Pub Date : 2024-11-01DOI: 10.1016/j.trgeo.2024.101439
Ping Xu , Wei Zhao , Shi-fan Qiao , Hui Dong
Dynamic compaction is an efficient method for strengthening roadbed. Evaluating the reinforcement effect and determining the improvement range is a hot topic in the research of dynamic compaction technology. However, it is difficult to analyze the reinforcement effect and improvement range of dynamic compaction of high stone-filled embankment of highways in the mountainous areas of southwest China due to the limited research. To better guide construction practice of dynamic compaction, three research methods were proposed to comprehensively investigate the dynamic compaction process, reinforcement effect and improvement range of embankments. The displacement characteristics of the surface and inside of the embankment under 3000 kN·m were studied, and the response, propagation and attenuation mechanisms of the dynamic stress induced by the hammer impact were also analysed. The results show that the vertical compression effect of impact energy is much greater than the horizontal shear effect, the vertical attenuation rate of dynamic stress is much smaller than the horizontal attenuation rate under dynamic compaction, and the vertical effective reinforcement depth is approximately twice as large as the horizontal effective reinforcement width. The reinforcement boundaries are approximately an ellipse, and the optimum tamping point spacing in multi-point tamping is 2 ∼ 2.5 times the hammer diameter. The theoretical analysis and simulation results are well agreement with the field-measured data from the construction site of the Pan-Xing highway in Guizhou Province, China, which provides theoretical and technical support for determining the construction parameters of dynamic compaction of a high stone-filled embankments in mountain highways.
{"title":"Comprehensive investigation on the reinforcement effect of the dynamic compaction of high stone-filled embankments","authors":"Ping Xu , Wei Zhao , Shi-fan Qiao , Hui Dong","doi":"10.1016/j.trgeo.2024.101439","DOIUrl":"10.1016/j.trgeo.2024.101439","url":null,"abstract":"<div><div>Dynamic compaction is an efficient method for strengthening roadbed. Evaluating the reinforcement effect and determining the improvement range is a hot topic in the research of dynamic compaction technology. However, it is difficult to analyze the reinforcement effect and improvement range of dynamic compaction of high stone-filled embankment of highways in the mountainous areas of southwest China due to the limited research. To better guide construction practice of dynamic compaction, three research methods were proposed to comprehensively investigate the dynamic compaction process, reinforcement effect and improvement range of embankments. The displacement characteristics of the surface and inside of the embankment under 3000 kN·m were studied, and the response, propagation and attenuation mechanisms of the dynamic stress induced by the hammer impact were also analysed. The results show that the vertical compression effect of impact energy is much greater than the horizontal shear effect, the vertical attenuation rate of dynamic stress is much smaller than the horizontal attenuation rate under dynamic compaction, and the vertical effective reinforcement depth is approximately twice as large as the horizontal effective reinforcement width. The reinforcement boundaries are approximately an ellipse, and the optimum tamping point spacing in multi-point tamping is 2 ∼ 2.5 times the hammer diameter. The theoretical analysis and simulation results are well agreement with the field-measured data from the construction site of the Pan-Xing highway in Guizhou Province, China, which provides theoretical and technical support for determining the construction parameters of dynamic compaction of a high stone-filled embankments in mountain highways.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101439"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652766","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101438
Zhixing Deng , Linrong Xu , Qian Su , Yuanxingzi He , Yongwei Li
Understanding the long-term deformation of high-speed railway subgrade is essential for solving deformation issues and managing operations. Machine learning methods are commonly used to predict subgrade cumulative deformation (SCD). However, traditional machine learning models for SCD prediction have poor generalization to new data and lack visualization. Hence, this study proposes a novel method using an empiricism-constrained neural network (ECNN) and SHapley Additive exPlanations (SHAP) analysis for predicting SCD of high-speed railways. Firstly, the SCD prediction dataset is constructed and divided into training and test sets. Then, neural network models are developed using the training set, and the optimal model is determined based on the comprehensive scoring results on the test set. The optimal model couples empirical information into the neural network with loss function modification, to create the ECNN model. Finally, the interpretability of the ECNN model is analyzed using the SHAP method. The results indicate that the Bi-directional Gated Recurrent Unit (Bi-GRU) model is the optimal model with the highest CSI value of 23. The ECNN model outperforms the Bi-GRU in generalization to new data, especially in long-term SCD prediction with limited training data. Contribution analysis shows that the top two features influencing the prediction are St-1 (54.4%) and St-2 (30.4%), consistent with the findings of the ablation analysis. The research results can provide a new reference for predicting the SCD of high-speed railways.
