrid apertures. -
Experimental Investigation of Geogrid Reinforced Unpaved Sections Under Repeated Loads
Krishneswar Ramineni, Nripojyoti Biswas, Anand Jagadeesh Puppala, Md. Ashrafuzzaman KhanThe chapter presents a detailed experimental investigation of geogrid-reinforced unpaved pavement sections under repeated loads. The study aims to measure vertical stresses at the interface between the base and subgrade layers using large-scale repeated plate load tests. Three pavement test sections were constructed with different geogrid reinforcements, along with one unreinforced section as a control. The performance of the geogrid-reinforced sections was evaluated using vertical stress reduction factors and stress distribution angles. The results showed significant reductions in vertical stress and improved stress distribution patterns in the reinforced sections, highlighting the potential of stiffer geogrids in enhancing pavement performance and service life. The study contributes to a better understanding of the reinforcement effect and stress distribution in reinforced and unreinforced pavement sections, offering valuable insights for future design recommendations.AI Generated
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AbstractRutting has been one of the major pavement distresses that affect the performance and longevity of pavements constructed on weak or soft subgrades. Rutting is often associated with excessive deformation of the pavement layers under wheel loads, caused by layer densification and excessive vertical stress on the subgrade exceeding subgrade strength. Over the past two decades, geosynthetics have been used to reduce this excessive deformation by decreasing the vertical stresses on the subgrade. The primary objective of this study was to determine the effect of high-moduli geogrid-reinforced layers in reducing the vertical stresses on the subgrade. The current study addresses the objective by experimental investigation on reinforced pavement layers subjected to repeated loads. The experimental investigation involves conducting laboratory-based large-scale repeated load tests on geogrid-reinforced pavement sections constructed over weak subgrades. Based on the large-scale repeated load test results, it was observed that the geogrid-reinforced pavement sections reduced the vertical stress on the subgrade by 35–75% as compared to the unreinforced sections. -
Performance Evaluation and Validating Design Inputs of Geogrid Reinforced Flexible Pavement Overlying Soft Subgrade: Insights from Laboratory to Field Testing
Praveen Bodhanam S, Deeraj Kumar Reddy Kambam, Ramu BaadigaThe chapter delves into the challenges and solutions associated with constructing pavements over soft subgrades, highlighting the economic and environmental benefits of using geogrids. It explores the three primary mechanisms by which geogrids improve pavement performance: lateral restraint, load-bearing capacity, and membrane support. The study focuses on the modulus improvement factor (MIF) as a key design input, validating its value through large-scale laboratory tests and field experiments. The results demonstrate significant performance improvements, with MIF values indicating substantial reductions in pavement thickness and natural aggregate consumption. The chapter concludes with practical recommendations for optimizing pavement design, making it a valuable resource for professionals seeking to enhance the sustainability and efficiency of pavement construction.AI Generated
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AbstractConventional stabilization (using cement, lime, etc.) of soft subgrades incurs high project costs and raises environmental concerns. An alternative stabilization technique that can benefit the pavement without compromising design criteria and pavement performance is the foremost instigating aspect for highway industries. Thus, in this study, the on-field existing effective California Bearing Ratio (CBR) equal to 10% was first simulated in the large-scale test chamber. The prepared unstabilized and stabilized pavement base with Polyethylene terephthalate (PET) biaxial geogrid (PET80) (the ultimate tensile strength equal to 80 kN/m in the machine and cross-machine direction) sections were loaded with a static linear hydraulic actuator having a loading capacity of 100 kN for quantifying the benefit. The benefit rendered by geogrid is quantified in terms of Modulus Improvement Factor (MIF), which is used in mechanistic-empirical pavement design guidelines to assess the pavement's overall performance and reduce the use of natural aggregate. The crucial design inputs of MIF value tested at large-scale laboratory level are further validated in the field through conducting static plate load test for the initial design traffic of 150 MSA (Million Standard Axles) and CBR = 10%. The test results indicated a marginal difference in MIF values observed from laboratory and field validation. The MIF values of PET80 reinforced pavement obtained through laboratory and field were 1.96 and 1.89, respectively. Thus, the benefit indicated that the laboratory obtained MIF value was 1.04 times higher than the field. The overall reduction in asphalt and base layer was 38% and 15%, respectively, for MIF value considered in the study. -
