Pub Date : 2025-03-16DOI: 10.1016/j.trgeo.2025.101548
Gang Liu , Zhendong Qian , Leilei Chen , Jun Wan , Guoyang Lu , Wisal Ahmed , Shiu Tong Thomas Ng
To further improve the quality of bridge deck asphalt pavement (BDAP) and advance the level of bridge industrialization, a future sustainable prefabricated BDAP structure system is developed and its corresponding joint strengthening approach using the geosynthetics non-woven geotextile fabric (NWGF) is proposed for its assembly connection. Moreover, direct three-point bending and bending fatigue tests are conducted to evaluate the joint interface crack resistance performance, and the direct shear and pullout tests are implemented to assess interlayer bonding performance of the structure system after utilizing NWGF. Results show that the use of NWGF could effectively delay the joint interface cracking of prefabricated BDAP, significantly enhance the fatigue cracking life of the composite structure, and also be beneficial to improving the fracture toughness of the interlayer bonding. This research provides the joint scheme for assembly connection and corresponding joint strengthening approach, which promises the application of future sustainable prefabricated BDAP.
{"title":"Assembly connection joint strengthening approach using geosynthetics for future sustainable prefabricated bridge deck asphalt pavement","authors":"Gang Liu , Zhendong Qian , Leilei Chen , Jun Wan , Guoyang Lu , Wisal Ahmed , Shiu Tong Thomas Ng","doi":"10.1016/j.trgeo.2025.101548","DOIUrl":"10.1016/j.trgeo.2025.101548","url":null,"abstract":"<div><div>To further improve the quality of bridge deck asphalt pavement (BDAP) and advance the level of bridge industrialization, a future sustainable prefabricated BDAP structure system is developed and its corresponding joint strengthening approach using the geosynthetics non-woven geotextile fabric (NWGF) is proposed for its assembly connection. Moreover, direct three-point bending and bending fatigue tests are conducted to evaluate the joint interface crack resistance performance, and the direct shear and pullout tests are implemented to assess interlayer bonding performance of the structure system after utilizing NWGF. Results show that the use of NWGF could effectively delay the joint interface cracking of prefabricated BDAP, significantly enhance the fatigue cracking life of the composite structure, and also be beneficial to improving the fracture toughness of the interlayer bonding. This research provides the joint scheme for assembly connection and corresponding joint strengthening approach, which promises the application of future sustainable prefabricated BDAP.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"52 ","pages":"Article 101548"},"PeriodicalIF":4.9,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637804","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}
Pub Date : 2025-03-14DOI: 10.1016/j.trgeo.2025.101544
Junyi Duan , Shengji Liang , Yu Su , Yuliang Lin , Weiping Liu , Gang Wang , Li Lu
Ballastless railways constructed on expansive soils are susceptible to swelling-shrinkage deformation caused by variations in soil moisture, which poses a safety risk for train operations. However, limited investigation on integrated ballastless railway systems in previous studies has hindered the understanding of the heave performance of such railway systems. In this study, a comprehensive testing system at a 1:2 scale for a double-line ballastless railway was developed, encompassing the track slab, subgrade, and expansive soil foundation. A water immersion test was conducted to investigate the influence of foundation swelling on the heave response of the ballastless railway. The results revealed that the heave exhibited a transverse distribution resembling a groove shape, leading to noticeable tilting of the track slab, with a maximum angle of 0.34°, which far exceeded its allowable value. Therefore, it is crucial to pay attention not only to heave but also to track slab inclination when assessing the safety risks of ballastless railways. Furthermore, the underlying mechanisms related to railway heave attenuation and track slab inclination were discussed. During testing, the bulging of steel baffles on the test box induced lateral deformation within the foundation, reducing the swelling pressure and altering the rate of heave growth. By comparing the heave curves with and without the deformation release effect (DRE) defined in this study, it was observed that the DRE significantly mitigated both the heave and inclination of the track slab, with reductions of 18.1% and 26.3%, respectively. Therefore, uniformly distributing reduced-swelling holes within foundations is recommended as a potential measure for alleviating deformation issues associated with ballastless railways on expansive soils.
