Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 3
Integrating Mega Project Planning, Airfield Behavior, and Rail Transition Zones
- 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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Bio-modification of Concrete for Pavements
Samuel Ng, Jian ChuThe chapter delves into the bio-modification of concrete for pavements using Microbial Induced Carbonate Precipitation (MICP), a method that enhances the bonding between cement and aggregates, thereby reducing cement usage. The study investigates the optimal treatment conditions for river sand and sea sand, demonstrating significant strength gains in lean concrete. Notably, the use of sea sand, a cheaper and more environmentally friendly alternative to river sand, is explored, highlighting potential cost savings and sustainability benefits. The research provides compelling evidence for the practical application of MICP in the construction industry, aiming to reduce greenhouse gas emissions and promote sustainable practices.AI Generated
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AbstractLean concrete has been used for pavements or footpaths. However, the production of cement generates CO2, and thus to achieve green construction, we need to use less cement or substitute materials for cement. One method to reduce cement usage is to modify the aggregates used for lean concrete so that the bonding between cement and aggregates can be stronger and thus less cement can be used. A Microbial Induced Carbonate Precipitation (MICP) process has been adopted to treat aggregates used for lean concrete. The study shows that the aggregates modified by a MICP treatment could increase the cubic strength by 21.4% at 28 days of curing. Further studies were also carried out to use sea sand rather than river sand for lean concrete. The results also indicate that the strength of lean concrete made with MICP-treated sea sand was also increased by 24.8% at 28 days of curing when compared to untreated lean concrete made with river sand. This study is meaningful as the supply of river sand is much less than sea sand. On the other hand, sea sand is considered not suitable for lean concrete as chloride in sea sand will weaken the strength of lean concrete. This study appears to have established a method for sea sand to be used for lean concrete for pavements. -
Finite Element Analysis on the Distribution of Stress Through Layered Soils
Isuri Wijayarathne, Nalin de SilvaThis chapter delves into the application of Finite Element Analysis (FEA) to model the distribution of stress through layered soils, comparing the results with Boussinesq's theory and experimental data. It investigates the impact of various soil properties, such as density, elastic modulus, and Poisson's ratio, on stress distribution. The study also examines how changes in the thickness and position of soil layers affect stress propagation. By analyzing different soil combinations and layer configurations, the chapter provides valuable insights into the reliability of using FEA for stress distribution analysis in geotechnical engineering. The findings offer practical implications for designing foundations and understanding the behavior of layered soil systems under vertical loads.AI Generated
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AbstractEvaluation of stress distribution through soil strata is one of the fundamentals of geotechnical analysis. Vertical stress is attributed to the loading intensity and geostatic stress. Even though many analytical methods have been developed idealizing the soil as a homogeneous, isotropic, and elastic material, the soil consists of layers of different characteristics in reality. In this study, stress distribution under a strip footing through a two-layered system consisting of purely sandy and purely clayey soils where the sand at the top was analyzed with the finite element method using Plaxis 2D geotechnical software. The Mohr–Coulomb model was used to feed the characteristics of the soils to the computer software. Different test cases were simulated by changing the soil strength parameters; friction angle of sandy soils, undrained cohesion of clayey soils, and the thickness of two layers for selected soil types, while the total depth of the soil system was 8 m. The numerical results were compared with Boussinesq’s solutions which are linear elastic solutions. It shows that stress at a selected point is small when the soils are loose and soft compared to the soils which are dense and stiff. The lower the thickness of the sand layer higher the stress at a selected point. Vertical stress values of Boussinesq’s solutions agree with the finite element analysis values when moving away from the footing both in horizontal and vertical directions. -
Balanced Mix Design in Kansas
Ya Gao, Mustaque Hossain, Blair Heptig, Steven HouserThe chapter explores the adoption of Balanced Mix Design (BMD) in Kansas, a method that addresses the limitations of the Superpave system in asphalt pavement design. It focuses on the use of the IDEAL-CT test to evaluate the cracking resistance of Hot-Mix Asphalt (HMA) mixtures. The study analyzes the test results from 2020 to 2023, revealing significant variations in cracking resistance across different districts and recycled material contents. Notably, mixtures with higher recycled material content exhibit lower cracking resistance, indicating potential future performance issues. The chapter also discusses the challenges and considerations for implementing BMD in Kansas, including high variability in test results and the need for further investigation into the factors affecting cracking resistance.AI Generated
