Computers and Geotechnics最新文献_第4页

Adaptive FEM-SPH for anchored slope failure with fractal dimension crack analysis 基于分维裂纹分析的自适应有限元- sph法锚固边坡破坏

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107872

Zhengnan Tu , Qiang Xie , Jun Feng , Hexing Zhang , Yucheng Chen

Anchored slopes are widely used in geotechnical engineering, yet their failure mechanisms under ultimate loading-particularly crack evolution and slip-surface formation-remain insufficiently understood. This study develops an adaptive FEM-SPH coupling framework governed by a maximum-principal-strain criterion and validates it against a laboratory pull-out test on a single BFRP anchor. The method automatically converts excessively distorted finite elements into SPH particles while preserving stress and damage continuity, thus combining FEM accuracy in the small-strain regime with SPH robustness at large deformations. Validation confirms its capability to reproduce the measured load–displacement response and shear-damage evolution with high fidelity. A prototype slope from the Yunnan high-speed railway project was simulated under a unified crest-displacement loading of 500 mm for four anchoring layouts. The cross-arranged scheme achieves the highest peak contact stress and residual capacity due to multidirectional constraint, while gently inclined anchors mobilize higher axial forces and steeply inclined anchors exhibit faster crack-complexity growth. The box-counting fractal dimension D effectively quantifies the spatial evolution of crack networks, providing a geometric measure of damage complexity and its progression under large deformation, to be interpreted together with conventional mechanical responses. The D-S evolution exhibits a three-stage, nonlinear development of crack-network complexity and reveals layout-dependent differences in the growth rate and saturation of cracking, with the cross-arranged layout, within the present parameter space, combining the slowest complexity growth and a smooth approach to saturation with the highest global bearing capacity. From an engineering standpoint, the findings provide comparative references for representative anchorage layouts in large-deformation marly slopes.

锚固边坡在岩土工程中有着广泛的应用，但其在极限荷载作用下的破坏机制，特别是裂缝演化和滑面形成机制，目前还没有得到充分的了解。本研究开发了一个由最大主应变准则控制的自适应FEM-SPH耦合框架，并对单个BFRP锚进行了实验室拉拔试验。该方法在保持应力和损伤连续性的同时，将过度变形的有限元自动转换为SPH粒子，从而将小应变状态下的FEM精度与大变形状态下的SPH鲁棒性相结合。验证证实其能够高保真地再现所测载荷-位移响应和剪切-损伤演变。以云南高铁工程原型边坡为例，对4种锚固布置方式在500 mm统一顶移荷载下进行了模拟。由于多向约束，交叉布置方案的峰值接触应力和残余承载力最高，缓倾斜锚杆动员的轴向力更高，急倾斜锚杆的裂纹复杂性增长更快。盒计数分形维数D有效地量化了裂纹网络的空间演化，提供了大变形下损伤复杂性及其进展的几何度量，可以与常规力学响应一起解释。D-S演化表现为裂缝网络复杂性的三阶段非线性发展，并揭示了裂缝扩展速率和饱和度的分布差异，在当前参数空间内，以交叉布置的布局，结合了最慢的复杂性增长和最高的全局承载能力的平滑饱和。从工程角度看，研究结果可为具有代表性的大变形泥质边坡锚固布置提供比较参考。

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引用次数: 0

Three-dimensional fracture modelling of heterogeneous and anisotropic rock material under true triaxial compression 真三轴压缩条件下非均质和各向异性岩石材料三维裂缝建模

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107862

Hui Li, Shanyong Wang

Underground excavation inevitably disturbs natural in-situ stress equilibrium of rocks, leading to localized deformation, fracture initiation, and potential large-scale failure. Understanding the failure mechanisms of rock under complex stress states is of great importance for ensuring the safety and stability of underground structures. To this end, a mesoscale numerical approach combining Weibull random fields with a hybrid phase-field model is adopted to investigate the failure mechanisms of heterogeneous rock materials under true triaxial compression. The isotropic model is further extended to anisotropic formulation by incorporating an anisotropic crack surface density function to account for directional fracture behaviour. First, the isotropic model is calibrated against experimental data by simulating triaxial compression of intact cuboid sandstone specimens, with the effects of confining stress and mesoscale heterogeneity systematically analysed. Next, the influence of pre-existing notches on 3D crack propagation is studied using the calibrated model. Finally, the anisotropic model is used to simulate the failure of intact and notched laminated rocks. It is found that rock fracture behaviour is governed by the combined effects of confining stress, mesoscale heterogeneity, and notch geometry. The incorporation of anisotropic fracture toughness enables directional control of crack propagation along bedding planes, successfully capturing joint-induced compression–shear failure. The developed approach provides a robust tool for simulating 3D failure in heterogeneous and anisotropic rocks under complex loading conditions.

