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2025 | Book

Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 4

Applied Ground Improvement Methods

Editors: Cholachat Rujikiatkamjorn, Jianfeng Xue, Buddhima Indraratna

Publisher: Springer Nature Singapore

Book Series : Lecture Notes in Civil Engineering

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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.

Table of Contents

Frontmatter
Comparing Chemical Stabilizers for Improving Iowa Granular Road Bearing Capacity

Granular roads in Iowa are essential for transporting agricultural goods and providing access to isolated regions such as those containing rural homes. Regular maintenance is necessary to ensure the safety and comfort of all types of vehicles, including heavy farm and quarry trucks, as well as local residents’ cars. Strength and stability of a road’s aggregate layer are critical to the overall performance and longevity of granular roads. This study seeks to evaluate the performance of different chemical stabilizers for improving aggregate layer strength. Limestone, the primary aggregate utilized in Iowa was used in the study, and three proprietary chemical stabilizers were tested, including two ionic-based stabilizers and a single enzyme-based stabilizer. Laboratory-based California Bearing Ratio (CBR) tests were used to measure the strength. The optimized subgrade soil fraction that provided the highest CBR value was found to lie between 6 and 8%. The data were analyzed using a two-way Analysis of Variance (ANOVA) test that showed that the number of curing days, the type of chemical, and their interaction played a significant role in the CBR value of aggregate materials. Overall, this study highlights the importance of chemical stabilizers in improving the strength of granular roads in Iowa and provides valuable insights with respect to road maintenance and construction.

Mohammad Ahmad Alsheyab, Bo Yang, Halil Ceylan, Sunghwan Kim
Compaction Properties of Alkali-Activated Fly Ash and Slag Blends with Demolition Wastes

Rapid growth in infrastructure development has been occurring for many years as a result of urbanization and rise in global population, especially in road construction, where natural virgin aggregate and cement binder have been used heavily. Such growth is considered unsustainable due to the steep decline of natural resources in the past decades, as well as the excessive carbon dioxide coming from the production of cement. This study focuses on solving such problems by replacing natural virgin aggregate with demolition wastes such as crushed brick, recycled concrete, and reclaimed asphalt and substituting cement with geopolymer binder. While demolition wastes as replacement materials is not a new idea, one-part geopolymer, however, is a completely novel and better technology when compared to traditional methods of binding aggregates, especially in terms of sustainability, quick preparation time, and potential strength improvement in pavement base. One-part geopolymer technology involves the incorporation of fly ash and slag as precursor mixture as well as an alkali activator (sodium hydroxide) to develop the structural bond among the main aggregates for the majority of its strength. This study will investigate the effectiveness of this technology while being used in pavement base application. Evaluation of compaction properties will be carried out using different extensive geotechnical laboratory tests in combination with some compressive strength tests so that a conclusion can be reached. As a major benefit, the adoption of demolition wastes and one-part geopolymer will reduce the carbon dioxide output significantly, making them sustainable for generations.

Tung Doan, Arul Arulrajah, Suksun Horpibulsuk, Jian Chu, Guillermo A. Narsilio, Stephen Darmawan
Spectral-Based Solutions for Consolidation Analysis of Multilayered Soil under Various Drainage Boundary Conditions

Consolidation and settlement of soft soil ground are the main problems encountered for geotechnical engineers, and drainage boundary conditions play a crucial role in consolidation analysis and settlement prediction. Despite some theoretical approaches that have been proposed incorporating some particular drainage boundary conditions, there remains a dearth of rigorous analytical solutions for multilayered soils that effectively capture various drainage boundary conditions. This study presents a novel approach where the spectral method is used to capture the impact that drainage boundary condition has on the consolidation of multilayered soil. The drainage boundary condition over time is considered, while the excess pore water pressure (EPWP) profile across different soil layers can be described as a single expression using matrix operations. This proposed method is then verified with field investigations where the varying drainage condition is captured and compared with other solutions. The results show that the consolidation behavior will be overestimated if the traditional boundary conditions are used and the proposed method can predict the consolidation of soil with greater accuracy and flexibility. EPWP and settlement at different depths can be estimated such that they agree better with the field data, and the study also indicates that there is a noticeable discrepancy in the predicted consolidation when the drainage boundary condition is not considered properly.

Bin-Hua Xu, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Ning He, Thanh Trung Nguyen
Fundamental Study on Swelling Potential of Construction Sludge Treated with Cement and Paper Sludge Ash-Based Stabilizer

Construction sludge is generated from excavation works during tunnel constructions and pile constructions. The strength is very low because the sludge contains a lot of water. Thereby, the sludge cannot be used directly for construction of embankment, road subgrade, and back-filling. To overcome this issue, stabilizers can be used to improve the strength of the sludge. Meanwhile, paper sludge ash-based stabilizer (PSAS) has been recently developed in Japan. The paper sludge ash is a waste generated by the incineration of paper sludge discharged from paper mills. In this study, the PSAS and blast furnace cement class B (BFCB) were used as stabilizers to improve the strength of sludge. Then, the swelling potential of treated sludge with different initial water contents and per-compaction curing periods was investigated. CBR specimens were prepared in the laboratory to evaluate the swelling potential. The swelling potential of the treated sludge samples was compared with that of the untreated samples. Based on the test results, discussion was made on the effects of initial water content and per-compaction curing period on the swelling potential of treated and untreated samples. According to the result analysis, the lower the water content during compaction, the higher the swelling potential. However, a significant reduction of swelling potential was observed for the treated soil in comparison with the untreated samples. Furthermore, the difference in the swelling potential of treated samples due to differences in the number of per-compactions curing periods was insignificant.