{"title":"Experimental investigation of the heave behaviors of ballastless railways on expansive soil foundations","authors":"Junyi Duan , Shengji Liang , Yu Su , Yuliang Lin , Weiping Liu , Gang Wang , Li Lu","doi":"10.1016/j.trgeo.2025.101544","DOIUrl":"10.1016/j.trgeo.2025.101544","url":null,"abstract":"<div><div>Ballastless railways constructed on expansive soils are susceptible to swelling-shrinkage deformation caused by variations in soil moisture, which poses a safety risk for train operations. However, limited investigation on integrated ballastless railway systems in previous studies has hindered the understanding of the heave performance of such railway systems. In this study, a comprehensive testing system at a 1:2 scale for a double-line ballastless railway was developed, encompassing the track slab, subgrade, and expansive soil foundation. A water immersion test was conducted to investigate the influence of foundation swelling on the heave response of the ballastless railway. The results revealed that the heave exhibited a transverse distribution resembling a groove shape, leading to noticeable tilting of the track slab, with a maximum angle of 0.34°, which far exceeded its allowable value. Therefore, it is crucial to pay attention not only to heave but also to track slab inclination when assessing the safety risks of ballastless railways. Furthermore, the underlying mechanisms related to railway heave attenuation and track slab inclination were discussed. During testing, the bulging of steel baffles on the test box induced lateral deformation within the foundation, reducing the swelling pressure and altering the rate of heave growth. By comparing the heave curves with and without the deformation release effect (DRE) defined in this study, it was observed that the DRE significantly mitigated both the heave and inclination of the track slab, with reductions of 18.1% and 26.3%, respectively. Therefore, uniformly distributing reduced-swelling holes within foundations is recommended as a potential measure for alleviating deformation issues associated with ballastless railways on expansive soils.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"52 ","pages":"Article 101544"},"PeriodicalIF":4.9,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143637766","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101537
El Mehdi El Gana, Abdessalam Ouallali, Abdeslam Taleb
Scour around bridge piers is a major concern for structural safety, yet traditional estimation methods often lack accuracy. This study explores advanced machine learning models to improve scour depth prediction for various pier shapes. We compare three models: Random Forest (RF), Support Vector Regression (SVR), and a Genetic Algorithm-optimized Multilayer Perceptron (GA-MLP). A comprehensive dataset, enhanced through data augmentation, was used to train the models. This dataset covers diverse flow conditions, pier geometries, and sediment characteristics. the results demonstrate that Random Forest (RF) achieved the highest predictive accuracy, with a Mean Squared Error (MSE) of 0.018, a Coefficient of Determination (R2) of 0.90, and a Kling-Gupta Efficiency (KGE) of 0.84 on the test dataset.
{"title":"Scour depth prediction around bridge piers of various geometries using advanced machine learning and data augmentation techniques","authors":"El Mehdi El Gana, Abdessalam Ouallali, Abdeslam Taleb","doi":"10.1016/j.trgeo.2025.101537","DOIUrl":"10.1016/j.trgeo.2025.101537","url":null,"abstract":"<div><div>Scour around bridge piers is a major concern for structural safety, yet traditional estimation methods often lack accuracy. This study explores advanced machine learning models to improve scour depth prediction for various pier shapes. We compare three models: Random Forest (RF), Support Vector Regression (SVR), and a Genetic Algorithm-optimized Multilayer Perceptron (GA-MLP). A comprehensive dataset, enhanced through data augmentation, was used to train the models. This dataset covers diverse flow conditions, pier geometries, and sediment characteristics. the results demonstrate that Random Forest (RF) achieved the highest predictive accuracy, with a Mean Squared Error (MSE) of 0.018, a Coefficient of Determination (R<sup>2</sup>) of 0.90, and a Kling-Gupta Efficiency (KGE) of 0.84 on the test dataset.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101537"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577871","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101528
Boyang Xia , Gang Zheng , Haizuo Zhou , Yu Diao
The accurate evaluation of the failure mechanisms and characteristics of high-filled embankments reinforced by different basal reinforcements is essential for ensuring the safety of transportation infrastructure. This study conducted two centrifuge tests to investigate the failure mechanisms and characteristics of high-filled embankments reinforced by a geosynthetic and a concrete slab, respectively. The particle image velocimetry (PIV) technique was used to observe the initiation and progression mechanisms in the soft layer. The test results reveal that the geosynthetic-reinforced embankment exhibited a progressive shear failure mechanism and the soft layer exhibited strain-softening characteristics, while the embankment reinforced by the concrete slab exhibited instantaneous shear failure in a soft foundation. Based on numerical analysis, the relationship between the overall stability and the failure modes of the reinforced embankment system was revealed. The stiffness and layers of the basal reinforcements both had positive influence on the embankment stability when deep-seated rotational failure occurred. For embankment fills with low shear strength, employing a concrete slab as basal reinforcement led to general slope failure, and the global stability was determined by the shear strength of the embankment fill. The findings of this study may be useful for the design of transportation infrastructure.
