Transportation Geotechnics最新文献_第6页

DEM investigation on granular soil arching with emphasis on particle size distribution effect 颗粒土成拱的DEM研究，重点研究粒径分布效应

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-22 DOI: 10.1016/j.trgeo.2025.101872

Zhuofeng Li , Bo Yang , Peng Xia , Shuyu He , Shaokun Ma

Soil arching is a common load transfer mechanism in geotechnical engineering, which is significantly influenced by soil particle size distribution (PSD). Existing studies have not fully understood the PSD effect, specifically the mean particle size (d₅₀) and coefficient of uniformity (C_u), on the arching evolution and critical height. To this end, this study tries to investigate the PSD effect on the evolution of soil arching using the discrete element method. A series of two-dimensional trapdoor tests were simulated on eight specimens with varying d₅₀ and C_u. The macroscopic responses and microscopic mechanisms were systematically analyzed. Simulations reveal that an increase in d₅₀ or C_u leads to a reduction in the critical arching height. This indicates that coarser and better-graded granular soils promote a more rapid development of soil arching effect, thereby enhancing the initial load-transfer efficiency. At the microscopic level, specimens with larger d₅₀ develop stronger yet sparser force chains and exhibit greater normal contact force anisotropy, while specimens with higher C_u form denser contact networks with larger coordination numbers, resulting in more stable force transmission. The findings of this study strongly suggest that PSD significantly controls the soil arching development process through its governing role in fabric formation and force chain structure. Besides, the implications of this study offer direct relevance for optimizing backfill material design in geotechnical practices, notably in pile-supported embankments and underground excavation projects.

土成拱是岩土工程中常见的荷载传递机制，受土粒径分布的显著影响。现有研究尚未完全了解PSD对拱形演化和临界高度的影响，特别是平均粒径（d50）和均匀度系数（Cu）。为此，本研究尝试采用离散元法研究PSD对土拱演化的影响。在8个不同d50和Cu的试件上进行了一系列二维活板门试验。系统地分析了宏观响应和微观机理。模拟结果表明，增加d50或Cu会导致临界拱高降低。说明颗粒土越粗、级配越好，土拱效应发展越快，初始荷载传递效率越高。微观层面上，d50越大的试样力链越强但越稀疏，法向接触力各向异性越大；Cu越高的试样接触网络越密集，配位数越大，力传递越稳定。本研究结果强烈表明，PSD通过其对织物形成和力链结构的调控作用，显著控制了土拱的发展过程。此外，本研究的意义为岩土工程实践中回填材料的优化设计提供了直接的相关性，特别是在桩基路堤和地下开挖工程中。

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引用次数: 0

Seismic Performance and Fragility Assessment of Pile-Slab Retaining Walls Backfilled with Lightweight Foamed Concrete 轻泡沫混凝土桩板挡土墙抗震性能及易损性评价

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-22 DOI: 10.1016/j.trgeo.2025.101873

Rongwei Fan , Junjie Huang , Yanfei Pei , Honglin Sun , Hongyi Yao , Degou Cai , Xiaoduo Ou , Qian Su , Yongyi Shang

This study investigates the mechanical behavior and seismic performance of pile-slab retaining wall structures backfilled with lightweight foamed concrete (LFC) through a combination of laboratory testing and numerical simulation. A comprehensive material testing program was carried out to evaluate the strength evolution of LFC under uniaxial compression, from which key constitutive parameters such as elastic modulus and Poisson’s ratio were obtained. Based on these experimental results, a three-dimensional nonlinear finite difference model was developed, and dynamic time-history analyses were performed to assess the structural response under strong seismic loading. The results indicate that, compared with conventional soil backfill, LFC significantly reduces pile head horizontal displacement and seismic inertial forces, while its unique compressive deformation characteristics enhance overall structural stability. Furthermore, probabilistic seismic vulnerability analysis shows that the PGA values corresponding to a 50% probability of damage at levels I-IV increase by 25.8%, 19.6%, 13.3%, and 7.0%, respectively, for LFC backfill, indicating slower damage accumulation and improved seismic resilience. The study reveals the mechanisms by which LFC enhances energy dissipation and stress redistribution, thereby providing a theoretical basis and technical support for the optimized design of innovative retaining structures in seismic regions.

