Transportation Geotechnics最新文献_第7页

Influence of consolidation history on the transitional behavior of silty clay 固结历史对粉质粘土过渡特性的影响

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-30 DOI: 10.1016/j.trgeo.2025.101887

Jianhong Jiang , Sikang Tu , Jianguang Feng

Understanding the mechanical response of silt–clay transitional soils is increasingly important for underground transportation infrastructure, where complex stress paths and one-dimensional (K₀) consolidation histories are common. However, most existing studies rely on isotropic consolidation, leaving the effects of K₀ consolidation on transitional behavior insufficiently understood. This study presents a systematic series of undrained triaxial tests on reconstituted silty clay consolidated under isotropic and K₀ conditions across a range of overconsolidation ratios (OCRs). The results show that phase transformation—a hallmark of transitional soil behavior—appears only in isotropically consolidated specimens at low OCRs, whereas it does not occur in K₀-consolidated specimens tested under comparable OCRs. K₀-consolidated specimens exhibit a counter-intuitive non-monotonic relationship between void ratio and mean effective stress at the end of shearing, reflecting persistent anisotropic structural effects consistent with anisotropic critical state theory. While K₀ consolidation produces more complex stress–strain responses, the stress-ratio evolution remains broadly comparable to isotropically consolidated cases. Overall, the findings demonstrate that consolidation history critically governs the undrained behavior of silt–clay transitional soils and underscore the importance of incorporating realistic K₀ consolidation conditions in laboratory characterization and geotechnical design for transportation applications.

了解粉粘土过渡土的力学响应对地下交通基础设施越来越重要，在地下交通基础设施中，复杂的应力路径和一维（K0）固结历史是常见的。然而，大多数现有的研究依赖于各向同性固结，使得K0固结对过渡行为的影响没有得到充分的了解。本研究对各向同性和K0条件下的超固结比（ocr）范围内的重塑粉质粘土进行了一系列系统的不排水三轴试验。结果表明，相变-过渡土壤行为的标志-只出现在低ocr的各向同性固结样品中，而在可比ocr下测试的k0固结样品中则没有发生。k0固结试样在剪切结束时，孔隙比与平均有效应力之间表现出反直觉的非单调关系，反映了持续的各向异性结构效应，符合各向异性临界状态理论。虽然K0固结产生更复杂的应力-应变响应，但应力-比演化与各向同性固结情况大致相当。总的来说，研究结果表明，固结历史对粉质粘土过渡土的不排水行为起着关键的控制作用，并强调了在实验室表征和运输应用的岩土工程设计中纳入实际K0固结条件的重要性。

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引用次数: 0

Laboratory and field assessment of gypsum-modified aluminosilicate blends for expansive clay stabilization 石膏-改性铝硅酸盐混合物膨胀粘土稳定的实验室和现场评价

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-30 DOI: 10.1016/j.trgeo.2025.101884

Ayazhan Bazarbekova , Yong-Rak Kim , Dallas Little , Jong Suk Jung , Yong-Boo Park

Expansive clays pose significant challenges in civil engineering due to their high shrink–swell potential, which can compromise stability and cause structural damage. This study adopts a phased approach to develop effective stabilizer blends by integrating gypsum into industrial by-products, such as fly ash and slag, to enhance the durability of smectite-rich clay. In the first phase, gypsum-free blends were formulated to investigate the combined effects of additives and determine the optimal stabilizer content. The best-performing mix was then tested in a field implementation phase to validate its performance under real-world conditions. In the later phase, gypsum was incorporated and evaluated under wetting–drying (W–D) cycles to simulate environmental moisture fluctuations. The gypsum content was limited to avoid excessive sulfate reactions, particularly ettringite formation. An integrated framework, including strength testing, chemical assessment, and mineralogical analysis, was applied to unmodified, gypsum-modified, and gypsum-modified samples subjected to W–D cycling. Chemical treatment significantly improved strength, increasing the unconfined compressive strength (0.31 MPa) of untreated soil by about 6–8 times, with Class C fly ash and slag providing the best performance. The gypsum-modified blend retained ∼54 % of its initial strength after five W–D cycles, demonstrating improved resistance to moisture-induced deterioration. Mineralogical analyses indicated transformations such as smectite modification, ettringite formation, and calcite precipitation. These findings underscore gypsum’s role in enhancing the performance of expansive soils with moisture fluctuations and contribute to advancing stabilization strategies for resilient transportation infrastructure.