Model Test of the Influence of Cyclic Traffic Load on the Cumulative Deformations of GRS Bridge Abutment
Yafei Jia, Jun Zhang, Yewei ZhengThe chapter delves into the critical issue of cyclic traffic loads on geosynthetic reinforced soil (GRS) bridge abutments, a topic that has received limited attention in previous research. By conducting comprehensive model tests, the study evaluates the deformation response of GRS abutments under varying cyclic load amplitudes. The results reveal distinct patterns in footing settlement, facing displacement, and reinforcement strains, highlighting the complex interactions within the GRS system. The findings underscore the importance of considering load amplitude effects and elevation-specific responses in the design and reinforcement strategies for GRS bridge abutments. This research offers valuable insights that can inform more robust design strategies to enhance the stability and performance of these structures under dynamic loading conditions.AI Generated
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AbstractThis study investigates the deformation characteristics of geosynthetic reinforced soil (GRS) bridge abutment models under cyclic loading conditions through experimental methods. The GRS abutment models were built using well-graded sand as backfill material and biaxial geogrid for reinforcement. Settlements of the footings, displacements of the facing, and strains in the reinforcements were monitored and analyzed. The findings show that cumulative settlements increase as the cyclic load amplitude rises. Furthermore, facing displacement tends to increase with height, reaching its maximum at the top. The cyclic loading amplitude affects the strains in the upper reinforcements more significantly than those in the lower reinforcements. -
Measurement of Pressure Distribution on Roadbed Using Soil Bags During Plate Loading Tests
Ryunosuke Kido, Natsu Nishimura, Shuuhei Mitsutani, Shigeru Maruo, Makoto KimuraThe chapter delves into the innovative use of soil bags for constructing temporary roads, focusing on the measurement of pressure distribution during plate loading tests. It introduces the concept of 'do-nou' soil bags, which exhibit high bearing capacity under vertical loading. The study investigates the effects of different stacking methods—straight and staggered—and the number of layers on the pressure distribution among the soil bags and their transfer to the lower roadbed layer. The experimental setup includes a newly developed plate-loading test apparatus and the use of pressure measurement films. The results reveal that staggered stacking leads to larger displacement and more effective pressure transfer, highlighting the potential of soil bags for improving roadbed functionality. The chapter concludes by emphasizing the practical implications of these findings for the rational construction of roadbeds under varying loading and ground conditions.AI Generated
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AbstractWhen constructing temporary roads for disaster recovery, it is necessary to improve the ground or replace the soil with high-quality soil when the ground conditions at the site are not good. However, it may be difficult to procure and transport a sufficient quantity of high-quality soil for replacement at some sites. In addition, when using cement to improve the ground, for example, the high strength of the ground can be maintained for a long period of time, but disadvantages are also encountered with its use. A ground improved by the addition of cement cannot be restored to its original condition. Moreover, cement is relatively expensive and has a negative impact on the environment. The use of soil bags, known as “do-nou” in Japan, is one of the effective methods for constructing temporary roads. The advantages of soil bags are that the strength of the ground can be improved more easily and quickly without the need for heavy machinery or modification by cement, and that the damaged areas can be repaired by replacing damaged soil bags with new soil bags. Thus, a roadbed can be simply removed and rapidly restored to its original condition. The loading characteristics of soil bags arranged as a stacked structure need to be understood. In the present study, in order to evaluate the loading characteristics of soil bags, cyclic plate-loading tests were conducted to investigate the pressure transfer among the soil bags and from the soil bags to the lower roadbed layer. It was found from the experiments that the earth pressure was distributed over a wider area in the structure with the staggered stacking of the soil bags than in the structure with the flat stacking of the soil bags. -
Evaluating the Reliability and Repeatability of Novel Laboratory Equipment in Investigating the Performance of Geosynthetic-Reinforced Soils
