Transportation Geotechnics最新文献

{"title":"Prediction of California Bearing Ratio of nano-silica and bio-char stabilized soft sub-grade soils using explainable machine learning","authors":"","doi":"10.1016/j.trgeo.2024.101387","DOIUrl":"10.1016/j.trgeo.2024.101387","url":null,"abstract":"<div><div>This study investigates the prediction of the California Bearing Ratio (CBR) for nano-silica and bio-char stabilized soft sub-grade soils using explainable machine learning (ML) models. The research involves experimentally determining CBR values for soft sub-grade soils treated with varying proportions of nano-silica and bio-char. This data, along with soil properties such as grain size distribution, moisture content, and nano-silica and bio-char content, serve as inputs for training and testing various ML models. Among the 12 ML models evaluated, the Gradient Boosting Regression exhibits superior performance, achieving high accuracy (R² = 0.92) and low error rates (MSE = 0.45). The utilization of explainable artificial intelligence (XAI) techniques provides insight into the significant input features influencing CBR predictions, thereby enhancing the interpretability and reliability of the models.. The research findings, highlight the efficacy of machine intelligence in accurately predicting the CBR values of nano-silica and bio-char stabilized soft sub-grade soils. This research has significant implications for geotechnical engineering, offering a data-driven methodology to optimize soil stabilization practices and contribute to sustainable infrastructure development.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422797","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":"Advances in innovative sustainable transportation geotechnics","authors":"","doi":"10.1016/j.trgeo.2024.101397","DOIUrl":"10.1016/j.trgeo.2024.101397","url":null,"abstract":"<div><div>Transportation geotechnics integrates geotechnical engineering principles into planning, construction, and maintenance of transportation infrastructures such as roads, highways, railways, bridges, and tunnels, vital yet resource-intensive infrastructures that demand significant attention with respect to sustainable practices. Recently, there has been a growing emphasis on implementing sustainability approaches in transportation geotechnics. This shift holds promise for environmental, economic, and societal sustainability, with potential benefits that include reducing the construction industry’s carbon footprint, conserving natural resources, minimizing harmful emissions, and lowering transportation infrastructure costs. This review explores diverse strategies for advancing sustainability in transportation geotechnics, encompassing innovative materials, ground improvement techniques, and use of geosynthetics. Life-cycle assessments of sustainable transportation geotechnics in terms of environmental impacts have also been investigated. A case study is presented to illustrate the practical implementation of sustainable geosynthetics in the United States, offering practical insights into real-world implementations. Challenges, opportunities, and future directions in integrating sustainability into transportation geotechnics are also discussed, offering a roadmap for advancing environmentally-responsible and economically-viable infrastructure development.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446689","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":"Centrifuge modeling of the settlement and deformation of runway under cyclic impact load","authors":"","doi":"10.1016/j.trgeo.2024.101394","DOIUrl":"10.1016/j.trgeo.2024.101394","url":null,"abstract":"<div><div>A new device has been developed to simulate the cyclic impact load of aircraft in centrifuge model tests, enabling automatic control over the number of cycles and impact velocity. A series of centrifuge model tests were conducted using this device to analyze the influence of cyclic impact load on runway settlement and deformation. It is observed that a single impact leads to significant settlement initially, which eventually stabilizes over time. Higher impact loads require fewer impact numbers for the soil base to attain a stable state. The maximum vertical displacement of the soil base is located at the impact center line and diminishes with distance from the impact center line. Based on the vertical displacement of the soil base, the loading influential zone is demarcated as the near-ellipse shape. The formation process of the loading influential zone gradually proceeds from base surface to deeper base, and finally attains a state of stability. The vertical strain of foundation is used to describe the deformation, the soil deformation beneath the concrete pavement plate is relatively significant, with a decreasing trend as it moves away from the impact center line. Under the same impact load in shallow foundation, the point at which the vertical strain decreases to zero becomes approximately linear. Based on the concrete analysis of the settlement in each cycle, the evolution mechanism of the soil base under cyclic impact load is revealed. The soil initially shows predominantly plastic deformation, which transitions to predominantly elastic deformation in the later stages.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422795","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 and theoretical investigations of ground settlement around submerged defective pipelines","authors":"","doi":"10.1016/j.trgeo.2024.101395","DOIUrl":"10.1016/j.trgeo.2024.101395","url":null,"abstract":"<div><div>Subsurface settlement is often triggered by soil erosion above underground defective pipelines. However, there is currently insufficient research on calculation methods for estimating ground settlement caused by defective pipeline. In this work, a series of laboratory experiments were conducted to investigate the impacts of the soil particle size, hydraulic gradient, thick-span ratio, and full pipe flow velocity on ground settlement around submerged defective pipelines. A sensitivity analysis was performed to further examine these factors. The experimental results revealed that there are three settlement modes, primarily determined by soil skeleton particle size and the thick-span ratio<em>.