Transportation Geotechnics最新文献

{"title":"Effects of climate change on soil embankments for transport infrastructure","authors":"","doi":"10.1016/j.trgeo.2024.101324","DOIUrl":"10.1016/j.trgeo.2024.101324","url":null,"abstract":"<div><p>The climate is changing. Unequivocal global warming has brought significant changes to our climate system. The Intergovernmental Panel on Climate Change <span><span>[1]</span></span> concludes that climate change will result in both an increase in temperature and changes in the global water cycle, possibly leading to extreme drought–rainfall conditions and freeze–thaw cycles. These developments raise important questions: can existing transport infrastructure such as high-speed railway lines built on soil embankments cope with the aforementioned extreme weather conditions? Do we have enough reliable physical data to design future transportation systems?</p><p>This paper describes a novel environmental chamber capable of simulating, in a geotechnical centrifuge test, the effects of extreme cycles of temperature, rainfall and humidity on an embankment in flight. Using the recently developed centrifuge environmental chamber, a series of centrifuge tests were carried out to assess the influence of thermal cycles on the deformation mechanisms of soil embankments, the influence of extreme drought–rainfall conditions on the stability of embankment slopes, and slope deterioration mechanisms under freeze–thaw cycles. The thermo-hydro-mechanical behaviour of embankments is reported and discussed. Furthermore, new insights into the deformation and failure mechanisms of embankment slopes are revealed, and the design implications for future transport infrastructure are highlighted and discussed.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic responses of transversely isotropic and layered elastic media with imperfect interfaces under moving loads","authors":"","doi":"10.1016/j.trgeo.2024.101322","DOIUrl":"10.1016/j.trgeo.2024.101322","url":null,"abstract":"<div><p>Flexible pavement is widely used in engineering practice but is often subjected to the moving traffic loads, with imperfect contact behavior at the interfaces between adjacent layers. This study investigates transversely isotropic and layered elastic media with imperfect interfaces under moving vertical and horizontal loads using a semi-analytical method. The governing equation for moving loads is established within a Cartesian coordinate system and by virtue of the Galilean transformation, which is further decoupled into two ordinary differential equations in terms of the powerful Cartesian system of vector functions. General solutions for any layer are obtained, and the dual-variable position method is applied to derive the semi-analytical solutions for the layered pavement in the vector function domain. The lately introduced refined conversion algorithm, originally from the discrete convolution-fast Fourier transform (DC-FFT) algorithm, is applied to obtain the solution in the physical domain, which can efficiently remove the Gibbs effect near the source. The solutions are validated by comparison with existing solutions and numerical examples are presented to study the effect of interface modulus, moving load velocity, Young’s modulus of asphalt concrete and horizontal/vertical loading ratio on the surface dynamic response of the flexible pavement. Finally, the fatigue and rutting life of the pavement structures corresponding to different imperfect interface moduli are analyzed. The present solution provides practical guidance for the design of flexible pavement.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accelerated surface carbonation of non-plastic silt mixed with hydrated lime","authors":"","doi":"10.1016/j.trgeo.2024.101320","DOIUrl":"10.1016/j.trgeo.2024.101320","url":null,"abstract":"<div><p>Chemical stabilization via hydration reactions with cement or lime is a universally applied method to improve the mechanical properties of shallow soils. Accelerated soil carbonation is a nascent approach intended to bypass this reaction. Carbon dioxide gas is deliberately introduced at high concentrations to react with the alkali additives and precipitate a carbonate binder that permanently sequesters carbon dioxide in the process. A large soil box experiment was performed to examine the efficacy of an accelerated surface carbonation approach, which has the potential to be applied over large areas. High concentrations of carbon dioxide gas were introduced at grade beneath a seal to facilitate vertical penetration into lime-mixed silt. The real-time progression of accelerated soil carbonation was captured with a gas flowmeter and a distributed array of embedded thermocouples and bender elements for the first time. Post-carbonation measurements of binder content and California Bearing Ratio (CBR) verified the degree of carbonation and associated mechanical improvement. Synthesis of real-time monitoring data and post-carbonation measurements indicate carbonation progressed top-down 150 to 200 mm below grade within 5 h, resulting in a substantial increase in strength and stiffness. Potential challenges and benefits associated with adoption of accelerated surface carbonation are discussed.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141845515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the resilient and permanent deformation of a compacted waste foundry sand","authors":"","doi":"10.1016/j.trgeo.2024.101319","DOIUrl":"10.1016/j.trgeo.2024.101319","url":null,"abstract":"<div><p>The use of Waste Foundry Sands (WFS) as a construction material in geotechnical works is strategic because it allows the consumption of large amounts of this waste worldwide, typically discarded in landfills. Beyond the achievement of environmental requirements, the construction industry needs a comprehensive understanding of its mechanical properties, which is a challenge to enhance the recycling or reuse of WFS. This paper investigates the resilient and permanent deformation of a compacted WFS under repeated load. These features are necessary to understand the behavior of this material in the context of pavement design. A campaign of laboratory tests was carried out based on cyclic triaxial tests to measure resilient modulus (RM) and permanent deformation (PD). Specimens were prepared with different densities, which achieved