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AbstractAASHTO PP 105-20 defines Balanced Mix Design (BMD) as “an asphalt mix design using performance tests on appropriately conditioned specimens that address multiple modes of distress considering mix aging, traffic, climate, and location within the pavement structure.” The traditional Superpave mix design process only considered volumetric properties and mainly focused on rutting resistance. However, the effect of recycled materials, such as Reclaimed Asphalt Pavement (RAP), Reclaimed Asphalt Shingles (RAS), etc., are not considered, and the performance properties of these mixtures cannot be captured in the Superpave system. BMD could provide a performance-optimization process for asphalt mixtures. This new approach involves performance testing, including cracking and rutting tests. Despite promotion from various entities, Kansas is cautiously approaching this new development of HMA mixture design. In this study, the cracking test, IDEAL-CT, was conducted on several Kansas HMA mixtures containing recycled materials, and the results were generated to assess the applications of BMD in Kansas. This paper describes this assessment. -
A Simple and Economical Procedure for the Design of Capping Layers in Earthworks
J. C. Gress, M. Ferreira, L. BeeuwsaertThe chapter delves into the design of capping layers in French road construction, highlighting the differences in approach compared to other countries. It focuses on the ‘two-layer structure’ used in French pavement design, which relies on the characteristics of the capping layer and subgrade. The design of granular capping layers is discussed, including a relationship established in 1983 to determine the required thickness based on the elastic modulus of the granular material and subgrade. The chapter also explores the design of stabilised capping layers, detailing the current French approach using the GTS guidelines. It proposes a new relationship to calculate the thickness of stabilised capping layers, aiming to provide more economical solutions. The new relationship is compared to the GTS guidelines, showing good agreement for specific scenarios but less correlation for intermediate values. The chapter concludes by emphasizing the need for further refinement of the proposed relationship to better accommodate various stiffnesses at the formation level.AI Generated
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AbstractIn French road structure design, the capping layer is by default an essential element of it as it has to fulfil many functions. From an economical point of view, it is important to optimise its thickness as it is typically either made of imported granular or site-won stabilised materials. In 1983, a relationship was established by the main author to determine the thickness of granular capping layers covering all situations in terms of stiffness characteristics (subgrade, formation level and granular material). To date, in the case of stabilised capping layers, French engineers have simply been relying on well-established empirical tables published in the ‘GTS’ national notes for guidance. The major drawback of these tables is that only a few scenarios are covered. This article describes these methods of determining the thickness capping layers and completes it with a new approach in the case of stabilised materials so that all situations can be considered. -
Impact of Spatial Variability of Material Properties Compacted Geomaterials on Acceptance
Cesar Tirado, Soheil Nazarian, Navneet GargThe chapter delves into the critical role of proper compaction in achieving desired pavement performance, emphasizing the limitations of density measurements in ensuring construction quality. It explores the transition to modulus-based acceptance processes, which better align with mechanistic-empirical design parameters. The study analyzes the variability of compacted geomaterials across diverse construction sites, revealing significant spatial variability in modulus and moisture content. It highlights the challenges in establishing target moduli and the impact of this variability on acceptance processes. The chapter also discusses the importance of accounting for moisture content and the state of stress imparted by testing devices. Notably, it shows that achieving target density does not guarantee performance, and appropriate tolerances should be allowed to minimize disputes between contractors and transportation agencies.AI Generated
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AbstractProper compaction of unbound materials in the pavement structure is a key component towards achieving the desired performance of a well-designed pavement. Transportation agencies commonly use the nuclear density gauge as a part of their quality management program to ensure the desired compaction density is achieved. Because the mechanistic-empirical pavement structural design process makes use of modulus to characterize geomaterials, transportation agencies are seeking to transition to modulus-based methods for quality management. This paper presents the findings of a comprehensive study aimed at understanding the impact of in situ variability in stiffness, moisture content, and density of compacted geomaterials on construction quality acceptance. To conduct this study, a dataset was compiled from test sections selected from various pavement construction sites throughout the United States. A grid pattern of spot test locations was established along the test section where modulus-based testing using lightweight deflectometer alongside moisture and density measurements was systematically conducted. The study revealed instances where sites that met density requirements failed to meet acceptance when using a modulus criterion. Thus, achieving density is necessary but not sufficient, as the density and modulus are not directly related. -
