Transportation Geotechnics最新文献

Genetic programming-based closed-form solutions for predicting the compressive strength of cement-treated soils 基于遗传规划的水泥土抗压强度预测封闭解

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-04-01 Epub Date: 2026-02-13 DOI: 10.1016/j.trgeo.2026.101949

Muhammad Hasnain Ayub Khan , Akbar A. Javadi , Adel Abdallah , Olivier Cuisinier

This study presents closed-form predictive models for estimating the unconfined compressive strength (UCS) of cement-treated soils using two genetic programming techniques i.e., Gene Expression Programming (GEP) and Multi Expression Programming (MEP), addressing the limitations of existing closed-form predictive models that are often overly simplified, rely on a narrow set of input variables, or are tailored to specific soil types, thereby restricting their general applicability. An extended dataset comprising 328 data points was compiled from existing literature, covering both coarse- and fine-grained soils and incorporating key geotechnical and treatment-related parameters such as liquid limit (LL), fine content (FC), normalized compaction parameters (ρ_norm, w_norm), cement dosage (C), curing time (T), and porosity-to-volumetric cement ratio (η/C_iv). The dataset was pre-processed using min–max normalization and split evenly into training and testing sets. Through a systematic trial-and-error process, optimal configurations for GEP and MEP were identified. The optimal GEP and final MEP models demonstrated high predictive accuracy, achieving coefficients of determination (R²) of 0.86 and 0.92, respectively, and were further corroborated by low error room-mean-squared error, and mean absolute error. Closed-form mathematical expressions were derived from both models. Performance evaluation, including monotonicity and sensitivity analyses, confirmed the physical relevance of the models, with GEP showing higher physical consistency than MEP. Notably, feature importance varied between models: ρ_norm was most influential in MEP, while FC had the highest impact in GEP. Overall, the developed models offer accurate and physically meaningful tools for predicting UCS in cement-stabilized soils, contributing to improved design practices in cement-soil stabilization applications.

本研究提出了使用基因表达式编程（GEP）和多表达式编程（MEP）两种遗传编程技术估算水泥处理土壤无侧限抗压强度（UCS）的封闭形式预测模型，解决了现有封闭形式预测模型的局限性，这些模型通常过于简化，依赖于一组狭窄的输入变量，或者针对特定的土壤类型进行定制，从而限制了它们的一般适用性。从现有文献中编译了包含328个数点的扩展数据集，涵盖了粗粒和细粒土壤，并纳入了关键的岩土和处理相关参数，如液限（LL）、细粒含量（FC）、归一化压实参数（ρnorm, wnorm）、水泥用量(C)、养护时间(T)和孔隙率-体积水泥比（η/Civ）。采用最小-最大归一化方法对数据集进行预处理，并将数据集均匀分为训练集和测试集。通过系统的试错过程，确定了GEP和MEP的最佳配置。最优GEP和最终MEP模型具有较高的预测精度，决定系数（R2）分别为0.86和0.92，并进一步证实了较低的误差室均方误差和平均绝对误差。从这两个模型推导出封闭形式的数学表达式。性能评价，包括单调性和敏感性分析，证实了模型的物理相关性，GEP比MEP具有更高的物理一致性。值得注意的是，特征重要性在模型之间存在差异：ρnorm在MEP中影响最大，而FC在GEP中影响最大。总的来说，开发的模型为预测水泥稳定土中的UCS提供了准确且物理上有意义的工具，有助于改进水泥土稳定应用的设计实践。

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引用次数: 0

Railway ballast fouling detection using thermal imaging: integration of LSTM and XGBoost 铁路道砟污垢热成像检测：LSTM和XGBoost的集成

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-04-01 Epub Date: 2025-12-31 DOI: 10.1016/j.trgeo.2025.101889