{"title":"A novel method for subgrade cumulative deformation prediction of high-speed railways based on empiricism-constrained neural network and SHapley Additive exPlanations analysis","authors":"Zhixing Deng , Linrong Xu , Qian Su , Yuanxingzi He , Yongwei Li","doi":"10.1016/j.trgeo.2024.101438","DOIUrl":"10.1016/j.trgeo.2024.101438","url":null,"abstract":"<div><div>Understanding the long-term deformation of high-speed railway subgrade is essential for solving deformation issues and managing operations. Machine learning methods are commonly used to predict subgrade cumulative deformation (SCD). However, traditional machine learning models for SCD prediction have poor generalization to new data and lack visualization. Hence, this study proposes a novel method using an empiricism-constrained neural network (ECNN) and SHapley Additive exPlanations (SHAP) analysis for predicting SCD of high-speed railways. Firstly, the SCD prediction dataset is constructed and divided into training and test sets. Then, neural network models are developed using the training set, and the optimal model is determined based on the comprehensive scoring results on the test set. The optimal model couples empirical information into the neural network with loss function modification, to create the ECNN model. Finally, the interpretability of the ECNN model is analyzed using the SHAP method. The results indicate that the Bi-directional Gated Recurrent Unit (Bi-GRU) model is the optimal model with the highest <em>CSI</em> value of 23. The ECNN model outperforms the Bi-GRU in generalization to new data, especially in long-term SCD prediction with limited training data. Contribution analysis shows that the top two features influencing the prediction are <em>S</em><sub>t-1</sub> (54.4%) and <em>S</em><sub>t-2</sub> (30.4%), consistent with the findings of the ablation analysis. The research results can provide a new reference for predicting the SCD of high-speed railways.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101438"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652755","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101410
Fausto Molina-Gómez , Ricardo González-Olaya , Javier Camacho-Tauta
Earthquake-induced liquefaction is a relevant natural hazard due to the damages caused in numerous buildings, facilities and infrastructures worldwide. The damages caused to the infrastructure by this phenomenon are caused by the loss of stiffness and strength in granular soils, which leads to settlements and lateral spreading. Earthquake-induced liquefaction typically occurs in saturated deposits composed of non-plastic soils. Hence, the degree of saturation reduction is considered one of the most favourable and optimistic methods for liquefaction resistance mitigation. This paper explores the earthquake-induced liquefaction in saturated and gassy sands, varying their degree of saturation and state parameters. The state parameter was used to analyse the mechanical behaviour by combining the effects of relative density (or initial void ratio) with confinement pressure. Results show that liquefaction resistance improvement caused by the reduction in the degree of saturation is higher as the state parameter increases. This improvement can be described and quantified by multivariate models integrating the effects of degree of saturation and state parameter on liquefaction resistance. This provides a potential solution for improving the resilience of infrastructures susceptible to earthquake-induced liquefaction.
