Transportation Geotechnics最新文献

{"title":"A data-driven approach to quantify track buckling strength through the development and application of a Track Strength Index (TSI)","authors":"","doi":"10.1016/j.trgeo.2024.101359","DOIUrl":"10.1016/j.trgeo.2024.101359","url":null,"abstract":"<div><p>Railroads are increasingly adopting advanced technologies to enhance safety and state of good repair of their track infrastructure, some of which employ artificial intelligence-based inspection methods. The objectivity of these inspection techniques, along with their detailed measuring capabilities, has created opportunities for railroads to improve both inspection and operational efficiency. This is achieved through more frequent and precise track data collections and technical data aggregations. This paper explores the potential of these track inspection methods to address one of the few drawbacks of continuous welded rail (CWR): track buckling. While track buckling mechanics and prevention have been the subject of numerous studies, the need for a practical and objective method to assess resistance to buckling remains. Numerous track health indices for geometry parameters and some for railway components have been developed and utilized in various applications. Yet, the opportunity exists to develop a metric that combines geometric parameters with the condition levels of railway components, particularly designed to quantify the resistance of track to buckling. Such a holistic view of the track and network-wide time series analyses of the proposed metric demonstrate whether the buckling resistance improves, remains in a steady state, or declines. In this study, a sensitivity analysis conducted using CWR-Risk software identified misalignment amplitude, track curvature, lateral resistance, torsional resistance, and longitudinal resistance as the main factors contributing to buckling resistance. Based on the sensitivity study and with a focus on the capacity side of the track buckling equation, a methodology was proposed for converting inspection data into 10-point scales that were combined through weighted averaging into a single Track Strength Index (TSI) to quantitatively assess the resistance to buckling at a track-system level. The influence of ballast condition on TSI output was evaluated using 15 ballast configuration scenarios, ensuring that the index accurately reflects ballast deficiencies in a proportionate manner. Lastly, the proposed metric was tested leveraging revenue service data collected from a Class I railroad mainline in the United States.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001806/pdfft?md5=31f13c7b808e0f1517f15d4098cc9f71&pid=1-s2.0-S2214391224001806-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory characterisation of sand-tyre mix as bedding material for buried structures","authors":"","doi":"10.1016/j.trgeo.2024.101355","DOIUrl":"10.1016/j.trgeo.2024.101355","url":null,"abstract":"<div><p>Bedding material directly interacts with buried structures and supports to sustain external loadings such as traffic and overburden soil pressure. Therefore, soil-structure interaction plays an essential role in the stability and safety of buried structures. In particular focusing on underground pipelines, the annual rate of failures in Australia is around 19 % per 100 km of pipeline and can cost millions of Australian dollars in maintenance. Of these annual failures, ground vibrations from heavy traffic and construction activities are a major cause. In order to reduce such effects of ground vibrations on buried structures, this paper presents the possible application of sand-rubber mixes as a bedding material, where rubber is sourced from recycled tyres. The performance of sand-tyre mixes with regard to the potential for vibration reduction is assessed through this experimental study which comprises of particle size distribution, standard proctor compaction, permeability test, direct shear test, California Bearing Ratio and Repeated Load Test. From these tests, it was found that sand mixed with up to 20 % recycled tyre rubber was the most suitable mix for use as a bedding material.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001764/pdfft?md5=0b6ac1c15198ff7b26a232732f6002d1&pid=1-s2.0-S2214391224001764-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142096376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study on dynamic responses of ballasted and ballastless tracks at critical velocity","authors":"","doi":"10.1016/j.trgeo.2024.101354","DOIUrl":"10.1016/j.trgeo.2024.101354","url":null,"abstract":"<div><p>High-speed railways are becoming ubiquitous worldwide, demanding increased operational speeds. Yet, as trains near critical speeds, dynamic stress and embankment displacement escalate, jeopardizing safety. While significant strides have been made in studying these critical speeds, capturing the dynamic characteristics of all track responses remains elusive. This study presents a coupled train-track-ground model employing a 2.5D finite element approach integrated with a nonlinear soil model to investigate the influence of embankment and foundation properties on the critical speeds for both ballasted and ballastless tracks. The research resulted in the development of unified Dynamic Amplification Factor curves that consistently represent the dynamic behavior of various tracks as observed in multiple studies. Additionally, the applicability of simplified theoretical models for calculating critical speeds, such as the elastic half-space foundation and track-foundation models, was assessed. The findings suggest that the simplified models are suitable only under specific conditions. This research provides valuable perspectives on optimizing train speeds and ensuring the safety of diverse track types.