Mehdi Koohmishi , David P. Connolly

This paper presents an artificial intelligence (AI)-based approach to automate the structural health monitoring (SHM) of railway ballast through the fusion of long short-term memory and XGBoost (LSTM-XGB) to surface temperature data derived from infrared thermal images. In this context, machine learning models are trained using remotely acquired surface temperature data to classify fouling index based on thermal variations within ballast aggregates captured from thermograms. The long short-term memory (LSTM) component processes sequential time-series thermal data to predict preceding values, and the XGBoost (XGB) component classifies fouled ballast conditions based on identified patterns of surface temperature variations measured via infrared thermography (IRT). The results confirm the capability of the LSTM component to capture the time-series variations of a specimen’s surface temperature in a shorter timeframe as well as the superior performance of XGBoost compared to a random forest (RF) approach, in classifying fouled ballast conditions. Therefore, the LSTM-XGB model demonstrates higher efficiency compared to the standalone XGBoost model, since the predictive nature of LSTM over time-series temperature data enables capturing shorter time window for measuring ballast surface temperature and identifying patterns. Moreover, establishing a coarser classification of ballast fouling (categorized into three groups instead of five) significantly improves the model capability for accurate assessment of the ballast fouling conditions.

本文提出了一种基于人工智能（AI）的铁路道砟结构健康监测方法，该方法将长短期记忆和XGBoost （LSTM-XGB）技术与红外热像的表面温度数据相融合，实现了道砟结构健康监测的自动化。在这种情况下，机器学习模型使用远程获取的表面温度数据进行训练，以根据从热图中捕获的压载物骨料内的热变化对污垢指数进行分类。长短期记忆（LSTM）组件处理连续时间序列热数据来预测之前的值，XGBoost （XGB）组件根据红外热像仪（IRT）测量的表面温度变化模式对污染的压舱状况进行分类。结果证实了LSTM组件能够在更短的时间内捕获样品表面温度的时间序列变化，并且与随机森林（RF）方法相比，XGBoost在分类受污染的压舱条件方面具有优越的性能。因此，与独立的XGBoost模型相比，LSTM- xgb模型显示出更高的效率，因为LSTM对时间序列温度数据的预测特性可以捕获更短的时间窗口来测量压载水表面温度并识别模式。此外，建立更粗略的压载污垢分类（将压载污垢分为三组而不是五组）显著提高了模型准确评估压载污垢状况的能力。

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引用次数: 0

Brittle failure evaluation of rocks under freeze–thaw cycles based on an energy-based method 基于能量法的冻融循环下岩石脆性破坏评价

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.trgeo.2026.101940

Tao Wen , Wanying Huang , Bocheng Zhang , Ningsheng Chen , Fengyun Wang

The importance of the evaluation of the brittleness under freeze–thaw cycle is reflected in the slope stability and the safety construction of infrastructure in cold region. There are few studies on rock brittleness in various engineering applications under freeze–thaw (F-T) cycles in cold regions. Herein, existing methods for rock brittleness evaluation are concluded and their limitations are identified. To address these limitations, a novel brittleness index (BI) that comprehensively considers the energy evolution throughout the entire stages is proposed. The effectiveness of the proposed BI is verified the suitability of proposed BI in different rock types by utilizing four datasets of varying rock compositions. Afterwards, the samples collected from the Qinghai-Tibet Plateau were subjected to the F-T test, the proposed BI is validated by comparing it with four existing BIs using the data of F-T cycle tests on conglomerate and sandstones. The results demonstrate that with increasing confining pressure (CP), all selected BIs exhibit a downward trend under the same F-T cycle. Moreover, different F-T cycles have significant influence on rock failure under the same CP, and the proposed BI exhibiting a more pronounced trend compared to other BIs. These findings provide valuable support for research on the rock brittleness in resource exploration and engineering construction assessment especially in cold regions.