Laboratory Testing to Design an Asphalt-Treated Permeable Base for the Federal Highway Administration’s Pavement Test Facility
Ismaail Ghaaowd, Michael Adams, Jennifer Nicks, Scott ParobeckThe chapter details the extensive laboratory testing conducted to design an asphalt-treated permeable base for the Federal Highway Administration’s Pavement Test Facility. It highlights the importance of selecting base materials with optimal drainage qualities and the impact of binder content and grade on the performance of these materials. The study evaluates the resilient modulus, permeability, and tensile strength ratio of various aggregate and binder combinations, providing valuable data for pavement engineers. The results offer insights into the balance between stiffness and drainability, crucial for designing resilient and durable pavement structures. The chapter concludes with the selection of an optimal job mix formula for the asphalt-treated permeable base, which meets the required performance criteria for the Federal Highway Administration’s facility.AI Generated
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AbstractThe Federal Highway Administration reconstructed a new Pavement Test Facility (PTF) to perform accelerated testing on various pavement structures. Three of the eleven lanes were designed with an asphalt-treated permeable base (ATPB) to evaluate its impact on pavement response and performance. ATPBs are created by mixing an open-graded aggregate with a small percentage of asphalt binder; however, the job mix formula (JMF) and the compacted density of the mix all influence the stiffness, strength, and permeability of the resulting ATPB. To develop an appropriate JMF for the PTF, various unbound and ATPB specimens were prepared using three different locally sourced open-graded aggregates with 0 to 4% asphalt binder. Asphalt permeameter test specimens, 150 mm in diameter and 116 mm in height, were prepared using a Superpave gyratory compactor which also determines the minimum void ratio and the maximum density of the mix. The stiffness and strength of the ATPB specimens were measured by performing resilient modulus and quick shear tests on 150 mm by 300 mm compacted specimens. The stripping resistance of select ATPB specimens was evaluated by conducting tensile strength ratio tests. The findings showed that the asphalt binder content had a negative relationship with permeability and air voids but a positive relationship with stiffness. The binder grade and specimen gradation had a significant impact on moisture susceptibility. The results informed the selection of the ATBP JMF for the PTF. This paper provides an overview of the PTF design requirements and the ATPB experimental approach with the results. -
Investigation of Rut Formation in Asphalt Concrete Pavement
Bagdat Teltayev, Alibay Iskakbayev, Arystan Massanov, Yerbol Aitbayev, Azamat ZhaisanbayevThe chapter delves into the intricate issue of rutting in asphalt concrete pavements, focusing on a specific road section in Almaty, Kazakhstan. It presents a comprehensive analysis of the geometric and statistical characteristics of rut depths, traffic intensity, and the rutting effect of various public transport vehicles. The study underscores the inadequacies of current regulatory methods in predicting rut accumulation and highlights the need for advanced models to address this critical infrastructure challenge. Through detailed measurements and sophisticated calculations, the chapter offers valuable insights into the complex dynamics of rut formation, making it a must-read for professionals seeking to enhance the durability and safety of road pavements.AI Generated
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AbstractIn the article, in field (on the bus lane of a city road) using modeling and traffic flow analysis methods, the rut formation on an asphalt concrete pavement is studied. The maximum total rut depth on the road section under consideration reaches 92 mm; 5% of measured rut depths exceed 35 mm; 75% of them are more than the permissible value. Almost 1100 trolleybuses and buses pass along the bus lane of the road per day, the relative rutting effect of which is from 3.04 to 6.59; their permissible number of passages ranges from 37,823 to 82,069. The pavement structure on the experimental section with a total thickness of 50 cm is too weak for the actual traffic flow, which was the main reason for the premature destruction of the road due to unacceptable track sizes on the asphalt concrete surface. -
Evaluating the Effects of Particle Size Distribution on the Hydraulic Capabilities of the Granular Subbase Layers
Abishek R R, Sireesh SarideThe chapter explores the significance of particle size distribution (PSD) in the hydraulic performance of granular subbase (GSB) layers in flexible pavements. It delves into the structural and hydraulic functions of GSB layers, emphasizing their role in load distribution and water dissipation. The study evaluates the in-plane permeability and internal stability of GSB layers, highlighting the importance of optimal gradation to prevent moisture stagnation and premature pavement failure. Experimental tests using large-scale permeameters and analytical models in MATLAB validate the findings, offering a detailed methodology for assessing GSB layer performance.AI Generated