{"title":"Exploring liquefaction resistance in saturated and gassy sands at different state parameters","authors":"Fausto Molina-Gómez , Ricardo González-Olaya , Javier Camacho-Tauta","doi":"10.1016/j.trgeo.2024.101410","DOIUrl":"10.1016/j.trgeo.2024.101410","url":null,"abstract":"<div><div>Earthquake-induced liquefaction is a relevant natural hazard due to the damages caused in numerous buildings, facilities and infrastructures worldwide. The damages caused to the infrastructure by this phenomenon are caused by the loss of stiffness and strength in granular soils, which leads to settlements and lateral spreading. Earthquake-induced liquefaction typically occurs in saturated deposits composed of non-plastic soils. Hence, the degree of saturation reduction is considered one of the most favourable and optimistic methods for liquefaction resistance mitigation. This paper explores the earthquake-induced liquefaction in saturated and gassy sands, varying their degree of saturation and state parameters. The state parameter was used to analyse the mechanical behaviour by combining the effects of relative density (or initial void ratio) with confinement pressure. Results show that liquefaction resistance improvement caused by the reduction in the degree of saturation is higher as the state parameter increases. This improvement can be described and quantified by multivariate models integrating the effects of degree of saturation and state parameter on liquefaction resistance. This provides a potential solution for improving the resilience of infrastructures susceptible to earthquake-induced liquefaction.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101410"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554137","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101424
Shusen Liu , Jun Li , Shumin Lyu , Yi Fang , Xiaodong JI , Junjun Ni
The slopes adjacent to highways and railroads, which are subjected to both static loads and dynamic loads induced by vehicles and trains, undergo mechanical stresses of varying magnitudes. As long-term cyclic loading can weaken the soil strength and generate excessive deformation, it is necessary to investigate the influence of root distribution on the deformation characteristics of soil reinforced by roots under cyclic loading. With a special focus on the soil stress state, dynamic triaxial tests were conducted to investigate the deformation characteristics induced by cyclic loading, accounting for loading frequency, dynamic stress amplitude and root distribution attributes. The results demonstrate that the crossed arrangement outperforms other patterns under dynamic loads. Root crossed arrangement reduces the plastic deformation of the soil by 70% to 80% and the resilient deformation by 30% to 40%. The soil transient deformation resistance is significantly enhanced through root arrangement, while root cross arrangement leads to a remarkable improvement in the soil dynamic modulus and damping ratio by approximately 200%. The confirmation was obtained that the Hardin and Drnevich hyperbolic model exhibited exceptional conformity and could be effectively employed in analyzing root-reinforced soil.
{"title":"Deformation characteristics of root-reinforced soil under traffic induced cyclic loading","authors":"Shusen Liu , Jun Li , Shumin Lyu , Yi Fang , Xiaodong JI , Junjun Ni","doi":"10.1016/j.trgeo.2024.101424","DOIUrl":"10.1016/j.trgeo.2024.101424","url":null,"abstract":"<div><div>The slopes adjacent to highways and railroads, which are subjected to both static loads and dynamic loads induced by vehicles and trains, undergo mechanical stresses of varying magnitudes. As long-term cyclic loading can weaken the soil strength and generate excessive deformation, it is necessary to investigate the influence of root distribution on the deformation characteristics of soil reinforced by roots under cyclic loading. With a special focus on the soil stress state, dynamic triaxial tests were conducted to investigate the deformation characteristics induced by cyclic loading, accounting for loading frequency, dynamic stress amplitude and root distribution attributes. The results demonstrate that the crossed arrangement outperforms other patterns under dynamic loads. Root crossed arrangement reduces the plastic deformation of the soil by 70% to 80% and the resilient deformation by 30% to 40%. The soil transient deformation resistance is significantly enhanced through root arrangement, while root cross arrangement leads to a remarkable improvement in the soil dynamic modulus and damping ratio by approximately 200%. The confirmation was obtained that the Hardin and Drnevich hyperbolic model exhibited exceptional conformity and could be effectively employed in analyzing root-reinforced soil.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101424"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572534","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101444
L.X. Feng , J.O. Avesani Neto , J.G. Zornberg
This article presents back analyzed results from experimental full-scale field test zones involving unreinforced and geocell-reinforced layers with unbound aggregate infill subjected to in-situ Benkelman Beam test (BBT). The field tests were conducted on experimental test zones during the construction of a new highway. Two types of Unbound Granular Materials (UGM), placed on layers of various thicknesses, were employed in unreinforced and geocell-reinforced pavement zones. Deflection measurements were collected for the different pavement structure layers using the BBT. The main objectives of the testing program were (1) to back calculate the elastic moduli on all test zones in both unreinforced and reinforced layers; (2) to determine the improvement in elastic modulus of the UGM, as quantified by the Modulus Improvement Factor (MIF), which results from geocell reinforcement; (3) to compare the measured MIF with MIF values reported in the literature under similar conditions; and (4) to evaluate the accuracy of available analytical methods to estimate the MIF. The results demonstrated a significant improvement in the elastic modulus of the UGM using geocell reinforcement, with MIF values ranging from 2.6 to 3.3, depending on the fill material. One analytical method used to calculate MIF values was found to have good predictive capability, confirming its potential to the design of pavements with geocell-reinforced layers.
