International Journal for Numerical and Analytical Methods in Geomechanics最新文献

{"title":"Shakedown Limit Analysis of Layered Slab Track Substructures","authors":"Qingzhi Ye, Ge Yang, David P. Connolly, Qiang Luo, Kaiwen Liu, Tengfei Wang","doi":"10.1002/nag.70108","DOIUrl":"https://doi.org/10.1002/nag.70108","url":null,"abstract":"Shakedown analysis provides a mechanistic criterion for evaluating the long‐term stability of geomaterials subjected to infinite loading cycles, such as those induced by highways and railways. This study focuses on prefabricated slab tracks in high‐speed rail and introduces a computational method that explicitly considers stress responses at two critical locations: structural expansion joints and continuous slabs. Although expansion joints have occasionally been mentioned in prior studies, their role in shakedown analysis has not been systematically investigated. Addressing this gap, the present work extends the analysis to better reflect actual service conditions of slab tracks. By superimposing computed stress fields with self‐weight stresses, shakedown analyses of a two‐layer subgrade system were performed under varying soil parameters, following Melan's lower‐bound theorem. Results show that the trackbed surface is the most critical stress location. When the surface friction angle increases from 30° to 60°, shakedown capacity improves by about 32%, demonstrating that enhancing soil strength can significantly extend slab track design life. In contrast, increasing the stiffness ratio between the surface and bottom layers markedly reduces shakedown capacity, highlighting the importance of controlling stiffness contrasts within the subgrade. Thickness ratio variations also influence capacity, though less strongly. For practical application, a simplified closed‐form solution is proposed to estimate the bounds of shakedown axle loads at different train speeds. Overall, this study quantifies the sensitivity of shakedown capacity to key soil parameters and demonstrates that expansion joints play a pivotal role in governing track performance, thereby guiding safer, more durable slab track subgrades.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145295299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Nonlinear Stiffness of Granular Materials: A DEM Perspective on Stress Path Dependence","authors":"Hechen Zhou, Xiaoqiang Gu, Jing Hu","doi":"10.1002/nag.70105","DOIUrl":"https://doi.org/10.1002/nag.70105","url":null,"abstract":"While the effect of stress path on the nonlinear behavior of granular materials has long been recognized, its influence on stiffness degradation remains not fully understood and has not been systematically explored using the discrete element method (DEM) at the microscale. This study employs DEM to simulate triaxial tests and investigate the underlying mechanisms of stress path‐dependent nonlinear stiffness. The evolutions of microscopic parameters, including mechanical coordination number (<jats:italic>MCN</jats:italic>), contact slippage ratio (<jats:italic>R</jats:italic><jats:sub>s</jats:sub>), and anisotropies of contact normal and contact forces, were monitored. The results show that stress path significantly influences shear stiffness. At very small strain, shear stiffness is consistent across different stress paths under initial isotropic stress states but diversifies under anisotropic conditions. At small‐to‐medium strain, stiffness degradation rates vary with stress path and are further affected by initial stress condition and relative density. For isotropic stress states, paths associated with higher average normal contact force exhibit larger shear stiffness, lower <jats:italic>R</jats:italic><jats:sub>s</jats:sub> and higher <jats:italic>MCN</jats:italic>. By contrast, under anisotropic stress states, unloading paths demonstrate higher stiffness than loading paths, with a rapid decrease of <jats:italic>R</jats:italic><jats:sub>s</jats:sub> due to reverse particle motions. The influence of on stiffness diminishes in anisotropic conditions, making <jats:italic>R</jats:italic><jats:sub>s</jats:sub> and <jats:italic>MCN</jats:italic> the dominant factors, where higher <jats:italic>MCN</jats:italic> and lower <jats:italic>R</jats:italic><jats:sub>s</jats:sub> correspond to greater stiffness. A reference shear strain characterizing contact slippage is introduced, based on which several quantitative relationships are proposed to link contact slippage with stiffness degradation.