地下开挖不可避免地破坏岩石的天然地应力平衡，导致局部变形、起裂，并可能发生大规模破坏。了解岩石在复杂应力状态下的破坏机制，对保证地下结构的安全稳定具有重要意义。为此，采用威布尔随机场与混合相场模型相结合的中尺度数值方法研究非均质岩石材料在真三轴压缩下的破坏机制。通过加入各向异性裂缝表面密度函数来解释定向断裂行为，各向同性模型进一步扩展为各向异性公式。首先，通过模拟完整长方体砂岩试件的三轴压缩，根据实验数据对各向同性模型进行校正，系统分析围应力和中尺度非均质性对模型的影响；其次，利用校正后的模型研究了预先存在的缺口对三维裂纹扩展的影响。最后，采用各向异性模型对完整和缺口层状岩石的破坏进行了模拟。研究发现，岩石断裂行为受围应力、中尺度非均质性和缺口几何形状的综合影响。各向异性断裂韧性的结合使裂缝沿顺层面扩展的定向控制成为可能，成功捕获节理引起的压剪破坏。所开发的方法为模拟复杂加载条件下非均质和各向异性岩石的三维破坏提供了一个强大的工具。

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引用次数: 0

Transient responses of multilayered transversely isotropic half-space subjected to a rectangular oblique impact loading 多层横向各向同性半空间在矩形斜冲击载荷作用下的瞬态响应

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107875

Ye Yang , Mincai Jia , Qun Yan

To address the oblique impact effect in engineering, this paper develops a theoretical solution for non-axisymmetric transient problems based on a three-dimensional Cartesian coordinate system. By combining the dynamic differential equations with displacement potential functions, the expressions for the displacement responses of single-layered soil are derived via the double Fourier-Laplace transformation. The global stiffness matrix for a multilayered half-space is assembled from the analytically derived layer-element stiffness matrices. Transient displacement and stress responses in the time domain are then obtained through inverse transform algorithms. The accuracy of the proposed method is validated by comparing the solutions with the calculation results from finite difference method. Furthermore, the effects of transversely isotropic parameters, loading embedment depth, and impact inclination angle on the dynamic response of the soil are studied using the presented approach.

针对工程中存在的斜冲击效应，提出了一种基于三维直角坐标系的非轴对称瞬态问题的理论解。将动力微分方程与位移势函数相结合，通过双傅里叶-拉普拉斯变换导出了单层土的位移响应表达式。将解析导出的层单元刚度矩阵组合成多层半空间的整体刚度矩阵。然后通过逆变换算法得到时域内的瞬态位移和应力响应。通过与有限差分法计算结果的比较，验证了所提方法的准确性。在此基础上，研究了横向各向同性参数、荷载埋置深度和冲击倾角对土体动力响应的影响。

引用次数: 0

A Eulerian multiphase model for collapse and segregation of bidisperse granular columns 双分散颗粒柱崩塌和偏析的欧拉多相模型

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107877

Lei Niu , Liyan Zhang , Shuchen Cai , Kang He , Xin Chen

Granular collapse (landslide) is generally destructive to marine infrastructure and ecosystems. Although particle size distribution exerts a strong influence on collapse behavior, the specific mechanisms through which polydispersity affects granular collapse are not yet fully understood. In this study, a Eulerian multiphase model is developed to simulate the collapse of the bidisperse granular column. A bidisperse constitutive law that combines kinetic theory of granular flow (KTGF) and frictional dilation/contraction rheology is used to close the granular stresses. The KTGF incorporates anisotropic particle collisions and interstitial fluid drag, and the adopted drag model remains effective across dilute to dense particle volume fractions. The fluid turbulence model further accounts for density stratification arising from non-uniformity in the particle volume fraction. Both monodisperse and bidisperse granular collapse experiments were performed, and the predicted flow fields, runout distances, and segregation patterns show good agreement with the experimental observations. The results indicate that a higher proportion of coarse particles leads to a greater total runout distance and more pronounced segregation during bidisperse column collapse. Moreover, the choice of frictional viscosity model significantly influences the morphological evolution, underscoring the importance of accurately representing dilation and contraction effects. Overall, this study develops a multiphase framework for analyzing bidisperse granular collapse, providing valuable insights for hazard assessment and mitigation.