Kapila Ranjith Withanage, Kimitoshi Hayano, Hiromoto Yamauchi
Effects of Wet–Dry Cycles on Strength and Microstructural Behavior of Expansive Soil Stabilized with Alkali-Activated GGBFS

Expansive soils pose various problems to the existing transportation infrastructures by causing damages to pavements, railways, and embankments due to differential settlement, and volume changes in soils. Therefore, expansive soil if used in pavements must be stabilized by using some suitable means. The present study investigates the strength and durability of expansive soil stabilized with alkali-activated GGBFS (ground granulated blast furnace slag). In order to accelerate the hydration process, an alkali activator of low molarity (i.e., 5 M NaOH) is used to stabilize the subgrade expansive soil. GGBFS and alkali-activated GGBFS were added in the proportions of 5, 10, 15, 20, 25, and 30% to check the improvement in the strength properties of expansive soils after different periods of curing. The strength properties of stabilized soil were assessed by conducting various laboratory tests like unconfined compressive strength (UCS) and California bearing ratio (CBR). Durability study was also done by subjecting the soil specimens to 12 wet–dry cycles. The utilization potential of alkali activated GGBFS has been assessed from the mechanical, mineralogical, and morphological properties of stabilized soil. It was found that alkali-activated GGBFS can be effectively utilized for highway subgrade and sub-base applications.

Srikanth Kandalai, Anjan Patel
Soil Improvement Using Combined Vacuum and Fill Sur-Charge Method for the 3rd Runway of the Suvarnabhumi International Airport

This paper presents a case study for soil improvement using a combined vacuum and fill sur-charge preloading method for the 3rd runway of the Suvarnabhumi International Airport in Bangkok, Thailand. Prefabricated vertical drains of 10 m long was used. The preloading consisted of an average of 86 kPa of vacuum pressure plus a 22 kPa of fill sur-charge due to the granular fill and drainage layer. The vacuum preloading system adopted is described. Monitored settlements and pore water pressures are presented. The average ground settled monitored is around 70 cm and the average degree of consolidation as estimated using settlement data is higher than 90%. Degree of consolidation is also calculated using pores water pressure distribution monitored along the depth which gave a good verification of the degree of consolidation achieved.

Laudanski Gaëtan, Sevestre Julien, Chu Jian
Liquefaction Mitigation of a Submerged Silty Sand Site in Seismic Zone IV of India by Dynamic Compaction and Soil Replacement

Soil Liquefaction has been a major cause of damage to many Civil Engineering Structures like multi-storey buildings, storage tanks, bridges, etc. in seismically active areas during many past earthquakes. Therefore, it is essentially required to do Liquefaction Potential Analysis based on a detailed Geotechnical Investigation of a Site located in a seismically active zone and further suggest viable Liquefaction Mitigation Techniques for the Project concerned which may be a combination of more than one method using geotechnical fundamentals to produce an adequate solution for the concerned Site. A case study is being discussed and presented here wherein a combination of two most economical and easy to implement liquefaction mitigation techniques were recommended to be adopted at the proposed Seismic Zone IV site of India with a view that we could save our valuable available natural Mother Earth resources for our future generations with environmental sustainability as the prime focus. A combination of Dynamic Compaction and Soil Replacement at the top resulted in improved densification as well as converting a few liquefiable soil layers present to non-liquefiable ones, still leaving a few un-improved liquefiable layers at little shallow depths just below the ground level which made us to decide for geotechnical recommendations for the proposed Structure in favour of conventional footings with a rider to structurally stiffen the Structure to accommodate post-earthquake settlements, thus, avoiding deep pile foundation which would not have been cost-effective and could have used many available natural resources in the form of different Building Materials.

Anurag Kapoor
Advance Modeling of Soil Cement Mixing for Deep Excavation Using Plaxis 2D Concrete Model

Wet speed mixing (WSM) and deep cement mixing (DCM) are adopted as ground improvements on soft soil to support temporary earth retaining walls below excavation level for deep excavation. WSM and DCM are commonly modeled using Plaxis Mohr–coulomb model (method B) with undrained shear strength. Concrete model is adopted to model ground improvement with more realistic stress distribution to account for non-linearity of material behavior, and model tension in elastic until the tensile strength is reached. Case study of model WSM and DCM by using both Mohr–coulomb model and Concrete model for two projects successfully completed at reclamation land overlaying on soft Kallang Formation are presented, one is about 16 m deep excavation with temporary steel soldier pile wall lagged with sheet piles supported by 4-layer temporary strutting system and 4 m thick DCM at base of excavation. The other is for 19 m deep excavation with temporary steel pipe piles wall support by two-layer temporary steel struts and 4–11 m thick WSM at base of excavation.