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142096402","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":"Optimization of mixtures of soil, construction and demolition waste, and steel slag using the simplex-extreme vertices method","authors":"","doi":"10.1016/j.trgeo.2024.101361","DOIUrl":"10.1016/j.trgeo.2024.101361","url":null,"abstract":"<div><p>In the present study, a simplex-extreme vertices methodology was applied to investigate the optimal proportions of recycled aggregates from construction and demolition waste (CDWr) and fines of electric arc furnace oxidizing slag (FS) for the stabilization of two distinct tropical soils, enabling their use in structural pavement layers. The influence of mixture components content on the unconfined compressive strength (UCS) and California Bearing Ratio (CBR) was investigated using regression analyses and response surfaces. UCS and CBR were optimized, based on the application of the Desirability function approach for determination of the best mixture compositions. The regression models yielded high coefficients of determination (R² ≥ 0.83). The optimization methodology demonstrated that the best dry mass composition was 80 % soil, 0 % CDWr, and 20 % FS for the sandy soil; and 18 % soil, 62 % CDWr, and 20 % FS for the clayey soil. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed the formation of typical products of pozzolanic reactions after a 28-day curing period. Incorporating wastes and extending the curing period caused a decrease in expansion and an enhancement in the UCS and CBR values of the soils.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130213","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":"Thermo-mechanical response of sand-silt mixtures","authors":"","doi":"10.1016/j.trgeo.2024.101342","DOIUrl":"10.1016/j.trgeo.2024.101342","url":null,"abstract":"<div><p>The thermo-mechanical response under undrained conditions is crucial in evaluating the mechanical behaviors of sand-silt mixtures. A series of consolidated undrained triaxial shear tests were conducted to investigate the mechanical response of sand-silt mixtures with different fines contents, temperatures, and initial mean effective stresses. The results showed that the volume shrinkage was observed in all specimens during heating. The amplitudes of volume shrinkage were dependent on the fines content and initial mean effective stress. Moreover, the fines content and temperature significantly influence the peak strength, flow behavior, stress ratio at the undrained instability state, and collapsibility index. Furthermore, a unified critical state line has been established in the compression plane for both clean sand and binary mixture under different temperatures and fines contents. It is reliable and suitable to use the equivalent skeleton void ratio to illustrate the thermo-mechanical response of sand-silt mixtures under undrained conditions.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117546","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 analytical model for permeability coefficient of soil-structure interface composed of different capillaries","authors":"","doi":"10.1016/j.trgeo.2024.101352","DOIUrl":"10.1016/j.trgeo.2024.101352","url":null,"abstract":"<div><p>The soil-structure interface, representing the contact surface between soil and structures such as buildings or rocks, assumes critical importance in water-related projects like earth dams, cut-off walls, side slopes, foundation pits, and water tunnels. Monitoring reports and studies consistently identify this interface as a vulnerable zone susceptible to seepage-related accidents. Despite this recognition, research on the topic has been limited, with a predominant focus on experimental methods that tend to underestimate permeability. This paper presents an analytical model, grounded in capillary theory, for calculating the permeability coefficient of the soil-structure interface. The study explores the differences in permeability between the interfacial soil and far-field soil. The study concludes that the higher porosity of the interfacial soil (porosity ≥ 0.48) compared to the far-field soil (porosity: 0.26–0.48) is a key factor in rendering the soil-structure interface susceptible to seepage. The calculated permeability coefficient of the interface, in relation to experimental values, exhibits a consistent ratio of 2.5–2.6 when the soil porosity is below 0.43, indicating reliable predictive utility. Moreover, the permeability coefficient of the interfacial soil proves to be at least 4.05–6.67 times larger than that of the far-field soil, potentially leading to the creation of preferential seepage channels at the interface.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117547","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":"Pre- and Post-Improvement Performance of a Railway Embankment Stabilized with Ductile Inclusions","authors":"","doi":"10.1016/j.trgeo.2024.101362","DOIUrl":"10.1016/j.trgeo.2024.101362","url":null,"abstract":"<div><p>Large deflections and accumulation of permanent track geometry defects at railway soft spots cause significant operational issues including increased maintenance costs, decreased train speed, and, at an extreme, derailments and track failures. Reinforcing inclusions placed between the ties are a promising rehabilitation scheme to locally stabilize the embankment and transfer the loads to deeper, more suitable soils. In this paper we report the results of a long-term monitoring program to assess the performance of ductile inclusions, known commercially as “GeoSpike® elements”, to stabilize a rapidly deteriorating railway soft spot. Observations of track bed behavior are presented for 8 months prior to installation and 15 months after installation using a combination of LIDAR, Digital Image Correlation (DIC), and ShapeAccelArrays (SAA). Through the monitoring program, it was determined that the ductile inclusions decreased the average rate of deterioration by a factor of approximately 3, which allowed the frequency of site maintenance to be decreased from three times a year to once a year.