Transportation Geotechnics最新文献

{"title":"Mechanical behaviors of the geocell reinforced graded aggregates under train loading: Based on Indoor tests and DEM","authors":"Rongwei Fan ,&nbsp;Junjie Huang ,&nbsp;Yanfei Pei ,&nbsp;Zhichao Huang ,&nbsp;Haokun Zhang ,&nbsp;Zongyu Zhang ,&nbsp;Aibo Luo ,&nbsp;Qian Su","doi":"10.1016/j.trgeo.2025.101514","DOIUrl":"10.1016/j.trgeo.2025.101514","url":null,"abstract":"<div><div>Usually, a graded-aggregates layer with a given thickness is laid between a rigid subgrade (box subgrade, pile-plank subgrade) and a ballastless track structure. Such a configuration is realized to achieve features such as dynamic buffering, vibration reduction, energy dissipation, and limitation of uneven settlement. Geocells are typically used to reinforce the graded aggregates layer by enhancing its strength and stiffness. A dynamic test device was independently developed to investigate the mechanical behavior of geocell-reinforced graded aggregates under train loading. The test device can simulate the cyclic train loading and lateral confining pressure on graded aggregates. Subsequently, a comparative test of graded aggregates with geocell and without geocell was carried out by using the device. The above said experiments were simulated by a 3D discrete-element approach that considered the actual shape of the graded aggregate particles. The macroscopic mechanical property changes of graded aggregate under train loads were analyzed from microscopic behaviors such as particle contact and particle migration. This study is intended to provide a basis for optimizing and improving the dynamic performance and evaluation of the ballastless track sandwich subgrade with an upper rigid layer, a middle flexible layer, and a lower rigid layer during long-term service.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101514"},"PeriodicalIF":4.9,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395380","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":"Study on the sliding mechanism of slopes along railways in loess regions of China under the coupling effect of extreme rainfall and train vibration","authors":"Kai Han ,&nbsp;Jiading Wang ,&nbsp;Peng Xiao ,&nbsp;Dengfei Zhang ,&nbsp;Bo Cui ,&nbsp;Tao Xiao","doi":"10.1016/j.trgeo.2025.101513","DOIUrl":"10.1016/j.trgeo.2025.101513","url":null,"abstract":"<div><div>This study aims to investigate the sliding mechanism of slopes along railways in loess regions under the coupling effect of extreme rainfall and train vibration. Using the Baotou–Xi’an railway as a case study, a physical model of slopes along railways was developed to account for the impacts of dry-wet cycles, extreme rainfall, and train vibration. The experiments revealed that during the dry-wet cycle phase, the pore fractal dimension of the slope soil decreases from 2.95 to 2.81, indicating an increase in macropores, which enhances water transport efficiency in the soil. Following extreme rainfall, the pore water pressure and moisture content data of the soil approach peak levels, suggesting increased soil saturation and weakened stability. Subsequent vibration loading results in highly saturated soil, as evidenced by fluctuations in volumetric moisture content (from 48 % to 50.7 %) and pore water pressure (from 1.6 to 1.8 Kpa). Train vibration contributes to crack formation and expansion, while water infiltration establishes a pore-crack-seepage network. This network, combined with rainfall and train vibrations, destabilizes the soil structure and triggers landslides in loess regions along railways. The continuous application of vibration load further expands the sliding range. Meanwhile, an equation was derived to determine the sliding distance in relation to the number of vibratory loads applied. The sliding mechanism of slopes along railways under the combined influence of rainfall and train vibration has been preliminarily verified through micro, meso, and macroscopic perspectives.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101513"},"PeriodicalIF":4.9,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402637","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":"Vibration of the track-soil system due to a harmonic moving load on railway tracks resting on layered soils by 2.5D approach","authors":"Y.B. Yang ,&nbsp;L.T. Xie ,&nbsp;D.S. Yang ,&nbsp;J. Li ,&nbsp;Y.Z. Liu ,&nbsp;Z.L. Wang","doi":"10.1016/j.trgeo.2025.101519","DOIUrl":"10.1016/j.trgeo.2025.101519","url":null,"abstract":"<div><div>Research on the vibrations of track-soil coupling system has been enhanced by the rapid construction of high-speed railways worldwide. As part of the effort to address this problem, a dynamic analysis model composed of the track and soil subjected to a harmonic moving load is analyzed by the 2.5D approach. Focus is placed on the response of the track-soil system caused by the harmonic moving load at sub-critical, critical, and super-critical speeds. The track is modeled as a three-layered