Wenjiu Long, Siaw Shen Chong
Behaviour of Soft Soil Improved with Prefabricated Vertical Drains in Railways Under Cyclic Loading

Soft clays are prevalent in coastal areas of Australia, exhibiting low bearing capacity and considerable settlement upon loading, and must be improved as subgrades to meet the increasing demand for railway transportation soft soils beneath railway embankments are often subjected to train-induced cyclic loads generating higher excess pore water pressure (EPWP), reduced bearing capacity, and deformations under poor drainage conditions. These often lead to reduced efficiency in transportation and maintenance costs. Thus, it is important to investigate the behaviour of soft soils subjected to heavy cyclic loading and preventative actions. This paper provides a comprehensive review of the role of Prefabricated Vertical Drains (PVDs) in mitigating failures associated with railway subgrades under cyclic loading.

Sachini Dissanayake, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Aruni Abeywickrama
The Mechanical Behavior of Sand Treated with Sodium Silicate Under Saturated Condition Subjected to Wetting–Drying Cycles

Ground improvement is crucial for the design of structures built on weak soil, both currently and in the future. Chemical stabilization is increasingly favored in ground improvement practice. However, existing literature has focused on studying soil stabilized with conventional materials such as cement and lime, rather than exploring the potential of environmentally suitable chemical stabilizers. Furthermore, a comprehensive assessment of the impact of wetting–drying cycles and curing times has been limited in previous research. This study aims to address these gaps by investigating the mechanical behavior of sand treated with sodium silicate under saturated conditions, both before and after undergoing wetting–drying cycles. Direct shear tests were conducted to comprehensively analyze the shear performance of the sodium silicate-treated sand. The findings revealed that the critical content of sodium silicate for enhancing sand shear strength under saturated conditions is 3%, and that shear strength increases with longer curing times but decreases due to the impacts of wetting–drying (W–D) cycles.

Qingjie Yang, Sérgio D. N. Lourenço
Variations in the Vertical Acceleration During Rolling Dynamic Compaction

Rolling dynamic compaction (RDC), which involves towing a non-circular roller at a relatively high velocity, has been widely utilized in various construction projects for soil improvements. During the process, the roller rotates about one of its corners imparting a combination of kinetic and potential energy into the ground. In recent years, a continuous impact response (CIR) system has been introduced in practice, which measures and records the vertical accelerations of the impact roller as it runs around the construction sites. However, current applications of the CIR system have not considered the influences of the moisture contents and water tables. In this paper, 4 model tests at a scale of 1:10 were conducted to investigate the effects of these influencing factors. A 3-sided impact roller was deployed with an accelerometer attached to record the accelerations. Based on the measured data, as the soil becomes denser, the vertical accelerations increase with reduced contacting time due to increased stiffness. However, the accelerations are dependent on the initial soil conditions and cannot be directly linked to the final soil density.

Yuxiao Li, David Airey
A Comprehensive Review on Current Design Methods Used to Design Controlled Modulus Columns

Ground improvement using Controlled Modulus Columns (CMC) is an innovative technique, which is gaining momentum in Australia and many other parts of the world. Since there are no ground vibrations generated during the construction, this technique is highly appropriate for urban environments. Another added benefit is that the soil cuttings produced during the construction are eliminated, which is beneficial when dealing with contaminated sites or landfill sites. The installation stages of CMC, especially the auger penetration and grouting, contribute to forming a disturbed zone known as a smear zone around each column with increased stiffness and strength compared to in situ ground. It is identified that this smear zone is highly beneficial to the load-carrying capacity of columns. However, no research has been conducted so far to understand the smear zone effect and the significance of the smear zone on the load transfer mechanism of the column-improved ground and it has not been included in the current design practice. Therefore, this paper presents, background information, including an introduction to the context of CMC and the load transfer mechanism of CMC. Also, a review of current design methods adopted in practice is presented, including the design recommendations proposed by the ASIRI national project for rigid inclusions, which is the first-ever design guideline for the CMC improved ground.

T. Amarathunga, D. S. Liyanapathirana, W. Fuentes, C. J. Leo, P. Hu
Finite Element Analysis to Simulate Installation of Controlled Modulus Columns

Controlled Modulus Columns (CMC) are a ground improvement method based on column inclusions that have become popular in geotechnical practice due to their simplicity and efficiency in construction. They are installed in soil with a displacement auger that laterally displaces the surrounding soil. During the installation, CMC are associated with large soil deformations and highly nonlinear material behaviour. Hence, conventional small-strain finite element models are not effective in simulating the installation stages because the elements in the finite element model at the vicinity of the auger are grossly distorted. However, as a first step towards incorporating the installation effects of CMC in the column design, the adaptive remeshing finite element analysis procedure is performed in this study, which is available in ABAQUS/Standard and capable of performing a deep penetration problem while avoiding mesh distortion. The soil type considered in this study is sand and hence the constitutive behaviour is simulated using the Mohr–Coulomb Model. The load-carrying capacity of a controlled modulus column and the influence zone around a column during installation were determined considering the stress distribution and soil deformation around a column during installation.