膨胀粘土由于其高收缩膨胀潜力，可能会破坏稳定性并导致结构破坏，因此在土木工程中面临着重大挑战。本研究采用分阶段的方法，将石膏掺入工业副产物，如粉煤灰和矿渣中，开发有效的稳定剂混合物，以提高富蒙脱石粘土的耐久性。在第一阶段，配制无石膏共混物，以研究添加剂的综合作用并确定最佳稳定剂的含量。然后在现场实施阶段测试了性能最佳的混合物，以验证其在实际条件下的性能。在后期阶段，加入石膏并在干湿循环（W-D）下进行评估，以模拟环境湿度波动。石膏的含量是有限的，以避免过多的硫酸盐反应，特别是钙矾石的形成。综合框架，包括强度测试、化学评估和矿物学分析，应用于未经改性、石膏改性和石膏改性的样品进行W-D循环。化学处理显著提高了强度，未处理土的无侧限抗压强度（0.31 MPa）提高了约6-8倍，其中C类粉煤灰和渣的性能最好。石膏改性混合物在五次W-D循环后保持了初始强度的约54%，显示出对水分引起的劣化的改善抵抗能力。矿物学分析表明发生了蒙脱石改性、钙辉石形成和方解石沉淀等转变。这些发现强调了石膏在提高膨胀土湿度波动性能方面的作用，并有助于推进弹性交通基础设施的稳定策略。

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引用次数: 0

Activation of sintered red mud and its application as a cement substitute in foamed lightweight soil for backfilling engineering 烧结赤泥的活化及其在泡沫轻质土充填工程中替代水泥的应用

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-29 DOI: 10.1016/j.trgeo.2025.101881

Hongguang Jiang , Mengyuan Ma , Xizhen Song , Xiupeng Yue , Yixin Li , Deepak Patwa , Jianyang Gao , Zhanyong Yao

Sintered red mud (SRM), a solid by-product from aluminium electrolysis, poses serious environmental challenges due to its high alkalinity, large stockpile, and dust pollution. This study enhances the pozzolanic reaction potential of SRM, aiming to replace cement in foamed lightweight soil (FLS) for large-scale backfilling applications. Twenty mix designs were prepared with densities ranging from 600 to 1200 kg/m³ and cement replacement ratios of up to 67.81 %. The effects of the water-cement ratio, physicochemical properties of SRM, and activator on the density, workability, and mechanical performance of SRM-FLS were systematically evaluated. The hydration behaviour and microstructural evolution were examined to assess the pozzolanic reactivity and elucidate the underlying enhancement mechanism. Results show that the SRM-FLS achieved a 23 % increase in 28-day unconfined compressive strength (UCS), reaching 1.48 MPa at a 70 % cement replacement level. The material demonstrated good water stability (softening coefficient > 0.8) and deformation resistance (compression modulus: 133–167 MPa). Microstructural analysis revealed a refined pore structure (88.8 % pores < 100 μm) and an enhanced formation of C-S-H and CaCO₃ gels. A mixed design framework integrating mass balance, volumetric compatibility, and flowability control is proposed to guide practical application. The developed SRM-FLS offers both environmental and structural benefits, supporting a sustainable and cost-efficient solution for future infrastructure construction.

烧结赤泥（SRM）是铝电解过程中产生的固体副产物，其碱度高、储量大、粉尘污染严重，对环境构成了严峻的挑战。本研究提高了SRM的火山灰反应电位，旨在取代水泥在泡沫轻质土（FLS）中的大规模回填应用。配制了20种配合比，密度为600 ~ 1200kg /m3，水泥替代率高达67.81%。系统评价了水灰比、SRM的理化性质和活化剂对SRM- fls的密度、和易性和力学性能的影响。研究了水化行为和微观结构演变，以评估火山灰反应性并阐明潜在的增强机制。结果表明，SRM-FLS的28天无侧限抗压强度（UCS）提高了23%，在70%的水泥替换水平下达到1.48 MPa。该材料具有良好的水稳定性（软化系数>； 0.8）和抗变形性（压缩模量：133-167 MPa）。微观结构分析表明，孔隙结构精细（88.8%的孔隙<； 100 μm）， C-S-H和CaCO3凝胶的形成增强。为指导实际应用，提出了一种集质量平衡、体积相容性和流动性控制为一体的混合设计框架。开发的SRM-FLS具有环境和结构效益，为未来的基础设施建设提供可持续和经济的解决方案。

