Transportation Geotechnics最新文献_第2页

Effect of cyclic wetting on lateritic clay subgrade settlement and train-track dynamic response of high-speed railway

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101541

Weizheng Liu , Jiming Tan , Jun Wu , Lei Xu , Jiale Wan

Cyclic wetting of high-speed railway subgrade leads to excessive uneven settlement and intense wheel-rail dynamic response, seriously affecting operation comfort and safety. In this paper, the effect of cyclic wetting on accumulative deformation of lateritic clay was investigated by dynamic triaxial test. Incorporating the cyclic wetting effect, a prediction model of accumulative strain was developed for compacted lateritic clay. By considering dynamic accumulative strain as static creep, a novel method for calculating subgrade long-term settlement was proposed. Moreover, a 3-D train-track-subgrade coupled dynamic model was established accounting for evolving contact stress between track and subgrade, and the effectiveness was verified. The influence of moisture content, cyclic wetting times and dynamic stress on the subgrade settlement evolution was analysed. The vertical carbody acceleration, Sperling index, derailment coefficient and wheel load reduction rate were selected as evaluation indexes to study the influence of cyclic wetting on train operation performance. The results show that the accumulative strain increases nonlinearly with the increase of wetting amplitude, existing a critical moisture content of 1.5% above the optimal moisture content, exceeding which the accumulative plastic strain increases significantly. The accumulative strain increases significantly when the moisture content exceeds the critical value. With the increase of moisture content, cyclic wetting times and dynamic stress, the accumulative deformation of lateritic clay gradually changes from a stable type to an incremental damage type. With the increase of train speed, the growth rate of carbody vertical acceleration and Sperling index accelerate, resulting in greater sensitivity to cyclic wetting. For safe operations of high-speed railway, it is not recommended that the subgrade moisture content exceeds the critical moisture content.

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引用次数: 0

Study on the impact of rock shape and volume fraction on the dynamic properties of soil-rock mixtures

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101539

Libing Du , Xinrong Liu , Zhiyun Deng

The microstructure of a soil–rock matrix (SRM) is a determinant of its macroscopic physical and mechanical attributes. The influence of the shape and volume fraction (VF) of rock blocks on the dynamic properties of the SRM has not been subjected to quantitative analysis. Consequently, a suitable construction technique was developed for the fabrication of small-scale triaxial specimens incorporating artificial rocks of various shapes. A series of homogeneous SRM specimens with differing rock VFs and shapes were fabricated. These specimens were then exposed to a long-term dynamic load consisting of 15,000 cycles at a frequency of 1 Hz. The principal findings are summarized as follows: The construction method proposed is capable of producing small artificial rocks with dimensions of 3 mm or 5 mm in arbitrary shapes while maintaining consistency with the prototypes. The method holds significant promise for application in geotechnical testing. Under long-term dynamic loading, the rock VF effectively elevates the threshold cyclic stress ratio of the SRM, diminishes the Pore Water Pressure within the mixture, enhances the dynamic stiffness, and mitigates the cumulative strain. SRMs composed of rock shapes with increased angularity and reduced block sizes exhibit higher dynamic stiffness and cumulative strain. The threshold cyclic stress ratio for an SRM with a 40 % rock VF is approximately 0.04, and the pore pressure increment in the SRM exhibits a gradual change, which contrasts with the test outcomes for pure clay. The exponential-hyperbolic model provided a satisfactory fit for the pore pressure data, while the hyperbolic model yielded good fitting results for the cumulative strain of the SRM with a low rock VF. These findings contribute to an enhanced comprehension of the dynamic properties of railway subgrades filled with SRM under cyclic train loading conditions.