颗粒崩塌（滑坡）对海洋基础设施和生态系统具有普遍的破坏性。尽管粒径分布对颗粒坍塌行为有很大影响，但多分散性影响颗粒坍塌的具体机制尚未完全了解。本文建立了欧拉多相模型来模拟双分散颗粒柱的崩塌。结合颗粒流动动力学理论（KTGF）和摩擦扩张/收缩流变学的双分散本构律来关闭颗粒应力。KTGF考虑了各向异性颗粒碰撞和间隙流体阻力，所采用的阻力模型在稀颗粒体积分数和致密颗粒体积分数之间仍然有效。流体湍流模型进一步解释了由颗粒体积分数的不均匀性引起的密度分层。进行了单分散和双分散颗粒坍塌实验，预测的流场、跳动距离和偏析模式与实验结果吻合较好。结果表明：粗颗粒比例越高，双分散柱坍塌过程中总跳动距离越大，偏析越明显；此外，摩擦粘度模型的选择显著影响形态演变，强调了准确表征扩张和收缩效应的重要性。总的来说，本研究开发了一个多阶段框架来分析双分散颗粒坍塌，为危害评估和缓解提供了有价值的见解。

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引用次数: 0

A GSA-ML hybrid framework combined key geological parameters selection for deformation prediction of fractured rock slopes 结合关键地质参数选择的GSA-ML混合框架用于裂隙岩质边坡变形预测

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107876

Wenxiu Wang , Huanling Wang , Yizhe Wu , Chenglong Yang , Wei Bao , Yuxuan Liu

The deformation prediction of fractured rock slopes is a key challenge in hydropower engineering due to the heterogeneity and stochastic distribution of fracture systems. Traditional approaches often struggle to identify dominant fracture parameters and maintain predictive accuracy while preserving geological interpretability. This study proposes a hybrid feature selection and prediction framework that integrates Discrete Fracture Network (DFN) modeling, Finite Difference Method (FDM), Global Sensitivity Analysis (GSA), and Extreme Gradient Boosting (XGBoost). Eighteen fracture-related geometric and mechanical parameters were initially considered, with maximum slope displacement from DFN-FDM simulations as the output. Sensitivity ranking was performed using Pearson correlation, Sobol variance-based index, and PAWN density-based method (Probabilistic Analysis of Whisker Numbers). The results indicate that 11 parameters dominate slope deformation, reflecting both geometric configuration and mechanical heterogeneity. Based on ranked features, XGBoost surrogate models were established and evaluated through 10-fold cross-validation. The GSA-XGBoost achieves the lowest error, outperforming both the original model and PCA-based (Principal Component Analysis) surrogate model, while reducing dimensionality and retaining geological interpretability. Application to a fractured slope at BDa Hydropower Station demonstrates the framework’s capacity for parameter prioritization and reliable deformation prediction. This approach provides practical guidance for slope stability evaluation and support design in fractured rock masses.

由于裂隙系统的非均质性和随机性，裂隙边坡的变形预测是水电工程中的一个关键问题。传统方法往往难以确定主要裂缝参数，并在保持地质可解释性的同时保持预测精度。本研究提出了一个混合特征选择和预测框架，该框架集成了离散裂缝网络（DFN）建模、有限差分法（FDM）、全局灵敏度分析（GSA）和极端梯度增强（XGBoost）。最初考虑了18个与裂缝相关的几何和力学参数，并将DFN-FDM模拟的最大边坡位移作为输出。采用Pearson相关性、基于Sobol方差的指数和基于PAWN密度的方法（须数概率分析）进行敏感性排序。结果表明，11个参数主导了边坡变形，反映了边坡的几何形态和力学非均质性。基于排序特征，建立XGBoost代理模型，并通过10次交叉验证对模型进行评价。GSA-XGBoost实现了最低的误差，优于原始模型和基于pca（主成分分析）的代理模型，同时降低了维数并保留了地质可解释性。通过对BDa水电站断裂边坡的应用，验证了该框架的参数优选能力和可靠的变形预测能力。该方法对裂隙岩体边坡稳定性评价和支护设计具有实际指导意义。