冻融循环脆性评价的重要性体现在寒区边坡稳定性和基础设施安全建设中。目前对寒区冻融循环作用下各种工程应用中岩石脆性的研究较少。总结了现有的岩石脆性评价方法，并指出了其局限性。为了解决这些限制，提出了一种综合考虑整个阶段能量演化的新型脆性指数（BI）。利用四个不同岩石成分的数据集，验证了所提出的BI在不同岩石类型中的适用性。随后，对青藏高原采集的样品进行了F-T测试，并利用砾岩和砂岩的F-T循环测试数据与现有的4种BI进行了比较，验证了所提BI的有效性。结果表明：随着围压的增加，在相同的F-T循环下，所有选择的BIs均呈现下降趋势；在相同CP下，不同的F-T循环对岩石破坏有显著影响，且所提出的BI比其他BI表现出更明显的趋势。这些研究结果为资源勘探和工程建设评价中的岩石脆性研究提供了有价值的支持。

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引用次数: 0

Hydro-mechanical responses of irregular twin tunnels with unequal burial depths in anisotropic soil layer 各向异性土层中埋深不等的不规则双隧道的水力学响应

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-04-01 Epub Date: 2026-02-10 DOI: 10.1016/j.trgeo.2026.101933

Senlin Xie , Zhen Huang , Changqing Xia , Hao Zhang , Jie Shi , Xiangsheng Chen

Understanding the seepage-mechanical behavior of tunnels with complex geometries and layouts is essential for the safety and durability of underground structures in anisotropic soils. However, most existing studies focus on single circular tunnels under idealized conditions, while multi-tunnel interference, unequal burial depths, and noncircular sections-common in practical engineering-remain insufficiently addressed. This study develops a hybrid Physics-Informed Neural Network (with hard constraints)-Finite Element Method (PINN-FEM) framework to analyze the steady-state seepage and stress fields of anisotropic foundations containing dual-line tunnels with unequal depths and noncircular cross sections. The seepage continuity equation is first solved by the PINN to capture pore pressure distribution without mesh generation, and the predicted field is then interpolated and incorporated into the FEM as an external input to compute the stress-displacement response. This hybrid strategy combines the flexibility of PINN with the numerical robustness of FEM, achieving a balance between computational efficiency and physical accuracy. Results show that the PINN-predicted pore pressure agrees closely with reference solutions, confirming its effectiveness for complex boundary conditions. Results show that the PINN-predicted pore-pressure field agrees closely with reference solutions, achieving a global average L₂ error of 0.055 and a maximum relative error on the order of 10⁻³, demonstrating high accuracy under complex boundary conditions. A domain-size sensitivity analysis reveals that lateral boundary effects cannot be reliably assessed using a single universal criterion; however, a lateral extent of approximately five times the tunnel diameter provides a reasonable reference for preliminary model setup.tunnel number and burial-depth asymmetry dominate the hydro-mechanical response, producing changes of more than 60% in displacement and up to approximately 80% in stress components. Permeability anisotropy results in moderate variations (typically 15–40%) in stresses and displacements, whereas changes in cross-sectional shape mainly amplify local stress concentrations rather than global deformation. In addition, comparisons between constraint strategies confirm that hard-constrained PINNs markedly improve convergence stability and physical consistency relative to soft-constraint formulations. The proposed PINN–FEM framework provides an efficient and reliable tool for parametric and comparative hydro-mechanical analysis of complex tunnel systems in anisotropic soils.

了解具有复杂几何形状和布局的隧道的渗流力学行为对各向异性土壤中地下结构的安全性和耐久性至关重要。然而，大多数现有的研究都集中在理想条件下的单圆形隧道，而实际工程中常见的多隧道干扰、不均匀埋深和非圆形截面仍然没有得到充分解决。本研究建立了一种混合物理-神经网络（硬约束）-有限元（PINN-FEM）框架，用于分析非圆截面、等深双线隧道各向异性地基的稳态渗流和应力场。在不进行网格划分的情况下，首先利用PINN求解渗流连续性方程，获取孔隙压力分布，然后将预测场作为外部输入插值并纳入有限元计算中，计算应力-位移响应。这种混合策略结合了PINN的灵活性和FEM的数值鲁棒性，实现了计算效率和物理精度之间的平衡。结果表明，pinn预测的孔隙压力与参考解吻合较好，证实了其在复杂边界条件下的有效性。结果表明，pinn预测的孔隙压力场与参考解吻合较好，全局平均L2误差为0.055，最大相对误差为10−3，在复杂边界条件下具有较高的精度。区域大小敏感性分析表明，不能使用单一的通用标准可靠地评估横向边界效应；然而，横向范围约为隧道直径的五倍，为初步模型建立提供了合理的参考。隧道数和埋深不对称性主导着水-力学响应，产生超过60%的位移变化和高达约80%的应力分量变化。渗透率各向异性导致应力和位移的适度变化（通常为15-40%），而截面形状的变化主要放大了局部应力集中，而不是全局变形。此外，约束策略之间的比较证实，相对于软约束公式，硬约束pinn显著提高了收敛稳定性和物理一致性。所提出的PINN-FEM框架为各向异性土体中复杂隧道系统的参数化和对比水力力学分析提供了一种有效可靠的工具。