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引用次数: 0

Dynamic response and failure characteristics of the bedrock-soil layer slope reinforced by a novel anchor-pile: insights from a large-scale shaking table test 新型锚桩加固基土边坡的动力响应与破坏特征：来自大型振动台试验的启示

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-29 DOI: 10.1016/j.trgeo.2025.101882

Qiangshan Yu, Yingbin Zhang, Qiang Chen, Yao Xiao, Dejian Li, Ying Zeng, Haiping Chen, Zheng Wang

To mitigate earthquake-induced landslides along transportation routes in strong seismic regions, a novel anchor-pile system composed of flexible anchor cables and rigid frame piles is proposed for slope stabilization. This composite retaining structure has been increasingly adopted in seismically active areas, yet its seismic performance remains insufficiently understood. In this study, the dynamic response and failure characteristics of a bedrock-soil layer slope reinforced with the proposed anchor-pile were investigated through large-scale shaking table tests. A comprehensive analysis of the test data and observed phenomena revealed that the natural frequency of the slope significantly influences its dynamic response, while the Arias intensity of the input ground motion exerts a pronounced effect on the dynamic response of the retaining structure. As Arias intensity increases from 0.127 m/s to 2.69 m/s, the peak dynamic displacement, earth pressure, and axial force of the anchor-pile increase by factors of 9.73, 58.66, and 11.43, respectively. The failure process and modes of the slope can be categorized into four distinct stages: 1) Formation stage of tension cracks on slope top; 2) Penetration stage of tension cracks on slope top; 3) Sliding stage along tension cracks; 4) Deep sliding stage along the interface. Seismic landslide thrust is mainly resisted by the front pile’s bottom and rear pile’s upper sections; the upper anchor dominates, and beam–pile joints are weak points needing reinforcement. The findings of this study can be applied to the seismic design of this novel anchor-pile in strong earthquake regions.

为缓解强震区交通沿线地震引发的滑坡，提出了一种由柔性锚索和刚性框架桩组成的新型锚固桩体系。这种复合挡土墙结构在地震活跃地区的应用越来越多，但其抗震性能仍不清楚。通过大型振动台试验，研究了锚杆桩加固基土边坡的动力响应及破坏特征。综合分析试验数据和观测现象发现，边坡的固有频率对其动力响应有显著影响，而输入地震动的阿里亚斯强度对支护结构的动力响应有显著影响。当Arias强度从0.127 m/s增加到2.69 m/s时，锚杆桩的峰值动位移、土压力和轴力分别增加了9.73、58.66和11.43倍。边坡的破坏过程和破坏模式可分为4个阶段：1)坡顶张拉裂缝形成阶段；2)坡顶张拉裂缝的贯通阶段；3)沿张裂缝滑动阶段；4)沿界面深度滑动阶段。地震滑坡推力主要由前桩底部和后桩上部抵御；上部锚杆占主导地位，梁桩节点是薄弱环节，需加强加固。研究结果可用于强震地区新型锚杆桩的抗震设计。

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引用次数: 0

Frost heave characteristics of subgrade fine-grained filler in seasonally frozen region under stepwise cooling 阶梯式降温条件下季节性冻土区路基细粒填料冻胀特性

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-29 DOI: 10.1016/j.trgeo.2025.101868