本文采用室内试验与数值模拟相结合的方法，对轻泡沫混凝土（LFC）回填桩板挡土墙结构的力学性能和抗震性能进行了研究。采用综合材料试验方案，对LFC在单轴压缩下的强度演化进行了评价，获得了弹性模量和泊松比等关键本构参数。基于这些试验结果，建立了三维非线性有限差分模型，并进行了动力时程分析，以评估结构在强震荷载下的响应。结果表明：与常规土填土相比，LFC显著降低了桩顶水平位移和地震惯性力，其独特的压缩变形特性提高了整体结构的稳定性。此外，概率地震易损性分析表明，LFC回填体在I-IV级发生50%破坏概率时的PGA值分别增加了25.8%、19.6%、13.3%和7.0%，表明损伤积累速度较慢，地震恢复能力有所提高。研究揭示了LFC增强能量耗散和应力重分布的机制，为震区创新挡土结构优化设计提供理论依据和技术支持。

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引用次数: 0

Resilience assessment method of existing tunnels considering adjacent construction disturbance intensity 考虑相邻施工扰动强度的既有隧道回弹性评价方法

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-21 DOI: 10.1016/j.trgeo.2025.101871

Dechun Lu , Xu Meng , Qingtao Lin , Yongpeng Peng , Chenghe Yang , Shi Wei , Xiuli Du

The resilience of tunnel structures comprehensively reflects its functional change under external loads. The resilience value is related to the external load, and the classification of resilience levels should account for tunnel’s function. However, the relevant research is still lacking. Focusing on the scenario of adjacent construction disturbance, a resilience calculation model for existing tunnels that incorporates the disturbance load intensity (F), function of the existing tunnel (Q), and time (T) is proposed. A calculation method for disturbance load intensity (F) is developed using a game-theory-based AHP-CRITIC combined weighting approach, which considers both subjective and objective weights of multiple disturbance factors. By conducting 243 sets of numerical simulations under different load conditions and performing regression analysis, the relationship between existing tunnel’s function (Q) and disturbance load intensity (F) is established. Furthermore, a method is presented to determine the evolution curve of existing tunnel’s function (Q) over time (T) under specific load conditions. These studies enable the calculation of both resistance and recovery resilience indices of the existing tunnel under different disturbance load intensities. By introducing deformation control thresholds for the normal service, waterproofing, and load-bearing function of the existing tunnel, resilience classification boundaries for four resilience levels, that is, high, medium, low, and no, are determined. A function-based resilience classification methodology is established. The proposed method is applied to a case: Beijing Metro Line 12′s shallow tunnelling undercrossing the Qinghuayuan Tunnel. The disturbance load intensities F are obtained for nine construction schemes, along with their corresponding resistance and recovery resilience indices. The results reveal the variation of existing tunnel resilience with F and identify the resilience level for each scheme. Moreover, for the construction scheme adopted in the actual project, the resilience values calculated using the proposed method are in close agreement with those actual results, demonstrating the validity of the proposed method.

隧道结构的回弹性综合反映了其在外部荷载作用下的功能变化。回弹性值与外部荷载有关，回弹性等级的划分应考虑隧道的功能。然而，相关的研究仍然缺乏。针对相邻施工扰动情况，提出了一种考虑扰动荷载强度(F)、既有隧道函数(Q)和时间(T)的既有隧道回弹性计算模型。采用基于博弈论的AHP-CRITIC组合加权方法，综合考虑多个干扰因素的主客观权重，提出了干扰负荷强度(F)的计算方法。通过243组不同荷载条件下的数值模拟并进行回归分析，建立了既有隧道的函数Q与扰动荷载强度F之间的关系。在此基础上，提出了一种确定特定荷载条件下既有隧道功能Q随时间T演化曲线的方法。这些研究使既有隧道在不同扰动荷载强度下的抗力和恢复弹性指标得以计算。通过引入既有隧道正常使用、防水、承重功能的变形控制阈值，确定了高、中、低、无四个回弹等级的回弹分类边界。建立了一种基于功能的弹性分类方法。并以北京地铁12号线浅埋下穿青花园隧道为例进行了实例分析。得到了9种施工方案的扰动荷载强度F，以及相应的阻力和恢复弹性指标。结果揭示了既有隧道回弹性随F的变化规律，并确定了各方案的回弹性水平。此外，对于实际工程中采用的施工方案，用本文方法计算的回弹值与实际结果吻合较好，证明了本文方法的有效性。