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引用次数: 0

Biocementation of road pavements: An experimental investigation through physical modeling and accelerated testing 道路路面的生物胶结：通过物理模型和加速测试的实验研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-01-23 DOI: 10.1016/j.trgeo.2026.101913

Tianzheng Fu, Stuart Kenneth Haigh

Biocementation, owing to its non-intrusive nature, holds great promise as a non-disruptive solution for improving road pavements, particularly for rehabilitating those experiencing deterioration. The present study provides a direct proof of concept for this application. Full-depth physical models of a three-layer pavement structure, uncemented and biocemented, were constructed and subjected to accelerated testing under increasing wheel loads, with laser scanning and particle image velocimetry (PIV) combined to monitor surface and subsurface deformation. The results showed that both models exhibited a depression in the wheel path and an upheave on the side. The enhanced structural integrity of the biocemented model allowed it to experience significantly reduced deformation while sustaining higher loads. PIV analysis of subsurface displacement and strain fields revealed distinct deformation mechanisms. The uncemented model experienced localized failure within the poorly compacted base with a predominantly contractive response, while the biocemented model involved an active, vertically displacing zone beneath the wheel that underwent volumetric dilation, which was laterally confined by a passive zone on the side. These findings clearly demonstrate the effectiveness of biocementation in improving the structural performance of pavements. However, low treatment efficiency under unsaturated conditions presents a critical challenge for field implementation and warrants further investigations.

由于其非侵入性，生物水泥作为改善道路路面的一种非破坏性解决方案具有很大的希望，特别是对于修复那些经历退化的道路。目前的研究为这一应用提供了一个直接的概念证明。构建了三层路面结构的全深度物理模型，包括未胶结和生物胶结，并在车轮载荷增加的情况下进行了加速测试，使用激光扫描和粒子图像测速（PIV）相结合来监测地表和地下变形。结果表明，两种模型均表现出轮径凹陷和侧凸。生物胶结模型的结构完整性增强，使其在承受更高载荷的同时显著减少变形。地下位移场和应变场的PIV分析揭示了不同的变形机制。未胶结模型在压实度差的基础上发生局部破坏，主要是收缩响应，而生物胶结模型涉及车轮下方的主动垂直位移区，该区域经历了体积扩张，侧向受到一侧被动区域的限制。这些发现清楚地证明了生物胶结剂在改善路面结构性能方面的有效性。然而，非饱和条件下的低处理效率对现场实施提出了关键挑战，需要进一步研究。

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引用次数: 0

Direct shear–DEM evaluation of basic oxygen furnace (BOF) slag for railway ballast 铁路道砟用碱性氧炉炉渣直接剪切- dem评价

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.trgeo.2026.101938

Elijah Adebayonle Aremu, Doszhan Tuzelbayev, Jong Kim, Sung-Woo Moon

Integrated large-scale direct shear tests and discrete element method (DEM) simulations were used to evaluate basic oxygen furnace (BOF) slag as a sustainable partial replacement for natural crushed-stone ballast. Laboratory tests provided validation targets for a specific BOF source under low confinement (30–70kPa), while DEM reproduced the gradation and angular shapes using clumped particles. The simulations were calibrated to the measured shear stress–strain curves and then used to probe micromechanics, including coordination number, strong/weak contact partition, and fabric anisotropy. Across 0–100% BOF by volume, peak shear strength and peak friction angle decreased with increasing BOF; however, mixtures with 20–40% BOF retained performance only marginally below natural stone. Microstructurally, BOF addition reduced coordination and peak fabric deviator, shortened force chains, and increased contact-orientation randomness—features that explain the strength reductions. A compact pre-peak constitutive relation between fabric deviator and stress ratio,

