Recent Advances and Innovative Developments in Transportation Geotechnics

Table of Contents

1. Frontmatter

2. Bio-cementation for Ground Improvement with Special Reference to Transportation Infrastructure

   Mohamed A. Shahin, Kehinde Lemboye, Liang Cheng, Hayder H. Abdullah, Mohamed G. Arab

   Abstract

   Unstable soils, characterised by their loose, soft, erodible and collapsible nature, are prevalent worldwide, presenting significant engineering challenges due to their low-bearing capacity and high compressibility. Such problematic soils pose obstacles to civil infrastructure developments such as building foundations, roads, railways, tunnels and retaining walls. The traditional approach to mitigating these obstacles involves ground improvement techniques that utilise soil stabilisation with chemical additives such as lime or Portland cement. While these techniques enhance soil strength, stiffness and load-bearing capacity, they also cause serious environmental concerns. In this Theme Lecture paper, “bio-cementation” is introduced as an innovative and eco-friendly technology for ground improvement, with special reference to transportation infrastructure. This ground-breaking technology utilises earth-based bacteria or microorganisms for natural biological soil stabilisation, paving the way for superior and eco-friendly ground improvement in future civil engineering infrastructure projects.

3. Installation Effects on the Capacity of Open-Ended and Closed-Ended Pipe Piles

   Monica Prezzi, Venkata Abhishek Sakleshpur, Daniel G. Fridman

   Abstract

   The base and shaft capacities of piles depend on the method of pile installation, pile type, soil type, and stress state. Fully instrumented, open-ended, and closed-ended pipe piles were load tested side-by-side statically following a slow-maintained testing protocol at two sites in Indiana, USA. The piles were instrumented following a hybrid, dense instrumentation scheme with both vibrating-wire and electrical-resistance strain gauges along the entire length of the shafts. The open-ended piles were specially designed and assembled following a double-wall system to facilitate separation of the external and internal unit shaft resistances in every layer of the soil profile. The plug length ratio (PLR) and incremental filling ratio (IFR) were measured for the open-ended test piles. To gain insights on the impact of the formation and evolution of the soil plug during installation on the base capacity of pipe piles, one open-ended model pile and one closed-ended model pile were installed under similar conditions in a calibration chamber with digital image capabilities. This paper summarizes and discusses the results of the pile load tests. The load test results are compared with predictions obtained using modern CPT-based pile design methods available in the literature. An assessment of the design methods is made based on the field test results.

4. An Integrated Framework for Comprehensive Evaluation of Sustainability in Transportation Geotechnics

   Krishna R. Reddy, Jagadeesh Kumar Janga

   Abstract

   Transportation geotechnics is an important component in the construction of sustainable transportation infrastructure, playing a pivotal role in ensuring the stability, durability, and long-term performance of transportation networks. Incorporating sustainable practices into transportation geotechnics is essential for promoting environmental stewardship and achieving sustainable outcomes. While tools have been developed to evaluate the sustainability of engineering projects, many of them have primarily focused on environmental impacts, overlooking broader social and economic implications. To perform a comprehensive sustainability assessment, it is crucial to adopt a life cycle approach that considers multiple dimensions when evaluating a project’s sustainability. In view of this, a triple-bottom line sustainability assessment framework called “Qualitative Assessment of Life Cycle Sustainability (QUALICS)” has been recently developed. This paper aims to provide a brief description of the QUALICS framework and demonstrate its application to assess the sustainability of design alternatives using three case studies of sustainable practices in pavements and transportation geotechnics: (1) fly ash and lime-stabilized sub-grades for pavement; (2) a streetscape with features such as recycled-aggregate base course, pervious-concrete sidewalks, and bio-retention islands; and (3) utilization of recycled-aggregate sub-base in pavements. Based on these case studies, this paper showcases the versatility and applicability of the QUALICS framework and highlights the significance of considering sustainability across various dimensions.

5. AI-Based Ballasted Track GPR Application and Development

   Xuanyang Qin, Zhan Peng, Guoqing Jing

   Abstract

   The use of ground-penetrating radar (GPR) technology in railway maintenance and inspection has gained significant attention in recent years due to its non-destructive and efficient nature. This paper explores the application and development of artificial intelligence (AI) in conjunction with GPR for the assessment of ballasted tracks. The integration of AI algorithms enhances the interpretation of GPR data, providing a more accurate and automated method for detecting and predicting potential trackbed fouling. This article explores the innovative applications of machine learning and deep learning in GPR data processing for railway track engineering prospection, evaluating their potential, limitations, and future prospects, aiming to contribute to the advancement of railway infrastructure monitoring, with a focus on improving reliability, safety, and maintenance efficiency.