varying compaction energy (600, 1260, and 2700 kJ/m³) but keeping saturation degree varying in a narrow range. Results demonstrated that the resilient modulus ranges from approximately 80 to 380 MPa, with confining stress controlling its behavior and having a small effect on compaction energy. Permanent deformation reaches almost 3 % after 150.000 load cycles for the maximum confining and deviatoric stresses and is controlled by the confining and deviatoric stress. The WFS reached the shakedown state for all the densities and stress-state evaluated, in a pattern below plastic creep shakedown and plastic limit shakedown. The best models to describe the experimental results were investigated, and the fitting parameters were also found. The authors also demonstrated that the resilient modulus measured on the last 100.000 cycles of permanent deformation tests is similar to the values measured on resilient modulus tests, which allows to characterize the resilient and permanent deformation using only the permanent deformation tests.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141850994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics analysis of leakage diseases of Beijing underground subway stations based on the field investigation and data statistics","authors":"","doi":"10.1016/j.trgeo.2024.101317","DOIUrl":"10.1016/j.trgeo.2024.101317","url":null,"abstract":"<div><p>With a continuous increasing of the underground water level of Beijing, many leakage diseases induced by the structural defect have been exposed in the subway tunnels that have been put into operation. The leakage diseases of underground subway stations may severely cause the safety and durability problems of the structure. Moreover, it could affect the passenger experience and seriously threaten the operation safety. Therefore, this paper collected the leakage states of a total of 258 underground subway stations in 16 lines of Beijing by field investigation, which include the number of average leakage points, leakage types and classification, distribution scenes of leakage, the construction methods and operation ages of subway stations and so on. Besides, in order to further investigate the causes of the leakage diseases, three typical cases of Beijing subway stations with severe leakage diseases, which were constructed by different methods, were selected to carry out the statistical analysis of leakage disease. The typical positions of leakage diseases of Beijing subway stations with different construction methods were presented by three-dimensional modelling, and the leakage characteristics of each station were analyzed. Finally, based on the field investigation and data statistics, a data-based Bayesian network leakage prediction model to evaluate the leakage risk of subway stations was constructed. This research can provide an intuitive reference for early warning, monitoring and prevention of leakage diseases of metro subways in operation.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141960597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of rock cutting performance of conical cutting tool based on commonly measured rock properties","authors":"","doi":"10.1016/j.trgeo.2024.101318","DOIUrl":"10.1016/j.trgeo.2024.101318","url":null,"abstract":"<div><p>Efficiency of rock cutting process plays a critical role in performance of mechanical excavation units. The composition of cutting forces (normal and drag force acting on cutting tools) and the total force (F_T), specific energy (SE), and percent of fine material (FM) produced in cutting process are important indicators of efficient cutting process. The other key factors in assessment of machine performance are tool wear, energy consumption, dust production, and machine maintenance, availability, and utilization. In this study, small scale linear cutting experiments were performed with a conical pick on thirteen sedimentary and metamorphic weak to medium strength rock samples at a range of 0.5 to 6 mm cutting depths in unrelieved cutting mode. F_T was measured by using a 3D dynamometer and recorded by the data acquisition system, and FM was determined by sieve analysis. Finally, SE was calculated using both the cutting force signal and the volume of the cuttings for each test. Subsequently, an analysis of the effective cutting geometry was performed based on cutting depth, using the specific energy as an indicator of cutting efficiency. Statistical and regression analysis was used to correlate F_T, SE, and FM with the rock properties and cutting geometry. The results revealed that the uniaxial compressive strength, Schmidt rebound number, and density are the main parameters that affect F_T and SE, and the brittleness index is the main parameter that affects FM. A nonlinear predictive model is introduced that offers a reasonable estimate of F_T, SE, and FM to assist engineers in determining the effective operational cutting geometry for a given rock type for unrelieved cuts.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141845689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"System reliability analysis of geogrid reinforced retaining wall using random finite element method","authors":"","doi":"10.1016/j.trgeo.2024.101316","DOIUrl":"10.1016/j.trgeo.2024.101316","url":null,"abstract":"<div><p>Stabilizing earthwalls is extremely important in geotechnical engineering projects and has become an integral part of transportation infrastructures. Meanwhile, geogrid reinforced retaining walls have been the attention of designers due to their advantages. On the other hand, the soil heterogeneity and the requirement of investigating the internal (geogrid rupture and geogrid pullout) and external (global and lateral displacement) stability modes of these structures have necessitated performing system reliability analysis. In this study, finite element in conjunction with random fields is used to evaluate the reliability of these walls. For this purpose, a finite element program is coded in MATLAB to obtain internal and external safety factors considering staged construction. The deterministic program is extended to a stochastic framework to account for spatial variability of soil parameters in retained backfill, foundation soil, and reinforced fill. In the last part of this study, reliability indices of stability modes are calculated to obtain the series system reliability index, utilizing the Sequential Compounding Method (SCM). The results indicated that the effect of soil heterogeneity is more significant on internal stability modes compared to external stability modes especially geogrid pullout. The results of the system reliability analysis demonstrated more critical conditions thus the reliability index of the system was less than the reliability index of individual components.