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引用次数: 0

Thermal response and effectiveness of water impoundment pre-thawing foundation for high-speed railway subgrade in island permafrost regions 海岛多年冻土区高速铁路路基蓄水预融地基热响应及有效性

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-20 DOI: 10.1016/j.trgeo.2025.101867

Degou Cai , Xiaohe Liu , Hongye Yan , Binglong Zhu , Yuxin Wang , Yong Wang

This study addresses the challenge of controlling thermal stability of island permafrost in high-speed railway subgrades affected by climate warming, increased wetting, and engineering disturbances. A novel foundation treatment technology based on water impoundment pre-thawing is proposed. This approach enhances heat exchange via water injection into foundation pits, enabling active and controlled acceleration of thawing within highly unstable, high-temperature permafrost layers. The objective was to achieve uniform pre-construction settlement and mitigate differential deformation after construction. Field experiments at the Riyuexia test section of the Harbin–Yichun High-Speed Railway (HYHSR) deployed a monitoring system to track ground temperature evolution across three stages: water impoundment, drainage, and filling. Results demonstrated that during the water impoundment stage, water’s high heat capacity and limited thermal conductivity resulted in gradual thawing. Following drainage, the exposed subgrade base absorbed increased heat, causing rapid temperature rise in shallow layers. During the filling stage, the fill material served as an additional heat source, further promoting permafrost thawing and ultimately yielding nearly complete thawing within the monitored depth. Overall, the study elucidates thermal boundary effects and permafrost degradation mechanisms during water impoundment pre-thawing and confirms the effectiveness of technology in enhancing foundation thermal uniformity and controlling thaw settlement. This study offers a novel method and practical framework for designing high-speed railway subgrades in high-latitude island permafrost regions, with significant practical implications for climate-resilient permafrost engineering systems.

本研究解决了气候变暖、湿度增加和工程干扰影响下高速铁路路基海岛冻土热稳定性控制的挑战。提出了一种基于蓄水预融的地基处理新技术。这种方法通过向基坑注水来增强热交换，从而在高度不稳定的高温永久冻土层中实现主动和可控的加速融化。目的是实现均匀的施工前沉降和减轻施工后的差异变形。在哈伊高铁日月峡试验段的现场试验中，部署了一个监测系统，跟踪地温在蓄水、排水和填土三个阶段的演变。结果表明：在蓄水阶段，水的高热容和有限的热导率导致其逐渐融化；排水后，暴露的路基基底吸收了更多的热量，导致浅层温度迅速上升。在填筑阶段，填筑材料作为一个额外的热源，进一步促进冻土融化，最终在监测深度内几乎完全融化。总体而言，研究阐明了蓄水预融过程中的热边界效应和冻土退化机制，证实了该技术在提高地基热均匀性和控制融化沉降方面的有效性。本研究为高纬度海岛永久冻土区高速铁路路基设计提供了一种新颖的方法和实用框架，对气候适应性永久冻土区工程系统具有重要的实际意义。

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引用次数: 0

Metaheuristic-optimized XGBoost model for accurate prediction of rock fragmentation in mining projects 基于元启发式优化的XGBoost模型的矿山破碎度精确预测

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-20 DOI: 10.1016/j.trgeo.2025.101854