6. The Importance of Rock Mass Characterization for Rock Socketed Foundations

   Vasantha Wijeyakulasuriya, Siva Sivakumar, Ajith Dissanayake

   Abstract

   Rock mechanics investigations undertaken by the Department of Transport and Main Roads (TMR) in Queensland, Australia, as part of the pre-tender information for the Second Gateway Bridge (Duplication) have been revisited. In addition to the conventional rock substance characterization, this investigation included rock direct shear tests (CNS and CNL) and a significant number of rock pressuremeter testing to provide specialist rock mechanics information for the design of rock socketed foundations. This paper is focused on the major rock lithology intercepted, i.e., sandstone. Sandstone in the Sydney basin has been widely researched, and the findings from this study are compared with the published information on the Sydney Sandstone as well as from other sources. Findings published by the Second Gateway Bridge Designers are used for comparison where relevant, especially on the test piles which can serve as a useful reference.

7. Recent Advances in the Use of Artificial Intelligence for Rigid Airfield Pavement Analysis and Design

   Halil Ceylan, Orhan Kaya, Sunghwan Kim

   Abstract

   Historically, analysis and design methodologies for rigid airfield pavement systems have primarily relied on empirical equations derived mostly based the field performance. However, the FAA has implemented mechanistic-based approaches, including three-dimensional finite-element (3D-FE) procedures, for the design and analysis of rigid airfield pavements. This decision was made in response to the emergence of new wide-body aircraft and other design complexities, such as heavier aircraft and intricate gear configurations. On the other hand, the time-consuming nature of 3D-FE computation for analyzing multiple slabs subjected to aircraft and environmental loads has rendered routine design and analysis impractical. To address this issue, AI-based alternatives offer significant potential for producing accurate and rapid rigid pavement-response estimations compared to traditional FE-based design programs. Using AI-based modeling is a convenient option instead of conducting lengthy 3D-FE computations. In this paper, we introduce a recent FAA-sponsored research study conducted at Iowa State University (ISU) that utilizes AI-based alternatives to performing full 3D-FE computation for analyzing and designing rigid airfield pavement systems. The paper contains two case studies: (1) creating strong AI models to predict critical rigid airfield pavement responses and analyze top-down cracking behavior and (2) developing fast AI-based models to predict pavement foundation response and moduli for designing new and rehabilitated rigid airfield pavement structures. The capability of AI-based surrogate-response models for analyzing and designing rigid airfield pavement systems is successfully demonstrated and discussed in this paper.

8. Shear and Hydraulic Behavior of Compacted Foamed Glass Aggregates for Transportation Earthworks

   Jennifer E. Nicks, Ismaail I. Ghaaowd, Michael T. Adams

   Abstract

   Recycled foamed glass aggregate (FGA) is an emerging material in the USA for use as a lightweight structural backfill. FGA is considered a sustainable solution, with advantageous engineering properties noted throughout the literature, but since the FGA market in the USA began less than 10 yr ago, independently assessing the behavior of the FGAs available for highway transportation agencies became necessary. The Federal Highway Administration (FHWA) has therefore made a concerted effort to evaluate the physical, mechanical, and hydraulic properties of US-manufactured, recycled FGAs under varying compaction efforts and loading conditions. This paper presents some initial findings from large-scale laboratory testing performed to evaluate shear strength and permeability of FGA under different compaction ratios and applied normal stresses. The overall results demonstrate that the breakage of FGAs due to compaction can have advantageous impacts, such as an increase in density and shear strength. While compaction does reduce permeability, FGA is still a free-draining material. The findings suggest that FGA is a viable substitute for sustainable, niche geotechnical applications; however, understanding the in-place FGA engineering properties is needed to develop better construction specifications and design guidance to ensure serviceability in transportation earthwork projects.