{"title":"Evaluation of the elastic modulus improvement in geocell-reinforced unbound aggregates: Full-scale experimental sections on a highway","authors":"L.X. Feng , J.O. Avesani Neto , J.G. Zornberg","doi":"10.1016/j.trgeo.2024.101444","DOIUrl":"10.1016/j.trgeo.2024.101444","url":null,"abstract":"<div><div>This article presents back analyzed results from experimental full-scale field test zones involving unreinforced and geocell-reinforced layers with unbound aggregate infill subjected to in-situ Benkelman Beam test (BBT). The field tests were conducted on experimental test zones during the construction of a new highway. Two types of Unbound Granular Materials (UGM), placed on layers of various thicknesses, were employed in unreinforced and geocell-reinforced pavement zones. Deflection measurements were collected for the different pavement structure layers using the BBT. The main objectives of the testing program were (1) to back calculate the elastic moduli on all test zones in both unreinforced and reinforced layers; (2) to determine the improvement in elastic modulus of the UGM, as quantified by the Modulus Improvement Factor (MIF), which results from geocell reinforcement; (3) to compare the measured MIF with MIF values reported in the literature under similar conditions; and (4) to evaluate the accuracy of available analytical methods to estimate the MIF. The results demonstrated a significant improvement in the elastic modulus of the UGM using geocell reinforcement, with MIF values ranging from 2.6 to 3.3, depending on the fill material. One analytical method used to calculate MIF values was found to have good predictive capability, confirming its potential to the design of pavements with geocell-reinforced layers.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101444"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702371","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101448
Obed Takyi Bentil, Chao Zhou
Subgrade soils can experience varying suction (equivalent to moisture) and temperature, which could affect the modulus of subgrade soil and the response of flexible pavements. The influence of these two factors on pavement performance has not been explored on purpose despite their importance in a changing climate. In this study, a simple approach was proposed for analyzing pavement performance with consideration of suction and temperature effects on soil modulus. Modulus values at different conditions of suction and temperature are calculated using a semi-empirical equation. Then, they are utilized in the numerical software KENLAYER to evaluate the stress and strain distributions in pavements composed of an asphalt layer, base layer, and subgrade layer based on linear elastic theory. The computed results are used to predict the rutting and fatigue cracking using some field-calibrated semi-empirical equations. In parametric studies using this method, the suction and temperature-dependent modulus of a clayey soil determined from laboratory experiments was applied. The results reveal that an increase in subgrade soil modulus due to drying and cooling can reduce the total rut depth mainly due to a reduction of the vertical compressive strain in the subgrade layer. For instance, a change in suction from 0 to 150 kPa (equivalent to optimum moisture content of the clayey soil) can lead to a 34% decrease in the total rut depth. However, the effects of an increase in soil subgrade modulus on fatigue cracking are influenced by the asphalt thickness. A reduced subgrade modulus because of wetting and heating decreases horizontal tensile strain (less susceptible to fatigue cracking) at the lowest section of relatively thinner asphalt but increases horizontal tensile strain for thicker asphalt.
{"title":"Pavement performance analysis considering the influence of suction and temperature on subgrade soil modulus","authors":"Obed Takyi Bentil, Chao Zhou","doi":"10.1016/j.trgeo.2024.101448","DOIUrl":"10.1016/j.trgeo.2024.101448","url":null,"abstract":"<div><div>Subgrade soils can experience varying suction (equivalent to moisture) and temperature, which could affect the modulus of subgrade soil and the response of flexible pavements. The influence of these two factors on pavement performance has not been explored on purpose despite their importance in a changing climate. In this study, a simple approach was proposed for analyzing pavement performance with consideration of suction and temperature effects on soil modulus. Modulus values at different conditions of suction and temperature are calculated using a semi-empirical equation. Then, they are utilized in the numerical software KENLAYER to evaluate the stress and strain distributions in pavements composed of an asphalt layer, base layer, and subgrade layer based on linear elastic theory. The computed results are used to predict the rutting and fatigue cracking using some field-calibrated semi-empirical equations. In parametric studies using this method, the suction and temperature-dependent modulus of a clayey soil determined from laboratory experiments was applied. The results reveal that an increase in subgrade soil modulus due to drying and cooling can reduce the total rut depth mainly due to a reduction of the vertical compressive strain in the subgrade layer. For instance, a change in suction from 0 to 150 kPa (equivalent to optimum moisture content of the clayey soil) can lead to a 34% decrease in the total rut depth. However, the effects of an increase in soil subgrade modulus on fatigue cracking are influenced by the asphalt thickness. A reduced subgrade modulus because of wetting and heating decreases horizontal tensile strain (less susceptible to fatigue cracking) at the lowest section of relatively thinner asphalt but increases horizontal tensile strain for thicker asphalt.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101448"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702373","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101450