{"title":"Failure mechanisms and characteristics of high-filled embankments with different types of basal reinforcement","authors":"Boyang Xia , Gang Zheng , Haizuo Zhou , Yu Diao","doi":"10.1016/j.trgeo.2025.101528","DOIUrl":"10.1016/j.trgeo.2025.101528","url":null,"abstract":"<div><div>The accurate evaluation of the failure mechanisms and characteristics of high-filled embankments reinforced by different basal reinforcements is essential for ensuring the safety of transportation infrastructure. This study conducted two centrifuge tests to investigate the failure mechanisms and characteristics of high-filled embankments reinforced by a geosynthetic and a concrete slab, respectively. The particle image velocimetry (PIV) technique was used to observe the initiation and progression mechanisms in the soft layer. The test results reveal that the geosynthetic-reinforced embankment exhibited a progressive shear failure mechanism and the soft layer exhibited strain-softening characteristics, while the embankment reinforced by the concrete slab exhibited instantaneous shear failure in a soft foundation. Based on numerical analysis, the relationship between the overall stability and the failure modes of the reinforced embankment system was revealed. The stiffness and layers of the basal reinforcements both had positive influence on the embankment stability when deep-seated rotational failure occurred. For embankment fills with low shear strength, employing a concrete slab as basal reinforcement led to general slope failure, and the global stability was determined by the shear strength of the embankment fill. The findings of this study may be useful for the design of transportation infrastructure.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101528"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549312","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101535
Shirong Yan , Xinzhuang Cui , Xiaoning Zhang , Hao Zeng , Yefeng Du , Jiayi Lang
It is essential for improving the accuracy of subgrade compactness detection to realize the real-time determination of gravimetric moisture content during subgrade compaction. In this study, a subgrade gravimetric moisture content semi-empirical model is established to evaluate the influence of subgrade filling materials types and compactness on the subgrade gravimetric moisture content. The laboratory and field tests for different subgrade types are carried out to collect the subgrade dielectric constant under different compactness. The proposed semi-empirical model is fitted based on the experimental results and the data from the literature. The Ground Penetrating Radar (GPR) technique is then employed to obtain gravimetric moisture content by collecting the dielectric constant of the subgrade in the field test based on the proposed semi-empirical model. The results after removing anomalous data are compared with the results from the time domain reflectometry (TDR) technique. The results show that the subgrade dielectric constant subgrade increases with the gravimetric moisture content growth. And the higher compactness, the higher the dielectric constant with the same gravimetric moisture content. It can be explained that the higher compactness of the subgrade means better water retention. The proposed semi-empirical model obtains the subgrade gravimetric moisture content satisfactorily considering the types and the compactness of the subgrade, as illustrated in comparison with other models in the literature. Based on this, the GPR technique measures subgrade gravimetric moisture content more accurately compared to the TDR technique after removing anomalies. It has the advantages of not disturbing the subgrade, a wide range of applications, and high measurement accuracy, and can realize real-time non-destructive testing. This study provides a basis for determining subgrade gravimetric moisture content in real-time and non-destructive and it is important to improve the accuracy of subgrade quality evaluation.