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引用次数: 0

The influence of pile–soil–pile interaction on the vertical response of end-bearing pile groups in soil on bedrock subjected to a vertical load at the soil’s surface

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101525

Freddie Theland , Geert Lombaert , Stijn François , Abbas Zangeneh , Fanny Deckner , Jean-Marc Battini

The influence of pile–soil–pile interaction on the vertical response of end-bearing pile groups when subjected to an incident wave field generated from a vertical load at the soil’s surface is investigated. A numerical model which allows for considering or disregarding the influence of pile–soil–pile interaction is adopted. Vertical end-bearing pile groups with different pile axial stiffness and pile-to-pile spacing are considered. This study shows that in contrast to floating piles in homogeneous soil, the interaction effects caused by wave scattering between the piles are important for end-bearing piles. These may either reduce or amplify the group response, depending on the wavelength in the soil, the spacing between the piles, the pile slenderness and the pile–soil stiffness ratio. The interaction between the piles which are aligned in the direction transverse to the propagation direction of the incident wave field is found to amplify the group response at certain frequencies. Reducing the pile spacing in this direction is found to influence the vertical vibration response of end-bearing pile group foundations considerably by shifting the amplification effects due to pile–soil–pile interaction to higher frequencies.

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引用次数: 0

The effect of particle shape on particle breakage and shape evolution in gravelly soils

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101538

Fanwei Ning, Degao Zou, Gengyao Cui, Jingmao Liu, Duo Li, Yongkui Fu

Gravelly soils are widely used in transportation geotechnical engineering, with particle shape and breakage significantly influencing their mechanical behavior. In this study, an abrasion machine was used to generate particles with varying angularity. Subsequently, a series of consolidated drained triaxial tests were conducted to investigate the effects of initial particle shape on both particle breakage and shape evolution. The results indicated that particle breakage increased with higher particle angularity under the same confining pressure. Moreover, materials with higher angularity exhibited a more pronounced decrease in large particles, attributed to distinct particle breakage modes. Particle breakage not only altered the gradation but also led to shape evolution. Angular particles tended to lose angularity due to particle breakage, whereas initially rounded materials exhibited enhanced angularity. As particle breakage progressed, particles with different initial roundness converged toward a similar shape. Based on the experimental data, an empirical formula was proposed to predict the evolution of particle shape during shear processes. This study provides a theoretical foundation for predicting the long-term performance of gravelly soils, with important implications for material selection and stability assessment in transportation geotechnical engineering.

{"title":"The effect of particle shape on particle breakage and shape evolution in gravelly soils","authors":"Fanwei Ning, Degao Zou, Gengyao Cui, Jingmao Liu, Duo Li, Yongkui Fu","doi":"10.1016/j.trgeo.2025.101538","DOIUrl":"10.1016/j.trgeo.2025.101538","url":null,"abstract":"<div><div>Gravelly soils are widely used in transportation geotechnical engineering, with particle shape and breakage significantly influencing their mechanical behavior. In this study, an abrasion machine was used to generate particles with varying angularity. Subsequently, a series of consolidated drained triaxial tests were conducted to investigate the effects of initial particle shape on both particle breakage and shape evolution. The results indicated that particle breakage increased with higher particle angularity under the same confining pressure. Moreover, materials with higher angularity exhibited a more pronounced decrease in large particles, attributed to distinct particle breakage modes. Particle breakage not only altered the gradation but also led to shape evolution. Angular particles tended to lose angularity due to particle breakage, whereas initially rounded materials exhibited enhanced angularity. As particle breakage progressed, particles with different initial roundness converged toward a similar shape. Based on the experimental data, an empirical formula was proposed to predict the evolution of particle shape during shear processes. This study provides a theoretical foundation for predicting the long-term performance of gravelly soils, with important implications for material selection and stability assessment in transportation geotechnical engineering.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101538"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549311","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}

引用次数: 0

Numerical studies of ballastless track-embankment vibrations considering track irregularities

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101536

Zihao Jin , Wei Zhang , Yixin Li , Xueyu Geng

High-speed railway systems require precise modelling of track-embankment dynamics to assess structural stability and safety. Existing models struggle to capture the complex nonlinear interactions between trains and track infrastructure. To overcome this limitation, a three-dimensional finite element (3D FE) model was developed to simulate the dynamic responses of track-embankment coupling systems based on the Wuhan-Guangzhou high-speed railway, and it was validated with field measurements. The proposed model innovatively incorporates the geometric complexities of railhead and wheel tread surfaces, along with multiple track irregularities, ensuring realistic simulations. An empirical filtering rule was introduced to address high-frequency numerical noise, enhancing data processing accuracy. The validated model was used to investigate the effects of train speed and track irregularities on the vertical and lateral vibrations of railway system. Results show that vibration intensity rises as train speed increases, with vertical rail vibrations being 1.9 to 2.9 times stronger than lateral vibrations. Moreover, track irregularities amplify embankment vibrations, particularly at higher frequencies and shallower depths, while soil damping mitigates this effect at greater depths. These findings provide valuable insights into the dynamic behaviour of ballastless track-embankment systems and contribute to the development of design and maintenance strategies for high-speed railway infrastructure.