Jian Guo , Liang Jia , Zhiqiang Wei , Kai Yao , Ruijie Wu
Loess has poor engineering performance and needs to be improved for engineering applications by adding a large amount of lime or cement, which is not consistent with the goal of “carbon peaking and carbon neutrality”. In this study, nano-SiO2 (NS) and nano-MgO (NM) were applied to improve the engineering performance of low-dosage lime/cement- stabilized loess. The improvement mechanisms of each binder on loess were analyzed by X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) tests. The impact of binder dosage and curing time (T) on unconfined compressive strength (UCS), resilient moduli (MR), California bearing ratio (CBR), internal friction angle (φ), cohesion (c), and compression coefficient (a1-2) of each stabilized loess were also explored by conducting a range of laboratory experiments. The results show that the addition of NS did not result in the formation of new substances. However, the formation of MH was noted with the addition of NM. The combination of lime and NS can significantly enhance the UCS, CBR, MR, and c of the stabilized loess, followed by the combination of cement and NS. With the increasing NM content, the above mechanical indices first increased and then decreased for the stabilized loess. Both the binder content and type caused a lesser impact on the φ and a1-2 than on other mechanical indices. Moreover, the mix ratio and feasibility of each stabilized loess applied in various engineering fields were analyzed based on relevant standards and the construction requirements of lime and cement. Finally, estimation models were established for the above mechanical indices of lime-NS stabilized loess, which can provide a reference for engineering design and quality control.
{"title":"Mechanical properties and engineering applications of low-dosage cement/lime-stabilized loess improved with nano-MgO and nan-SiO2","authors":"Jian Guo , Liang Jia , Zhiqiang Wei , Kai Yao , Ruijie Wu","doi":"10.1016/j.trgeo.2024.101450","DOIUrl":"10.1016/j.trgeo.2024.101450","url":null,"abstract":"<div><div>Loess has poor engineering performance and needs to be improved for engineering applications by adding a large amount of lime or cement, which is not consistent with the goal of “carbon peaking and carbon neutrality”. In this study, nano-SiO<sub>2</sub> (NS) and nano-MgO (NM) were applied to improve the engineering performance of low-dosage lime/cement- stabilized loess. The improvement mechanisms of each binder on loess were analyzed by X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) tests. The impact of binder dosage and curing time (<em>T</em>) on unconfined compressive strength (<em>UCS</em>), resilient moduli (<em>M</em><sub>R</sub>), California bearing ratio (<em>CBR</em>), internal friction angle (<em>φ</em>), cohesion (<em>c</em>), and compression coefficient (<em>a</em><sub>1-2</sub>) of each stabilized loess were also explored by conducting a range of laboratory experiments. The results show that the addition of NS did not result in the formation of new substances. However, the<!--> <!-->formation of MH was noted with the addition of NM. The combination of lime and NS can significantly enhance the <em>UCS</em>, <em>CBR</em>, <em>M</em><sub>R</sub>, and <em>c</em> of the stabilized loess, followed by the combination of cement and NS. With the increasing NM content, the above mechanical indices first increased and then decreased for the stabilized loess. Both the binder content and type caused a lesser impact on the <em>φ</em> and <em>a</em><sub>1-2</sub> than on other mechanical indices. Moreover, the mix ratio and feasibility of each stabilized loess applied in various engineering fields were analyzed based on relevant standards and the construction requirements of lime and cement. Finally, estimation models were established for the above mechanical indices of lime-NS stabilized loess, which can provide a reference for engineering design and quality control.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101450"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723727","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101417
Shan Huang , Chunlei Xin , Danqing Song , Wenkai Feng , Xiaoli Liu , Enzhi Wang , Tenghui Xu , Xiaohui Xiong
Intense fault dislocation within active fault zones can significantly impact the integrity of fault-crossing underground structures. This research examines the Daliang tunnel on the Lanzhou to Urumqi High-Speed Railway, which was severely damaged by the Menyuan great earthquake (Mw 6.7) in Qinghai Province, China, on January 8, 2022. The background of the earthquake and basic design information of Daliang high-speed railway tunnel is introduced. Field investigations demonstrate the seismic-induced damage, caused by the left-lateral strike-slip fault, can be categorized into five levels: extremely severe, severe, moderate, slight, and basically intact, which helps establish clear identification segments. A detailed analysis of damage mechanisms is conducted for each severity level, revealing that sections near the seismogenic fault experienced significant seismic damage, including pronounced uplift deformation of the roadbed slab, torsional fracture of the lining structure, alignment deformation, and extensive lining detachment, due to the combined effects of transient dislocation and the release of strong seismic motions from seismogenic fault. Other affected sections, affected by seismic vibrations and multiple contributing factors, exhibited varying