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001831/pdfft?md5=dabb1b873a290ec8a623690beb6a6e62&pid=1-s2.0-S2214391224001831-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142084117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Explicit consideration of geomaterial uncertainties in the load resistance factor design of piles driven into rock-based intermediate geomaterials","authors":"","doi":"10.1016/j.trgeo.2024.101358","DOIUrl":"10.1016/j.trgeo.2024.101358","url":null,"abstract":"<div><p>The study presents a method for estimating the end bearing of piles driven into rock-based intermediate geomaterials (IGMs). Existing design methods, rooted in soil mechanics, often fall short when applied to IGMs. Moreover, the geomaterial (geological and ground properties) uncertainties are neglected and the piles are designed based on subsurface information from distant boreholes. To address this gap, the study introduces an approach that explicitly considers geomaterial uncertainties by combining empirical models and geostatistical simulation to predict end bearing. Using data from 87 piles driven into various rock-based IGMs with dynamic load testing as the construction control technique, this study introduces the Proposed Design Method (PDM) for the prediction of end bearing. PDM is compared to the Current Design Method (CDM), which is based on traditional soil-mechanics methods. Predictions from these methods are subsequently evaluated against the measured end bearings. The results demonstrate that while the PDM yields comparable predictions to the CDM, it offers a more robust consideration of geomaterial uncertainties. The PDM leads to an approximate 13.60% to 19.35% increase in uncertainties compared to CDM across various IGMs. These findings advance the understanding of pile behavior in the presence of geomaterial uncertainties and inherent variability.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142076294","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 backward erosion piping of a double-layer dike foundation under variable exit geometries","authors":"","doi":"10.1016/j.trgeo.2024.101353","DOIUrl":"10.1016/j.trgeo.2024.101353","url":null,"abstract":"<div><p>Double-layer dike foundation is composed of a weakly permeable overlying clay layer and a highly permeable underlying sand layer, which is one of the most common stratum types in dike engineering with the highest probability of catastrophic damage, and the main danger is backward erosion piping. Existing research on backward erosion piping of double-layer dike foundation has not fully considered the influence of the exit on the erosion process. Therefore, a self-designed test device is used to assess the influences of the size, position and type of different exits, and the circular exit is connected with the slot exit via the exit area to explore the critical identification conditions and the pipe development mechanism toward the upstream direction under different exit geometry conditions. The results show that both the local and global hydraulic gradients borne by the exit are inversely proportional to the exit area and are less notably affected by the location of the exit. The development process of slot exit pipes differs from that of circular exit pipes, and pipes are usually developed alternately at the two corners of the exit near the upstream end and then converge into one pipe. The average pipe depth and width are proportional to the exit size and the seepage length. With increasing average pipe area of the slot exit, pipes develop more rapidly after head enhancement, and the damage to the dike foundation increases.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048950","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 response of dry sands subjected to dual patch impact loads of a wheeled helicopter","authors":"","doi":"10.1016/j.trgeo.2024.101345","DOIUrl":"10.1016/j.trgeo.2024.101345","url":null,"abstract":"<div><p>Dual patch impact loads are applied through two tires attached to a single landing gear during the landing of wheeled helicopters. To investigate the dynamic response of dry sands under dual patch impact loads from wheeled helicopters, model tests and validated numerical simulations were performed. The findings reveal that the settlement pattern in the shallow sand layer exhibits a characteristic W-shape, with the maximum settlement occurring directly beneath the center of each tamper. The time-history curve of the vertical dynamic pressure along the centerline of each tamper shows a single peak pulse with a duration of approximately 0.01 s. The peak value diminishes with increasing depth. Both the settlement and dynamic vertical soil pressure are dependent on impact energy, increasing as impact energy rises. The center-to-center spacing between the two tampers has a minimal effect on the maximum settlement and peak dynamic soil pressure along the centerline of each tamper. However, it significantly affects the maximum settlement and peak dynamic soil pressure along the centerline between the two tampers. As the spacing increases, the maximum settlement and peak dynamic soil pressure along the centerline between the two tampers decrease due to the attenuation of interaction between the two tampers.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142076293","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}