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AbstractThe hydraulic performance of the flexible pavement is defined by the particle size distribution (PSD), thickness, and degree of compaction of the Granular Subbase (GSB) layer. Transportation agencies like the Indian Roads Congress (IRC) and the American Association of State Highway and Transportation Officials (AASHTO) insist that the GSB layer intends to have a minimum in-plane permeability of 300 m/day to attain optimal performance. In addition, the designers should consider the concept of internal stability of granular filters so that a stable gradation is ensured even under the impact of external factors such as seepage and vibrations. In this study, newly proposed GSB gradations were evaluated for their in-plane permeability characteristics and internal stability, and the results were compared with those of the existing GSB gradations. The in-plane permeability characteristics are evaluated experimentally through a large-scale permeameter under different hydraulic gradients. The internal stability of the GSB gradations is evaluated analytically using the internal stability index. The comprehensive test results indicated that the effects of PSD and hydraulic gradients highly influenced the in-plane permeability of the GSB. The open-graded GSB materials are intended to have a higher rate of permeability and a lower internal stability index than the dense-graded GSB materials. -
Geotechnical and Geophysical Characterization of Delhi Metro Tunnel Alignment: Section Between RK Ashram and Nabi Karim
Ravi Sundaram, Sorabh Gupta, Sanjay Gupta, Saurabh SharmaThe chapter delves into the intricate geotechnical and geophysical characterization of the Delhi Metro tunnel alignment between RK Ashram and Nabi Karim stations. It begins with an introduction to the Delhi Metro system and its expansion plans, focusing on the specific section under construction. The geological context of the project area is detailed, with an emphasis on the varying strata along the alignment. The scope of the investigation is outlined, including borehole drilling, dilatometer tests, electrical resistivity tomography, and seismic refraction tests. Each station, RK Ashram and Nabi Karim, is examined individually, with detailed analyses of borehole data, geophysical tests, and the resulting combined geotechnical and geophysical profiles. The tunnel section between the stations is also thoroughly investigated, with a focus on the overburden and rock characteristics. The chapter concludes by highlighting the importance of combining geotechnical and geophysical methods for effective site characterization and reducing construction risks. The comprehensive approach and detailed methodology make this chapter a valuable resource for professionals in the field.AI Generated
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AbstractTo evaluate the stratigraphy along an underground tunnel alignment between RK Ashram and Nabi Karim for the Delhi Metro, a detailed study was performed. This included geotechnical investigation by drilling boreholes, performing in situ permeability tests and dilatometer tests together with geophysical surveys such as seismic refraction tests, electrical resistivity tomography, and cross-hole seismic tests. Using a combination of geotechnical and geophysical testing, a reliable geotechnical-cum-geophysical model was developed to characterize the ground profile and trend of rock along the metro alignment. -
Foam Penetration Behavior in EPB Shield Tunneling: Insights from Model Experiments
He Huang, Wan-Huan ZhouThe chapter delves into the intricate dynamics of foam penetration during EPB shield tunneling, leveraging model experiments to simulate real-world conditions. It examines the pore pressure distribution and foam velocity, revealing two distinct hydraulic gradient regions in the sand column. The study finds a power-law relationship between foam velocity and hydraulic gradient, similar to Darcy's law but with different coefficients. These findings suggest that foam penetration can enhance tunnel face stability, akin to filter cake in slurry shield tunneling. The correlation between the permeability coefficient and foam properties with sand characteristics offers valuable insights for future research and practical applications in tunneling projects.AI Generated
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AbstractSoil conditioning is crucial in maintaining stability during earth pressure balance (EPB) shield tunneling. Understanding the properties of the soil conditioner and its impact on soil is essential for ensuring the safety of the tunneling. This study focuses on investigating the penetration behavior of foam, a commonly used soil conditioner, in saturated sand. Experiments were conducted using a sand column device to simulate the foam penetration process in different sand beds. The experimental results reveal that foam penetration in the sand forms two linear pore pressure drop regions with different gradients, with the foam penetration area occupying the majority of the pore pressure. The foam penetration also introduces a flow velocity reduction in the sand column, resulting in blocking. Furthermore, a notable correlation emerged between the foam penetration velocity and the hydraulic gradient, akin to Darcy's law but with a different expression equation. The findings contribute to enhancing our understanding of soil conditioning in EPB shield tunneling and support the design of safer and more efficient tunneling processes. -