Jiacheng Qiu, Yue Chen, Yuekai Xie, Jianfeng Xue, Chaminda Gallage, Mark JaksaThe chapter focuses on the evaluation of a novel small-scale laboratory testing mould designed to assess the performance of geosynthetic-reinforced soils. It begins by introducing the significance of geosynthetics in roadway constructions and the challenges associated with existing testing methods. The study then presents the design and setup of the testing apparatus, including the testing mould, loading device, and sample preparation methods. Preliminary tests reveal inconsistencies in test results due to variations in sample densities. Subsequent modifications to the sample preparation process, such as the use of a pluviator and vibrational compaction over a larger plate, demonstrate improved repeatability and consistency. The study concludes by highlighting the critical role of vertical confining pressures in activating the reinforcing effects of geocomposites and emphasizes the importance of standardized sample preparation methods for reliable test results.AI Generated
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AbstractGeosynthetics have been employed as reinforcements to improve pavement behaviours. Previous attempts have been made to compare the performance of geosynthetic-reinforced soils with unreinforced soils through large-scale laboratory tests. However, large-scale testing is considered time-consuming and costly, which reduces the repeatability and reliability of such tests. Therefore, it is crucial to develop a small-scale testing apparatus, which is capable of evaluating the reinforcing effects of geosynthetics in pavements. In this study, a small-scale laboratory testing method was employed to investigate the performance of geocomposites in improving the penetration resistance of the reinforced soil system. Several tests were performed to validate the repeatability of the proposed testing apparatus. The results of this study demonstrate the capability of the developed testing method to produce consistent and repeatable results, which highlights its potential application in measuring the reinforcing effects of geosynthetics in pavements. -
Effect of Granular Layer Properties on the Stabilisation of Weak Subgrade with Geosynthetics
Shehan Mithila, Arnold Fernando, Shiran Jayakody, Yilin Gui, Chaminda Gallage, A. Shahkolahi, Raymond Chow, Nadeej PriyankaraThe chapter delves into the challenges faced by geotechnical engineers when designing road pavements on weak subgrades, particularly those with expansive clay found in regions like Queensland, Australia. Traditional methods of subgrade treatment, such as thickening the granular cover or subgrade replacement, are scrutinized for their environmental and sustainability concerns. Geosynthetics, specifically geotextiles and geogrids, are presented as optimal solutions for enhancing subgrade characteristics. The study focuses on comparing the performance of two different gravel types in geosynthetic reinforced subgrades under monotonic loading conditions. Laboratory tests were conducted to evaluate strain modulus and ultimate bearing capacity, revealing significant improvements when using high-quality gravel. The findings highlight the importance of gravel type selection in designing gravel-stabilized subgrades, emphasizing the potential for cost-effective solutions in road construction projects.AI Generated
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AbstractWeak and soft subgrades present significant challenges for road pavements construction and conventional stabilization methods have become outdated due to environmental and economic concerns. The use of geosynthetics has become increasingly popular as a sustainable technique for subgrade improvement. However, limited research has been conducted focusing on the quantification of factors affecting on the stiffness improvement of weak subgrades with a granular layer and composite geogrids. This study focuses on examining the effect of gravel type on subgrade stabilization using model box tests conducted in a scaled model pavement steel box measuring length, width, and height as 1 m, 1 m and 1.2 m, respectively. The subgrade condition was kept constant for all tests and constructed to a thickness of 500 mm, maintaining CBR value as 2.5%. The gravel “Type 2.1 and Type 2.5” specified as the best and lowest quality gravel in “MRTS05- Unbound pavements” were used in 200 mm thick gravel layer for each test, respectively. Composite geogrid was placed at the gravel-subgrade interface in these tests. All the tests were subjected to a monotonic load applied on the top surface using a 200 mm diameter circular plate until reaching the point of ultimate failure obtaining parameters; vertical deformation and stress distribution to analyze the load bearing capacity and stiffness. The outcomes of the study verified the effect of granular layer properties on designing stabilized subgrades with geosynthetic reinforcement. -
Assessment of Geogrid Reinforcement on the Performance of Stabilized Subgrades Under Different Loading Conditions
Arnold Fernando, Shehan Mithila, Shiran Jayakody, Yilin Gui, Chaminda Gallage, Amir Shahkolahi, Nadeej PriyankaraThe chapter delves into the critical role of geogrid reinforcement in improving the stability and performance of subgrade soils, which are essential for maintaining the integrity of transportation infrastructure. By conducting systematic laboratory experiments, the authors investigate the behavior of geogrid-reinforced subgrades under cyclic and monotonic loading conditions. The study reveals that geogrid reinforcement significantly reduces rutting and enhances the ultimate bearing capacity and stiffness of subgrade soils. These findings are crucial for developing effective design guidelines and optimizing pavement performance under various loading scenarios. The chapter also highlights the sustainability benefits of using geogrids, such as reducing the need for natural gravel and extending the lifespan of pavements.AI Generated