Jitendra Khatti , Swapnil Mishra , Athanasia D. Skentou , Panagiotis G. Asteris

Rock fragmentation plays a critical role in determining the cost of a mining project, as the expenses related to loading, hauling, and crushing the fragmented rock directly impact the overall project cost. Conventional methods for evaluating fragmentation, such as Kuz–Ram models, size-distribution functions, and classical comminution laws, often fall short. These methods do not consider the complex interactions among geology, blast design, and timing. Even the Modified Kuz–Ram model, which includes the Blastability Index, performs inconsistently in jointed and heterogeneous rock conditions. Therefore, the present research introduces a new optimized extreme gradient boosting (XGBoost) model by comparing the Arithmetic Optimization (AOA), Brainstorm Optimization (BOA), Quantum-inspired Evolutionary (QEA), Tiki-Taka Optimization (TTA), and Whale Optimization (WOA) algorithms optimized XGBoost models to predict rock FGT. For that purpose, the database was collected from the opencast Mine of Ramagundam, Telangana, India. This investigation uses spacing-to-burden ratio, total explosive, firing pattern, joint angle, and maximum charge per delay (Q) as features to assess the rock FGT. This investigation has analyzed the accuracy and reliability of the optimized XGBoost models using ten performance metrics, QQ plot, regression error characteristics, generalizability analysis, reliability indexes, overfitting analysis, and Anderson-Darling test. Finally, the TTA_XGBoost model outperformed the AOA, BOA, QEA, and WOA-optimized XGBoost models with a Deviation of Runoff Volume (DRV) of 0.0872, Kling-Gupta Efficiency (KGE) of 0.7784, Kullback Leibler Divergence (KLD) of 0.4348, and Jensen Shannon Divergence (JSD) of 0.0997. The Local Interpretable Model-Agnostic Explanations (LIME) analysis reveals that the joint angle and maximum charge per delay (Q) features significantly impact the rock FGT assessment. Also, it was observed that the optimized XGBoost model achieves over 95% performance when the features are weakly multicollinear.

岩石破碎在决定采矿项目成本中起着至关重要的作用，因为与破碎岩石的装载、运输和破碎相关的费用直接影响到整个项目的成本。评估碎片化的传统方法，如库兹-拉姆模型、大小分布函数和经典的粉碎定律，往往是不够的。这些方法没有考虑地质、爆破设计和定时之间复杂的相互作用。即使是包含可爆性指数的修正库兹-拉姆模型，在节理和非均质岩石条件下的表现也不一致。因此，本研究通过比较算法优化（AOA）、头脑风暴优化（BOA）、量子启发进化（QEA）、Tiki-Taka优化（TTA）和鲸鱼优化（WOA）算法优化的XGBoost模型，提出了一种新的优化的极限梯度提升（XGBoost）模型来预测岩石FGT。为此目的，数据库是从印度特伦甘纳的Ramagundam露天矿收集的。该研究使用空药比、总炸药、射击模式、节理角度和最大每延迟装药量(Q)作为评估岩石FGT的特征。本研究利用十大性能指标、QQ图、回归误差特征、概率性分析、可靠性指标、过拟合分析和Anderson-Darling检验对优化后的XGBoost模型的准确性和可靠性进行了分析。TTA_XGBoost模型的径流量偏差（DRV）为0.0872，KGE为0.7784，Kullback Leibler散度（KLD）为0.4348，Jensen Shannon散度（JSD）为0.0997，优于AOA、BOA、QEA和woa优化的XGBoost模型。局部可解释模型不可知解释（LIME）分析表明，节理角和最大每延迟装药量(Q)特征对岩石FGT评价有显著影响。此外，当特征是弱多重共线时，优化后的XGBoost模型的性能达到95%以上。

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引用次数: 0

Modelling matric suction effects on rigid inclusion foundations using existing unsaturated pile models 利用现有非饱和桩模型模拟刚性包体地基的基质吸力效应

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-19 DOI: 10.1016/j.trgeo.2025.101862

Bantayehu Uba Uge , Yuancheng Guo , Jun Zhao , Yunlong Liu , Mudassir Mehmood , Chenyu Lv , Yanyan Xia

While geotechnical engineering has made great strides in dealing with the mechanical behaviour of earth materials, including reinforcing soft grounds, established principles are now being challenged by a new reality of continuous shift in environmental variables due to global warming. In natural environment, the interface of geomaterials and substructures plays a vital role, a role that is compromised by matric suction-induced changes in the soil stress state. To enhance geo-infrastructure resilience, it is important to incorporate changing environmental conditions into the design, especially in the face of seasonal climates. For this aim, this article synthesizes and conceptually applies established unsaturated pile models to rigid inclusion (RI) foundations under varying matric suction. More specifically, it extends the modified shear displacement method to the load efficiency factor (E_ff) analysis of RI systems, incorporating soil–water characteristic curves and suction-dependent stiffness. The approach is validated through previous study of a 2 × 2 RI foundation under controlled groundwater fluctuation, demonstrating how suction loss redistributes load toward the inclusions and increases E_ff. The approach offers practitioners a predictive tool to enhance RI foundation resilience under seasonal moisture variations.