Geotechnical Conditions for Construction of Savski Trg Metro Station as a Part of the Belgrade Metro Line One
Nemanja Stanic, Dragoslav Rakic, Josip Isek, Slavoljub SimicThe chapter delves into the geotechnical conditions for the construction of the Savski Trg Metro Station, a crucial part of Belgrade's Metro Line One. It begins with an introduction to the historical context of Belgrade's metro line planning and the specifics of the Savski Trg interchange station. The geotechnical investigations conducted in 2021 and 2022 are extensively covered, including engineering-geological mapping, exploratory drilling, piezometer boreholes, and geophysical surveys. The discovered geological units, ranging from Middle and Upper Miocene sediments to recent anthropogenic deposits, are described in detail. The results of field and laboratory tests, such as SPT and CPT tests, are used to determine physical and mechanical parameters for geotechnical modeling. The chapter also outlines the construction phases of the metro station, including the use of Plaxis 2D Ultimate software for geotechnical analyses. The analyses involve bottom-up and top-down construction methods, and the results demonstrate the stability and safety of the designed retaining systems. The chapter concludes with a verification of the construction methods and the overall stability of the retaining structures, providing a comprehensive guide for the construction of this complex metro station.AI Generated
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AbstractIn order to solve serious traffic congestion in Belgrade, a number of studies regarding the Belgrade Metro construction have been carried out since 1973. However, only in 2019, the routes of the future metro lines 1 and 2 were defined as a part of the General Metro Construction Project. The lines are designed to intersect at the location of Sava Square, where an interchange metro station will be built. It represents a complex geotechnical structure consisting of three different parts: a part of the metro station for line 1, a part of the metro station for line 2, and a common part for both metro lines. Due to the complexity of construction and different depths of the diaphragm walls, deeper than 40 m on the part of metro line 2, phased construction is planned. In this regard, determination of geotechnical modeling for each part separately as well as geotechnical design are presented including the analysis of phased methods of excavation, influence of pore and effective stresses on the stability of the diaphragm wall, lateral and vertical displacements as well as the interaction between diaphragm walls and reinforced concrete slabs. -
Geotechnical Considerations in Buried Pipeline Design Crossing Transport Corridors
Burt Look, Roozbeh MirjaliliThe chapter delves into the critical geotechnical considerations for buried pipeline design, specifically focusing on the challenges posed by soil properties and vehicle loads at transport corridor crossings. It examines the limitations of the current Australian Standard AS2566, particularly in equating embedment zone soil and native soil parameters. The authors employ a finite element method (FEM) to assess pipe deflections, revealing significant differences compared to the AS2566 approach. The FEM analysis accounts for variations in soil stiffness and compaction efforts, providing a more accurate representation of pipe behavior under various ground conditions. The study highlights the importance of considering these factors to ensure acceptable pipe deflections and safe pipeline design. The chapter also includes a sensitivity analysis that explores the impact of different soil modulus values and compaction efforts, offering valuable insights into the design and construction of buried pipelines.AI Generated
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AbstractThe Australian standard (AS2566) for buried pipes provides a design methodology and recommends ground parameters for design. The values referred to as soil modulus equate an embedment modulus (which is a soil–pipe modulus reaction) and a native soil modulus. For low-height fills and small-diameter pipes, the equated native soil modulus value used does not significantly affect a calculated deflection. As live load, depth or pipe diameter increases, these inconsistencies become apparent. Where pipeline crossings at road or rail corridors occur, the limitations of AS2566 become apparent. When finite element method (FEM) is used to examine soil–pipe interactions, input soil parameter values different from those provided in AS2566 must then be used. Case studies of a finite element analysis for a large-diameter buried pipe subject to traffic loading are compared with the AS2566 design procedure. The limitations of equations used in calculating the pipe deflection are shown. -
Analyses of Rules for Distinctions Between Shallow and Deep Tunnels