structure comprising the rails, sleepers and ballast and the underlying soil is simulated by the 2.5D finite and infinite elements. The train load is treated as a single moving load oscillating with self frequency <span><math><msub><mi>f</mi><mn>0</mn></msub></math></span>. A thorough investigation is presented for the effects of the moving load with various self frequency <span><math><msub><mi>f</mi><mn>0</mn></msub></math></span> at the sub-critical, critical, and super-critical speeds on the ground response. In addition, the effects of the rail and soil properties on the rail response were assessed, as well as on the differential responses of the rails and the ground. The findings of the paper include: (1) The critical speed of the soil is deeply affected by the material properties of the soil and the track, as well as the self frequency <span><math><msub><mi>f</mi><mn>0</mn></msub></math></span> of the load. Particularly, using a stiffer soil or a lighter track helps to mitigate the ground response, while increasing the critical speed <span><math><msub><mi>c</mi><mrow><mi>c</mi><mi>r</mi></mrow></msub></math></span>. (2) A decrease in the shear wave speed ratio of the soil tends to enhance the fluctuation of the ground vibration. At zero self-frequency, increasing soil layer depth <em>H</em> may increase the maximum displacement, while decreasing the vibration fluctuation; as the self-frequency <span><math><msub><mi>f</mi><mn>0</mn></msub></math></span> rises, the effect of soil layer depth <em>H</em> on ground response further diminishes. (3) An increase in the self frequency <span><math><msub><mi>f</mi><mn>0</mn></msub></math></span> of the moving load tends to decrease both the ground response and the level of fluctuation. (4) The higher-frequency rail response for a lighter track on stiffer soils is pronounced prior to arrival of the load at <span><math><mi>t</mi><mo>=</mo><mn>0</mn><mspace></mspace><mi>s</mi></math></span>, while the lower-frequency rail response for a heavier track on a softer soil is more significant after <span><math><mi>t</mi><mo>=</mo><mn>0</mn><mspace></mspace><mi>s</mi></math></span>.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101519"},"PeriodicalIF":4.9,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402638","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":"Geotechnical characterisation and sustainability assessment of plastic waste inclusions on a cement-treated fine-grained soil for pavement applications","authors":"Charakho N. Chah ,&nbsp;Sreedeep Sekharan ,&nbsp;Vimal Katiyar","doi":"10.1016/j.trgeo.2025.101515","DOIUrl":"10.1016/j.trgeo.2025.101515","url":null,"abstract":"<div><div>Global economic growth leads to massive plastic waste increase, posing severe environmental challenges worldwide. Addressing it demands innovative solutions like repurposing plastics for construction. Extensive engineering and environmental assessments can accelerate their adoption. This study explores the potential incorporation of plastic waste (in flake and pellet forms) into a cement-treated fine-grained soil through a comprehensive geotechnical experimental testing program and Life Cycle Assessment (LCA) study to assess their environmental sustainability. Experimental investigations were conducted on four distinct plastic types, namely polypropylene (PP), high-density polyethylene (HDPE), polylactic acid (PLA), and polyethylene terephthalate (PET), with varying weight percent inclusions of 2 %, 4 %, and 6 %. Results revealed a decreasing trend in maximum dry densities and strength (both unconfined compressive strength (UCS) and split tensile strength (STS)) with increasing plastic content. Sorptivity of soil generally increased with plastic inclusions, yet in the case of PET, for plastic content &gt; 4 %, a notable drop in the rate of increase was observed. California bearing ratio (CBR) test results indicated a reduction in the CBR values by up to 18.33 % for 6 % plastic inclusions. LCA study findings favoured plastic flakes over pellets as a more sustainable material choice, exhibiting a lower environmental impact across all assessed indicators. This research findings offer insights into the potential utilization of plastic waste and promote sustainable geomaterial choices in road pavement construction.