T. Amarathunga, D. S. Liyanapathirana, W. Fuentes, C. J. Leo, P. Hu
Full-Scale Modeling Test on Mud Pumping in Ballastless Track

Mud pumping is an undesirable subgrade distress in ballastless high-speed railway, significantly affecting the ride comfort and posing a threat to train operation safety. In this study, a full-scale physical model of the ballastless slab track was developed. A rainfall simulator was installed, and various testing sensors were embedded in the trackbed to investigate the phenomenon of mud pumping in ballastless tracks. The results revealed a three-stage process for the intruded rainwater, including the initial vertical infiltration, the following horizontal infiltration, and the eventual roadbed saturation. A significant excess pore water pressure gradient (PWP) was created vertically in the roadbed due to the moving train loads. Similarly, a small longitudinal gradient was also observed. Both PWP gradients indicated the spatial migration of fine particles within the roadbed. The contact pressure distribution under the concrete base varied notably under different roadbed conditions. In the saturated state, the maximum dynamic soil stress, initially located at side of the concrete base transitioned toward the track center. The findings contribute to a deeper understanding of mud pumping mechanism in ballastless tracks.

Zhangbo Wan, Xuecheng Bian, Yunmin Chen
Controlled Modulus Columns Ground Improvement for Sydney Gateway Project

The proposed alignment for Sydney Gateway predominantly requires new embankments with a relatively small proportion of cut and at grade pavements. These embankments are founded on compressible soil and municipal landfill, which are expected to undergo consolidation under the increased effective stress imposed by the new embankment loading. Rigid inclusions in the form of Controlled Modulus Columns (CMCs) have been adopted to meet the design criteria settlement requirements. Primarily, CMCs were adopted to support nine embankment bridge approaches with fill heights reaching up to 9.1 m. CMC ground improvement was also adopted to support a box underpass structure and a new road through Tempe Tip mainly consisting of shallow cuttings and embankments on a municipal landfill. This paper presents an overview of the CMC design features for the Sydney Gateway. The aim of the paper is to highlight how upfront support from specialist geotechnical contractor to the main contractor and the designer ensured efficient and practical ground improvement solutions were designed.

Alexandre Hubaut, Douglas Warne, Jonathan Hale
Controlled Modulus Columns Supporting Approach Embankment for Clarence River Bridge at Harwood, NSW

As part of the Woolgoolga to Ballina Upgrade project, CMC ground improvement was required to treat the soft soil between 22 and 34 m below surface level to support the structural zone of the new southern approach embankment of Hardwood bridge with design embankment height reaching up to 8.0 m. Wick drains were designed to meet the design requirement within the general embankment area. A combination of CMC and wick drains were designed within the transition zone between the structural zone and the general embankment to allow the settlement to transition between the more restrictive settlement criteria within 20 m behind the abutment and away from the abutment. This paper details the development of the ground improvement design from the early investigation to construction. Design was performed through finite element modelling using FE software Plaxis. Quality control measures and testing of the design have been summarised to verify that the construction has been performed to the designers intent.

Silvia Ferrero, Alexandre Hubaut, Sergei Terzaghi
Case Study on Embankment Failure of Bridge at Mahe–Thalassery Bypass, Kerala, India

Transportation infrastructure needs significant financial costs, and due to growing traffic volume and changing weather, it is prone to degradation and failure. The National Highway Authority of India started construction of the Thalassery–Mahe bypass in October 2018, and it was nearing completion in March 2023. Between Dharmadam bridge and Balam underpass, the area was waterlogged, and geotechnical investigation shows the top 15 m of very soft clay. Ground improvement with timber pile over which composite layers of geocells/geotextiles were provided for embankment foundation. Retaining walls were constructed on both sides, and filling of the embankment was planned up to 8.50 m. When embankment work reached a height of 6.50 m, failure in the foundation system was noted due to bearing capacity failure with cracks in the retaining wall and embankment. The upheaval of soils in the water-logged area outside the retaining wall was noted. Forensic investigation studies showed inadequate improvement of the strength of clay and stresses induced are much higher than in design. To counter-surcharge loads, it was suggested to provide balancing berms outside the RC walls. Numerical modelling of the embankment system was carried out for optimum balancing berm design. Since failure had happened and the compacted fill of 6.50 m was completed, it was difficult and time-consuming to adopt new ground improvement techniques to improve the soft clay deposit beneath after removing the fill. Instead of further filling, bored cast in situ DMC Piles terminating with adequate anchorage into the hard rock were adopted with structural girder and slab till embankment height is within 2 m to complete the project in the scheduled time.

