Transportation Geotechnics最新文献

{"title":"Experimental assessment of freeze–thaw characteristics and microscopic mechanisms of coal-based solid waste improved loess filler","authors":"Libo Wu ,&nbsp;Jiawei Yang ,&nbsp;Shijin Feng ,&nbsp;Hongxin Chen ,&nbsp;Huiyang Liu ,&nbsp;Zhanju Lin ,&nbsp;Sanjay Nimbalkar","doi":"10.1016/j.trgeo.2025.101606","DOIUrl":"10.1016/j.trgeo.2025.101606","url":null,"abstract":"<div><div>To tackle freeze–thaw damage in loess layers by seasonal freeze–thaw cycles (FTC) and the growing coal-based solid waste crisis in Northwest China, we propose using coal-based solid waste to enhance loess for more stable, sustainable infrastructure. This paper investigates the freeze–thaw behaviors and microscopic mechanisms of loess modified with 6%, 15% coal gasification slag (CGS) and 30%, 50% coal gangue (CGA), using FTC tests, SEM analysis, and CT scans. Key aspects were analyzed include frost heave, thaw settlement, temperature, moisture distribution, and microstructural changes. The results show that adding 15% CGS reduces average frost heave and thaw settlement by 72.6% and 70.8% during the first 2 FTC, while 50% CGA cuts frost heave by 62.5% over 5 FTC, demonstrating strong potential for freeze–thaw resistance. The addition of CGS and CGA can also reduce temperature fluctuation and thermal conductivity of loess, enhancing the internal temperature stability. Moreover, adding 50% CGA could help regulate water content distribution after FTC and densify the structure of improved loess, while adding CGS leads to aggregates formation within modified loess particles.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"54 ","pages":"Article 101606"},"PeriodicalIF":4.9,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308167","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":"Performance evaluation of geogrid-stabilized steel slag layer of pavement under repeated cyclic loading","authors":"Ahmet Erdağ ,&nbsp;Seyhan Fırat ,&nbsp;Mohamad Yaman Fares ,&nbsp;Nihat Sinan Işık ,&nbsp;Bora Cetin","doi":"10.1016/j.trgeo.2025.101603","DOIUrl":"10.1016/j.trgeo.2025.101603","url":null,"abstract":"<div><div>In this study, combinations of Electric Arc Furnace (EAF) slag, geogrid, and subgrade material were subjected to laboratory tests, and their deformation and strength responses under cyclic loading were evaluated. EAF slag with an average particle size (D50) of 7 mm was tested in combination with conventional subgrade material in cyclic triaxial and large-scale tests. The primary objective of this study is to ascertain the viability of EAF slag as a base or subbase material and to explore the role of a multi-axial, multi-aperture shape geogrid in stabilizing the EAF slag layer and subgrade within the pavement system. The experimental findings demonstrate that EAF slag can be effectively utilized in the subbase layer due to its high strength and interlocking properties. The mechanical performance of the slag exhibits competitive outcomes in comparison to conventional materials in terms of resilient modulus and deformation resistance. When geogrid was incorporated into the base course, substantial reductions in permanent deformation and strain accumulation were observed. For instance, after 100,000 loading cycles, the deformation beneath the loading plate was measured at 12 mm in the slag–geogrid–subgrade system and 35 mm in the slag–subgrade system, indicating a 65 % reduction. Moreover, the lateral deformation around the loading plate was reduced by 58 %, and cumulative strain was reduced by 78 %. The resilient modulus tests (i.e., repeated load triaxial testing) revealed that the EAF slag provides sufficient stiffness to be used in road foundation applications. At high bulk stress levels (e.g., σ₃ = 137.9 kPa), the resilient modulus of the slag-containing systems was found to be comparable to conventional materials. Geogrid increased this value by 10–25 %, contributing to enhanced bearing capacity. These findings indicate that EAF slag has strong potential as a sustainable alternative to conventional materials and can be utilized effectively in the base course layer. Furthermore, when stabilized with a multi-axial, multi-aperture shape geogrid, the deformation of the pavement is significantly reduced, and the overall stiffness of the pavement foundation is improved.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101603"},"PeriodicalIF":4.9,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271762","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":"Mechanically coupled distributed dynamic strain measurement for track systems and earthworks","authors":"David Milne ,&nbsp;Ali Masoudi ,&nbsp;John Harkness ,&nbsp;Ben Lee ,&nbsp;Geoff Watson ,&nbsp;Louis Le Pen ,&nbsp;Gilberto Brambilla ,&nbsp;William Powrie","doi":"10.1016/j.trgeo.2025.101605","DOIUrl":"10.1016/j.trgeo.2025.101605","url":null,"abstract":"<div><div>Distributed optical fibre sensors are one of the few sensing technologies that could be embedded into our infrastructure to provide quantitative and mechanistic measurements of the condition of the infrastructure at network scales. This study considers the analysis of a sensing fibre deployed along 50 m of rail with a 7.5 m section