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AbstractGeogrid stabilization has gained significant attention in recent years as an effective method for enhancing the performance of subgrade soils. However, the reinforcement effect of the geogrids under different loading conditions has not been thoroughly investigated, which hinders a comprehensive understanding of subgrade stabilization. Therefore, this paper aims to investigate and compare the behavior of a stabilized subgrade with geogrids reinforcement under cyclic loading and monotonic loading conditions. The experiments were conducted within a steel model box measuring 1.0 m (length), 1.0 m (width), and 1.2 m (height). The subgrade layer was consistently maintained at a thickness of 500 mm and strength of 2.5% California Bearing Ratio (CBR). A granular layer of high-quality material with a thickness of 200 mm was applied on top of the weak subgrade and geogrid was placed at the interface between the granular layer and subgrade. The tests were conducted in a controlled laboratory setting, specifically measuring vertical displacement in response to monotonic and cyclic loading. The results were then analyzed to evaluate ultimate bearing capacity, stiffness and rutting thereby estimating the effect of geogrids on stabilization of weak subgrades. These findings are anticipated to contribute significantly to the development of design guidelines for stabilized subgrade with geogrids reinforcement. By incorporating these insights, the design, and optimization of geogrid reinforcement systems for subgrade stabilization can be enhanced, ultimately resulting in improved performance and increased longevity of transportation infrastructure. -
Load-Bearing Behaviour of Geosynthetic Reinforced Soil Bridge Abutment for Railways with Waste Coal OB as Backfill Soil: Model Tests
Shilpa S. Vadavadagi, Sowmiya ChawlaThe chapter delves into the load-bearing behavior of geosynthetic reinforced soil bridge abutments, focusing on the use of waste coal overburden as backfill material. It begins by introducing the concept of mechanically stabilized earth (MSE) walls and their applications in railway infrastructure. The study then explores the challenges and benefits of using alternative backfill materials due to the global depletion of natural resources. The main body of the chapter presents detailed model tests and numerical analyses on back-to-back MSE walls subjected to cyclic loading, conducted at a 1:10 scale. These tests assess the feasibility and performance of waste coal overburden as a backfill material. The results of the model tests are compared with finite element analyses, showing a close correlation in wall displacements. Additionally, the chapter includes a parametric study and AI application to predict geogrid tensile forces, utilizing various machine learning models. The study concludes with key findings on the effectiveness of connected wall models in reducing displacement and the influence of overlapping lengths on tensile forces. Overall, the chapter offers valuable insights into the sustainable use of waste materials in civil engineering projects, making it a compelling read for professionals in the field.AI Generated
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AbstractBack-to-back MSE walls are a novel use of reinforced soil technology, and they are frequently implemented for bridge approaches and width-restricted highway and railway embankments. Urbanization has, however, led to an increase in the construction of transportation infrastructures. An investigation on model back-to-back MSE walls supporting railways has been carried out on a strong clay foundation. The foundation soil was clay with the desired shear strength. The model was conducted with a scale of 1/10th supporting railway tracks. Geogrid was used as a reinforcement, and wooden blocks were used as modular blocks for wall facings. The effects of different overlapping methods and distance between both walls on wall behavior have been evaluated. The scarcity of usable natural backfill soil for construction has been an alarming concern. Thus the recycled waste coal mine over dump was used as subballast/backfill soil. The coal mine overburden dump was used as a sustainable alternative to natural backfill/subballast. Cyclic loading simulating train loadings have been simulated in the model tests. Connected case of the model test was conducted in the laboratory. A finite element comparison of the model tests has also been conducted. A parametric study was carried out on back-to-back MSE walls subjected to heavy axle loads. Artificial intelligence-based ensemble models were used to predicted the geogrid tensile forces obtained from the parametric study. -
How Does Multi-layer Reinforcement Affect the Performance of Geogrid Stabilised Pavement on Soft Subgrades?