Anil Joseph, Akhil Anil, Swetha Sherin Biju, Shini S. Pomson
Settlement Analysis for Construction of a Road Embankment Over Soft Soil Deposits: A Case Study from Taree, NSW, Australia

This paper presents the procedure adopted for the three-dimensional numerical simulation of a road embankment constructed over deep alluvial deposits at a site in Taree, NSW, Australia. The road embankment forms part of mixed-use development along the banks of the Manning River and extends for a length of about 450 m, has a maximum height of 4.9 m and crosses a small creek. The creek runs below the eastern end of the embankment via a concrete culvert with wingwalls. A series of geotechnical investigations along the proposed alignment of the embankment have been completed and identified soft compressible soils. This information was used to develop a 3D subsurface model. The Three-Dimensional Finite Element (3D FE) consolidation analysis was carried out using PLAXIS 3D program. Staged modelling was completed to simulate the construction of the embankment, preloading and the long-term traffic surcharge loading. The analysis was carried out to provide guidance on both the magnitude and period over which settlements will occur. This allowed advice to be provided on the preload period required to limit the magnitude of settlements to those that could be tolerated by the concrete culvert, wingwalls, retaining walls, services and road pavement. Monitoring of the embankment during construction and preloading was completed over an eight-month period. The monitoring results were then used to calibrate and refine the predicted embankment settlement and potential impact on the concrete culvert, wingwalls, retaining walls, services and road pavement over their design life.

Ali Parsa-Pajouh, Woodie Theunissen
Shear Strength Characteristics of Bio-Cemented Soil-Steel Interface

This study investigates the capability of the microbially induced calcite precipitation (MICP) method to enhance the shear strength parameters of soil-steel interfaces. A set of modified direct shear tests, designed based on the Taguchi design of experiments method, are conducted on poorly-graded loose sand samples, which are bio-treated and prepared against a rough steel surface. Data analysis is performed using the analysis of means (ANOM). The direct shear tests show that introducing the bio-cementation process effectively improves the interface properties, leading to a significant increase in the shear strength of the sand-steel interface. Scanning electron microscopy (SEM) analyses of the bio-treated samples demonstrate the successful precipitation of calcium carbonate between the soil particles and the interface. Moreover, this research introduces a cost-effective approach by utilizing a novel culture medium for the bacteria, incorporating waste materials. These findings contribute to the advancement of the MICP method for improving soil-structure interfaces, offering potential benefits for large-scale geotechnical engineering projects.

Hamid Mortazavi Bak, Arman Khoshghalb, Babak Shahbodagh, Tahereh Kariminiya
Controlled Modulus Columns and Shallow Footings for Bridge Foundations on a Western Australian Project

Three bridges in the southwest region of Western Australia were founded on shallow footings located over controlled modulus columns (CMCs). Shallow footings alone were enough to provide adequate bearing performance. The incorporation of CMCs for this foundation solution was rather to ensure settlement and movement were within tolerances for the basis of design requirements, schedule constraints, cost considerations and ground conditions particularly unique to the region. This paper will discuss how the CMCs helped mitigate the potential effects of settlement and rotational movement of bridge abutments and mechanically stabilised earth (MSE) walls. The settlement performance was measured throughout construction and the results showed much less and quicker settlements than predicted. This allowed for corresponding construction on top such as pavements to proceed in a schedule constrained project. The implementation of CMCs also offered advantages in terms of construction efficiency with the installation of CMCs generally faster and less disruptive than other ground improvement methods. Both displacement and replacement methods were used, owing to the ground conditions unique to the region. The challenges of CMC installations and related ground conditions are discussed. This paper will surmise that the use of controlled modulus columns under shallow footings for bridge foundations offers a promising alternative to traditional foundation techniques.

Eddy Yong, Hugo Acosta Martinez
Enhanced Cyclic Resistance of Low Plasticity Soil Using Biopolymer

The demand for more eco-friendly and efficient solution for soil stabilisation has become highly imperative in recent years, given the burning issue of climate change and environmental degradation. Although numerous efforts have been carried out to develop new methods adopting naturally occurring materials and processes, there are still very limited their successful applications in practice. Among them, the use of biopolymers has shown great potential. As there is still a significant lack of understanding of how this solution can performance under cyclic loading such as road and railway contexts, this study aims to investigate cyclic behaviour of Xanthan Gum (XG)-treated soil. A low plasticity soil prone to mud pumping was collected from the field and mixed with different XG contents (0.5–2% by mass), followed by a series of cyclic triaxial tests mimicking subgrade work condition. The results show that biopolymer can significantly promote cyclic resistance of soil by substantially reducing the accumulated excess pore pressure and minimising ultimate axial strain (<2.5%). With only 0.5% XG content, the soil can mitigate considerably its localised behaviour induced by heavy cyclic loads, thus alleviating the formation slurry at shallow layers of subgrade foundation.