buried beneath the line of the rail in the trackbed. The fibre was interrogated using a Distributed Acoustic Sensing (DAS) system based on Phase Optical Time Domain Reflectometry (ϕ-OTDR). This technique offers a short gauge length and high sample rate suited for measurement of moving loads. Data were captured as the site was trafficked by passing trains. Complementary simulation and measurements (using accelerometers and pressure sensors) were used to aid and improve the interpretation of the signal from the sensing fibre. In general, the measured signal agreed with the simulation indicating that the buried fibre provides a means of measuring horizontal strain in the ground under moving loads. Results from the different measurement systems led to a consistent interpretation of site behaviour, particularly where local variation of stiffness and load distribution were detectable at the same locations along the track. These analyses support the idea that DOFS have the potential for providing quantitative and high-resolution, and hence, high-utility sensing by interrogating an optical fibre embedded in infrastructure.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101605"},"PeriodicalIF":4.9,"publicationDate":"2025-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263397","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":"Soybean urease intensified magnesia carbonation for soil solidification: Strength and durability under drying-wetting and soaking conditions","authors":"Ya-Qing Gao,&nbsp;Jia-Feng Ji,&nbsp;Si-Yuan Qu,&nbsp;Yi-Zhao Huang,&nbsp;Jia He","doi":"10.1016/j.trgeo.2025.101604","DOIUrl":"10.1016/j.trgeo.2025.101604","url":null,"abstract":"<div><div>Magnesia carbonation can be adopted as a soil solidification technology for geotechnical engineering. Recent studies have shown that urea decomposition under the catalyzation of ureolytic bacteria can provide a carbon source for magnesia carbonation. Although many related studies have been reported, the mechanical behaviour of the magnesia solidified soil, especially its durability and long-term performance, still require further deep investigations. Besides, the use of plant urease instead of bacteria for magnesia carbonation is also of research interest and requires further studies. In this study, we used crude soybean urease for the catalyzation of urea decomposition in order to provide carbon source for magnesia carbonation (soybean urease intensified magnesia carbonation, SIMC). The mechanical behaviour and durability of SIMC solidified soil under drying-wetting and soaking conditions in acid rain solution were investigated. For SIMC samples, the addition of urea and urease as internal carbon sources led to a much higher strength compared with those without them. The optimum urea concentration was 2 mol/L, and higher concentrations could have negative impact on the strength. As for magnesia, the highest strengths were obtained when the addition was 8 %. During the drying-wetting cycles and soaking tests with acid rain water, there was a generally moderate decreasing trend in strength for the SIMC samples with more drying-wetting cycles or soaking durations. However, the strength reduction ratio, which was defined as the long-term strength in acid environment to that in neutral environment, was much higher compared to the PC samples, implying a much stronger resistance to acid rain water. The mineralogical analysis revealed that hydrated magnesium carbonates were the major effective cementing materials.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101604"},"PeriodicalIF":4.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262224","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":"Simplified Analysis Method of Stone Column Reinforced Foundations Based on Homogenization Technique","authors":"Fangyue Luo ,&nbsp;Yang Li ,&nbsp;Yangping Yao ,&nbsp;Ga Zhang","doi":"10.1016/j.trgeo.2025.101601","DOIUrl":"10.1016/j.trgeo.2025.101601","url":null,"abstract":"<div><div>Stone columns are a resultful measure to increase the bearing capacity of soft or liquefiable foundations. The centrifuge model test and finite element method were employed to investigate the bearing capacity and deformation behavior of the stone column-reinforced foundation. Study shows that the modulus of the reinforced foundation exhibits significant anisotropy. A bulging deformation area is identified in the reinforced foundation where obvious horizontal deformation of the stone column occurs. The ratio of the column stress and soil stress is observed to change violently in this area. A homogenization technique is consequently deduced by employing the column-soil stress ratio as a key variable. The definition of the column-soil stress ratio is extended to reasonably describe the column-soil interaction under different stress levels and its approximation method is given. Based on the Duncan- Chang E-ν model, a simplified method using the homogenization technique is proposed for the stone column reinforced foundation. The proposed homogenization technique and simplified method have been validated by the centrifuge model tests and finite element analyses. This method properly addresses the nonlinear spatial characteristic of deformation and the anisotropy of the stone column reinforced foundation.