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引用次数: 0

Coupled effect of cyclic wet-dry environment and vibration event on desiccation crack and mechanical characteristics of polypropylene fiber-reinforced clay 干湿循环环境和振动事件对聚丙烯纤维增强粘土干燥裂纹和机械特性的耦合影响

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101542

Usama Khalid , Zia ur Rehman , Ashfaq Ahmad

This study investigates the role of polypropylene fibers (PFs) in mitigating the combined effects of wet-dry (W-D) cycles and vibration event (VE), such as earthquake or machine vibrations, on the desiccation cracking and mechanical behavior of clay through model tests. A comprehensive experimental program was conducted using compacted clayey soil specimens, treated with various PF percentages (i.e., 0.2 %, 0.4 %, 0.6 %, and 0.8 %) and untreated (i.e., 0 % PF). These specimens were subjected to multiple W-D cycles, with their behavior documented through cinematography. Desiccation cracking and mechanical responses were evaluated after each W-D cycle and subsequent VE. Results indicated that surface cracking, quantified by morphology and crack parameters i.e., crack surface ratio (R_sc), total crack length (L_tc), and crack line density (D_cl), increased with progressive W-D cycles. Higher PF content in soil significantly reduced desiccation cracking across all W-D phases, attributable to the enhanced tensile strength and stress mitigation provided by the fibers. Following VE, surface crack and fragmentation visibility decreased due to the shaking effects, as indicated by reductions in R_sc and D_cl. However, L_tc increased slightly, suggesting either crack persistence or lengthening. Higher PF content resulted in a more substantial reduction in R_sc and D_cl and a reduced increase in L_tc after VE. W-D cycles led to increased cone index (CI) values, reflecting enhanced compactness due to shrinkage which enhances with PF content showing improved soil resistance to loading. Meanwhile, VE reduced CI values following W-D cycles, particularly in near-surface layers, PF content mitigates this reduction, demonstrating that PF contributes to a more stable soil matrix. Also, PF content decreased the soil deformation under W-D cycles and subsequent VE.

{"title":"Coupled effect of cyclic wet-dry environment and vibration event on desiccation crack and mechanical characteristics of polypropylene fiber-reinforced clay","authors":"Usama Khalid , Zia ur Rehman , Ashfaq Ahmad","doi":"10.1016/j.trgeo.2025.101542","DOIUrl":"10.1016/j.trgeo.2025.101542","url":null,"abstract":"<div><div>This study investigates the role of polypropylene fibers (PFs) in mitigating the combined effects of wet-dry (W-D) cycles and vibration event (VE), such as earthquake or machine vibrations, on the desiccation cracking and mechanical behavior of clay through model tests. A comprehensive experimental program was conducted using compacted clayey soil specimens, treated with various PF percentages (i.e., 0.2 %, 0.4 %, 0.6 %, and 0.8 %) and untreated (i.e., 0 % PF). These specimens were subjected to multiple W-D cycles, with their behavior documented through cinematography. Desiccation cracking and mechanical responses were evaluated after each W-D cycle and subsequent VE. Results indicated that surface cracking, quantified by morphology and crack parameters i.e., crack surface ratio (<em>R<sub>sc</sub></em>), total crack length (<em>L<sub>tc</sub></em>), and crack line density (<em>D<sub>cl</sub></em>), increased with progressive W-D cycles. Higher PF content in soil significantly reduced desiccation cracking across all W-D phases, attributable to the enhanced tensile strength and stress mitigation provided by the fibers. Following VE, surface crack and fragmentation visibility decreased due to the shaking effects, as indicated by reductions in <em>R<sub>sc</sub></em> and <em>D<sub>cl</sub></em>. However, <em>L<sub>tc</sub></em> increased slightly, suggesting either crack persistence or lengthening. Higher PF content resulted in a more substantial reduction in <em>R<sub>sc</sub></em> and <em>D<sub>cl</sub></em> and a reduced increase in <em>L<sub>tc</sub></em> after VE. W-D cycles led to increased cone index (CI) values, reflecting enhanced compactness due to shrinkage which enhances with PF content showing improved soil resistance to loading. Meanwhile, VE reduced CI values following W-D cycles, particularly in near-surface layers, PF content mitigates this reduction, demonstrating that PF contributes to a more stable soil matrix. Also, PF content decreased the soil deformation under W-D cycles and subsequent VE.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101542"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619314","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}