9. Unsaturated Soil Mechanics in Engineering Practice Using the Equivalent Method

   Adrian R. Russell

   Abstract

   The objective of this paper is to assist the uptake of unsaturated soil mechanics in strength and stability problems in engineering practice. It gives examples of research outcomes related to slope and shallow foundation stability determinations and shows how they can be applied routinely in hand calculations and commercial software using the equivalent method. The equivalent method involves capturing suction influences through an equivalent cohesion and an equivalent unit weight and then doing a total stress analysis. It also outlines industry changes and trends, including good practices and commonly made mistakes, relevant to way unsaturated soils are accounted for and the way suction is measured and implemented into a geotechnical model.

10. Recommendation for the Use of Micropiles to Ensure the Reliability of the Railway Track

    Askar Zhussupbekov, Abdulla Omarov, Abilkhair Issakulov

    Abstract

    A damaged railway line in Astana, Kazakhstan, which is located on soft soil, is the subject of an investigation, and possible remedial options are discussed in this paper. We conducted an analysis and geotechnical investigation using modern soft soil improvement techniques to identify the most effective strategies for stabilizing the damaged subgrade and to suggest remedial actions. The methods and procedures for stabilizing the soft soil were selected taking into account the need to ensure uninterrupted train traffic on the line, the largest equipment that could be used on the site, and the height restrictions imposed by overhead power lines. It was proposed to use vertical and horizontal micropiles for reinforcement to ensure the stability and reliability of the railway track. Recommendations for the restoration of the soft soil beneath the damaged section of the railway line, derived from the geotechnical investigations, are presented and illustrated in this paper. Understanding the relationship between soil and structure on problematic soft soils has been made possible by these studies.

11. Seismic Response of Tunnels in Soft Soil—Status and Future Prospects

    Deepankar Choudhury, Rishav Baishya

    Abstract

    For the safe functioning of tunnels, dynamic loading conditions, such as earthquakes, must be considered for design. The main idea here is to review tunnel responses under soft soil conditions and emphasize work done to date toward the seismic response of tunnels. Specifically, various parameters influencing tunneling, effects on tunnel structure, and ground failure due to seismic excitations are discussed. After that, a review of different closed-form solutions used for the transverse and longitudinal analysis of the response of tunnel structures is presented. Next is the study of various numerical models of tunnel systems with adjacent structures, both above and near the ground surface, like buildings, bridges, and buried pipelines. Here, the discussions are based on the different computational modeling procedures adopted by researchers and the effect of soil–tunnel structure interaction arising during seismic events. Subsequently, a review of interactions between underground tunnels and adjacent ground structures is also presented. The paper discusses the effects of segmental jointed tunnels under earthquake loads and the seismic vulnerability of tunnels. Finally, the article tries to stimulate ideas for new work in these areas for the researchers. Thus, emphasis is given to the identification of current gaps in understanding the seismic response of tunnels in soft soil.

12. A 10-Year Research on Sustainable Pavement Materials

    Suksun Horpibulsuk, Menglim Hoy, Apichat Suddepong, Artit Udomchai, Apinun Buritatum, Teerasak Yaowarat, Kongsak Akkharawongwhatthana, Chakkrid Yeanyong, Jitwadee Horpibulsuk, Manilika Mobkrathok, Punvalai Choenklang, Apisit Laomuad, Karn Karntatam, Avirut Chinkulkijniwat, Arul Arulrajah

    Abstract

    This paper summarizes 10-year research on sustainable road construction by using recycled materials such as construction and demolition (C&D) materials; waste by-products, which are fly ash, steel slag, and calcium carbide residue; synthetic and natural fiber-reinforcement; and synthetic and natural polymers in various pavement applications. Advanced techniques were used to analyze the mechanical properties and suitability of these materials as replacements for virgin aggregates. The research identifies optimal material compositions, demonstrating improved pavement performance and environmental and economic benefits. Findings highlight the potential of using recycled materials like bottom ash and natural fibers, advocating for sustainable and cost-effective road construction practices. The research contributes to the development of durable and environmentally friendly road infrastructure, with implications for future urban and high-traffic applications.