虽然岩土工程在处理土材料的力学行为方面取得了很大的进步，包括加固软土地基，但由于全球变暖，环境变量不断变化的新现实正在挑战既定的原则。在自然环境中，岩土材料和子结构的界面起着至关重要的作用，而这种作用被基质吸力引起的土壤应力状态变化所削弱。为了增强地质基础设施的弹性，将不断变化的环境条件纳入设计非常重要，特别是在面对季节性气候时。为此，本文将已建立的非饱和桩模型综合并在概念上应用于变基质吸力下的刚性包体（RI）地基。更具体地说，它将改进的剪切位移法扩展到RI系统的载荷效率因子（Eff）分析，纳入了土-水特征曲线和吸力相关刚度。通过对地下水波动控制下的2 × 2 RI地基的研究，验证了该方法的有效性，证明了吸力损失如何将荷载重新分配给包裹体并增加Eff。该方法为从业者提供了一种预测工具，以提高季节性湿度变化下的RI基础弹性。

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引用次数: 0

A predictive model for cumulative plastic deformation in saturated soft clay subjected to intermittent-cyclic loading 饱和软黏土在间歇循环荷载作用下累积塑性变形的预测模型

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-19 DOI: 10.1016/j.trgeo.2025.101866

Jiaqiang Yang , Zhiliang Wang , Banglu Xi , Mingliang Chen , Zhenhua Zhang , Wenling Tian , Liyuan Yu

To address the limitations of conventional cyclic triaxial tests without drainage in simulating the actual loading characteristics of railway traffic, this study conducts intermittent cyclic triaxial tests to systematically investigate the dynamic response behavior of saturated soft clay under partial drainage conditions. The experimental framework comprehensively incorporates the intermittent period of train-induced loads and the realistic drainage behavior of soils, with explicit consideration of pore water pressure dissipation during unloading intervals. The results indicate that, in contrast to the continuous accumulation of pore water pressure observed under continuous cyclic loading, intermittent-cyclic loading leads to a periodic dynamic evolution pattern characterized by an initial increase followed by gradual dissipation. Furthermore, the drainage consolidation occurring during intermittent periods induces a significant increase in cumulative plastic strain, although the rate of accumulation progressively decreases as the soil undergoes hardening, eventually reaching a stable state. Based on these findings, a novel predictive model for cumulative plastic deformation is proposed. This model independently quantifies the effects of soil strength, cyclic stress ratio (CSR), and loading frequency, maintaining clear physical significance of input parameters while enhancing predictive accuracy across varying operational conditions. The present study elucidates the mechanism of periodic pore water pressure dissipation under intermittent loading and its influence on soil deformation behavior, thereby providing a solid experimental foundation for the prediction of long-term soil foundation settlement in rail transit systems.

针对传统不排水循环三轴试验在模拟铁路交通实际荷载特性方面的局限性，本研究开展了间歇循环三轴试验，系统研究了部分排水条件下饱和软土的动力响应特性。该试验框架综合考虑了列车加载间歇期和土体的实际排水特性，并明确考虑了卸载间隙孔隙水压力的消散。结果表明：与连续循环荷载作用下孔隙水压力的持续积累不同，间歇循环荷载作用下孔隙水压力呈现先增大后逐渐消散的周期性动态演化模式；间断性排水固结导致累积塑性应变显著增加，但累积速率随土体硬化逐渐减小，最终达到稳定状态。在此基础上，提出了一种新的累积塑性变形预测模型。该模型独立量化了土壤强度、循环应力比（CSR）和加载频率的影响，在保持输入参数明确的物理意义的同时，提高了不同运行条件下的预测准确性。本研究阐明了间歇荷载作用下孔隙水压力周期性耗散的机理及其对土体变形行为的影响，为轨道交通系统地基长期沉降预测提供了坚实的实验基础。

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引用次数: 0

Influence of sequential twin stacked tunnelling on deformation and load-transfer mechanisms of battered piled rafts under lateral and combined loading 序贯双桩隧道开挖对横向和组合荷载作用下破桩筏变形及荷载传递机制的影响

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-18 DOI: 10.1016/j.trgeo.2025.101852

Mukhtiar Ali Soomro , Sharafat Ali Darban , Rizwan Ali Soomro , Zhen-Dong Cui , Amir Detho , Saim Bin Shahab