ϕ_{d} = a {(τ / σ_{n})}^{b}

, provided excellent fits for the overall and strong contact networks. These results offer mechanism-based guidance for mixture design: limited BOF substitution (20–40%) provides a practical balance supporting material-circularity potential while maintaining shear capacity within a narrow penalty band. The study demonstrates how DEM-informed fabric metrics, interpreted alongside large-scale testing, can support the adoption of industrial by-products in railway ballast without compromising key mechanical requirements.

采用大型直剪试验和离散元法（DEM）模拟相结合的方法，对碱氧炉（BOF）炉渣作为天然碎石压载物的可持续性部分替代进行了评价。实验室测试为低约束（30-70kPa）下的特定BOF源提供了验证目标，而DEM使用团块颗粒再现了梯度和角形状。将模拟结果与实测剪应力-应变曲线进行校准，然后用于探测微观力学，包括配位数、强弱接触分配和织物各向异性。在0 ~ 100%转炉体积范围内，峰值抗剪强度和峰值摩擦角随转炉体积的增大而减小；然而，含20-40% BOF的混合物保留的性能仅略低于天然石材。微观结构上，BOF的加入降低了织物的配位和峰值偏差，缩短了力链，增加了接触方向的随机性——这些特征解释了强度降低的原因。织物偏差与应力比之间存在紧密的峰前本构关系，即ϕd= A (τ/σn)b，为整体和强接触网络提供了良好的拟合。这些结果为混合料设计提供了基于机理的指导：有限的转炉替代（20-40%）提供了一个实际的平衡，支持材料循环潜力，同时将剪切能力保持在一个狭窄的惩罚带内。该研究展示了基于dem的织物指标，以及大规模测试的解释，如何在不影响关键机械要求的情况下，支持铁路道砟中工业副产品的采用。

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引用次数: 0

Numerical investigation of train-induced ground vibrations in ballastless embankment considering wheel–rail geometric nonlinearity 考虑轮轨几何非线性的无砟路堤列车诱发地面振动数值研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-01-31 DOI: 10.1016/j.trgeo.2026.101934

Zihao Jin , Wei Zhang , Xueyu Geng

Predicting train-induced ground vibrations is essential for assessing the environmental impact of high-speed rail systems. However, many existing numerical models rely on simplified wheel–rail interaction formulations, which can lead to unreliable predictions due to inaccurate representation of the excitation source. In this study, a novel three-dimensional (3D) Vehicle–Track–Embankment–Ground (VTEG) finite element (FE) model is developed, explicitly incorporating rail irregularities and fully coupled wheel–rail geometric interaction. The proposed model is validated against field measurements in terms of subgrade dynamic soil stresses and ground surface vibration velocities. A parametric case study identifies two characteristic velocities. Critical Velocity I (CV I) closely corresponds to the Rayleigh wave velocity of the weakest supporting soil layer, whereas Critical Velocity II (CV II), associated with the peak maximum dynamic displacement (MDD) of track, lies between the Rayleigh wave velocities of the softest ground layer and the embankment base. Comparative analyses show that a conventional 2.5D linear FE model provides adequate accuracy under weakly dynamic conditions (V ≤ CV I) but progressively underestimates the track MDD as train speed approaches CV II. At CV II, the peak MDD is underestimated by approximately 14.6% relative to the proposed 3D nonlinear model, with about 54% of this discrepancy attributable to reduced model dimensionality and the remaining 46% to linear wheel–rail contact assumptions. Furthermore, foundation reinforcement markedly increases both CV I and CV II and reduces the peak MDD by approximately 43.5%, thereby effectively mitigating resonance-like behaviour at ultra-high train speeds. In addition, foundation reinforcement significantly suppresses ground-borne vibrations and modifies the characteristics of surface wave propagation, producing more circular wavefronts within the reinforced zone while maintaining Mach-cone-type features outside. These findings provide quantitative guidance for vibration assessment, modelling strategy selection and mitigation design in high-speed railway engineering.