Thanh T. Nguyen, Buddhima Indraratna, Ramesh Gedela
Relationship Between Water Absorption and Fiber Properties of Pulp used as Ground Improvement Material

Japan, where forests cover 70% of the country's land, has a system to provide a large and stable supply of high-quality pulp from thinned lumber and offcuts. However, with the recent digitization of society, the demand for paper has been drastically decreasing, and there is an urgent need to develop new applications for pulp to replace paper. Since pulp production is enormous, amounting to several hundred thousand tons per year at a single mill, new uses must be found. On the other hand, ensuring resilience to natural disasters, such as the frequent occurrence of heavy rainfall disasters due to global warming, is a social issue facing Japan. Muddy soil generated in large quantities by large-scale construction projects and disasters needs to be treated and reused in an environmentally friendly manner. Pulp has a high-water absorption characteristic and is used as a water absorbent in diapers and other products in combination with polymer absorbent. Therefore, the suitability of pulp as a new material for treating muddy soil have been examined. As a result of evaluating the water absorbency of a total of six types of pulp, it was found that the pulp had superior water absorbency to that of absorbent derived from used paper, which has an established reputation as a muddy soil treatment material. It was also confirmed that regardless of the pulp manufacturing method, pulp derived from softwoods with longer fiber lengths had higher water absorbency.

Yasuo Sawamura, Takumi Kojima, Ryunosuke Kido, Takuto Shakuno, Yutaka Nuruki, Shoichi Miyawaki, Hiroyuki Horii, Hiroyuki Nagai, Masayuki Doi, Nariatsu Fujii
Characterizing the Degradation Threshold of Biocemented Sands for Transportation Infrastructure: Insights from Resonant Column Test

Biocemented soils present a promising sustainable alternative to traditional Portland cement and asphalt in road embankment construction and remediation. However, the cyclic loading experienced by transportation infrastructures like roads over extended periods explicitly leads to performance degradation. Biocementation, achieved through Microbially Induced Calcite Precipitation (MICP) using ureolytic bacteria or Enzyme-Induced Calcite Precipitation (EICP) with urease enzymes, precipitates calcium carbonate (calcite) as a bonding agent within the soil matrix. Despite the environmental appeal of biocemented soils, their durability under cyclic and repeatable loads remains relatively unexplored. This paper investigates the modulus degradation of biocemented sand subjected to cyclic loading, considering various strain amplitudes and confinement levels. The experimental program involves subjecting two distinct specimens—one uncemented and the other cemented—to three confinement levels (50, 100, and 200 kPa). Each specimen undergoes incremental torque amplitudes to elucidate stiffness behavior across a spectrum of strain levels. Additionally, resilient modulus estimates are obtained for different strain levels, and a critical strain threshold is identified. The primary objective of this research is to unveil fatigue susceptibility criteria, offering crucial insights into the performance of biocemented soils. By doing so, this study contributes to the advancement of sustainable and durable infrastructural solutions, particularly in the context of road construction and maintenance.

Piyush Vyas, Chukwuebuka Nweke
Reassessment of the Performance of Ground Improvement of a Bridge Approach Embankment

The ground improvement of the approach embankments for abutments of a major bridge was designed as part of a highway upgrade project in northern New South Wales, Australia. The adopted soft ground treatment approach was to preload and surcharge the ground using prefabricated vertical drains to accelerate the consolidation process. Hold point for surcharge removal at the southern abutment was released after the review and back-analysis of available monitoring data (mainly settlement plates, piezometers, extensometers and hydrostatic profile gauges). The surcharge was removed in March 2018 and the bridge approach was constructed in June 2019. In mid-October 2019, settlement of the approach slab was noted with some major cracking of the F-type barrier. CPTu testing and reassessment of the performance of the main embankment and approach embankment were carried out. The back-analysis results were used to predict the future performance of the approach embankment and its impact on the piled foundation. A few lessons learned with regard to the design approach, back-analysis and construction staging are presented.

Ashok Peiris, Kim Chan, David Groth, Graham Yip
Design and Performance Evaluation of Temporary Working Platforms in Challenging Ground Conditions

Temporary working platforms play a crucial role in providing stability and safety for construction activities including piling and crane lifts on transport infrastructure projects. This paper focuses on the design and performance evaluation of steel/geogrid-reinforced working platforms for the operation of crawler cranes utilised for bridge construction as part of the West Gate Tunnel Project over the Maribyrnong River in Melbourne, Australia. Working platform designs conventionally adhere to available codes such as BRE470 and TWF2019. However, these codes may not suit flexible platforms constructed over soft soils like Coode Island Silt (CIS). CIS is a challenging soft soil in Melbourne known for its significant compressibility and nonlinear stress–strain behaviour making it difficult to meet the strict serviceability design criteria for working platforms. This study adopts an innovative approach that deviates from conventional industry standards to provide efficiency, safety and economic viability for working platforms. Settlement monitoring data from field trials was used to back-analyse undrained and partially drained elastic moduli. This helps establish a site-specific correlation between elastic modulus and undrained shear strength, instead of relying on generic published correlations for soft soils. Additionally, a three-dimensional finite element model was developed to accurately simulate the soil structure interaction and to perform sensitivity analyses to optimise the design considering various combinations of platform composition, thickness and reinforcement type and quantity. The outcomes of this study together with the post-construction performance evaluation provide valuable insights into the design of temporary working platforms, particularly on challenging ground conditions.