Yanyong Xiang, Hasan M. D. ShahadThe chapter 'Analyses of Rules for Distinctions Between Shallow and Deep Tunnels' delves into the critical distinctions between shallow and deep tunnels, focusing on the strategic implications for tunneling. It introduces the concept of primary supports with flexible stiffness for deep tunnels and high stiffness for shallow tunnels, emphasizing the importance of ground arching and environmental stability. The study critiques current practices, such as using the height of a potential collapse arch and empirical ground pressure measurements, and introduces theoretical models like the Terzaghi ground pressure theory and Protodyakonov model. Numerical simulations are employed to verify the theoretical findings, highlighting significant differences between calculated distinction depths and those specified in design codes. The chapter concludes with observations on the relationship between ground pressure ratios, rock stability, and distinction depths, providing valuable insights for professionals in the field.AI Generated
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AbstractDistinctions between shallow and deep tunnels are conducive to pursuing suitable strategies for tunneling. This paper first examines the current practices on the rules for distinctions between shallow and deep tunnels and then conducts both theoretical and numerical analyses of these rules for tunneling in homogeneous ground, to shed some observations on the relevant issues: (1) The distinction depth increases when the prescribed ground pressure ratio decreases and vice versa. (2) For a specific ground pressure ratio value, the worse the rock stability, the larger the distinction depth. (3) The distinction depths calculated by using the Terzaghi formula are more conservative than the China design code. (4) The distinction depths by using the Protodyakonov formula are even more conservative. (5) The distinction depths by using the Terzaghi formula can be verified by finite element simulations of tunnel excavations. -
Rheological Consolidation Characteristics of Soil Around Tunnel Under Exacerbated Leakage Conditions Based on Boltzmann Function
Anfeng Hu, Senlin Xie, Zhirong XiaoThe chapter delves into the complex interplay between soil consolidation and rheological properties around tunnels, particularly under conditions of exacerbated leakage. It introduces the Boltzmann function to model the continuous increase in tunnel permeability, which has been overlooked in previous studies. The research employs the general Voigt model to describe the rheological properties of saturated soft soil and investigates the dissipation of excess pore water pressure under different leakage exacerbation modes. The study highlights that the dissipation rate and shape of the excess pore water pressure curve are closely tied to the specific leakage deterioration pattern. Notably, the presence of independent dampers in the Voigt model leads to incomplete dissipation of excess pore water pressure, regardless of the leakage pattern. The findings provide valuable insights into the long-term behavior of tunnels in soft, saturated soil, contributing to the design and maintenance of safer and more durable underground infrastructure.AI Generated
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AbstractThe Boltzmann growth function is introduced to study the soil consolidation behavior caused by shield construction disturbance when the lining permeability deteriorates, and the general Voigt model is used to characterize the rheological properties of saturated soft soil. Based on the Terzaghi–Rendulic theory, the governing equations for the consolidation of saturated soft soil around the tunnel were established. The shield tunnel project in Kunming’s peat soft soil area is taken as an example to analyze the consolidation property. The results show the speed and curve shape of the excess pore water pressure dissipation are closely related to the leakage exacerbation mode of the lining. Increasing the number of Kelvin bodies results in slower dissipation of pore pressure, resulting in incomplete dissipation and pronounced step-like behavior. -
Simulation Study on the Construction Parameters of Ultra-Deep Diaphragm Wall of High Pressurized Water Sand Layer
Meng Li, Yao Shan, Zhining Chen, Peng DaiThe chapter delves into the critical role of diaphragm walls in maintaining the stability of deep foundation pits, particularly in complex geological conditions. It highlights the dynamic changes in soil pressure and displacement fields during excavation, which can significantly affect the safety of surrounding structures. The study employs numerical simulation and orthogonal experiments to evaluate the impact of various construction parameters, such as elastic modulus, wall thickness, support system stiffness, and cross-sectional area. The research focuses on optimizing these parameters to control the horizontal displacement of diaphragm walls, ensuring the safety and reliability of deep foundation pits in high-pressure water sand layers. The findings provide valuable insights for engineers and researchers aiming to enhance the design and construction practices of such critical infrastructure projects.AI Generated
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AbstractWhen a large deep foundation pit is constructed in a typical complex stratum with high pressurized water sand layer, the displacement response of the diaphragm wall will develop gradually and dynamically with the active loss or passive extrusion of the stratum, which will put the enclosure structure in a dangerous state once it exceeds the limit value required by the current standard. Reasonable determination of the important construction parameters of diaphragm wall under such stratigraphic conditions is essential to the fine control of deep foundation pit enclosure structure construction, and is also a prerequisite to ensure the safety and reliability of deep foundation pits and the surrounding environment. This paper uses numerical simulation to carry out orthogonal experiments, selects the elastic modulus of diaphragm wall, diaphragm wall thickness, support stiffness and support cross-sectional area as experimental factors, takes the horizontal displacement of the diaphragm wall as the safety evaluation index, and the reliability of the model was verified through on-site testing. The innovative construction parameter selection method proposed in this paper will provide a basis for the design of deep foundation pit envelope structure, and provide a reference for the design of intelligent foundation pit. -