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引用次数: 0

Improved p-y curve modeling for large-diameter monopiles in asymmetric scour conditions in sandy soils 沙质土非对称冲刷条件下大直径单桩的改进p-y曲线建模

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107880

Ben Wu, Siau Chen Chian

Scour is a critical factor affecting the bearing capacity of monopile foundations for offshore wind turbines (OWTs). Influenced by factors such as flow direction, turbulence structures and sediment heterogeneity, the geometry of scour holes often exhibit asymmetry. This study investigates the effects of geometric asymmetry of scour holes on the bearing capacity of large-diameter monopiles through the finite element method (FEM) in sandy soil. A self-developed Python Application Programming Interface (Python-API) program is implemented to automatically extract p-y curves from FEM results. The proposed FEM approach is validated through comparison with existing centrifuge test data. A series of parametric analyses is subsequently conducted, revealing that scour hole asymmetry has a minor influence on monopile deformation and the location of rotation center, but has a pronounced impact on the ultimate soil resistance. Among all geometric parameters, the ultimate soil resistance is most sensitive to variations in depth asymmetry, whereas the effects of width and slope asymmetry are negligible. Under the combined influence of pile diameter, the depth asymmetry continues to exhibit a strong correlation with ultimate soil resistance. Findings from the parametric analyses are adopted to improve the existing p-y curve model, which is subsequently validated against existing centrifuge tests and analytical solutions.

冲刷是影响海上风力发电机组单桩基础承载力的重要因素。受水流方向、湍流结构和泥沙非均质性等因素的影响，冲刷孔的几何形状往往呈现不对称性。采用有限元方法研究了砂质土中冲刷孔几何不对称对大直径单桩承载力的影响。实现了自行开发的Python应用编程接口（Python- api）程序，可自动从有限元结果中提取p-y曲线。通过与现有离心机试验数据的对比，验证了所提出的有限元方法的有效性。随后进行的一系列参数分析表明，冲刷孔不对称对单桩变形和旋转中心位置的影响较小，但对极限土抗力的影响较大。在所有几何参数中，土壤极限阻力对深度不对称最为敏感，而宽度和坡度不对称的影响可以忽略不计。在桩径的综合影响下，桩深不对称继续与极限土阻力表现出较强的相关性。采用参数分析的结果来改进现有的p-y曲线模型，随后根据现有的离心机试验和分析解进行验证。

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引用次数: 0

Nonlocal binary-medium constitutive model for quasibrittle materials: A framework with implicit gradient enhancement 准脆性材料的非局部二元介质本构模型：隐式梯度增强框架

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107885

Yanbin Chen , Enlong Liu , Ziyin Cai

To address the pathological mesh dependency inherent in strain-softening simulations of quasibrittle materials, this paper presents a novel implicit gradient-enhanced computational framework for nonlocal binary-medium models. The core innovation lies in the synergistic integration of gradient-enhanced regularization with the multiscale homogenization theory underpinning binary-medium models. This approach preserves the sound physical foundation of the constitutive theory while effectively remedying non-objectivity in localized failure analysis through a Helmholtz-type partial differential equation. Within this regularized framework, a new nonlocal binary-medium constitutive model is developed. It comprises a porous elastic medium governed by Hashin–Shtrikman upper bounds and an elastic–perfectly plastic frictional medium with an innovative yield criterion, homogenized via an extended Mori–Tanaka scheme. Critically, to capture complex breakage modes, the model introduces an equivalent strain measure driven by the Unified Strength Theory. This novel feature enables the model to account for the influences of hydrostatic pressure and the stress Lode angle, which are crucial aspects often overlooked in previous models. Numerical investigations, implemented via a Bubnov–Galerkin scheme, confirm that the gradient-enhanced framework ensures mesh-objective solutions during strain-softening regimes. The model successfully replicates a comprehensive suite of quasibrittle behaviors, including multi-stage stress–strain responses, stiffness degradation, tension-compression asymmetry, and sensitivities to both confining pressure and the Lode angle. This work establishes a theoretically rigorous and computationally robust paradigm for modeling breakage progression, significantly advancing the predictive accuracy for engineering applications involving localized failure and material instability.