Yuzhi Zhang , Yihan Cui , Meng Wang , Wei Yang , Xiaokang Li , Anhua Xu

Frost heave in fine-grained railway subgrades results from coupled thermo-hydraulic processes, in which water migration and phase change jointly drive the growth of ice lenses under time-varying temperature fields. Most laboratory protocols impose fixed thermal gradients, obscuring the non-steady “memory” effects that characterize natural winter cooling. In this study, we conducted unidirectional freezing tests on subgrade silt collected from the Shuozhou–Huanghua heavy-haul railway under stepwise cooling. Local deformation was resolved using digital image correlation, and temperature, moisture, and water supply histories were simultaneously monitored. Stepwise cooling reproduced field realistic gradient amplification and freezing-front deceleration, yielding staged growth of thin-layer belts and ice lenses. Classical segregation potential (SP) analysis confirmed that lowering the cold-end temperature increased both |dT/dx| and the heave rate per unit thermal gradient. Building on crystallization kinetics, we introduced a fractional condensation potential (FCP), a non-local metric coupling a fractional-order time derivative of heave with the instantaneous thermal gradient, to quantify the history-dependent, condensation-controlled contribution to ice-lens accretion. The combined SP–FCP framework reconciles hysteretic staging in cryostructure evolution with gradient forcing and provides practical indicators for frost susceptibility ranking, as well as drainage and thermal-control strategies in seasonally frozen subgrades.

细粒铁路路基冻胀是热-液耦合过程的结果，在时变温度场下，水运移和相变共同驱动冰透镜的生长。大多数实验室方案施加固定的热梯度，模糊了冬季自然冷却的非稳定“记忆”效应。本研究对朔黄重载铁路路基淤泥进行了分步冷却的单向冻结试验。利用数字图像相关技术解决局部变形问题，同时监测温度、湿度和供水历史。逐级冷却再现了场逼真的梯度放大和冻结锋减速，产生了薄层带和冰透镜的阶段性生长。经典偏析势（SP）分析证实，降低冷端温度会增加|dT/dx|和单位热梯度的升沉速率。在结晶动力学的基础上，我们引入了分数凝结势（FCP），这是一种非局部度量，将升沉的分数阶时间导数与瞬时热梯度耦合在一起，以量化依赖于历史的凝结控制对冰透镜吸积的贡献。SP-FCP组合框架协调了冻土结构演化的滞后阶段和梯度强迫，并为季节性冻结路基的霜敏感性排序以及排水和热控制策略提供了实用指标。

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引用次数: 0

Influence of geogrid stabilization on ballast breakage under monotonic triaxial loading 单调三轴加载下土工格栅稳定对压载物破碎的影响

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-27 DOI: 10.1016/j.trgeo.2025.101880

Phuriwit Jaikaew, Yu Qian

Railway ballast particle breakage leads to fines generation, increases fouling, reduces drainage capacity, and ultimately weakens track performance. While geogrids are known to stabilize ballast by limiting particle movement and redistributing contact stresses, their effectiveness in reducing breakage, particularly at different ballast depths, remains unclear. This study employs a large-scale monotonic triaxial testing framework to evaluate particle breakage in clean ballast, with and without geogrid stabilization, under both loose and compacted density conditions. Each specimen was divided into four vertical zones: Top, Top-Mid, Bottom-Mid, and Bottom, and particle size groups were color-coated to enable breakage tracking. The results show that geogrid-stabilized specimens exhibited greater strength and stiffness in both density conditions. For loose ballast, geogrid inclusion reduced total particle breakage by approximately 27%, with the most significant reduction occurring in the middle zones. In contrast, for compacted ballast, the total breakage remained nearly unchanged with geogrid use; however, breakage was more evenly distributed across all zones, with noticeable reductions in the Top and Top-Mid zones. Corner breakage dominated in the middle zones, and splitting breakage near the top and bottom. Marsal’s breakage (B_g) index proved most sensitive for zone-by-zone evaluation. The findings highlight the benefit of geogrids in mitigating ballast degradation and emphasize the importance of zone-specific analysis under varying density conditions. The proposed monotonic triaxial framework provides a mechanistic baseline for future cyclic triaxial studies, where repetitive loading will further clarify long-term stress redistribution, particle migration, and cumulative breakage under realistic railway service conditions.