Observations of Tunnelling Effects on a Large Diameter Jointed Steel Pipe in Rock
Ashok Peiris, Audrey Poon, Kim ChanThis chapter delves into the monitoring results and observations of tunnelling effects on a large diameter jointed steel pipe in rock. The study focuses on the impact of road tunnel excavation on a 2.5-meter diameter pressurized water pipe, highlighting the changes in rock stress and displacements at different relative positions between the tunnel face and pipe. The authors present extensive data from extensometers, inclinometers, and multi-directional strain gauges, providing a comprehensive analysis of ground movements and pipe deformations. The chapter discusses the progression of external monitoring results and internal strain measurements, offering valuable insights into the behavior of jointed pipes under tunnelling conditions. The case study involves a major road project in New South Wales, where twin road tunnels were constructed over a 96-year-old water tunnel, presenting a unique challenge due to the high lock-in stresses in the rock. The chapter concludes with a summary of the observed stress relief movements and their implications for the design and analysis of pipe-rock interactions associated with tunnel excavations.AI Generated
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AbstractThis paper presents the monitoring results of a 2.5 m diameter pressurized water supply tunnel (Water Tunnel) with segmental steel liners, subjected to ground movements caused by the excavation of a twin road tunnels crossing above the Water Tunnel with an excavation clearance of 7.5 m excavation. Discussion is provided on the progression of the external monitoring results for ground movements based on extensometers, inclinometers and piezometers, as well as internal monitoring results for the Pressure Tunnel based on multi-directional strain gauges. -
Coupled Hydro-Thermal Response of Unsaturated Soils Under Non-isothermal Conditions
Arvind Kumar, Asal Bidarmaghz, Arman KhoshghalbThe chapter delves into the intricate hydro-thermal processes in unsaturated soils under non-isothermal conditions, emphasizing the significance of these processes in enhancing the energy efficiency of shallow geothermal energy systems. It introduces the concept of energy piles and their role in reducing fossil fuel consumption by harnessing shallow geothermal energy. The study focuses on the unique behavior of energy piles in unsaturated soils, highlighting the differences in energy efficiency and mechanical response compared to saturated or dry soils. The authors develop a numerical model to validate the reliability of the hydro-thermal response in unsaturated soils, using coarse sand as a case study. The chapter presents preliminary results demonstrating the impact of coupled multiphysical processes on heat transfer and moisture migration, showcasing the advantage of faster thermal response in partially saturated soils. The study concludes by discussing the implications of these findings on the performance of thermal applications in unsaturated soils, particularly in the context of energy piles, and sets the stage for future research on the mechanical response of energy piles in these conditions.AI Generated
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AbstractEnergy piles are often partly or fully embedded in unsaturated soils. Design of energy piles assuming the surrounding soil is dry or fully saturated may lead to underestimation or overestimation of their performance, in terms of heat exchange efficiency as well as structural stability. To achieve a safe and efficient design of energy piles in unsaturated soils, it is crucial to quantify the coupled hydro-thermal (HT) processes involved in unsaturated soils subjected to non-isothermal conditions. Studies focusing fundamentally on the critical TH multiphysical processes surrounding energy piles are scarce, especially for unsaturated soils. Much of the literature on energy piles in unsaturated soils employ simplified conduction–convection heat transfer in porous media using the saturation-dependent thermal conductivity for their simulations while avoiding detailed mass and heat transfer and without any emphasis on vapor transport and latent heat transfer. This study discusses the coupled multiphysics processes in unsaturated soils with careful attention on the effect of vapor transport and latent heat transfer. Overall, the study proposes a numerical modeling scheme for unsaturated soils under non-isothermal conditions and provides a detailed analysis of the heat and moisture migration in unsaturated coarse sand.
- Title
- Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 3
- Editors
-
Cholachat Rujikiatkamjorn
Jianfeng Xue
Buddhima Indraratna
- Copyright Year
- 2025
- Publisher
- Springer Nature Singapore
- Electronic ISBN
- 978-981-9782-21-5
- Print ISBN
- 978-981-9782-20-8
- DOI
- https://doi.org/10.1007/978-981-97-8221-5
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