为了解决准脆性材料应变软化模拟中固有的病态网格依赖，本文提出了一种新的隐式梯度增强计算框架，用于非局部二元介质模型。核心创新在于梯度增强正则化与支撑二元介质模型的多尺度均匀化理论的协同集成。该方法既保留了本构理论的良好物理基础，又有效地弥补了局部破坏分析中通过亥姆霍兹型偏微分方程进行的非客观性问题。在此正则化框架下，提出了一种新的非局部二元介质本构模型。它包括一个由Hashin-Shtrikman上界控制的多孔弹性介质和一个具有创新屈服准则的弹塑性摩擦介质，通过扩展的Mori-Tanaka方案进行均匀化。关键是，为了捕捉复杂的破坏模式，该模型引入了由统一强度理论驱动的等效应变测量。这一新颖的特征使模型能够考虑静水压力和应力Lode角的影响，这是以前模型中经常忽略的关键方面。通过Bubnov-Galerkin格式实施的数值研究证实，梯度增强框架确保了应变软化过程中的网格目标解。该模型成功地复制了一套全面的准脆性行为，包括多阶段应力-应变响应、刚度退化、拉压不对称以及对围压和Lode角的敏感性。这项工作建立了一个理论上严谨、计算上稳健的断裂过程模型，显著提高了涉及局部破坏和材料不稳定的工程应用的预测精度。

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引用次数: 0

Phase field modeling of fracture propagation upon cavity pressurization in layered rock 层状岩石空腔加压作用下裂缝扩展的相场模拟

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-31 DOI: 10.1016/j.compgeo.2025.107883

Lingfu Liu , Zahera Jabeen , Chloé Arson

Understanding the failure mechanisms that govern fracture propagation in layered rocks is essential for predicting fracture geometry and optimizing subsurface operations. This study presents a phase-field modeling framework to systematically investigate the effects of stiffness contrast, fracture energy release rate, and in-situ stress on quasi-static fracture propagation around pressurized cavities embedded in layered rock systems. A modified strain energy decomposition scheme is introduced to distinguish between tensile (Mode I) and shear (Mode II) failure, which makes it possible to effectively capture mixed-mode fracture patterns. Simulation results reveal several key insights: (1) In homogeneous media, localized fractures that initiate from a pressurized cavity propagate in Mode I, while deviatoric strain energy may lead to extensive partially damaged zones under high compressive in-situ stresses; (2) Material heterogeneity, particularly variations in Young’s modulus and shear fracture energy release rate, significantly influences fracture paths, branching, and transitions in failure mode; (3) In rock masses that contain a soft and weak interlayer (similar to a vein), high stiffness contrast and low shear resistance in the thin interlayer can trigger fracture bifurcation and lead to shear-dominated branch formation within the interlayer. This study provides mechanistic insights into fracture deflection, arrest, and bifurcation phenomena that are critically important, yet often inadequately captured by conventional modeling approaches.

了解层状岩石中控制裂缝扩展的破坏机制对于预测裂缝几何形状和优化地下作业至关重要。该研究提出了一个相场建模框架，系统地研究了刚度对比、裂缝能量释放率和地应力对层状岩石系统中受压腔周围准静态裂缝扩展的影响。引入了一种改进的应变能分解方案来区分拉伸（I型）和剪切（II型）破坏，从而可以有效地捕获混合模式断裂模式。模拟结果揭示了以下几个关键问题：(1)在均质介质中，受压空腔产生的局部裂缝以I型扩展，而在高压地应力下，偏应变能可能导致大面积的部分损伤区；(2)材料的非均质性，特别是杨氏模量和剪切断裂能量释放率的变化，显著影响断裂路径、分支和破坏模式的转变；(3)在含有软弱夹层（类似于矿脉）的岩体中，薄夹层的高刚度对比和低剪切阻力可触发裂缝分叉，导致夹层内以剪切为主的分支形成。该研究提供了裂缝挠曲、止裂和分叉现象的机理见解，这些现象非常重要，但传统的建模方法往往无法充分捕捉到。

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引用次数: 0

Formulation and implementation of a gradation-state-dependent constitutive model for crushable particles under monotonic proportional loadings 单调比例加载下可破碎颗粒级配本构模型的建立与实现