</em> The full pipe flow velocity and hydraulic gradient significantly affected the settlement range, with the settlement range increasing as either the flow velocity or hydraulic gradient increased. Additionally, a new calculation model based on Manning’s equation was developed to predict soil settlement. The error between the calculation and experiment results was less than 15%, demonstrating the accuracy and effectiveness of the proposed method.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434014","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 settlement deformation law of new and old subgrade of expressway reconstruction and expansion based on CPTU","authors":"","doi":"10.1016/j.trgeo.2024.101392","DOIUrl":"10.1016/j.trgeo.2024.101392","url":null,"abstract":"<div><div>In the reconstruction and expansion of expressways in soft soil areas, controlling the differential settlement between the new and existing subgrades is of vital importance. To investigate the settlement and deformation characteristics of both the new and existing subgrades, piezocone penetration test (CPTU) and dissipation tests were conducted on these subgrades. The CPTU dissipation data was utilized to determine the soil’s degree of consolidation, and settlement calculations for the new and existing road subgrades were based on the CPTU test results. Subsequently, a finite element model was developed using the CPTU test findings to analyze the horizontal displacements, vertical settlements, and differential settlements of the new and existing subgrades before and after the reconstruction and expansion. Based on the measured settlement results, the new and old subgrade settlement calculation results are verified. The outcomes revealed that the degree of consolidation for the existing road subgrade of the Lianhuai Expressway ranged between 42 % and 96 %. The maximum horizontal displacement of the subgrade pre- and post-expansion occurred at the slope toe. Before expansion, the maximum vertical settlement was observed along the road’s centerline, while after expansion, it was located in the centerline of the widened section. The maximum additional settlement amounted to 274.77 mm. During the new road construction phase, the differential settlement between the new and existing road subgrades increased rapidly over time, peaking at its maximum value. However, during the operational phase of the new road, this differential settlement tapered off as time progressed.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422793","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":"Energy redistribution in railway transition zones by geometric optimisation of a novel transition structure","authors":"","doi":"10.1016/j.trgeo.2024.101383","DOIUrl":"10.1016/j.trgeo.2024.101383","url":null,"abstract":"<div><div>Railway transition zones are critical regions in railway infrastructure that are subjected to excessive operation-driven degradation due to energy concentration within these zones. This work presents a heuristic approach to optimise the geometry of the transition structure and investigate its influence on the strain energy distribution in the railway transition zones (RTZs), with a specific focus on embankment-bridge transitions equipped with a newly proposed ’Safe Hull-Inspired Energy Limiting Design (SHIELD)’ transition structure. For this purpose, a number of three-dimensional finite element models are used to analyze different geometric profiles of SHIELD in a systematic manner. By altering SHIELD’s geometry across longitudinal, transversal, and vertical directions, the influence of the different geometric profiles on the total strain energy distribution across the trackbed layers (ballast, embankment, and subgrade) is studied in terms of spatial and temporal variations. The results establish the contribution of geometry to energy redistribution in all three directions and present an optimum geometry for the type of transition under study. It is found that among all the profiles, the longitudinal geometric profile of SHIELD has the most significant impact on the strain energy distribution, while the transversal profile primarily influences the ballast layer, and the alteration of vertical profiles enhance the local redistribution of strain energy in the vicinity of the transition interface. The preliminary optimisation (heuristic approach) presented in this work provides the starting point for full-scale optimisation to obtain tailored shapes of transition structures such that there is neither a concentration of energy nor an obstruction in the flow of energy in RTZs.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446688","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":"Enhancing plate compactor efficiency: A study on frequency effects for different soil types","authors":"","doi":"10.1016/j.trgeo.2024.101393","DOIUrl":"10.1016/j.trgeo.2024.101393","url":null,"abstract":"<div><div>In this study, compaction tests on three soil types (glacial aggregate mixture, amphibolite aggregate and sand-gravel mixture) were conducted in a full-scale plate compactor experiment under different frequency scenarios, specifically between 74 and 84 Hz. The experimental approach included measuring bulk density through photogrammetry and soil sampling at different layer depths. This methodology enabled the direct assessment of Relative Compaction (RC). Furthermore, soil stiffness was measured during compaction via a lightweight dynamic plate. Findings revealed that lower compaction frequencies generally resulted in denser compaction near the surface, while higher frequencies improved compaction at greater depths. Additionally, the study explored the relationship between dynamic modulus and RC. The study highlights the need for advanced, rapid compaction assessment methods, given the limitations of current techniques. The results indicate that within the analyzed range of compaction frequencies, both the dynamic modulus and RC requirements are achieved after the same number of compactor passes, regardless of the selected frequency scenario. Therefore, opting for a lower frequency can reduce fuel consumption and equipment wear while maintaining compaction objectives, leading to better overall efficiency.