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An efficient framework of optimized ensemble paradigm for estimating resilient modulus of subgrades","authors":"","doi":"10.1016/j.trgeo.2024.101315","DOIUrl":"10.1016/j.trgeo.2024.101315","url":null,"abstract":"<div><p>This study employs an efficient framework of ensemble and <em>meta</em>-heuristic optimization algorithm for estimating resilient modulus (M_R) of subgrades with and without considering the influences of freeze–thaw cycles. Notably, M_R is one of the most important stiffness characteristics used in pavement design. The proposed framework combines an ensemble paradigm, random forest regression (RFR), and a widely used <em>meta</em>-heuristic optimization algorithm, grey wolf optimizer (GWO). The outcomes of the established RFR-GWO framework were compared with six regression and neural network-based paradigms namely linear regressor, Gaussian process regression, support vector regressor, artificial neural network, emotional neural network, and multilayer perceptron neural network. For model design and validation, two datasets of A-4, A-6, and A-7–6 (as per AASHTO classification) soils were gathered from the literature. As per experimental results, the developed RFR-GWO achieved the highest degree of accuracy against both datasets with the coefficient of correlation ranging between 0.9970 and 0.9880. To demonstrate the robustness of the established RFR-GWO framework, the impact of the influencing parameters was also investigated via parametric analysis. Overall, the developed RFR-GWO has demonstrated its capability to assist engineers in estimating the subgrade M_R during the initial stage of engineering projects.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141714211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geogrid stabilization in ballasted trackbed for high-speed railways","authors":"","doi":"10.1016/j.trgeo.2024.101314","DOIUrl":"10.1016/j.trgeo.2024.101314","url":null,"abstract":"<div><p>Ballasted tracks are widely constructed worldwide both for normal, high-speed, and heavy haul railways, which consist of large amounts of diverse-sized gravel particles for a ballast layer of approximately 30 cm just below sleepers. With the increase in in-service time, various distresses, such as particle breakage, ballast fouling, hardening ballast bed, and excessive settlement occur. To clarify the occurrence and evolution mechanism behind these distresses and explore relevant countermeasures, element, model, and field tests have been extensively conducted in last decades, as well as numerical approaches. Geogrid that developed in geotechnical engineering region was found effective in constraining ballast movement and reducing particle breakage in railway engineering. The stabilization effect had also been extensively investigated by element tests and Discrete Element Method (DEM). However, the optimal location of paving geogrid in ballast layer remains unclear to date. Inspired by reproducing the service condition of ballast layer and verifying the obtained results from laboratories, several reduced-scale and full-scale model apparatuses were developed worldwide. One typical apparatus of them established in Zhejiang University has the capacity to mimic the actual train load up to the maximum train speed of 360 km/h and axle load of 30 tons, by which the effect of geogrid on ballasted track stabilization was further validated. It was found that the settlement of the ballast layer was reduced by more than 40 % as a triaxial geogrid was installed at the bottom of the ballast layer. Moreover, the vibration of ballast was significantly decreased even 15 cm above the geogrid. Afterward, field tests were conducted with the same triaxial geogrid installed at the bottom of the ballast layer, notable settlement and vibration reductions effectively proved the stabilization effect of the geogrid. In short, through an overall review on the development and application of geogrids for ballasted track stabilization, these discussions would contribute to a more comprehensive understanding of the internal stabilization mechanism and an efficient application in practice in future.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal imaging analysis of ballast fouling: Investigating the effects of parent rock and fouling materials through IRT passive camera","authors":"Mehdi Koohmishi ,&nbsp;Sakdirat Kaewunruen ,&nbsp;Guoqing Jing ,&nbsp;Yunlong Guo","doi":"10.1016/j.trgeo.2024.101313","DOIUrl":"https://doi.org/10.1016/j.trgeo.2024.101313","url":null,"abstract":"<div><p>This study explores the use of infrared thermography (IRT) technology for the non-destructive evaluation of ballast fouling in railway tracks, focusing on the influence of parent rock types and fouling materials. Utilizing thermal imaging, the research investigates how variations in ballast conditions affect surface temperature, which serves as an indicator of structural integrity and health. The experimental setup involved ballast samples derived from three different rock types—basalt, limestone, and andesite—fouled with commonly encountered materials like sand and clay at varying percentages. Results demonstrate that fouling level and type significantly influence the thermal signatures captured by IRT passive camera. Notably, ballast derived from darker rocks exhibited higher temperatures, indicating greater emissivity, while fouled ballast showed distinct temperature patterns compared to clean samples, emphasizing the potential of thermal imaging in detecting and quantifying fouling in ballast layers. This research underscores the viability of IRT passive camera in the routine maintenance and monitoring of railway infrastructure, providing a foundation for further development of integrated diagnostic tools for railway management systems.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141607437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}