13. Use of Geosynthetic Materials for Rail Stabling and Maintenance Yard Construction at a Contaminated Site

    Udeshini Pathirage, Gabriele Di Marco, Gary Schmertmann, Jamie McIlquham

    Abstract

    Geosynthetic materials were used extensively in site remediation works prior to construction of a light rail stabling and maintenance yard for the Parramatta Light Rail project, an infrastructure project owned by Transport for New South Wales, Australia. The site was previously a chemical manufacturing premises that had experienced contamination of soil, groundwater, and ground gas, notably including hexavalent chromium (Cr (VI)) and volatile chlorinated hydrocarbon compounds (VCHs). The site also had areas of uncontrolled fill unsuitable for track and associated structure foundations. The geosynthetic materials used in the remediation works included geomembranes, geogrids, and drainage and venting materials. These materials were used in remediation design for containment and isolation of contaminated materials, infiltration reduction, restriction of contaminated groundwater flow, and foundation improvement. The paper describes the remediation design and discusses site requirements, constraints, and design solutions, with emphasis on the use of geosynthetic materials. Remediation works were completed in September 2021.

14. Significance of Rock Slopes Monitoring for the Protection of Transportation Networks and Recreational Coastal Areas

    Anna Giacomini, Abigail Watman, Davide E. Guccione, Farshad Bahootoroody, Klaus Thoeni

    Abstract

    Rock slope instabilities, such as rockfalls and rockslides, can threaten human life along major transportation networks and recreation coastal areas, affect safety during infrastructure construction and significantly interrupt transportation along highways and railways with substantial economic losses. Accurate predictions of the associated risks and their effective reduction require a thorough collection of rock mass structural conditions and triggering events’ evolution with time to infer appropriate modelling parameters for the design and implementation of the most suitable mitigation measures. Close-range terrestrial photogrammetry and Unmanned Aerial Vehicles (UAVs) have been used to monitor hazardous and hardly accessible rock slopes located above popular recreational areas along the Newcastle coastline in NSW. Valuable inventories of rock mass structural data and rockfall spatial–temporal occurrence and magnitude have been collected to identify major structures affecting rock slope stability and sources of rock instabilities (detachments) over extended periods of time. Their volume and frequency have been accurately estimated. Results highlight the crucial role played by the identification of appropriate input parameters to adequately simulate realistic rockfall scenarios and the significance of the frequency of data collection for accurate predictive modelling.

15. Liquefaction Countermeasure for Residential Buildings Using Gravel-Mixed Tire Chips and Its Validation Through an Integrated Approach

    Hemanta Hazarika, Yutao Hu, Gopal Santana Phani Madabhushi, Stuart Kenneth Haigh

    Abstract

    The vertical drain method, widely used to prevent earthquake-induced liquefaction, utilizes vertical drains to dissipate excess pore water pressure and reduce liquefaction risk. Hazarika et al. (Soils Found 60:315–326, 2020 [11]) developed a cost-effective technique to shield residential buildings from such damage, using a mixture of tire chips and gravel (GTCM) under foundations. This approach also shows promise as a drainage enhancer in vertical drains. Incorporating GTCM in vertical drains, the research involved small-scale shaking table tests, two-dimensional simulations, and cyclic undrained triaxial tests to validate its efficacy. The findings indicated that GTCM drains effectively prevent foundation soil liquefaction, with optimal results observed at a gravel content of 50–60% by volume, striking a balance between controlling excess pore water pressure and maintaining drain stiffness.

16. Effect of High Groundwater on Flexible Culvert Response to Truck Loading

    Ian Moore, Oliver Kearns, Neil Hoult

    Abstract

    Design of flexible culverts to support vehicle loads is routinely based on soil behaviour where the groundwater table is assumed to be at or below the culvert invert (so that pore pressures are negligible in the backfill beside and above the pipe). To investigate the potential limitations of this assumption, a new facility has been developed at Queen’s University which permits high groundwater experiments to be conducted on corrugated steel culverts (where groundwater can be controlled within the test chamber). The effects of high groundwater (like those during a storm) are being studied, where pore pressures reduce the effective stresses and modulus of the soil near the pipe structure, which change the soil–pipe interaction. The ability to introduce and control groundwater is also allowing experiments studying soil erosion beside the test pipe, as a result of inflows through perforations in the pipe walls (due to simulated corrosion). The facility is being used to study pipe responses to vehicle loading (represented by a pair of wheels on a truck axle) under normal groundwater conditions where the water table is at or below the pipe invert, under high groundwater conditions (where the groundwater level is near the ground surface), and after the development of soil erosion. These studies are of importance to highway engineers responsible for assessing culvert capacity and setting load ratings.