{"title":"Research on the determination of subgrade gravimetric moisture content under different compactness based on the ground penetrating radar","authors":"Shirong Yan , Xinzhuang Cui , Xiaoning Zhang , Hao Zeng , Yefeng Du , Jiayi Lang","doi":"10.1016/j.trgeo.2025.101535","DOIUrl":"10.1016/j.trgeo.2025.101535","url":null,"abstract":"<div><div>It is essential for improving the accuracy of subgrade compactness detection to realize the real-time determination of gravimetric moisture content during subgrade compaction. In this study, a subgrade gravimetric moisture content semi-empirical model is established to evaluate the influence of subgrade filling materials types and compactness on the subgrade gravimetric moisture content. The laboratory and field tests for different subgrade types are carried out to collect the subgrade dielectric constant under different compactness. The proposed semi-empirical model is fitted based on the experimental results and the data from the literature. The Ground Penetrating Radar (GPR) technique is then employed to obtain gravimetric moisture content by collecting the dielectric constant of the subgrade in the field test based on the proposed semi-empirical model. The results after removing anomalous data are compared with the results from the time domain reflectometry (TDR) technique. The results show that the subgrade dielectric constant subgrade increases with the gravimetric moisture content growth. And the higher compactness, the higher the dielectric constant with the same gravimetric moisture content. It can be explained that the higher compactness of the subgrade means better water retention. The proposed semi-empirical model obtains the subgrade gravimetric moisture content satisfactorily considering the types and the compactness of the subgrade, as illustrated in comparison with other models in the literature. Based on this, the GPR technique measures subgrade gravimetric moisture content more accurately compared to the TDR technique after removing anomalies. It has the advantages of not disturbing the subgrade, a wide range of applications, and high measurement accuracy, and can realize real-time non-destructive testing. This study provides a basis for determining subgrade gravimetric moisture content in real-time and non-destructive and it is important to improve the accuracy of subgrade quality evaluation.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101535"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510611","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101507
Sepehr Chalajour, James A. Blatz
Piles are structural elements, transferring the superstructure’s loads to competent layers, through skin friction and end-bearing. Surcharge loads application and following consolidation induce downward movement in the soil adjacent to piles installed in a compressible layer. This movement generates negative skin friction (NSF) that acts downward at the pile-soil interface, resulting in an additional axial force added to the shaft and excessive pile settlement known as drag force (DF) and downdrag (DD), respectively. This study aims to evaluate the mobilized DF on a driven H-pile installed in clay till using three-dimensional (3D) nonlinear finite element (FE) analysis. The numerical model was validated against field data from an instrumented H-pile as part of a two-span bridge (Daly Overpass) on PTH10 in Manitoba, Canada. The calculated axial force and water total head indicated good agreement with the measured field data. Parametric analyses examined the effects of pile cross-sectional area, length, material, and applied pile head load magnitude on DF. Results showed that DF and DD values differ for piles within the cap, depending on the geometry and direction of the load application on the piles. For this project’s geometry, the maximum axial force (MAF) applied on the pile due to the embankment construction and following consolidation for the most critical pile location can reach approximately 27 % of the pile total capacity measured at the end of initial driving. Additionally, the DF and DD at the most critical pile location were 25 % and 37.5 % higher than the least critical pile scenario, respectively. Increasing the pile’s cross-sectional area and length led to an increase in DF and a downward shift of the neutral plane (NP). However, increasing the applied dead load on the pile reduced the DF and caused the NP to shift upward toward the pile head. Additionally, more DF was generated along the steel pile compared to the concrete pile.
{"title":"Prediction of drag force on piles subjected to negative skin friction induced by bridge embankment construction based on measured field data","authors":"Sepehr Chalajour, James A. Blatz","doi":"10.1016/j.trgeo.2025.101507","DOIUrl":"10.1016/j.trgeo.2025.101507","url":null,"abstract":"<div><div>Piles are structural elements, transferring the superstructure’s loads to competent layers, through skin friction and end-bearing. Surcharge loads application and following consolidation induce downward movement in the soil adjacent to piles installed in a compressible layer. This movement generates negative skin friction (NSF) that acts downward at the pile-soil interface, resulting in an additional axial force added to the shaft and excessive pile settlement known as drag force (DF) and downdrag (DD), respectively. This study aims to evaluate the mobilized DF on a driven H-pile installed in clay till using three-dimensional (3D) nonlinear finite element (FE) analysis. The numerical model was validated against field data from an instrumented H-pile as part of a two-span bridge (Daly Overpass) on PTH10 in Manitoba, Canada. The calculated axial force and water total head indicated good agreement with the measured field data. Parametric analyses examined the effects of pile cross-sectional area, length, material, and applied pile head load magnitude on DF. Results showed that DF and DD values differ for piles within the cap, depending on the geometry and direction of the load application on the piles. For this project’s geometry, the maximum axial force (MAF) applied on the pile due to the embankment construction and following consolidation for the most critical pile location can reach approximately 27 % of the pile total capacity measured at the end of initial driving. Additionally, the DF and DD at the most critical pile location were 25 % and 37.5 % higher than the least critical pile scenario, respectively. Increasing the pile’s cross-sectional area and length led to an increase in DF and a downward shift of the neutral plane (NP). However, increasing the applied dead load on the pile reduced the DF and caused the NP to shift upward toward the pile head. Additionally, more DF was generated along the steel pile compared to the concrete pile.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101507"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549323","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101533