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"127 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalized Thermo‐Hydro‐Mechanical Responses of Functional Gradient Pipeline‐Surrounding Soil System Considering Interfacial Conditions","authors":"Zhangna Xue, Hongtao Zhang, Jianlin Liu, Minjie Wen","doi":"10.1002/nag.70107","DOIUrl":"https://doi.org/10.1002/nag.70107","url":null,"abstract":"The optimal design of the marine pipeline‐seabed foundation system is a pressing and pivotal challenge that urgently needs to be solved in the field of oil and gas storage and transportation. It would be interesting to know how the pipeline material and the thermal contact resistance affect the pipeline‐foundation thermal consolidation mechanism. In this paper, the pipeline is firstly designed as a functional gradient material, and the soil is regarded as a saturated pore‐thermoelastic medium. Secondly, consider the thermal resistance effect between the pipeline and the surrounding soil. Laplace transform and its inverse transformation are employed to solve the generalized thermo‐hydro‐mechanical responses of the functional gradient pipeline‐surrounding soil system, which is subjected to thermal loadings. The effects of functional gradient functions, carbon fiber contents, functional gradient parameters, and thermal contact resistances on the temperature, displacement, radial stress, and pore water pressure are analyzed. Numerical results show that the introduction of the functional gradient material and thermal contact resistance will reduce the heat transfer efficiency of the pipeline, and thereby decrease the deformation and pore water pressure of the surrounding soil.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"18 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145282951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Numerical Investigation on Behavior of Ordinary and Bio‐Grouted Stone Columns in Clay","authors":"Xiaocong Cai, Ling Zhang","doi":"10.1002/nag.70100","DOIUrl":"https://doi.org/10.1002/nag.70100","url":null,"abstract":"The application of biochemical reinforcement techniques in ordinary stone columns (OSCs) has garnered considerable interest, with scarce investigations into their micromechanical behavior and particle‐scale interactions. Three‐dimensional discrete‐element method (DEM) models are developed to analyze the micromechanical behavior of bio‐grouted stone columns (BSCs) and OSCs in clay under vertical loading. The DEM models of clay foundation, OSC, and BSC are successively verified by experimental works. The column‐soil stress ratio (<jats:italic>n</jats:italic>), radial stress coefficient (<jats:italic>K<jats:sub>ps</jats:sub></jats:italic>), contact force distribution, porosity change, coordination number, and load‐displacement behavior of BSC and OSC were compared. Furthermore, the effects of contact‐bond strength (<jats:italic>σ<jats:sub>cb</jats:sub></jats:italic>), column length‐to‐foundation thickness (<jats:italic>L/H</jats:italic>), area replacement ratio (<jats:italic>A<jats:sub>r</jats:sub></jats:italic>), relative density (<jats:italic>D<jats:sub>r</jats:sub></jats:italic>), loading plate diameter‐to‐column diameter (<jats:italic>D<jats:sub>L</jats:sub>/D</jats:italic>), sand particle size‐to‐clay particle size ratio (<jats:italic>S<jats:sub>s</jats:sub>/S<jats:sub>c</jats:sub></jats:italic>) on the behavior of BSC and OSC are systematically investigated and evaluated through a parametric study. The numerical results show that the bulging forms at the bottom of the BSC and within 3<jats:italic>D</jats:italic> in OSC. The passive earth pressure coefficient (<jats:italic>K<jats:sub>p</jats:sub></jats:italic>) design method underestimates the bearing capacity of BSC but overestimates that of OSC and geosynthetic‐encased stone column (GESC). Dilation is observed in OSC, whereas compression occurs in BSC. Short‐floating BSCs with an <jats:italic>L/H</jats:italic> less than 0.33 are not recommended in deep clay deposits. Large‐diameter GESC exhibits a lower bearing capacity, in contrast to the large‐diameter BSC. The bearing capacity of BSC with an <jats:italic>S<jats:sub>s</jats:sub>/S<jats:sub>c</jats:sub></jats:italic> of 2.5–3.5 is similar to the OSC, indicating that the change in size of column material from reduced‐scale models to field‐scale implementations requires careful consideration.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"54 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the Structure and Mechanical Properties of an Innovative Type of Yielding Bolt in Squeezing Surrounding Rock Tunnel","authors":"Zhichun Liu, Fei Wu, Yinji Wang, Xiaolong Guo, Xuebing Lin, Lijun Tan","doi":"10.1002/nag.70103","DOIUrl":"https://doi.org/10.1002/nag.70103","url":null,"abstract":"To address the challenges of large deformation, prolonged deformation time, and inadequate support force in squeezing surrounding rock tunnels, a novel graded yield bolt has been developed. The mechanical properties of this new yield bolt were investigated through laboratory tests and numerical simulations. The analysis