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101601"},"PeriodicalIF":4.9,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231528","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":"Elucidating the strain rate-dependent mechanical properties of unsaturated red clay under controlled thermal and suction environments","authors":"Fengjie Yin ,&nbsp;Guoqing Cai ,&nbsp;Xuzhen He ,&nbsp;Yanlin Su ,&nbsp;Xu Yang ,&nbsp;Wenjie Zheng","doi":"10.1016/j.trgeo.2025.101600","DOIUrl":"10.1016/j.trgeo.2025.101600","url":null,"abstract":"<div><div>This study investigates the strain-rate-dependent mechanical properties of unsaturated red clay under varying temperatures and matric suction conditions through triaxial shear tests on red clay fill materials from the Sichuan-Tibet Railway region. The tests were conducted with multiple shear strain rates, complemented by advanced microstructural analysis techniques such as mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM), to examine the evolution of pore structure. The results indicate that high matric suction significantly reduces the rate-dependency of strength in red clay fill materials, whereas temperature has a relatively smaller effect. As matric suction increases, the strain-rate parameter decreases across different temperatures, with a diminishing rate effect observed at higher suction levels. Compared to temperature, strain rate has a more pronounced influence on failure time. An increase in strain rate leads to a significant reduction in failure time. At low strain rates, failure time exhibits substantial variability, while at high strain rates, the effects of temperature and matric suction on failure time become less significant. Under high-temperature conditions, the strength of red clay is enhanced, and failure time is delayed. These findings provide critical theoretical support for controlling settlement deformation and predicting failure times of subgrade fill materials under complex climatic conditions, offering valuable insights for engineering applications.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101600"},"PeriodicalIF":4.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144263396","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":"Low-carbon binders in six test deep mixing cases – variation of in-situ strength","authors":"Juha Forsman ,&nbsp;Monica Löfman ,&nbsp;Jari Ikävalko ,&nbsp;Leena Korkiala-Tanttu","doi":"10.1016/j.trgeo.2025.101597","DOIUrl":"10.1016/j.trgeo.2025.101597","url":null,"abstract":"<div><div>In ground improvement by column stabilization, lime-cement has been traditionally used as a binder in the Nordic countries. Due to the very high CO₂ emission factor of lime-cement, there is an increasing need to transition to low-carbon alternative binders. However, no long-term case studies are available for most of low-carbon binders, and thus in-situ stabilization tests (e.g. test columns) are necessary when developing and using new recycled materials. This article presents the experiences of six column stabilisation test sites utilizing 11 low-carbon binder types, with lime-cement as reference. The low-carbon binder mixtures may contain e.g. gypsum, blast furnace slag, fly ash, and waste lime. The work focuses on the curing of the stabilized soil (soilmix) and the variation in the in-situ shear strength. The characteristic shear strength value of soilmix developed from the tests is a conservative average value based on laboratory and/or quality control (QC) sounding results. The observed variability in shear strength values for soilmix is quantified via coefficient of variation (COV). Extensive data was used to investigate the effect of various factors on COV. Shear strength of soilmix is known to be significantly affected by the water content of un-stabilized soil and the water-to-binder ratio; However, based on the observed results, the water content, the undrained shear strength of un-stabilized clay, or the curing time do not affect the COV for any of the binder types considered. In the examined clays, the water content was in the scale of 50–150 % and the vane shear strength was 7–25 kPa. The effect of the strength of soilmixes and the number of observations (sample amount) appears to have some minor effect on the COV. The effect varies slightly by binder type.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101597"},"PeriodicalIF":4.