Jose Augusto V.S. Ramos, Arthur de O. Lima, Marcus S. Dersch, J. Riley Edwards
The railroad track system and its components are a critical transportation asset that is responsible for transmitting rolling stock wheel loads to the roadbed. To ensure safe and efficient operations, railroads perform frequent track inspections, some of which generate substantial amounts of track health data. Furthermore, with the rise of data science tools and methods, the potential for these data to move maintenance and safety towards more robust analysis is fostered. Recently, railroads around the world have increased their use of data trending for geometry prediction but they do not always cover how the boundary conditions are also changing over time. This study presents an evaluation of the relationship between the change of track geometry condition and ballast profile on both curved and tangent track segments. The stochastic approach proved to be a valid comparative method for the existing and emerging datasets. Track geometry profile degradation was shown to have significant correlation with both the Ballast Health Index (BHI) and initial value of profile. Additionally, profile degradation was found to be more accelerated in regions with poorer initial geometry profiles and higher initial BHI values. Findings have the potential to improve maintenance effectiveness and prioritization and provide a method for quantifying track degradation rates under different operating and maintenance conditions.
{"title":"Stochastic investigation of the relationship between track geometry and ballast degradation rates","authors":"Jose Augusto V.S. Ramos, Arthur de O. Lima, Marcus S. Dersch, J. Riley Edwards","doi":"10.1016/j.trgeo.2025.101533","DOIUrl":"10.1016/j.trgeo.2025.101533","url":null,"abstract":"<div><div>The railroad track system and its components are a critical transportation asset that is responsible for transmitting rolling stock wheel loads to the roadbed. To ensure safe and efficient operations, railroads perform frequent track inspections, some of which generate substantial amounts of track health data. Furthermore, with the rise of data science tools and methods, the potential for these data to move maintenance and safety towards more robust analysis is fostered. Recently, railroads around the world have increased their use of data trending for geometry prediction but they do not always cover how the boundary conditions are also changing over time. This study presents an evaluation of the relationship between the change of track geometry condition and ballast profile on both curved and tangent track segments. The stochastic approach proved to be a valid comparative method for the existing and emerging datasets. Track geometry profile degradation was shown to have significant correlation with both the Ballast Health Index (BHI) and initial value of profile. Additionally, profile degradation was found to be more accelerated in regions with poorer initial geometry profiles and higher initial BHI values. Findings have the potential to improve maintenance effectiveness and prioritization and provide a method for quantifying track degradation rates under different operating and maintenance conditions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101533"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508650","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101531
M. Nobahar , S. Khan , H.K. Chia , I. La-Cour
The existence of dispersive clay soils can cause serious erosion, void, and structural damage due to an imbalance of the electrochemical forces within the particles, which causes the soil particles to be repulsive instead of being attracted to each other. Dispersivity is observed in several highway embankments in Mississippi, and the embankments have eroded and developed voids over time. The current study investigated the root cause of the voids observed within the subgrade of the state highway 477 in Mississippi and evaluated the dispersivity of high cations-based soil. As part of an investigative initiative, a 2D Ground Penetration Radar (GPR) of the highway embankment road to make a 2D profile of the soil subsurface media was surveyed to reveal that potential hotspots were overlooked, leading to suspected soil dispersivity and subsequent issues. To assess the extent of visible voids and sinkholes, dispersive tests, including the Double Hydrometer Test (DHT), were conducted to evaluate the dispersivity of the clay soils. A series of boreholes were drilled along the roadway to collect the soil samples, determine their physical properties, and identify clay soil dispersity within the soil profile. Following the confirmation of dispersive soil existence through these tests, advanced analyses, such as Scanning Electron Microscope (SEM) to identify the microstructures and the ionic compositions of the soil particles and Toxicity Characteristic Leaching Procedure Tests (TCLPT) to assess the solubility of high concentrated elements in liquid, were performed to comprehend the root cause of the soil dispersion. Based on the results of the analysis, the GPR wave cannot pass through the subgrade, which mostly happens due to the presence of the charge within the soil. Based on SEM, DHT, and TCLP test results, the soil samples have high cations, including the presence of K + . Moreover, a similar distribution of the ionic compositions was observed among the majority of the soil samples; however, the percent of dispersion regarding clay soil particles varied.