Amir Shahkolahi, Chaminda GallageThe chapter delves into the effectiveness of multi-layer geogrid reinforcement in enhancing the performance of geogrid-stabilised pavement on soft subgrades. It begins by discussing the current use of geosynthetics for subgrade stabilisation and the limitations of single-layer reinforcement. The study then presents a large-scale laboratory cyclic plate load test and a full-scale field trial, comparing the performance of unreinforced, single-reinforced, and double-reinforced pavement sections. The results demonstrate that double reinforcement significantly improves the stiffness and rutting performance of the granular layer and subgrade, offering a more robust solution compared to single-layer reinforcement. The chapter concludes by highlighting the advantages of multi-layer reinforcement and recommending optimal geogrid layer distances for maximum benefit.AI Generated
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AbstractMost studies and research projects in the world including past and on-going studies in Australia have been conducted on geosynthetic reinforced sections where the geosynthetic reinforcement was placed between the soft subgrade and the granular material. Very little experimental work has been conducted to document the mechanism of multiple layers of geogrid in the aggregate section. Most empirical and mechanistic-empirical design methods are also based on a single layer of geosynthetics reinforcement at the subgrade level. A critical need lies in the area of multiple layers of geogrid in the granular layer. This paper presents the mechanism of multi-layer geogrid reinforcement and its effect on the geogrid reinforced flexible pavements. Results from large-scale laboratory dynamic plate load tests as well as a full-scale field trial will be presented to compare the performance of double-layer geogrid reinforced granular pavement with single-layer reinforced and unreinforced sections. -
Subgrade Fluidization Under Cyclic Loading and Preventive Measure by Geosynthetics
Joseph Arivalagan, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Andy WarwickThe chapter investigates the onset of subgrade fluidization in soft soils due to dynamic stress and excess pore water pressure. It highlights the role of geosynthetics, such as geotextiles and geogrids, in stabilizing subsoils and improving drainage. The study also presents the performance of wick drains and geocomposites in mitigating soil fluidization potential. Experimental setups, including Dynamic Filtration Tests, are detailed, along with the analysis of soil samples from mud pumping sites. The chapter offers practical insights and solutions for enhancing the stability of ballast tracks and managing critical drainage conditions.AI Generated
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AbstractThe demand for increased axle loads and speeds of trains can diminish the stability of track substructure, leading to potential particle migration or slurry pumping under critical drainage conditions. This paper primarily focuses on the role of geosynthetics in mitigating the risk of soil fluidization potential under cyclic load. Laboratory experiments were conducted to evaluate the effectiveness of geosynthetics including geotextiles, geocomposites, and prefabricated vertical drains (PVDs). The laboratory study indicates that subgrade instability primarily occurs due to the migration of fines towards the subgrade surface and the substantial increase in moisture content (MC). Dynamic Filtration Tests (DFTs) reveal that geocomposite inclusion in rail tracks can reduce the fluidization potential of soft soils and the combined prefabricated vertical drains-geocomposite system can be used to mitigate the critical excess pore water pressure (EPWP) that accumulates in shallow or deeper soil layer due to activated radial drainage paths. -
Influence of Geosynthetic Encasement Stiffness on the Deformation Behavior of Geosynthetic Encased Stone Columns Composite Foundation Under Dynamic Loading
Mingchang Ji, Fuxiu Li, Yewei ZhengThe chapter delves into the impact of geosynthetic encasement stiffness on the dynamic performance of geosynthetic encased stone columns (GESC) composite foundations. Through shaking table tests, it examines how different levels of encasement stiffness influence the deformation behavior of GESC under dynamic loading. The study compares the performance of GESC with varying encasement materials, highlighting that higher stiffness encasements result in reduced settlement and improved structural integrity. The findings offer valuable insights into optimizing the design of GESC foundations for enhanced seismic resilience, particularly in challenging soil conditions.AI Generated
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AbstractThis paper details an experimental investigation involving shaking table tests on two composite foundations consisting of geosynthetic encased stone columns (GESC) with varying levels of geosynthetic encasement stiffness. The main objective is to examine the effect of the stiffness of geosynthetic encasement on the deformation behavior of the foundation models subjected to dynamic loading. The scaled-down foundation models were scaled in accordance with the similitude principles considering model size, stiffness of geosynthetic encasement, and input motions. The construction of the foundation models involved the use of gravel, sand, and geotextile reinforcement, and subsequently subjected to a sequence of sinusoidal excitations with rising amplitude. Results indicate the cumulative column settlements and soil settlements of the two foundation models increase notably as the input acceleration rises. The model with high stiffness of geosynthetic encasement has smaller settlements under the identical input motions in comparison to the model with low stiffness of geosynthetic encasement and has better seismic behavior in terms of settlement. In summary, with an increase in the stiffness of geosynthetic encasement, the deformation behavior of GESC composite foundation under dynamic loading is effectively improved. -