铁路道砟颗粒破碎，产生细粒，增加结垢，降低排水能力，最终削弱轨道性能。虽然已知土工格栅通过限制颗粒运动和重新分配接触应力来稳定压舱物，但它们在减少破碎方面的有效性，特别是在不同压舱物深度时，仍不清楚。本研究采用大尺度单调三轴试验框架，对有无土工格栅稳定、松散和压实密度条件下的清洁压舱物颗粒破碎情况进行了评估。每个标本被分为四个垂直区域：顶部，顶部-中部，底部-中部和底部，并且颗粒大小组被涂上颜色以进行破损跟踪。结果表明，在两种密度条件下，经土工格栅稳定的试件均表现出较大的强度和刚度。对于松散的压载物，土工格栅包覆减少了约27%的总颗粒破碎，其中最显著的减少发生在中间区域。相比之下，对于压实压舱物，使用土工格栅时，总破碎量几乎保持不变；然而，破损在所有区域的分布更加均匀，在Top和Top- mid区域明显减少。中间区域以角破坏为主，顶部和底部附近以劈裂破坏为主。Marsal的破碎度（Bg）指数对逐区评价最敏感。研究结果强调了土工格栅在减轻压舱物退化方面的好处，并强调了在不同密度条件下进行区域特定分析的重要性。提出的单调三轴框架为未来的循环三轴研究提供了一个机制基线，其中重复加载将进一步阐明现实铁路服务条件下的长期应力重新分布、颗粒迁移和累积破坏。

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引用次数: 0

Multi-objective Optimization of Railway Transition Zones with Machine Learning: Application to Prefabricated Epoxy Asphalt Cured Track Bed 基于机器学习的铁路过渡区多目标优化：在预制环氧沥青固化轨道床上的应用

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-26 DOI: 10.1016/j.trgeo.2025.101879

You Wu , Chenguang Shi , Yunhong Yu , Yulou Fan , Jun Yang

Transition zones in high-speed railways suffer from abrupt stiffness variations that induce irregular dynamic responses and accelerate infrastructure deterioration. This study presents a surrogate-assisted multi-objective optimization framework that combines finite element (FE) simulations, a neural network-based surrogate model, and the NSGA-II algorithm to address this challenge. A validated 3D FE model of prefabricated epoxy asphalt cured track beds (PEACT) was used to generate 341 layout scenarios covering 13 response parameters. These data were used to train a neural network, which served as a static surrogate predictor for evaluating layout performance during the optimization process. The results show that module layout has a limited effect on peak responses but significantly improves smoothness, with three categories of optimal configurations identified. Compared with direct FE-based optimization, the proposed framework achieves substantial computational efficiency and provides data-driven design guidance for PEACT transition zones. This framework exemplifies the potential of hybrid data–simulation approaches to enhance adaptive and efficient railway infrastructure design.

高速铁路过渡区存在刚度突变，导致动力响应不规则，加速基础设施劣化。本研究提出了一个代理辅助多目标优化框架，该框架结合了有限元（FE）模拟、基于神经网络的代理模型和NSGA-II算法来解决这一挑战。采用经过验证的预制环氧沥青固化轨道床（PEACT）三维有限元模型，生成了覆盖13个响应参数的341种布局方案。这些数据用于训练神经网络，该网络作为静态代理预测器，用于评估优化过程中的布局性能。结果表明，模块布局对峰值响应的影响有限，但显著提高了平滑性，并确定了三类最优配置。与直接基于fe的优化方法相比，该框架提高了计算效率，为PEACT过渡区提供了数据驱动的设计指导。该框架体现了混合数据模拟方法在增强适应性和高效铁路基础设施设计方面的潜力。

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引用次数: 0

Characterization of pressure filtration behavior and filter cake properties in excavated sand-containing shield slurry: A CFD-DEM study 开挖含砂盾构浆压滤特性及滤饼特性：CFD-DEM研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-25 DOI: 10.1016/j.trgeo.2025.101877