degrees of damage, such as bottom bulging, fragmentation of the lining inner surface, multi-directional crack propagation, and localized peeling, as well as less discernible distribution patterns. Based on seismic damage classification, zoning, and detailed analysis of seismic damage mechanisms, this study proposes eight seismic resilience evaluation indicators for assessing the seismic damage of fault-crossing high-speed railway tunnels. These indicators include the cross-section area invasion rate, cross-section CPⅢ offset, and cross-section hundred-meter axial displacement rate, among others. A new quantitative standard for seismic resilience specific to fault-crossing high-speed railway tunnels is developed. The application of fuzzy set theory and fuzzy logic in evaluating the seismic resilience capabilities of fault-crossing high-speed railway tunnels is investigated. A resilience evaluation framework for assessing the seismic resilience of fault-crossing high-speed railway tunnels is established. Quantitative comprehensive assessments are conducted on 38 selected seismic damage sections to identify the extent of damage. The results validate the rationality and effectiveness of the proposed performance evaluation system for assessing seismic damage in fault-crossing high-speed railway tunnels. This research provides important references for the post-earthquake structural resilience performance recovery, structural safety assessment, and development of methodologies related to the seismic resilience of fault-crossing high-speed railway tunnels.
{"title":"Resilience assessment of the seismic damage mechanism of the Daliang high-speed railway tunnel in the 2022 Menyuan earthquake (Mw 6.7) in China","authors":"Shan Huang , Chunlei Xin , Danqing Song , Wenkai Feng , Xiaoli Liu , Enzhi Wang , Tenghui Xu , Xiaohui Xiong","doi":"10.1016/j.trgeo.2024.101417","DOIUrl":"10.1016/j.trgeo.2024.101417","url":null,"abstract":"<div><div>Intense fault dislocation within active fault zones can significantly impact the integrity of fault-crossing underground structures. This research examines the Daliang tunnel on the Lanzhou to Urumqi High-Speed Railway, which was severely damaged by the Menyuan great earthquake (Mw 6.7) in Qinghai Province, China, on January 8, 2022. The background of the earthquake and basic design information of Daliang high-speed railway tunnel is introduced. Field investigations demonstrate the seismic-induced damage, caused by the left-lateral strike-slip fault, can be categorized into five levels: extremely severe, severe, moderate, slight, and basically intact, which helps establish clear identification segments. A detailed analysis of damage mechanisms is conducted for each severity level, revealing that sections near the seismogenic fault experienced significant seismic damage, including pronounced uplift deformation of the roadbed slab, torsional fracture of the lining structure, alignment deformation, and extensive lining detachment, due to the combined effects of transient dislocation and the release of strong seismic motions from seismogenic fault. Other affected sections, affected by seismic vibrations and multiple contributing factors, exhibited varying degrees of damage, such as bottom bulging, fragmentation of the lining inner surface, multi-directional crack propagation, and localized peeling, as well as less discernible distribution patterns. Based on seismic damage classification, zoning, and detailed analysis of seismic damage mechanisms, this study proposes eight seismic resilience evaluation indicators for assessing the seismic damage of fault-crossing high-speed railway tunnels. These indicators include the cross-section area invasion rate, cross-section CPⅢ offset, and cross-section hundred-meter axial displacement rate, among others. A new quantitative standard for seismic resilience specific to fault-crossing high-speed railway tunnels is developed. The application of fuzzy set theory and fuzzy logic in evaluating the seismic resilience capabilities of fault-crossing high-speed railway tunnels is investigated. A resilience evaluation framework for assessing the seismic resilience of fault-crossing high-speed railway tunnels is established. Quantitative comprehensive assessments are conducted on 38 selected seismic damage sections to identify the extent of damage. The results validate the rationality and effectiveness of the proposed performance evaluation system for assessing seismic damage in fault-crossing high-speed railway tunnels. This research provides important references for the post-earthquake structural resilience performance recovery, structural safety assessment, and development of methodologies related to the seismic resilience of fault-crossing high-speed railway tunnels.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101417"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652767","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101430
Salah Alnaser K Ahmed , Amir Hossein Vakili , İnan Keskin , Mehmet İnanç Onur