Kaveh Ranjbar Pouya, Parisa Rahimzadeh Oskooei, Jeffrey Lau, Paul Menton
Influence of Compaction Moisture on the Mechanical Behavior of Soil-Gravel Mixtures

The accumulation of permanent deformation is a structural defect that typically occurs in the form of Rutting (ATR) and can compromise the comfort and safety of users when traveling on roads. This article addresses the concern about permanent deformation in soil-aggregate mixtures in road pavement projects, especially after the transition from empirical design methods to mechanistic-empirical methods guided by pavement mechanics. Through a series of tests conducted using the repeated load triaxial equipment, with different proportions of aggregate/fine materials and tropical soil, it was observed that when compacting samples of soil-aggregate mixtures at their corresponding optimum moisture content, the fine matrix, in some cases, exceeds its optimum moisture content. As a result, the values of permanent deformation become excessively high, which can render the use of these mixtures in pavement layers unfeasible. However, the study also indicates that soil-aggregate mixtures with higher proportions of aggregate/fine materials and certain types of soils showed satisfactory results. This suggests the need to revise the definition of the optimum compaction moisture content for the design. This revision is crucial to ensure the proper performance of these mixtures in pavement layers.

Camila Antunes Martins, Antônio Carlos Rodrigues Guimarães, Maria Esther Soares Marques, Ciro José de Azevedo Júnior
Evaluation of Fine-Grained Tropical Soils’ Resilient Behaviour for Pavement Design

Tropical soils have demonstrated good mechanical behaviour when applied to pavement layers, contrary to current standards. In Brazil, a mechanistic-empirical method for pavement design—the MeDiNa method—has been implemented. This method uses the concept of resilient modulus through a composite model to evaluate pavements. Thus, this article discusses the mechanical behaviour through resilient modulus analyses. Laboratory tests were performed on ten samples of tropical fine-grained lateritic soils from São Paulo (Brazil). The results were evaluated according to constitutive models to predict the performance of the resilient modulus. Additionally, the materials were evaluated for highway pavement design. Results showed that, even though the materials are fine-grained, the soils exhibited good resilient behaviour and were suitable for application in pavement layers, due to their lateritic classification.

Cláudio Rafael Cicuto Landim Alves Moreira, Antonio Carlos Rodrigues Guimarães, Filipe Almeida Corrêa Nascimento, Juliana Tanabe Assad dos Santos
Practical Outcomes of a Numerical Study into Soil Arching in Geosynthetic Reinforced Column-Supported Embankments

This paper presents the practical outcomes of a numerical study into soil arching in geosynthetic reinforced column-supported embankments (GRCSEs). The study offers insights into the nature of the failure mechanism above the column head and the development of a plane of equal settlement within the embankment. For embankment geometries likely adopted by GRCSE designers, the results indicate either a punching failure or inverted general bearing failure develops above the column head projecting into the embankment. It is found that an inverted general bearing failure generally develops if a plane of equal settlement can be established within the embankment. Based on these findings, an opportunity is presented to optimise the thickness of load transfer platforms in GRCSEs and to adopt more economical fill types above the load transfer platform. The results presented in this paper have implications for the practical and efficient design of embankments commonly adopted in transport infrastructure projects.

Edward J. Smith, Abdelmalek Bouazza, Louis E. King
Ground Improvement over Soft Clay for the Main Access Road to and from Port Macquarie Airport

This paper describes the selection and design of ground improvement for a 260 m section of the upgrade of Boundary Street forming the main access road to and from Port Macquarie Airport. Boundary Street is currently a single-lane (each direction) road constructed over soft clay which extends to a depth of 10 m for a 260 m section of the project. It is the only access to and from the regional airport and future business park and is subject to flooding during minor event. In 2017, Port Macquarie and Hastings Council proposes to upgrade the road to twin carriageways in each direction cater for the predicted growth of the airport and the demand for increased capacity within the surrounding infrastructure. A number of solutions to deal with the soft ground conditions were considered, including building a bridge, or ground improvement techniques to reduce post-construction settlement and differential settlement following the road upgrade. Ground improvement options including surcharging with or without wick drains and the use of rigid inclusions were considered. A major constraint on the choice of ground improvement options was the adjacent wetland and sensitivity of fauna habitat to construction activities. Following an extensive optioning study, the use of rigid inclusions was adopted to provide a balanced solution between cost and minimising the risk of damaging adjacent wetland and its habitats. The design optioneering process and design of the rigid inclusion ground improvement are presented in this paper.