Zhanchao Yin , Qingsong Zhang , Bin Liu , Dongzhu Zheng , Xiao Zhang

The infiltration of slurry and the formation of filter cakes on excavation faces are critical for maintaining tunnel stability by controlling slurry pressure transmission. However, most existing studies focus on bentonite-only slurries and overlook the inevitable mixing of excavated soil with slurry during shield tunneling. This study employs a coupled Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) approach to investigate the infiltration behavior of sand-containing slurry into granular soils. Simulations were conducted with varying mass ratios (MR) of sand to bentonite particles and size ratios (SR) between sand and bentonite particles. The study examines particle clogging behavior under pressure and evaluates filter cake formation and performance under different MR and SR combinations. Additionally, constriction size distribution (CSD) analysis was applied to characterize pore structures in both the sand column and the external hybrid filter cake induced by particle filtration. Numerical results indicate that the sand content in the slurry does not alter the overall infiltration pattern but significantly affects the infiltration process. Another key finding is that although increased sand content prolongs the infiltration duration of slurry particles, optimal sealing performance at the sand-slurry interface is achieved with a moderate sand content. Further analysis discusses consistencies and discrepancies between simulations and infiltration tests, particularly emphasizing the impact of particle surface energy. Results demonstrate that the combination of high surface energy and high sand content compromises filter cake sealing integrity, hindering effective slurry pressure transfer. These findings deepen the understanding of slurry infiltration and filtration mechanisms in practical shield tunneling and provide valuable insights for optimizing stability control and operational parameters.

浆体的入渗和滤饼在开挖面上的形成是控制浆体压力传递来维持隧道稳定的关键。然而，现有的研究大多集中在纯膨润土浆体上，忽视了盾构隧道开挖过程中不可避免的开挖土与浆体的混合。本研究采用计算流体力学(CFD)-离散元法（DEM）耦合方法研究含砂浆体在颗粒土中的入渗行为。在砂与膨润土颗粒质量比（MR）和砂与膨润土颗粒粒径比（SR）不同的情况下进行了模拟。该研究考察了颗粒在压力下的堵塞行为，并评估了不同MR和SR组合下滤饼的形成和性能。此外，采用收缩尺寸分布（CSD）分析方法对砂柱和颗粒过滤后的外部混合滤饼的孔隙结构进行了表征。数值结果表明，砂浆中含砂量不会改变整体入渗模式，但会显著影响入渗过程。另一个重要发现是，尽管增加含砂量延长了泥浆颗粒的渗透时间，但在适度含砂量的情况下，砂浆界面的密封性能最佳。进一步的分析讨论了模拟和入渗试验之间的一致性和差异，特别强调了粒子表面能的影响。结果表明，高表面能和高含砂量的组合影响了滤饼密封的完整性，阻碍了有效的泥浆压力传递。这些发现加深了对实际盾构隧道中浆体渗透和过滤机制的理解，并为优化稳定性控制和操作参数提供了有价值的见解。

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引用次数: 0

Study on the Vibration Response of the Slab Track Coupling System under the Influence of Shear Hinge 剪切铰作用下板轨耦合系统振动响应研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-25 DOI: 10.1016/j.trgeo.2025.101878

Tong Wu, Ruiyao Wang, Xueyi Zhu

The structural form and configuration of metro tracks significantly influence vibration transmission during train operations. As a key connecting component of slab tracks, shear hinges enhance end restraints and improve continuity between adjacent slabs, thereby affecting load transfer within the track structure. In this study, a refined shear hinge system is introduced, and a three-dimensional substructure coupling model is proposed. Coupled models of the steel spring floating slab track(SSFST)-shear hinge system and the integral ballastless track(IBT)-shear hinge system are developed, both accounting for substructure interactions, The models are validated using field data from Hangzhou Metro Line 1. Based on this, systematic comparisons between SSFST and IBT under different train speeds are performed, focusing on the dynamic responses of the rail, slab, tunnel, and ground surface. Results show that rail acceleration increases nonlinearly with speed, with greater responses at slab joints than at mid-span. SSFST exhibits higher slab responses than IBT, while the shear hinge effectively reduces slab-end displacements and sustains stronger dynamic effects at high speeds. At the tunnel and environmental levels, SSFST demonstrates superior vibration attenuation, whereas IBT shows a “sawtooth” displacement pattern under high-speed conditions, while SSFST remains stable. Ground surface vibrations are relatively weak due to the large burial depth, yet train speed still plays a decisive role-vibrations intensify at low speeds but diminish at higher speeds.