Assessing the subsurface geological conditions beneath a structure is crucial, as soils inherently tend to lose intergranular strength when subjected to static or dynamic loads. Applying dynamic loads can result in the propagation of stress waves through the soil, leading to deformation of the soil structure and causing more significant damage than static loads. Extensive research has been conducted on treating dynamic characteristics of clay soil properties using traditional additives such as lime and cement. To achieve better results and address the limitations of conventional materials in soil improvement, there is a growing trend towards using non-traditional stabilizers, referred to as ’recycled and sustainable’ materials. These include, for example, silica fume, polypropylene fibers, steel slag, fly ash, rubber tire particles, basalt, and recycled and crushed glass, which are currently being deeply investigated to improve the dynamic behavior of clay soils. The review article compares the effects of traditional and sustainable stabilizers on dynamic engineering properties of soils. It also highlights the engineering significance and innovations in the use of such materials. While traditional stabilizers effectively improve soil strength and durability, they pose environmental challenges, including increased CO2 emissions and brittleness under seismic stress. Innovations focus on refining these techniques and incorporating sustainable alternatives, such as waste-derived materials, to enhance soil properties, improve seismic performance, and reduce environmental impact. The study underscores the need for developing cost-effective, eco-friendly solutions for modern infrastructure. It systematically analyzes recent topics on soil stabilization using these additives, examining parameters that influence the dynamic properties of stabilized clay soils. Furthermore, it reviews microstructural changes due to stabilization and their impact on dynamic properties, offering suggestions for future research.
{"title":"A state-of-the-art review on the dynamic characteristics of untreated and treated soils by traditional, recycled, and sustainable stabilizers","authors":"Salah Alnaser K Ahmed , Amir Hossein Vakili , İnan Keskin , Mehmet İnanç Onur","doi":"10.1016/j.trgeo.2024.101430","DOIUrl":"10.1016/j.trgeo.2024.101430","url":null,"abstract":"<div><div>Assessing the subsurface geological conditions beneath a structure is crucial, as soils inherently tend to lose intergranular strength when subjected to static or dynamic loads. Applying dynamic loads can result in the propagation of stress waves through the soil, leading to deformation of the soil structure and causing more significant damage than static loads. Extensive research has been conducted on treating dynamic characteristics of clay soil properties using traditional additives such as lime and cement. To achieve better results and address the limitations of conventional materials in soil improvement, there is a growing trend towards using non-traditional stabilizers, referred to as ’recycled and sustainable’ materials. These include, for example, silica fume, polypropylene fibers, steel slag, fly ash, rubber tire particles, basalt, and recycled and crushed glass, which are currently being deeply investigated to improve the dynamic behavior of clay soils. The review article compares the effects of traditional and sustainable stabilizers on dynamic engineering properties of soils. It also highlights the engineering significance and innovations in the use of such materials. While traditional stabilizers effectively improve soil strength and durability, they pose environmental challenges, including increased CO<sub>2</sub> emissions and brittleness under seismic stress. Innovations focus on refining these techniques and incorporating sustainable alternatives, such as waste-derived materials, to enhance soil properties, improve seismic performance, and reduce environmental impact. The study underscores the need for developing cost-effective, eco-friendly solutions for modern infrastructure. It systematically analyzes recent topics on soil stabilization using these additives, examining parameters that influence the dynamic properties of stabilized clay soils. Furthermore, it reviews microstructural changes due to stabilization and their impact on dynamic properties, offering suggestions for future research.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101430"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593479","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 : 2024-11-01DOI: 10.1016/j.trgeo.2024.101427
Jinhong Li , Hongyuan Fu , Xiang Qiu , Yong Wu , Jingchen Chen
During the operation period of a red clay low embankment, significant uneven settlement can occur due to vehicle loads, seriously threatening the smooth flow of roads and transportation safety. To better inform the design and filling of red clay low embankment road structures, this study combines model tests and numerical simulations to investigate the dynamic response characteristics of various pavement structures on red clay low embankments under vehicular loads. It examines how different moisture contents, embankment parameters, driving parameters, and pavement structures affect the vertical dynamic stress, acceleration, and deformation of red clay low embankments. The results show that the vertical dynamic stress and acceleration decrease rapidly along the depth and transverse width directions, and then slowly decrease. Increased vehicle loads and speeds lead to greater vertical dynamic stress and acceleration, whereas higher elastic modulus and embankment soil thickness result in lower values. Additionally, increasing water content intensifies the vertical acceleration response in red clay low embankments. The influence degree of different factors on the dynamic characteristics of red clay low embankment is: vehicle load > driving speed > embankment thickness > elastic modulus of embankment soil. The red clay low embankment under vehicular loading belongs to the deformation concentration area within 0 to 0.4 m from the top surface of the embankment. A comparative analysis of the dynamic characteristics of six common pavement structures for red clay low embankments shows that rutting-resistant pavement structures perform the best. The proposed new type of red clay low embankment upper pavement structure can effectively avoid the problem of base water damage caused by the capillary water rise of red clay.