17. Recent Advances in Computational Methods, Predictions, and Applications to Critical Zones in Railways

    Sanjay Nimbalkar, Piyush Punetha, Naveen Kumar Meena, Mohammad Adnan Farooq

    Abstract

    Accurate evaluation of the mechanical response of railway tracks subjected to train-induced repeated loading is a prerequisite for their proper design and maintenance planning. A multitude of approaches have been developed over the years to accurately predict some of the most crucial aspects of track behaviour. This theme paper presents the recent advances in computational methods that can be employed to predict the performance of railway tracks and demonstrates their capabilities. Firstly, the suitability of the finite element (FE) method in understanding the soil arching mechanism, which governs the behaviour of the pile-supported railway embankments, is demonstrated. The influence of pile spacing on the soil arching mechanism is illustrated. Subsequently, the utilisation of the FE method in evaluating the performance of the ballasted and slab tracks is explored. The vertical stress variation and the accumulation of settlement in both tracks are compared. In addition, a novel computational approach based on a geotechnical rheological track model is presented that can be employed to predict the long-term performance of a standard section of the railway track as well as the critical zones, such as bridge-embankment transitions. Finally, the practical applications of the computational techniques and their future scope are discussed.

18. Pavements of the Future: Decarbonisation, Digitalisation and Environmental Responsibility

    Abir Al-Tabbaa

    Abstract

    Many recent transportation-related strategy documents present roadmaps for how to deliver net zero through decarbonisation, digitalisation and environmental responsibility. This keynote lecture presents an overview of current strategies in the content of the UK highways and pavements highlighting the many challenges that we currently face and providing examples of current research initiatives that are tackling those challenges.

19. Geotechnical Engineering for Large Infrastructure Projects Such as Offshore Wind Farms

    Britta Bienen

    Abstract

    Offshore wind farms are not only major infrastructure projects in themselves, but also tend to require significant investment in related infrastructure such as port facilities. Geotechnical engineering underpins the safe, reliable design and operation of all these infrastructures. Australia must build 41 GW of offshore wind power by 2040 to reach its CO₂ emission targets. To put this into context, the installed capacity in 2022 was 64 GW—globally, and there is not a single offshore wind turbine installed in Australia to date. Foundations have grown with the size of offshore wind turbines and are large structures that have to be accommodated at the marshalling port, be ensured to be installed to target depth offshore—often in complex seabed conditions—before withstanding millions of load cycles over typically 30 years of wind turbine operation offshore. This paper focuses on new solutions of rapid pile installation with low acoustic emissions and provides an outlook with a view of Australia’s challenging seabed conditions.

20. Experimental Study on the Biodegradation in Xanthan Gum-Treated Sandy Loam and Mitigation Using Biochar

    Xueyu Geng

    Abstract

    Biopolymers are eco-friendly materials used to enhance soil mechanical strength. However, due to the degradation effects of microbials, the strength of biopolymer-reinforced soil tends to attenuate over time. To address this issue, this study introduces another bio-based green material, biochar, to reinforce the soil in combination with the biopolymer. Static and dynamic triaxial tests were conducted to investigate the reinforcement effects. Water-soluble carbohydrates and β-glucosidase activity, along with soil’s internal friction angle and cohesion, were measured after curing samples for 1, 7, 14, 21, and 28 days to quantify biodegradation. A scanning electron microscopy (SEM) test was performed to illustrate microstructure changes due to biodegradation and to reveal how biochar mitigates the degradation process in biopolymer-treated soil. It was found that xanthan gum forms hydrogels through hydrolysis reactions and establishes hydrogel bonds among soil particles, enhancing the soil’s static and dynamic strength. However, microbes can degrade these hydrogels, resulting in a significant attenuation of soil reinforcement. Due to biochar’s porous morphology and hydrophilic functional groups, the free water in the soil is gradually released and participates in the hydrolysis of xanthan gum. Additionally, hydrogels are captured by the voids in the biochar, leading to stronger inter-particle binding. Consequently, the strength of XG-treated soil exhibits a trend of slow growth over time. Biochar’s angular structure enhances interlocking and embedding among particles, leading to a 42% increase in shear strength compared to untreated soil, and a 21% increase compared to soil treated with xanthan gum alone. Therefore, the combined approach of xanthan gum and biochar is advisable for reinforcing soil in engineering practice.