地铁轨道的结构形式和配置对列车运行过程中的振动传递有重要影响。剪切铰作为板式轨道的关键连接部件，增强了两端约束，提高了相邻板间的连续性，从而影响轨道结构内部的荷载传递。本文介绍了一种精细化剪切铰系统，并建立了三维子结构耦合模型。建立了考虑子结构相互作用的钢弹簧浮板轨道(SSFST)-剪力铰系统和整体无碴轨道(IBT)-剪力铰系统的耦合模型，并利用杭州地铁1号线的现场数据对模型进行了验证。在此基础上，系统比较了不同列车速度下SSFST和IBT的动力响应，重点研究了钢轨、楼板、隧道和地面的动力响应。结果表明：钢轨加速度随速度呈非线性增长，在跨中节点处的响应大于在板节点处的响应；SSFST比IBT表现出更高的板响应，而剪切铰有效地减少了板端位移，并在高速下维持了更强的动力效应。在隧道和环境水平上，SSFST表现出优越的振动衰减，而IBT在高速条件下表现出“锯齿”位移模式，而SSFST保持稳定。由于埋深大，地表振动相对较弱，但列车速度仍起决定性作用，低速时振动加剧，高速时振动减弱。

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引用次数: 0

Prediction for freeze–thaw cycles induced degradation of dynamic shear modulus in Qinghai loess: structural damage concept-based model-Case study 青海黄土冻融循环引起动剪模量退化的预测：基于结构损伤概念的模型——实例研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-23 DOI: 10.1016/j.trgeo.2025.101875

Hao Wu , Shuai Shao , Yutong Zhang , Bin Zhang , Zechi Wang , Yufei Ji , Shaoying Zhang

Freeze-thaw cycles (FTCs) and earthquakes are key factors contributing to foundation deformation and instability in loess engineering in cold regions. Seismic loading acting on loess weakened by FTCs can lead to catastrophic failure(e.g., landslides, settlement). FTCs degrade loess stiffness by causing microstructural damage. To quantify this damage and explore its impact on dynamic properties, this study examined the influence of FTCs on the microstructure and dynamic property of loess from Qinghai Province, China using scanning electron microscopy (SEM) and cyclic simple shear(CSS) tests. Image-Pro Plus(IPP) was used to quantitatively analyze changes in pore and particle structures. The results show that after FTCs, soil particles break apart, become more angular, and rearrange. The total pore area increases, with a higher proportion of large and medium pores. The dynamic shear modulus exhibits a total attenuation of 64.64%, with the first cycle contributing up to one-third of the overall reduction. A random forest model identified key microscopic characteristic parameters governing the degradation of the initial dynamic shear modulus. According to damage theory and considering the evolution of pore and particle structures, structural parameters representing loess integrity were proposed. A dynamic shear modulus prediction model was then developed, which effectively accounts for structural disturbance. These findings advance geohazard forecasting by coupling microstructural damage metrics with dynamic stiffness, offering a novel tool for slope-stability and subgrade-settlement assessments in cold region loess.

冻融循环和地震是寒区黄土工程地基变形失稳的关键因素。地震荷载作用于经FTCs削弱的黄土上可导致灾难性破坏(例如：、滑坡、沉降)。FTCs通过引起微结构损伤来降低黄土的刚度。为了量化这种损伤并探讨其对动力特性的影响，本研究利用扫描电镜（SEM）和循环单剪（CSS）试验研究了FTCs对青海黄土微观结构和动力特性的影响。使用Image-Pro Plus（IPP）定量分析孔隙和颗粒结构的变化。结果表明：在FTCs作用下，土壤颗粒破碎、棱角化、重新排列；总孔隙面积增大，大、中孔隙比例增大。动剪切模量总体衰减为64.64%，其中第一个周期的衰减量占整体衰减量的三分之一。随机森林模型确定了控制初始动剪切模量退化的关键微观特征参数。根据损伤理论，考虑孔隙结构和颗粒结构的演化，提出了表征黄土完整性的结构参数。建立了动态剪切模量预测模型，有效地反映了结构扰动。这些研究结果通过将微观结构损伤指标与动力刚度相结合来促进地质灾害预测，为寒区黄土的边坡稳定性和路基沉降评估提供了一种新的工具。

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