{"title":"Evaluating dispersivenss of high cations content clay soil","authors":"M. Nobahar , S. Khan , H.K. Chia , I. La-Cour","doi":"10.1016/j.trgeo.2025.101531","DOIUrl":"10.1016/j.trgeo.2025.101531","url":null,"abstract":"<div><div>The existence of dispersive clay soils can cause serious erosion, void, and structural damage due to an imbalance of the electrochemical forces within the particles, which causes the soil particles to be repulsive instead of being attracted to each other. Dispersivity is observed in several highway embankments in Mississippi, and the embankments have eroded and developed voids over time. The current study investigated the root cause of the voids observed within the subgrade of the state highway 477 in Mississippi and evaluated the dispersivity of high cations-based soil. As part of an investigative initiative, a 2D Ground Penetration Radar (GPR) of the highway embankment road to make a 2D profile of the soil subsurface media was surveyed to reveal that potential hotspots were overlooked, leading to suspected soil dispersivity and subsequent issues. To assess the extent of visible voids and sinkholes, dispersive tests, including the Double Hydrometer Test (DHT), were conducted to evaluate the dispersivity of the clay soils. A series of boreholes were drilled along the roadway to collect the soil samples, determine their physical properties, and identify clay soil dispersity within the soil profile. Following the confirmation of dispersive soil existence through these tests, advanced analyses, such as Scanning Electron Microscope (SEM) to identify the microstructures and the ionic compositions of the soil particles and Toxicity Characteristic Leaching Procedure Tests (TCLPT) to assess the solubility of high concentrated elements in liquid, were performed to comprehend the root cause of the soil dispersion. Based on the results of the analysis, the GPR wave cannot pass through the subgrade, which mostly happens due to the presence of the charge within the soil. Based on SEM, DHT, and TCLP test results, the soil samples have high cations, including the presence of K + . Moreover, a similar distribution of the ionic compositions was observed among the majority of the soil samples; however, the percent of dispersion regarding clay soil particles varied.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101531"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511221","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101540
Ida-Maria E. Savila , Leena K. Korkiala-Tanttu , Juha A. Forsman , Monica S. Löfman
Recovery of field samples provides unique information about the strength and the long-term functionality of deep stabilized soil in actual transportation infrastructures. This paper presents the results of uniaxial compressive tests for the stabilized field samples of two railway sites and one street site located in Finland. Based on the research findings, there is considerable variation in the shear strength of the field samples, with coefficients of variation (COV) ranging from 0.12 to 0.61. However, the average strengths across all sites achieved their target values set during design. The results demonstrate a significant increase in strength over time, especially at the older research sites. In a railway site where deep stabilization was performed 3.5 years ago, the average shear strength of the stabilization was 797 kPa, which is more than seven times greater than the target strength for the stabilized columns. The relationships between shear strength and deformation ratios for the columns and soil surrounding the columns exceed the assumed ratio values presented in the guidelines of Finnish Transport Infrastructure Agency (FTIA), which present a value of less than 20 for completed stabilization. Based on the results of all sites, the deformation ratio between columns and clay was found to be as much as 101. This result implies that the stress concentrates more on the columns than assumed in the FTIA’s guidelines. Nevertheless, the structures have performed well without any visible differences in settlement or other damages.