Helen Chow, Patrick Wong
Evaluating Indirect Tensile Strength (ITS) of Dry-Processed Rubberised Stone Mastic Asphalt (SMA) Mixture

The utilisation of crumb rubber through a dry process is a practical and economical method to confront the challenges of tyre recycling and environmental sustainability. This study aimed to identify the mechanical behaviour of the rubberised SMA mixture. Therefore, the Response Surface Methodology (RSM) was used to investigate the effect of independent variables such as binder content, CR content, curing time and CR size on mechanical response variables. Analysis of Variance (ANOVA) based on Indirect Tensile Strength (ITS) of the asphalt mixtures was performed to analyse the data. A quadratic polynomial model effectively fitted the experimental results and reliably predicted performance outcomes with an acceptable level of accuracy. This study reveals that alongside independent variables, their interactions are pivotal, as evidenced by the varying behaviour of ITS under different interaction scenarios. Recognising these interactions is crucial for precise design, ensuring efficient performance in rubberised SMA pavements.

M. Zakerzadeh, B. Shahbodagh, J. Ng, N. Khalili
Embankment Construction on Swampy Area Using Controlled Modulus Columns (CMC) for Standard Gauge Railway Project in Tanzania

The new Standard Gauge Railway (SGR) is a railway system in Tanzania, consisting of a 1,224-km-long single line with a design speed of 160 km/h and linking the country to the neighboring countries of Rwanda, Uganda, Burundi, and the Democratic Republic of Congo. The railway line alignment passes over some soft soil areas where the soil condition consisted of soft and organic clays with a high ground water table, which made the ground conditions swampy and required ground improvement prior to embankment construction. The chainage where the ground improvement is required involves a 6.5-m-high embankment and a culvert construction. The paper presents the design and construction procedures of the controlled modulus columns (CMC) to transfer the load of the foundation block onto a stiffer layer of soil or rock via load transfer platform. As a result, the settlement of the foundation block was reduced while increasing the bearing capacity.

Lami Karagoz, Altan Erdem, Hasan Burak Gokce
Numerical Simulation of Triaxial Tests on Recycled Concrete Aggregates

The utilisation of waste is a key approach to moving towards a sustainable environment. A lot of research is going on about different waste materials to make them reusable for various activities in the construction industry. Recycled concrete aggregate is one of the industrial wastes that can be used as a base and sub-base course material in the construction of roads. Previous studies explored various aspects of its performance to minimise the use of natural aggregates. In this study, experimental results of consolidated drained triaxial tests of recycled concrete aggregate are simulated on PLAXIS 2D software considering the Hardening soil model with small strain and NorSand model. The experiments are conducted under 40, 70 and 100 kPa cell pressure. The comparison between experimental and numerical data of recycled concrete aggregate indicated that the NorSand model works better than the hardening soil model in terms of capturing stress–strain with post-peak softening behaviour.

Adnan Anwar Malik, Hong Le Owen, Syed Kamran Hussain Shah, Umair Ali
Improved Mechanical and Fatigue Durability of Cement-Stabilized Recycled Concrete Aggregate–Lateritic Soil Using Natural Rubber Latex

This study explores the efficacy of Natural Rubber Latex (NRL) as an additive in enhancing the mechanical properties and durability of cement-stabilized Recycled Concrete Aggregate (RCA) and Lateritic Soil (LS) blends for pavement applications. The research focused on determining the optimal NRL content and evaluating the performance of the stabilized blends under environmental stress represented by wetting–drying (w-d) cycles. Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS) tests were conducted alongside Scanning Electron Microscopy (SEM) to assess the microstructural integrity of the materials. The results demonstrated that the inclusion of NRL at a 5% rubber-to-cement (r/c) ratio significantly improved the initial UCS, ITS, fatigue life, and durability performance of the RCA:LS blends. The 70:30 RCA:LS blend outperformed the 50:50 blend, indicating a composition-dependent response to NRL addition. The findings suggest NRL's potential in sustainable pavement construction, with implications for enhancing strength in stabilized pavement materials.

Menglim Hoy, Suksun Horpibulsuk, Ngoc Quynh Tran, Veena Phunpeng
Peka Peka to Ōtaki Expressway: Design and Performance of the Embankment Construction on Soft Soil

Situated in Kāpiti Coast, Wellington, New Zealand, the Peka Peka to Ōtaki Expressway is a 13 km, 4-lane upgraded route of State Highway 1. It joins the southern section reaching the MacKays to Peka Peka Expressway and extends north past Taylors Road intersection. The expressway construction involved ground improvement works as the alignment encountered very soft and compressible soils reaching depths of approximately 7 m. The underlying reasons for such soft soil conditions were unique topographical and geological factors, leading to poorly drained ground conditions. This paper presents the improvement techniques employed to manage these geotechnical challenges and treat the soft soils. Additionally, it provides insights into the monitoring program implemented during construction, as well as the subsequent evaluation of the effectiveness of the soft soil improvement work.

Razel Ramilo, Tim Haxell, Richard Mulvad Cole
Metadata
Title
Proceedings of the 5th International Conference on Transportation Geotechnics (ICTG) 2024, Volume 4
Editors
Cholachat Rujikiatkamjorn
Jianfeng Xue
Buddhima Indraratna
Copyright Year
2025
Publisher
Springer Nature Singapore
Electronic ISBN
978-981-9782-25-3
Print ISBN
978-981-9782-24-6
DOI
https://doi.org/10.1007/978-981-97-8225-3