引用次数: 0

Investigation on load sharing ratio of piles and soil in GRPS embankment with different pile types and geogrid layers under long-term cyclic loading

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101534

Kaifu Liu , Shiyu Xu , Minjie Wen , Weiqiang Feng , Zhiqing Zhang , Zhangbo Wan

Geosynthetic-reinforced pile-supported (GRPS) embankments are a primary method for mitigating subgrade settlement. However, the load transfer mechanism between piles and soil remains incompletely understood, with the load sharing ratio (LSR) between piles and soil serving as a critical indicator for this mechanism. This study conducted a model test at a similarity ratio of 1:10 to investigate the effects of load amplitude, load frequency, number of geogrid layers, and pile types on the LSRs of piles and soil in GRPS embankments. The test results show that the pile’s LSR increases with rising values of these parameters, while the corresponding LSR of the soil decreases. Among these parameters, the number of geogrid layers has the least effect on the LSRs of both piles and soil. Furthermore, the rigid long pile demonstrates a higher LSR than the flexible short pile, attributed to its greater stiffness. The influence of load frequency on the LSRs of the rigid long pile is also less significant compared to the flexible short pile. Variations of LSR increment can be predicted using a formula that incorporates the number of loading cycles. These findings provide deeper insights into the load transfer mechanism in the pile-soil system, contribute to the optimization of GRPS embankments design practice, and ultimately enhance performance and reliability of the GRPS embankments in geotechnical engineering applications.

{"title":"Investigation on load sharing ratio of piles and soil in GRPS embankment with different pile types and geogrid layers under long-term cyclic loading","authors":"Kaifu Liu , Shiyu Xu , Minjie Wen , Weiqiang Feng , Zhiqing Zhang , Zhangbo Wan","doi":"10.1016/j.trgeo.2025.101534","DOIUrl":"10.1016/j.trgeo.2025.101534","url":null,"abstract":"<div><div>Geosynthetic-reinforced pile-supported (GRPS) embankments are a primary method for mitigating subgrade settlement. However, the load transfer mechanism between piles and soil remains incompletely understood, with the load sharing ratio (LSR) between piles and soil serving as a critical indicator for this mechanism. This study conducted a model test at a similarity ratio of 1:10 to investigate the effects of load amplitude, load frequency, number of geogrid layers, and pile types on the LSRs of piles and soil in GRPS embankments. The test results show that the pile’s LSR increases with rising values of these parameters, while the corresponding LSR of the soil decreases. Among these parameters, the number of geogrid layers has the least effect on the LSRs of both piles and soil. Furthermore, the rigid long pile demonstrates a higher LSR than the flexible short pile, attributed to its greater stiffness. The influence of load frequency on the LSRs of the rigid long pile is also less significant compared to the flexible short pile. Variations of LSR increment can be predicted using a formula that incorporates the number of loading cycles. These findings provide deeper insights into the load transfer mechanism in the pile-soil system, contribute to the optimization of GRPS embankments design practice, and ultimately enhance performance and reliability of the GRPS embankments in geotechnical engineering applications.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"51 ","pages":"Article 101534"},"PeriodicalIF":4.9,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549308","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}