Effect of Geosynthetics in Asphalt Pavement Base Course on Bearing Reinforcement
Kenichi Sato, Mei Akimitsu, Masaru Shimazaki, Junichi Hironaka, Yusaku IsobeThe chapter delves into the impact of geosynthetics on the reinforcement of asphalt pavement base courses, addressing the critical issue of base course strength reduction due to rainwater penetration. It highlights the potential of geosynthetics in extending the service life of road pavements and reducing maintenance costs. The study employs both small soil tank experiments and FEM analysis using PLAXIS 3D to understand the friction characteristics and deformation behavior of geosynthetics. Key findings include the increased bearing capacity and reduced deformation in pavements reinforced with geosynthetics, with woven fabrics showing superior performance compared to geonets. The chapter concludes with a call for further research using geogrids and actual base course materials, emphasizing the need for accurate simulation of frictional resistance between geosynthetics and soil.AI Generated
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AbstractIt is an important issue to reduce the life cycle cost of Asphalt (As) pavement, which has a huge stock of more than 1.2 million km in Japan, in order to maintain and manage it. In this research, geosynthetics are installed in the base course to propose measures to extend the service life of As pavements by reinforcing the base course. In this paper, each material property was determined from friction property tests of geosynthetics and triaxial compression tests of silica sand. In addition, the effect of reinforcing the bearing capacity of the base course by laying geosynthetics was examined from both model experiments and analysis using loading tests in a small soil tank and FEM analysis. As a result, it was confirmed that the bearing capacity was increased by placing geosynthetics in the soil. -
Remediation of Landslide Affected Road Using Geocell Reinforcement
M. M. Biabani, D. Trani, B. TarrantThe chapter focuses on the remediation of a landslide-affected road in the Shoalhaven region of NSW, where heavy rainfall triggered major slope failures. The study highlights the use of geocell reinforcement as a temporary solution to stabilize the road embankment. It delves into the performance of geocell systems in mitigating lateral and vertical deformations, as well as the results of slope stability and finite element analyses. The findings demonstrate the effectiveness of geocell reinforcement in improving the performance of the road embankment, even under high groundwater levels and traffic loads. The chapter offers valuable insights into the design and implementation of geocell reinforcement in landslide-affected areas, making it a compelling read for professionals interested in geotechnical engineering and road infrastructure.AI Generated
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AbstractRecord-breaking rainfall from February to July 2022 caused widespread damage to multiple road sections within the local government area of Shoalhaven NSW, Australia. With approximately 2059 mm of rainfall in the Kangaroo Valley area alone, which was more than double the rainfall what residents would normally experience, Shoalhaven City Council experienced the wettest year on record. As a direct result of this rainfall, multiple sections along several roads have been severely affected by slope instability resulting in road damage (including 98 landslips affecting 23 roads) restricting local residents from accessing even nearby towns. Accordingly, the local Council sought feasible options that could provide temporary yet safe access to local residents. Among a number of feasible options considered, the proposed use of geocell reinforcement was selected as the preferred short-term remediation option to temporarily restore road use and facilitate safe passage. This paper presents a case study of the performance of a landslide-impacted section of Wattamolla Rd, Woodhill, NSW that was stabilised with geocell reinforcement. Limit equilibrium method and finite element analysis were undertaken to design the temporary access through the landslide affected section of the road. This study showed that geocell can effectively be used as a temporary solution and has feasibility as a permanent solution, where roads are impacted by landslide. Results showed that by confining infill material, geocell minimised axial deformations and lateral spreading and provided a semi-rigid platform that improved the stability of the road embankment.
- Title
- Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 8
- Editors
-
Cholachat Rujikiatkamjorn
Jianfeng Xue
Buddhima Indraratna
- Copyright Year
- 2025
- Publisher
- Springer Nature Singapore
- Electronic ISBN
- 978-981-9782-41-3
- Print ISBN
- 978-981-9782-40-6
- DOI
- https://doi.org/10.1007/978-981-97-8241-3
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