{"title":"Mechanical properties of stabilized soil: study on recovered field samples from deep stabilization sites","authors":"Ida-Maria E. Savila , Leena K. Korkiala-Tanttu , Juha A. Forsman , Monica S. Löfman","doi":"10.1016/j.trgeo.2025.101540","DOIUrl":"10.1016/j.trgeo.2025.101540","url":null,"abstract":"<div><div>Recovery of field samples provides unique information about the strength and the long-term functionality of deep stabilized soil in actual transportation infrastructures. This paper presents the results of uniaxial compressive tests for the stabilized field samples of two railway sites and one street site located in Finland. Based on the research findings, there is considerable variation in the shear strength of the field samples, with coefficients of variation (COV) ranging from 0.12 to 0.61. However, the average strengths across all sites achieved their target values set during design. The results demonstrate a significant increase in strength over time, especially at the older research sites. In a railway site where deep stabilization was performed 3.5 years ago, the average shear strength of the stabilization was 797 kPa, which is more than seven times greater than the target strength for the stabilized columns. The relationships between shear strength and deformation ratios for the columns and soil surrounding the columns exceed the assumed ratio values presented in the guidelines of Finnish Transport Infrastructure Agency (FTIA), which present a value of less than 20 for completed stabilization. Based on the results of all sites, the deformation ratio between columns and clay was found to be as much as 101. This result implies that the stress concentrates more on the columns than assumed in the FTIA’s guidelines. Nevertheless, the structures have performed well without any visible differences in settlement or other damages.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101540"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619199","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}
Pub Date : 2025-03-01DOI: 10.1016/j.trgeo.2025.101543
Panpan Tang, Akbar A. Javadi, Raffaele Vinai
Calcium carbide residue (CCR), a calcium-rich industrial waste, shows promise in improving mechanical properties of weak soils when used alone or in combination with pozzolanic materials and alkaline activators. This study comprehensively investigated the mechanical performance and stabilisation mechanism of CCR, CCR-fly ash, and alkaline-activated CCR-fly ash on kaolin clay, aiming to clarify their differences in mechanisms, identify their limitations, and promote effective application. The contribution of CCR, fly ash, alkaline activator, and initial water content of soil on enhancing soil strength was quantitively assessed through signal-to-noise ratio and analysis of variance (ANOVA) based on the Taguchi method. The stabilisation mechanism of different CCR-based materials was investigated by assessing the morphological and mineralogical features of stabilised samples. Taguchi analysis revealed that the development of soil strength was primarily influenced by initial water content in the early curing stage, while the contribution of fly ash became larger over time. Variation in CCR content had a limited effect on soil strength across all curing periods, as indicated by low contribution values and low statistical significance in ANOVA. The microstructural analyses revealed a low degree of formation of C-S-H and C-A-H gels in soil stabilised with CCR alone and CCR combined with fly ash, while alkaline activated CCR-fly ash stabilised soil exhibited the coexistence of C-A-S-H and N-A-S-H gels. Taguchi superposition model was effectively used to estimate compressive strength results and supported the determination of suitable CCR-based materials for specific strength requirements.
{"title":"Calcium carbide residue for clay stabilisation: mechanical and microstructural properties","authors":"Panpan Tang, Akbar A. Javadi, Raffaele Vinai","doi":"10.1016/j.trgeo.2025.101543","DOIUrl":"10.1016/j.trgeo.2025.101543","url":null,"abstract":"<div><div>Calcium carbide residue (CCR), a calcium-rich industrial waste, shows promise in improving mechanical properties of weak soils when used alone or in combination with pozzolanic materials and alkaline activators. This study comprehensively investigated the mechanical performance and stabilisation mechanism of CCR, CCR-fly ash, and alkaline-activated CCR-fly ash on kaolin clay, aiming to clarify their differences in mechanisms, identify their limitations, and promote effective application. The contribution of CCR, fly ash, alkaline activator, and initial water content of soil on enhancing soil strength was quantitively assessed through signal-to-noise ratio and analysis of variance (ANOVA) based on the Taguchi method. The stabilisation mechanism of different CCR-based materials was investigated by assessing the morphological and mineralogical features of stabilised samples. Taguchi analysis revealed that the development of soil strength was primarily influenced by initial water content in the early curing stage, while the contribution of fly ash became larger over time. Variation in CCR content had a limited effect on soil strength across all curing periods, as indicated by low contribution values and low statistical significance in ANOVA. The microstructural analyses revealed a low degree of formation of C-S-H and C-A-H gels in soil stabilised with CCR alone and CCR combined with fly ash, while alkaline activated CCR-fly ash stabilised soil exhibited the coexistence of C-A-S-H and N-A-S-H gels. Taguchi superposition model was effectively used to estimate compressive strength results and supported the determination of suitable CCR-based materials for specific strength requirements.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101543"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619201","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号