引用次数: 0

Integral railway bridges with different transition zone designs

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101509

Alexander Stastny , Ronald Stein , Franz Tschuchnigg

Integral bridges interact strongly with their backfills, especially due to seasonal thermal loading. So far, most research has focused on this cyclic soil–structure interaction of integral bridges with granular backfills. However, due to higher train speeds or axle loads, railway transition zones internationally must often be designed with wedge-shaped cement-bound granular mixtures. Also, transition slabs are widely used for longer integral bridges. Therefore, a numerical investigation is presented on the cyclic soil–structure interaction of integral bridges with different railway backfill designs. The main focus lies on the cyclic mobilization of lateral stresses and settlements in the backfill. Next to well-graded granular backfill, the comparison includes two forms of cement-bound wedges as well as concrete transition slabs. The numerical studies further cover both, varying bridge lengths and abutment heights. The obtained results highlight significantly different settlement accumulations for the various transition zone designs. A comparison with analytical design approaches is conducted and recommendations for the design of transition zones for integral bridges with different total lengths are derived. In the second part of the paper, results of a three-year-long monitoring of an integral railway bridge are presented. The cyclic development of both earth pressure and settlements are investigated by means of 3D FE back analysis. The study reveals that the interaction behaviour and earth pressure distribution is strongly affected by a concrete sealing layer of (only) 30 cm at mid-height of the backfill. The measured behaviour can be reproduced well, which further confirms the eligibility of the FE model and its calibrated constitutive model.

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引用次数: 0

Utilising construction and demolition waste in soft soil stabilisation: A prediction model for enhanced strength and stiffness

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101530

Ecem Nur Barisoglu , Taher Ghalandari , Diederik Snoeck , Ramiro Daniel Verástegui-Flores , Gemmina Di Emidio

Utilising recycled materials, such as construction and demolition waste (C&DW), into soil improvement projects offers a promising solution to reduce the environmental impact of the C&DW industry. This approach helps address issues related to waste generation, resource depletion, and environmental degradation, while enhancing the overall sustainability and resilience of soil stabilisation efforts. This study investigates the effectiveness of incorporating recycled C&DW into cement-treated peat and clayey soils to enhance their strength and stiffness. To achieve this goal, laboratory experiments were conducted on over 296 soil specimens to assess their Unconfined Compressive Strength (UCS), small-strain Young’s modulus (E₀) and shear modulus (G₀). These tests included varying curing times (28, 60, 90, and 120 days), different cement and recycled material content, and water-to-cement ratios. Moreover, laboratory testing methods for determining geotechnical parameters are often time-consuming and prone to challenges. In this context, reliable predictive models, such as artificial neural networks (ANNs), offer an efficient alternative for accurately assessing these parameters.

The findings of this research reveal that, along with cement content, the water-to-cement ratio (w/c) and curing time are key factors influencing the strength and stiffness of treated soft soils, underscoring their critical role in soil stabilisation. Additionally, while minimizing cement content and increasing RM yield improvements in both peat and clay, the effect is more pronounced in peat due to the time-dependent nature of pozzolanic reactions. This suggests that achieving optimal performance with increased strength and stiffness requires a carefully balanced RM content. Finally, the study demonstrates that ANN-based models can accurately predict the strength and mechanical properties of soft soils, offering a viable alternative to traditional UCS and FFR tests.

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引用次数: 0

Swelling and chemical degradation of sulfur-bearing fillers in high-speed railway subgrade: Effect of pH on ion release and material deterioration 高速铁路路基中含硫填料的膨胀和化学降解：pH 值对离子释放和材料劣化的影响

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-03-01 DOI: 10.1016/j.trgeo.2025.101546

Zihang Liu , Zhangjun Dai , Xiaodong Song , Lanqiang Yang , Fei Yu , Shanxiong Chen

The deformation and degradation of sulfur-bearing fillers are critical factors affecting the long-term performance of high-speed railway subgrade materials. This study investigates the swelling and chemical degradation behavior of sulfur-bearing fillers under different pH environments (acidic pH = 2.03, neutral pH = 6.97, and alkaline pH = 11.95). Advanced analytical methods, including Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Ion Chromatography (IC), were utilized to explore the structural and chemical changes in these materials. Results demonstrate that alkaline conditions significantly accelerate degradation, characterized by a higher rate of SO₄²⁻ release and an increase in porosity to 25.65 %, compared to 12.87 % in acidic conditions. The degradation process comprises three distinct stages: rapid initial degradation, intermediate deceleration, and final stabilization. Under alkaline conditions, the formation of white precipitates and increased fissures were observed, indicating severe structural deterioration. Conversely, acidic environments exhibit an inhibitory effect on filler degradation, characterized by reduced ion release rates and lower total ion concentrations. These findings enhance the understanding of the degradation mechanism of sulfur-bearing fillers and provide a basis for improving subgrade material selection and durability design in high-speed railway projects.

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引用次数: 0