预测列车引起的地面振动对于评估高速铁路系统的环境影响至关重要。然而，许多现有的数值模型依赖于简化的轮轨相互作用公式，由于激发源的不准确表示，这可能导致不可靠的预测。在这项研究中，建立了一个新的三维（3D）车辆-轨道-堤岸-地面（VTEG）有限元（FE）模型，明确地考虑了轨道不规则性和完全耦合的轮轨几何相互作用。根据路基动土应力和地表振动速度的实测数据，验证了该模型的有效性。一个参数化的案例研究确定了两个特征速度。临界速度I （CV I）与最弱支撑土层的瑞利波速密切对应，而与轨道最大动力位移峰值（MDD）相关的临界速度II （CV II）位于最软土层和路堤基底的瑞利波速之间。对比分析表明，传统的2.5维线性有限元模型在弱动态条件下（V≤CV I）具有足够的精度，但随着列车速度接近CV II，其对轨道MDD的估计会逐渐低估。在CV II中，相对于提出的三维非线性模型，峰值MDD被低估了约14.6%，其中约54%的差异归因于模型维数的降低，其余46%归因于轮轨线性接触假设。此外，地基加固显著增加了CV I和CV II，并将峰值MDD降低了约43.5%，从而有效地缓解了超高列车速度下的类共振行为。此外，地基加固显著抑制了地面振动，改变了表面波的传播特性，在加固区域内产生更多的圆形波前，而在外部保持马赫锥型特征。研究结果为高速铁路工程的振动评估、建模策略选择和减振设计提供了定量指导。

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引用次数: 0

DIC-Based Investigation into Failure Mechanisms and Geogrid Optimization of Eccentrically Loaded Footings above Void 基于dic的空心上偏心支承破坏机理及土工格栅优化研究

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-02-05 DOI: 10.1016/j.trgeo.2026.101937

Changjie Liu , Heng Zhao , Zeyu Xu , Gaoqiao Wu , Yunhao Chen , Biao Luo , Chuhan Xie , Jie Xu , Minlong Zhou

Ground loss from road tunnelling beneath surface buildings can generate localized subsurface voids, threatening the serviceability and safety of shallow foundations. This study performs DIC-assisted laboratory model tests to investigate the bearing response of an eccentrically loaded strip footing in sand above a tunnelling-induced void, with geogrid reinforcement adopted as a mitigation measure. The experimental program is organized by the following dimensionless groups: the eccentricity ratio e/B, the void burial depth H/D, the void horizontal position S/D and the geogrid embedment and length ratios u/B and L/B. Full-field DIC observations clearly reveal the evolution of failure paths and disturbed zones and provide the first comprehensive set of full-field displacement maps for the coupled footing–void–geogrid system under eccentric loading. The results show that increasing e/B reduces the ultimate bearing capacity, intensifies footing rotation,　and shifts the disturbed zone toward the unloaded side. The failure mode is governed by the combined effects of the void and the footing influence zone. For example, when the footing influence zone overlaps with the void, the stress path tends to develop toward the void, and the ultimate bearing capacity decreases accordingly. When the cover thickness or the void’s horizontal offset exceeds the footing influence zone, the failure mode can be approximated as a “no-void” condition.Geogrid reinforcement markedly improves the capacity and exhibits optima in u/B and L/B: a distinct optimal u/B appears at larger e/B, whereas a plateau-type optimal range emerges at smaller e/B, the required L/B increases with e/B. Under the present conweuration, void effects become negligible when H/B≈3. For geogrid mitigation, the recommended embedment depth is u/B≈0.2–0.4 for e/B≳0.3 (with u/B≈0.2 at e/B = 0.4), and the plateau range is u/B≈0.6–1.2 for e/B ≤ 0.1, a practical reinforcement length is L/B≈8.