The increasing demand for underground space in dense urban areas has led to the construction of twin stacked tunnels, creating complex soil-structure interactions with nearby piled foundations. This study investigates the effects of twin stacked tunnelling on the performance of a (2 × 2) battered piled raft system in soft clay using three-dimensional coupled-consolidation finite element analyses. A hypoplastic clay model was employed to capture soil stiffness degradation and stress-path-dependent behaviour, calibrated through laboratory tests and validated against centrifuge data. The first tunnel was excavated adjacent to the pile shaft, and the second tunnel at varying depths near the pile toe, below the pile toe, and beneath the raft (denoted by StackTwinST, StackTwinSB, and StackTwinSU, respectively). Additional analyses examined the effects of combined vertical-lateral loading conditions and construction sequence. Results show that the first tunnel excavation caused stress release and degradation of mobilized shear stiffness, reducing shaft resistance in the upper pile portion by up to 28 %. The second tunnelling increased deformation, particularly beneath the raft (StackTwinSU), with maximum lateral displacement of 8.6 % of pile diameter and raft tilting of 0.64 %. Under combined loading, lateral displacement and bending moments increased up to ninefold compared with lateral-only conditions, while vertical load carried by the raft decreased from 20 % to 16.5 %. Changing the construction sequence by excavating the deeper tunnel first (StackTwinTS, StackTwinBS, StackTwinUS) resulted in larger lateral movements and tilting (up to 0.77 %) due to progressive stiffness degradation in upper soil layers. These findings demonstrate that the tunnelling sequence critically governs the deformation mechanisms and stability of battered piled raft systems, with the deeper-first sequence leading to substantial soil-structure interaction.

在人口密集的城市地区，对地下空间的需求不断增加，导致双堆式隧道的建设，与附近的桩基础产生复杂的土-结构相互作用。采用三维耦合固结有限元分析方法，研究了双叠垛隧道开挖对软粘土（2 × 2）桩筏系统性能的影响。一个发育不良的粘土模型被用来捕捉土壤刚度退化和应力路径依赖的行为，通过实验室测试校准并根据离心机数据进行验证。第一条隧道在桩身附近开挖，第二条隧道在桩趾附近、桩趾下方和筏板下方不同深度开挖（分别用StackTwinST、StackTwinSB和StackTwinSU表示）。附加分析考察了竖向横向荷载条件和施工顺序组合的影响。结果表明，第一次隧道开挖引起应力释放和动剪刚度退化，使上桩部分轴阻力降低28%。第二次隧道开挖增加了变形，特别是在筏板下方（StackTwinSU），最大横向位移为桩径的8.6%，筏板倾斜为0.64%。在联合荷载作用下，筏体的横向位移和弯矩增加了9倍，而筏体所承受的垂直荷载从20%下降到16.5%。通过先开挖较深的隧道（StackTwinTS、StackTwinBS、StackTwinUS）来改变施工顺序，由于上部土层的刚度逐渐退化，导致较大的横向移动和倾斜（高达0.77%）。这些发现表明，掘进顺序对破碎桩筏体系的变形机制和稳定性起着关键的控制作用，深优先顺序导致了大量的土-结构相互作用。

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引用次数: 0

The effect of selecting different stress states in laboratory tests on the predicted permanent deformation of soils 室内试验中选择不同应力状态对土体永久变形预测的影响

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-18 DOI: 10.1016/j.trgeo.2025.101856

João Victor Lima Alencar , Alfran Sampaio Moura , Juceline Batista dos Santos Bastos , Iuri Sidney Bessa , Jorge Barbosa Soares , Moises Braga Martins , Lucas Feitosa de Albuquerque Lima Babadopulos

Modeling permanent deformation (PD) in pavement sublayer materials is essential for predicting pavement performance. The present study evaluated the influence of stress state, by means of the stress pair (confining stresses, σ₃, and deviator stresses, σ_d) considered on the calibration of a permanent deformation model widely used in Brazil. A total of 54 repeated load triaxial (RLT) tests were performed on 6 different soils, each subjected to 9 stress pairs, resulting in 130 combinations per material. Model coefficients were obtained by multiple linear regression. The results indicated that reducing the number of stress pairs improves the coefficients of determination (R²), but may compromise the model’s global predictive capacity, especially for pairs not included in the fitting. In 61% of cases analyzed, predictions fell outside the fitted range, highlighting the model’s sensitivity to pair selection. Some coefficients showed high variability, with differences exceeding 100% even for the same material, compromising their physical interpretation. Application of this methodology to literature data confirmed these trends and showed that different stress pair selection significantly affects the regression coefficients, even when R² values are high. Numerical modeling with MeDiNa software reinforced the practical relevance of these findings, revealing that changes in the coefficients of just one layer resulted in differences of up to 22% in total pavement deformation and 92% in the deformation of the base layer. It is concluded that defining technical criteria for stress pair selection is essential for consistent predictions. Further studies are recommended to deepen the understanding of pavement stresses and their impact on permanent deformation.