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144254046","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 interaction mechanisms of soil overlying embedded foundations under reverse faults","authors":"Li Guan ,&nbsp;Daosheng Ling ,&nbsp;Chengbao Hu ,&nbsp;Xiangyang Yu ,&nbsp;Kunming Song","doi":"10.1016/j.trgeo.2025.101596","DOIUrl":"10.1016/j.trgeo.2025.101596","url":null,"abstract":"<div><div>The continuous expansion of transportation networks has led to an increasing number of extra-long and large-scale transportation infrastructures being constructed adjacent to, crossing, or traversing active faults. In high-speed transportation infrastructure where foundations with embedded depths are commonly employed, the interaction between embedded foundations and fault rupture emerges as a critical issue in transportation geotechnics. This study systematically investigated reverse faulting effects through 26 experimental configurations combining foundation positions, embedded depths, and structural loads. Three foundation-rupture interaction modes were identified, and their transitional relationships were defined based on ground surface and foundation displacement characteristics. The proposed damage-based classification approach enhanced traditional methodologies through two key advancements: First, it incorporated structural loading — a factor persistently neglected in prior studies; Second, it utilized observable ground surface and foundation displacements to develop mitigation strategies adaptable to unpredictable subsurface rupture propagations.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"54 ","pages":"Article 101596"},"PeriodicalIF":4.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322517","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":"Performance of adjacent metro tunnels during deep excavation: A case study in Hangzhou","authors":"Zhaorui Lin ,&nbsp;Yalong Jiang ,&nbsp;Changjie Xu ,&nbsp;Minliang Chi ,&nbsp;Tao Fang ,&nbsp;Lingxiao Guan ,&nbsp;Guohui Feng ,&nbsp;Gang Lin","doi":"10.1016/j.trgeo.2025.101585","DOIUrl":"10.1016/j.trgeo.2025.101585","url":null,"abstract":"<div><div>This study investigates the construction of a large basement adjacent to two overlapping subway tunnels in a soft-soil area in Hangzhou. A year-long onsite monitoring program is conducted to investigate the effects of excavation and underground-structure construction on the immediately adjacent tunnels. The main monitoring items include the tunnel’s horizontal displacement, the horizontal convergent deformation of the tunnel section, and the roadbed settlement. Measurement results show that excavation triggers the displacement of the subway tunnel toward the pit, the elongation of the tunnel tube sheet, and the uplift of the roadbed, among which horizontal displacement occurs the most readily. The construction of the metro structure increases the displacement of the metro tunnel toward the foundation pit and the bulge of the roadbed but minimally affects the convergent deformation of the tunnel cross-section. The tunnels adjacent to the pit area are affected the most by excavation, whereas the overlapping tunnels increase the overall stiffness of the area and constrains the deformation of the tube sheet. The station facilities connect the uplink and downlink of the tunnel, thus promoting interline deformation and diminishing the effect of pit excavation on tunnel deformation. This study provides a useful reference for similar project cases in the Hangzhou area to ensure the safety of adjacent subway tunnels during basement excavation.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"53 ","pages":"Article 101585"},"PeriodicalIF":4.9,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144222206","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":"Estimation of unsaturated small-strain shear modulus in a laboratory test box and field site from a soil-water characteristic curve","authors":"Lucas Acheampong,&nbsp;L. Sebastian Bryson","doi":"10.1016/j.trgeo.2025.101599","DOIUrl":"10.1016/j.trgeo.2025.101599","url":null,"abstract":"<div><div>The small-strain shear modulus plays a significant role in analyzing soil-structure interactions and the stiffness properties of earth materials under static and dynamic loading conditions. Traditionally, this parameter is determined through seismic wave measurements in the laboratory and in the field. Alternatively, it can be determined in the field by performing dynamic cone penetrometer tests and subsequently converting to California Bearing Ratio (CBR) values using empirical equations, and finally to modulus using another empirical equation. However, this multistep process is both labor-intensive and prone to compounded errors stemming from the use of numerous empirical relationships. In this study, an approach was introduced for estimating the small-strain shear modulus for preliminary analysis based on the soil–water characteristic curve (SWCC) and a saturated small-strain shear modulus. The proposed model, developed using laboratory small-strain shear modulus data, was tested on soils compacted within a laboratory test box. In addition, a correlation was derived from the test box to modify the proposed model to make it applicable to field soils. The modified model was applied to a field site to predict measured small-strain shear modulus, which was determined from shear wave velocity and SWCC fitting parameters derived from textural characteristics and electrical resistivity. The predicted data showed satisfactory agreement with the measured data at the field site. Overall, the study demonstrates the effectiveness of the proposed model in predicting small-strain shear modulus for both small laboratory specimens and field data.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"52 ","pages":"Article 101599"},"PeriodicalIF":4.9,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144178037","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}