focused on the effects of the wall thickness of both large and small gradient sleeves, as well as the length and inclination angle of the resistance‐increasing head on the mechanical properties of the bolt. Furthermore, based on deformation classification and utilizing numerical simulation software, the supporting effectiveness of the yielding anchor under various deformation levels was examined. The results indicate that the new yielding bolt exhibits a graded yielding function, which can be categorized into three stages: elastic deformation, first yielding, and second yielding. The yield load value increases with the wall thickness of the large gradient sleeve and the length of the resistance‐increasing head. The yield load initially increases and then decreases with increasing wall thickness of the small gradient sleeve, and it decreases with an increase in the inclination angle of the resistance‐increasing head. Regardless of the deformation grade, the performance of the new yield bolt surpasses that of conventional bolts, with the advantages of the new yield bolt becoming more pronounced at higher deformation grades.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Block Collapse Prediction and Reinforcement Optimization in Tunnels Based on Discontinuous Deformation Analysis and Machine Learning Models","authors":"Hongyun Fan, Liping Li, Yuguang Fu, Hongliang Liu, Xiangyu Chang, Xin Gao","doi":"10.1002/nag.70102","DOIUrl":"https://doi.org/10.1002/nag.70102","url":null,"abstract":"<jats:label/>Block collapse is one of the most common geological hazards encountered during tunnel construction, characterized by its sudden occurrence and severe consequences. Currently, the prediction and prevention of tunnel block collapse rely primarily on theoretical analysis, numerical simulations, and physical experiments. However, these approaches often oversimplify real‐world conditions and lack efficiency. This study proposes a prediction and reinforcement optimization method for block collapse by integrating discontinuous deformation analysis (DDA) with machine learning method. First, DDA method was employed to simulate tunnel block collapse under structural plane inclination angles of 15°, 30°, and 45°. The corresponding simulation errors compared to model test results were 2.68%, 3.76%, and 1.01%, respectively, demonstrating the accuracy of the DDA approach in modeling block collapse. Next, a dataset of 142 block collapse scenarios under varying conditions was established, encompassing multiple parameters. Among them, the spacing, inclination angle, and internal friction angle of structural planes were identified as having the most significant influence on collapse behavior. Subsequently, five machine learning models were developed to predict collapse height, affected area, and perimeter deformation. All models achieved high coefficients of determination (<jats:italic>R</jats:italic><jats:sup>2</jats:sup>), with XGBoost exhibiting the best performance. Finally, a data‐driven method for optimizing reinforcement parameters was introduced by integrating the DDA and XGBoost models. Based on prediction results for Cases 128–142, the number of required rock bolts was successfully reduced from 255 to 98 using the proposed optimization strategy. This research provides a valuable reference for the design of reinforcement measures in practical tunnel construction in rock masses.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"204 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145260777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analytical Solution for Seepage Fields Around Drained Diversion Tunnels Considering Arbitrary Ground Leakages","authors":"An Jiang, Zheng Hu, Zhong Xuan Yang","doi":"10.1002/nag.70097","DOIUrl":"https://doi.org/10.1002/nag.70097","url":null,"abstract":"High‐diversion tunnels are often designed as drained systems to mitigate pressure differences between the tunnel interior and surrounding soil, commonly resulting in elevated hydraulic pressure and seepage infiltration toward the ground surface, posing risks to structural integrity and surface stability. This study presents a novel analytical solution for the seepage field around drained diversion tunnels considering arbitrary ground leakages. The solution integrates conformal transformation, the method of separation of variables, and trigonometric orthogonality, and demonstrates applicability for both deep and shallow‐buried diversion tunnels. Parametric analyses reveal that both the total water outflux and the flow velocity outside the tunnel are highly sensitive to the total head difference, tunnel radius, burial depth, and spatial distribution of ground leakage regions (e.g., leakage length, interval, and proximity to the tunnel vault). Notably, hydraulic pressure