道路隧道在地表建筑物下开挖造成的地面损失会产生局部的地下空洞，威胁浅基础的使用能力和安全性。本研究进行了dic辅助的实验室模型试验，以研究隧道诱导空洞上方砂土中偏心加载条形基础的承载响应，并采用土工格栅加固作为缓解措施。试验方案按偏心比e/B、空隙埋深H/D、空隙水平位置S/D、土工格栅嵌入与长度比u/B和L/B进行无因次分组。现场DIC观测清晰地揭示了偏心荷载作用下地基-空洞-土工格栅耦合系统的破坏路径和扰动区演化过程，并首次提供了一套完整的现场位移图。结果表明：e/B的增大降低了地基的极限承载力，加剧了地基的转动，扰动区向卸荷侧偏移；破坏模式受空洞和基础影响区共同作用的支配。例如，当基础影响区与孔洞重叠时，应力路径有向孔洞方向发展的趋势，极限承载力相应降低。当覆盖层厚度或空洞水平偏移量超过基础影响区时，其破坏模式可近似为“无空洞”状态。土工格栅加筋显著提高了承载力，且在u/B和L/B均表现出最优，较大的e/B出现明显的最优u/B，较小的e/B出现平台型最优范围，所需的L/B随e/B增大而增大。当H/B≈3时，孔隙效应可以忽略不计。对于土工格栅，当e/B≥0.3时，推荐埋设深度为u/B≈0.2 ~ 0.4（当e/B = 0.4时，u/B≈0.2），当e/B≤0.1时，平台范围为u/B≈0.6 ~ 1.2，实际加固长度为L/B≈8。

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引用次数: 0

Efficient improvement of physicochemical properties and plant growth in sandy ecological substrates: performance and mechanisms of biochar-based materials 有效改善沙质生态基质的理化性质和植物生长：生物炭基材料的性能和机制

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-01-08 DOI: 10.1016/j.trgeo.2026.101901

Daxiang Liu , Yexiong Zhou , Zhihai Xu , Qiangbing Song , Yuliang Qin , Zuosen Luo , Yao Xiao , Xudong Hu , Dong Xia , Liming Liu , Mingtao Zhou , Huafeng Deng , Wennian Xu , Yueshu Yang

Engineering damaged exposed slopes often experience severe soil degradation, with soils predominantly composed of weathered bedrock. When such soils are used as ecological slope protection substrates, they commonly exhibit inadequate geotechnical strength and low fertility, which severely restrict the effectiveness and long-term durability of ecological slope protection engineering. Addressing this challenge, this study investigates the potential of combining biochar (BC) and microbially induced calcium precipitation (MICP) to enhance the structural and ecological performance of sandy ecological substrates (SSs). A series of pumping-grouting and plant cultivation experiments were conducted to evaluate the individual and synergistic effects of BC and MICP. Results showed that BC improved porosity and plant growth but reduced dry density, shear strength, and disintegration resistance. MICP significantly increased mechanical strength but inhibited plant growth. When combined, BC facilitated microbial adhesion and CaCO₃ precipitation, enhancing MICP performance while reducing BC degradation. However, excessive BC content negatively impacted substrate strength and mineralization efficiency. Optimization experiments identified ideal conditions: 1-2% BC by mass, bacterial concentration at OD₆₀₀ = 1.0, and calcium acetate and urea at 1.0 mol/L. This optimized scheme significantly improves the structural and ecological performance of SSs with minimal adverse effects on vegetation, demonstrating strong potential for practical ecological slope engineering applications.