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-29 DOI: 10.1016/j.compgeo.2025.107858

Yaolan Tang , Zongce Li , Zhihang Li , Jiarui Chen , Chunshun Zhang , Dapeng Wang

This study presents a gradation-state-dependent constitutive model for crushable granular materials, formulated for monotonic proportional loading, and implements it within a finite-element framework. An improved gradation evolution law is first developed, featuring a simplified mathematical form and a direct parameter-calibration procedure. Next, the Lode-angle dependence of the critical stress ratio is captured via a newly derived g(θ) function, and a refined relation for the critical-state void ratios is introduced accordingly. A closed-form expression for the tensorial tangent stiffness is then derived, and a self-adaptive integration algorithm is incorporated into the UMAT implementation to enhance numerical robustness and computational efficiency. Overall, the proposed model and numerical approach provide a framework for simulating the mechanical behaviour of crushable granular materials, offering potential for further implementation in geotechnical and engineering analyses.

本研究提出了可破碎颗粒材料的梯度状态相关本构模型，为单调比例加载制定，并在有限元框架内实现。提出了一种改进的梯度演化规律，简化了数学形式，采用了直接的参数标定方法。其次，通过新导出的g（θ）函数捕获临界应力比的Lode-angle依赖关系，并相应地引入了临界状态空隙比的精炼关系。推导了张拉切线刚度的封闭表达式，并将自适应积分算法引入到UMAT实现中，以提高数值鲁棒性和计算效率。总的来说，所提出的模型和数值方法为模拟可破碎颗粒材料的力学行为提供了一个框架，为进一步在岩土和工程分析中实施提供了潜力。

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引用次数: 0

Modeling mesoscopic homogenization of bentonite pellet/powder mixture: inclusion of pellet expansion and powder compression deformation effects 膨润土颗粒/粉末混合物的细观均匀化建模：包含颗粒膨胀和粉末压缩变形的影响

IF 6.2 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-12-29 DOI: 10.1016/j.compgeo.2025.107869

Rong-Sheng Deng , Wei-Min Ye , Bao Chen , Yong-Gui Chen , Qiong Wang

The low-density zones generated during the hydration of bentonite pellet/powder mixture could serve as potentially preferential paths for the radionuclide leakage. Currently utilized average dry density index is deemed insufficient for characterizing dynamic evolution of heterogeneous distribution. Also neglecting the effects of capillary water retention mechanism on hydraulic behavior leads to an inability to obtain a realistic water transfer in response to pellet expansion and powder compression. In this work, the mixture was discretized into a finite number of periodic arrangements of RVE units, each composed of an individual pellet and its adjacent powders. The effects of void ratio changes induced by hydration were incorporated into the existing SWRC model. An improved hydraulic model associated with capillary water retention was established. Meanwhile, interactions between the pellet and adjacent powders were analyzed using two independent sets of stress spaces. Eventually, a mesoscale double-structure hydro-mechanical model was proposed under the framework of the BExM constitutive model. The formulation was applied to model the hydro-mechanical behaviour of two tested mixtures characterized by different initial heterogeneities. Validations were made through reproducing unsaturated hydraulic behaviour, time-dependent swelling pressure profiles, and the transition from an initial granular state to a final homogenized state.

膨润土颗粒/粉末混合物水化过程中产生的低密度区可能是放射性核素泄漏的潜在优先路径。目前使用的平均干密度指数不足以表征非均质分布的动态演变。同时，由于忽略了毛细保水机制对水力特性的影响，导致无法获得球团膨胀和粉末压缩时的真实水传递。在这项工作中，混合物被离散成有限数量的周期性RVE单元，每个单元由单个颗粒及其相邻粉末组成。将水化引起的孔隙率变化的影响纳入现有的SWRC模型。建立了一种改进的毛细管保水性水力模型。同时，利用两组独立的应力空间分析了颗粒与相邻粉末之间的相互作用。最后，在BExM本构模型的框架下，提出了中尺度双结构水力学模型。该公式用于模拟两种具有不同初始非均质性的试验混合物的水力学行为。通过再现非饱和水力行为、随时间变化的膨胀压力曲线，以及从初始颗粒状态到最终均质状态的转变，进行了验证。

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引用次数: 0