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422884","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":"Dynamic responses and long-term damage evolution of tunnels in expansive strata under dynamic loads from high-speed trains","authors":"","doi":"10.1016/j.trgeo.2024.101391","DOIUrl":"10.1016/j.trgeo.2024.101391","url":null,"abstract":"<div><div>The combined effects of dynamic loads from high-speed trains and surrounding soil expansion pressure often lead to structure failure in tunnels during their service period. This study conducts a series of expansion pressure, expansion rate, and shear strength tests on expansive soil to analyze the impact of the initial moisture content and dry density on expansion behaviors. The results indicate that the expansion pressure is negatively (positively) correlated with the initial moisture content (dry density). The expansion rate decreases with increasing vertical pressure and initial moisture content. The expansive soil’s shear strength, internal friction angle, and cohesion are approximately linearly negatively correlated with initial moisture content. A three-dimensional dynamic computational model combining the train dynamic load, surrounding soil, and lining structure is established to study the tunnel’s dynamic responses and long-term damage evolution. The simulation results indicate that the combined effects of high-speed train dynamic loads and expansion pressure cause the tunnel’s maximum vertical acceleration and vertical displacement response to occur at the center of the invert. In contrast, the maximum peak of the minimum principal stress response occurs near the invert beneath the track. The minimum responses of the acceleration, vertical displacement, and peak of the minimum principal stress occur at the roof, hance, and wall, respectively. The tunnel’s vertical acceleration, vertical displacement, and peak minimum principal stress are positively correlated with expansion pressure (or train speed). When the train speed is below 300 km/h, changes in the expansion pressure (or train speed) do not alter the shape of the response envelope diagram or the relative intensity of the response at each measuring point. The upper structure of the tunnel (above the wall) experiences little damage, which is concentrated primarily in the invert and both side feet of the tunnel. Tensile damage is greater than compression damage, and the expansion pressure significantly affects the rate of damage development in tunnels during the first 15 years of service.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422890","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 and numerical study on mechanical properties of sand-contaminated ballast aggregates in confined condition","authors":"","doi":"10.1016/j.trgeo.2024.101390","DOIUrl":"10.1016/j.trgeo.2024.101390","url":null,"abstract":"<div><div>This study investigates the impact of sand contamination on the mechanical properties of railway ballasted tracks in confined condition. A combination of experimental confined uniaxial compression tests and discrete element method (DEM) simulations was employed. The experiments assessed the bulk density and elastic modulus of ballast aggregates, while the DEM simulations focused on sand movement, coordination numbers, and contact forces to elucidate the mesoscopic behavior. Findings from both experiments and simulations consistently demonstrate that sand contamination linearly increases the bulk density and causes a non-linear increase in the elastic modulus of ballast aggregates. With increasing degrees of sand contamination under vertical loading, both coordination numbers and contact forces are reduced. Sand intrusion initially leads to an uneven distribution of sand grains, primarily in the lower layer of the ballast aggregate; however, this distribution becomes more uniform when contamination exceeds 62.5%. The presence of sand particles diminishes the contact forces between ballast particles, thereby escalating the challenges associated with maintenance and repair.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356640","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":"A review of soil deformation and lateral pressure ratcheting phenomena in integral abutment bridges","authors":"","doi":"10.1016/j.trgeo.2024.101388","DOIUrl":"10.1016/j.trgeo.2024.101388","url":null,"abstract":"<div><div>Integral bridges have been proposed as a jointless design alternative to the traditional counterparts, possessing copious potential economic and structural advantages. However, due to the monolithic connection at the girder-abutment interface, longitudinal deformations from the superstructure must now be accommodated by the stiffness of the approach backfill and soil surrounding the foundation. Consequently, in addition to traffic loads, integral bridge approaches are subjected to long-term, cyclic loading due to diurnal and seasonal thermal variations. This has resulted in two progressive geotechnical phenomena: an escalation of lateral passive pressures at the abutment-soil interface and accumulated deformations near the bridge approach. Over the last two decades, several investigations on the approach backfill-abutment interaction have been carried out. However, previous reviews on integral bridges have not comprehensively discussed the theoretical aspects of these two complex geotechnical issues. Hence, this paper presents a discussion on the long-term response of stress ratcheting observed from controlled analyses, along with a comparison to that from field monitoring data. Subsequently, the occurrence of accumulated deformations, along with a correlation to the mechanism of the cyclic interaction is explored. The effects of foundation design choice and skew angle on the passive pressure accumulation and soil deformation behavior are then presented. Subsequently, approaches used to mitigate the effects of the backfill-abutment interaction are compared. From this review, it is apparent that outcomes based on available experimental and field investigations are yet inadequate to develop analytical models required to predict the long-term response of integral bridge approach backfills under various loading conditions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422794","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}