路面子层材料的永久变形（PD）建模是预测路面性能的关键。本文利用应力对（围应力σ3和偏应力σd）对巴西广泛使用的永久变形模型进行了标定，评价了应力状态对模型标定的影响。在6种不同的土壤上进行了54次重复加载三轴（RLT）试验，每个试验受到9个应力对，每种材料产生130种组合。通过多元线性回归得到模型系数。结果表明，减少应力对的数量提高了决定系数（R2），但可能会损害模型的全局预测能力，特别是对未包括在拟合中的应力对。在分析的61%的案例中，预测超出了拟合范围，突出了模型对配对选择的敏感性。有些系数表现出很高的变异性，即使对于相同的材料，差异也超过100%，从而影响了它们的物理解释。将该方法应用于文献数据证实了这些趋势，并表明即使在R2值很高的情况下，不同的应力对选择也显著影响回归系数。使用MeDiNa软件进行的数值模拟强化了这些发现的实际相关性，揭示了仅一层系数的变化就会导致路面总变形量的差异高达22%，而基础层变形量的差异高达92%。结论是，确定应力对选择的技术标准对于一致性预测至关重要。建议进一步研究以加深对路面应力及其对永久变形的影响的理解。

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引用次数: 0

Deformation and degradation behaviour of coal-fouled tyre chips intermixed steel slag ballast under cyclic loading 循环荷载下煤屑混合钢渣压载物的变形与降解行为

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2025-12-17 DOI: 10.1016/j.trgeo.2025.101869

Atif Hussain , Syed Khaja Karimullah Hussaini , Buddhima Indraratna , Yujie Qi

Steel slag and tyre chips are two waste products with potential for sustainable use in railway tracks.

While the previous studies have primarily focused on the benefits of utilizing steel slag as railway subballast, yet its suitability as railway ballast with and without tyre chips (TC) has not been comprehensively investigated. Moreover, the possible effect of coal fouling on the performance of TC-intermixed steel slag ballast is yet to be studied. Therefore, the current study assessed the influence of TC on the performance of slag-granite ballast mixture under coal-fouled condition using large-scale track simulation test (TST) and constant-head permeability apparatus. TST results indicated that vertical and lateral deformations of ballast increased, while the track stiffness (k) and ballast breakage index (BBI) decreased with the increase in proportion of tyre chips. The threshold content of tyre chips to be mixed with steel slag ballast (SSB) is identified as 10%. The study further established that the addition of coal leads to an increase in deformations, while reducing BBI of TC intermixed slag-granite ballast. Moreover, the addition of coal causes a significant reduction in hydraulic conductivity of the TC intermixed ballast. Further, the critical value of void contamination index is determined to be 25%.

钢渣和轮胎碎片是两种具有可持续利用潜力的废物。以往的研究主要集中在钢渣作为铁路载道子的效益上，但对其作为铁路载道子的适用性和不含轮胎屑的适用性研究较少。此外，煤结垢对tc -混钢渣压载物性能的可能影响还有待研究。因此，本研究采用大型轨道模拟试验（TST）和恒水头渗透仪，评估了煤污染条件下TC对炉渣-花岗岩压载混合物性能的影响。TST结果表明，随着轮胎碎片比例的增加，压载物的纵向和横向变形增加，轨道刚度(k)和压载物破碎指数（BBI）降低。确定钢渣镇流器（SSB）混合轮胎碎屑的阈值含量为10%。研究进一步证实，煤的加入使TC混渣-花岗岩压载物的变形增加，同时降低了BBI。煤的加入使TC混压载水导率显著降低。进一步确定孔隙污染指数临界值为25%。

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引用次数: 0