工程破坏的裸露边坡往往经历严重的土壤退化，土壤主要由风化的基岩组成。此类土作为生态护坡基质时，普遍存在岩土强度不足、肥力低的问题，严重制约了生态护坡工程的有效性和长期耐久性。针对这一挑战，本研究探讨了生物炭（BC）和微生物诱导钙沉淀（MICP）相结合提高沙质生态基质（SSs）结构和生态性能的潜力。通过一系列的灌浆和植物栽培试验，评价了BC和MICP的个体效应和协同效应。结果表明，BC改善了气孔率和植株生长，但降低了干密度、抗剪强度和抗崩解性。MICP显著提高了植物的机械强度，但抑制了植物的生长。当联合使用时，BC促进了微生物的粘附和CaCO3的沉淀，提高了MICP的性能，同时减少了BC的降解。然而，过量的BC含量会对基质强度和矿化效率产生负面影响。优化实验确定了理想条件：1-2% BC质量，细菌浓度OD600 = 1.0，乙酸钙和尿素浓度1.0 mol/L。该优化方案显著改善了边坡的结构和生态性能，对植被的不利影响最小，具有很强的生态边坡工程应用潜力。

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引用次数: 0

Mechanistic evaluation of reclaimed asphalt pavement (RAP) as base course: the role of binder aging in the response of RAP-virgin aggregate blends 再生沥青路面作为基层的力学评价：粘结剂老化在再生沥青路面-原生骨料共混物响应中的作用

IF 5.5 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2026-03-01 Epub Date: 2026-01-30 DOI: 10.1016/j.trgeo.2026.101925

Saad Ullah , Adnan Sadiq , Asad Mehmood , Debanjana Ghosh , Burak F. Tanyu

This study investigates the influence of binder properties of reclaimed asphalt pavement (RAP) specifically binder content and oxidative aging on the performance of RAP-virgin aggregate (VA) blends through repeated load triaxial (RLT) testing. RAP samples from four regional sources were characterized using standard index property tests, binder content determination, and Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy to quantify binder aging via an aging index. RAP-VA blends were prepared at as-is gradations in proportions of 20%, 30%, 60%, and 80% RAP, and tested under stress conditions representing higher, medium, and low traffic pavement structures representative of Illinois pavement and traffic conditions. Results demonstrate that PD performance depends on the interplay between binder content and aging index, rather than binder content alone. RAP with higher aging indices consistently exhibited superior resistance to deformation, even at high RAP contents. The threshold RAP content for deformation resistance at optimum moisture and maximum dry density, beyond which permanent deformation begins to increase, was found to vary depending on the pavement structure and traffic level typically ranging from 20 to 40% for pavements with thicker asphalt layers (high-volume roads) and 20–80% for thinner asphalt layers (medium- to low-volume sections). This variation arises primarily from differences in the binder characteristics of each RAP source, including binder content and aging index. RAP with higher binder content or a more oxidized (aged) binder tends to exhibit a stiffer yet more brittle response, which alters the blend’s deformation behavior and shifts the threshold RAP content at which performance begins to decline.

通过三轴重复载荷（RLT）试验，研究了再生沥青路面（RAP）粘结剂性能，特别是粘结剂含量和氧化老化对再生沥青-原生骨料（VA）共混物性能的影响。使用标准指数性能测试、粘合剂含量测定和衰减全反射傅里叶变换红外（ATR-FTIR）光谱对来自四个地区的RAP样品进行表征，通过老化指数量化粘合剂的老化。以20%、30%、60%和80% RAP的比例按原样配制RAP- va共混物，并在代表伊利诺伊州路面和交通状况的高、中、低交通路面结构的应力条件下进行测试。结果表明，PD的性能取决于粘结剂含量和老化指数的相互作用，而不仅仅是粘结剂含量。老化指数高的RAP，即使在RAP含量高的情况下，也表现出较好的抗变形性能。研究发现，在最佳水分和最大干密度下抗变形的阈值RAP含量（超过此值，永久变形开始增加）根据路面结构和交通水平而变化，对于较厚的沥青层（高容量道路），RAP含量通常为20 - 40%，对于较薄的沥青层（中低容量路段），RAP含量为20 - 80%。这种变化主要是由于每个RAP源的粘结剂特性不同，包括粘结剂含量和老化指数。粘结剂含量较高或氧化（老化）程度较高的RAP往往表现出更硬但更脆的响应，这改变了共混物的变形行为，改变了性能开始下降的临界RAP含量。

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引用次数: 0