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101515"},"PeriodicalIF":4.9,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387716","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":"Assessment on eco-solidified alkali residue reinforced soft soils for intelligent subgrade constructions","authors":"Jianhua Li ,&nbsp;Zicheng Zhang ,&nbsp;Xu Liu ,&nbsp;Xiaolei Jiao ,&nbsp;Jiale Li","doi":"10.1016/j.trgeo.2025.101516","DOIUrl":"10.1016/j.trgeo.2025.101516","url":null,"abstract":"<div><div>The realization of carbon neutrality can be effectively promoted by the utilization of industrial solid waste in road construction. The alkali residue (AR) is used to modify the soft soil to fulfill the requirement of subgrade construction. A series of compaction tests is performed by considering the coarse- and powdered-reinforced AR soils. The unconfined compressive strength (UCS) is tested with various contents of AR and curing ages. A dataset is established by summarizing the data from literature and laboratory tests. An intelligent model is proposed to design the treatment plan of filling soils in terms of UCS. The environmental impact of chloride diffusion is analyzed. Soluble chloride ions are immobilized using ground granulated blast slag (GGBS) and steel slag to achieve eco-friendly reinforcement of soft soil. The results of the study provide guidance for optimizing soft soil reinforcement performance for subgrade construction, improving resource utilization and reducing soil salinity.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101516"},"PeriodicalIF":4.9,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387718","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":"Geotechnical Application of Unmanned Aerial Vehicle (UAV) for Estimation of Ground Settlement after Filling and Compaction","authors":"Jong-Sub Lee ,&nbsp;Si Hyeon Jeong ,&nbsp;Geunwoo Park ,&nbsp;YoungSeok Kim ,&nbsp;Erol Tutumluer ,&nbsp;Sang Yeob Kim","doi":"10.1016/j.trgeo.2025.101517","DOIUrl":"10.1016/j.trgeo.2025.101517","url":null,"abstract":"<div><div>In geotechnical engineering field, unmanned aerial vehicles (UAV) have been widely used to monitor ground deformation. The objective of this study is to apply the UAV in the field and compare it with the on-site dynamic cone penetration test (DCPT), considering the ground deformation and strength characteristics. The calibration test results show that a flight altitude of 25 m, side-frontal overlap of 80–80 %, and camera angle at 80° is the most reliable compositions. For the field test, UAV scanning using the data model generated by the point cloud and DCPT up to a depth of 500 mm after filling and compaction were conducted. The field test results revealed that the ground settlement measured by the UAV and on-site test was similar, and a larger settlement occurred when the ground was weaker. Thus, the UAV can be efficiently used to assess the strength characteristics as well as ground settlement.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101517"},"PeriodicalIF":4.9,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402646","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":"Considerations on the ability of Supervised Neural Networks to estimate the 3D shape of particles from 2D projections","authors":"Danilo Menezes Santos,&nbsp;Alfredo Gay Neto","doi":"10.1016/j.trgeo.2025.101506","DOIUrl":"10.1016/j.trgeo.2025.101506","url":null,"abstract":"<div><div>Equipment to observe and classify granular media is widely used to capture granular systems morphologies. Although some equipment models are very efficient in analyzing samples with numerous grains, these tools present a limitation related to the inability to obtain directly the particle’s 3D shape. To overcome this drawback, different techniques have been applied to estimate the three-dimensional shape of grains from the analysis of their 2D projections. Despite the progress made, because it is an ill-posed problem, the developed methods have not yet provided a definitive solution. In this work, we investigated the ability of Supervised Neural Networks (SNN) to estimate the three-dimensional shape of some particles of Angular sand and Ottawa sand using data from single projections. We performed simulations employing the Discrete Element Method (DEM) and comparisons of shape descriptors to sets of reconstructed 3D particle shapes. The SNNs can adequately correlate and generate new particles from the analysis of 2D sand projections, showing potential applicability in the geometry reconstruction of granular materials.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101506"},"PeriodicalIF":4.9,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387717","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":"Assessment of the maintenance effect for rock ballast bed during tamping operation","authors":"Shunwei Shi ,&nbsp;Yanglong Zhong ,&nbsp;Chang Liu ,&nbsp;Xichong Ren ,&nbsp;Yixiong Xiao ,&nbsp;Chunyu Wang ,&nbsp;Liang Gao","doi":"10.1016/j.trgeo.2025.101511","DOIUrl":"10.1016/j.trgeo.2025.101511","url":null,"abstract":"<div><div>Tamping operation can damage rock ballast beds in railway; therefore, the assessment of maintenance effect is crucial for the safe running of a train. First, a ballasted track-tamping machine model was established using DEM-MFBD. Subsequently, a test method for the squeezing distance of tamping machine was developed and the model was verified. Using this model, the effects of tamping operation on mechanical states of rock ballast and sleeper were analyzed and the corresponding sensitive indicators were determined. Finally, the relationship between comprehensive mechanical state of ballast bed and squeezing distance was analyzed, and the assessment of maintenance effect was achieved. The results indicated that the coordination number and the compactness of ballast were sensitive to tamping, decreasing by 52.78% and 6.64% for 160 kN/mm stiffness, respectively. Additionally, the bottom contact density and pressure on sleeper were also sensitive to tamping, decreasing by 70.66% and 60.06%, respectively. The maintenance effect for rock ballast bed can be assessed according to the maximum squeezing distance of tamping machine.