红粘土低路堤在运行期间，由于车辆荷载的作用会产生明显的不均匀沉降，严重威胁道路的畅通和交通安全。为了更好地指导红粘土低路堤道路结构的设计和填筑，本研究结合模型试验和数值模拟，研究了红粘土低路堤上各种路面结构在车辆荷载作用下的动态响应特性。研究探讨了不同含水量、路堤参数、行车参数和路面结构如何影响红粘土低路堤的垂直动应力、加速度和变形。结果表明，垂直动应力和加速度沿深度和横向宽度方向迅速减小，然后缓慢减小。车辆荷载和速度增加会导致垂直动应力和加速度增大，而弹性模量和路堤土厚度增加则会导致数值减小。此外，含水量的增加会加剧红粘土低路堤的垂直加速度响应。不同因素对红粘土低路堤动态特性的影响程度分别为：车辆荷载；行驶速度；路堤厚度；路堤土的弹性模量。车辆荷载作用下的红粘土低路堤在距路堤顶面 0~0.4 m 范围内属于变形集中区。对六种常见的红粘土低路堤路面结构的动态特性进行比较分析表明，抗车辙路面结构的性能最好。所提出的新型红粘土低路堤上层路面结构可有效避免红粘土毛细水上升引起的基底水破坏问题。
{"title":"Research on dynamic response characteristics of red clay low embankment with different road structures under vehicle load","authors":"Jinhong Li , Hongyuan Fu , Xiang Qiu , Yong Wu , Jingchen Chen","doi":"10.1016/j.trgeo.2024.101427","DOIUrl":"10.1016/j.trgeo.2024.101427","url":null,"abstract":"<div><div>During the operation period of a red clay low embankment, significant uneven settlement can occur due to vehicle loads, seriously threatening the smooth flow of roads and transportation safety. To better inform the design and filling of red clay low embankment road structures, this study combines model tests and numerical simulations to investigate the dynamic response characteristics of various pavement structures on red clay low embankments under vehicular loads. It examines how different moisture contents, embankment parameters, driving parameters, and pavement structures affect the vertical dynamic stress, acceleration, and deformation of red clay low embankments. The results show that the vertical dynamic stress and acceleration decrease rapidly along the depth and transverse width directions, and then slowly decrease. Increased vehicle loads and speeds lead to greater vertical dynamic stress and acceleration, whereas higher elastic modulus and embankment soil thickness result in lower values. Additionally, increasing water content intensifies the vertical acceleration response in red clay low embankments. The influence degree of different factors on the dynamic characteristics of red clay low embankment is: vehicle load > driving speed > embankment thickness > elastic modulus of embankment soil. The red clay low embankment under vehicular loading belongs to the deformation concentration area within 0 to 0.4 m from the top surface of the embankment. A comparative analysis of the dynamic characteristics of six common pavement structures for red clay low embankments shows that rutting-resistant pavement structures perform the best. The proposed new type of red clay low embankment upper pavement structure can effectively avoid the problem of base water damage caused by the capillary water rise of red clay.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101427"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593399","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