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101511"},"PeriodicalIF":4.9,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376702","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":"Seismic stability analysis of anchored concave slopes","authors":"Ahmad Rajabian,&nbsp;Farshid Vahedifard","doi":"10.1016/j.trgeo.2025.101505","DOIUrl":"10.1016/j.trgeo.2025.101505","url":null,"abstract":"<div><div>Concave-facing profiles are frequently encountered in natural slopes and, more recently, in man-made slopes. The seismic stability of such concave slopes can be effectively improved by employing ground anchors. The concavity of the slope profile can be effective in the design of the soil anchoring system. Using the pseudo-static limit equilibrium (LE) approach and considering a rotational log-spiral failure mechanism, this paper analytically addresses the total anchor load required for the stability of concave soil slopes reinforced with pre-tensioned cable anchors under seismic loading conditions. The concave face of the slope is represented by a circular arc, the curvature of which is expressed by the mid-chord offset (MCO) parameter. A satisfactory agreement was found between the results predicted by the solution and those of the finite element method. The impact of profile concavity on the resulting total anchor load was explored by varying backslope inclination, vertical-to-horizontal seismic coefficient ratio, and the action point of the total anchor load. Further, a design example is presented to illustrate how the load of anchors for a given anchorage layout can be determined using the method. The results generally indicate that a concave slope requires less total anchor load to provide seismic stability compared to an equivalent planar one. However, the concavity impact decreases with increasing horizontal seismic coefficient and backslope inclination. Further, the direction of the vertical seismic coefficient was found to be effective on the impact of concavity.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101505"},"PeriodicalIF":4.9,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348211","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 longer crossties in railroad track transition zone: Finite element analysis and laboratory experimentation","authors":"Jaeik Lee,&nbsp;Arthur de O. Lima,&nbsp;Marcus S. Dersch,&nbsp;J.Riley Edwards","doi":"10.1016/j.trgeo.2025.101508","DOIUrl":"10.1016/j.trgeo.2025.101508","url":null,"abstract":"<div><div>Transition zones in railway tracks are characterized by abrupt changes in the track stiffness which induces differential track displacement and can result in settlement. Failure to promptly address these issues through maintenance activities can lead to accelerated track component degradation and a loss of passenger comfort. This study investigated the effectiveness of a conventional strategy involving the implementation of longer crossties to mitigate abrupt variation of track stiffness especially in the open track to bridge transition. The study initially explored various properties and layouts of elastomers (i.e., rubber pads) through finite element analysis (FEA) to determine the appropriate support condition as an alternative to ballast to ensure consistency across the tests. Different hardnesses and configurations of rubber pads were considered to replicate the behavior of the ballast, and a dual layer of 60 shore A rubber pads with 25 holes exhibited crosstie displacement of 0.16 in. (0.41 cm), aligning with the range of field data. Based on this selected support condition, three different crosstie lengths (i.e., 102 in. [259 cm], 132 in. [335 cm], and 168 in. [427 cm]) were evaluated through both FEA and laboratory experimentation. Modeling results showed a 4.2 % reduction in displacement under the rail seat for the 168 in. (427 cm) crosstie compared to the standard crosstie (i.e., 102 in. [259 cm]). Similarly, laboratory experimentation demonstrated an 8.2 % decrease in vertical rail displacement. These findings suggest that the implementation of longer crossties within the track transition zone may not be considered an ideal methodology for achieving a gradual increase in track stiffness.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101508"},"PeriodicalIF":4.9,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139452","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}