between adjacent ground leakage regions and flow velocity across the leakage regions increase with a lower ratio of burial depth to tunnel radius, fewer leakage regions, shorter leakage lengths, and larger head difference. The maximum water outflux consistently localizes in the central leakage region with magnitude fluctuations governed by the parity of the total leakage regions. The proposed analytical framework is further extended to address irregular cross‐sectional tunnel shapes via a gradient descent method and can be flexibly adapted to various boundary conditions. This work provides a computationally efficient tool for optimizing drainage designs and assessing leakage‐induced risks in diversion tunnel projects.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"158 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145235268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unified Permeability Modeling for Transitional Darcy/Non‐Darcy Flow Based on 3D Pore‐Level Numerical Flow Tests","authors":"Reika Nomura, Ryota Itto, Shinsuke Takase, Shuji Moriguchi, Kenjiro Terada","doi":"10.1002/nag.70095","DOIUrl":"https://doi.org/10.1002/nag.70095","url":null,"abstract":"This study presents a unified representation of the seepage characteristics of virtual soil, such as the transition zone from low‐velocity Darcy flow to high‐velocity non‐Darcy flow, by conducting 3D pore‐level fluid simulations. The process of defining a virtual test region as a representative volume element (RVE) and then assessing the apparent permeability from virtual 3D pore flow tests in this region is established as “numerical seepage flow testing” (NSFT). Rigid particles of a single size are placed in the virtual test area, with two types of particle configurations: regularly arranged and randomly arranged. Both low‐velocity Darcy and high‐velocity non‐Darcy flows are achieved by varying the macroscopic hydraulic gradient and other material or geometrical properties of the NSFT, such as the grain diameter or porosity, and the macroscopic seepage flow characteristics are discussed in terms of the relationship between the apparent permeability and the Reynolds number. We confirm that the individual relationships rely on the material or geometrical properties, propose a unified expression for apparent permeability by introducing the “permeability reduction ratio,” and use various empirically derived relationships between Darcy and non‐Darcy flow speeds and hydraulic gradients as references for this expression. The derived relationships confirm that the permeability reduction ratio is a function of the Reynolds number and porosity only, thus validating the proposed unified expression. Additionally, the effect of the regularity of the particle arrangement and the particle size distribution characteristics of the NSFT specimens are a factor that determines the functional form of the permeability reduction ratio.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145235267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Importance of Spatial Variability in Probabilistic Stability Analysis of Relatively Steep Undrained Slopes with a Foundation Layer","authors":"D. V. Griffiths, Desheng Zhu, Gordon A. Fenton","doi":"10.1002/nag.70087","DOIUrl":"https://doi.org/10.1002/nag.70087","url":null,"abstract":"The paper investigates the influence of a foundation layer on relatively steep undrained slopes with spatially variable soil strength. The definition of a relatively steep slope in this context is a slope angle that is steeper than that established by Taylor for the transition point between toe failures and base failures in uniform slopes which occurs at around 53°. It is shown that when the soil strength is spatially variable, critical failure mechanisms can pass into the foundation layer even in relatively steep slopes, which could never happen in a uniform soil. Although the worst‐case correlation length is a well‐established phenomenon in geotechnical reliability, it has usually been associated with slopes with relatively low factors of safety based on the mean. The paper demonstrates for the first time that even slopes with high factors of safety based on mean strength, can exhibit a striking worst‐case correlation length, confirming that failure to account for spatial variability can lead to unsafe predictions of the probability of failure.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Modelling Ice Lens Formation and Frost Heave in Unsaturated Soils","authors":"Zili Wang, Jidong Teng, Satoshi Nishimura, Sheng Zhang, Daichao Sheng","doi":"10.1002/nag.70091","DOIUrl":"https://doi.org/10.1002/nag.70091","url":null,"abstract":"Frost heave is a typical thermo‐hydro‐mechanical coupling process, which can lead to significant threats to the infrastructures in cold regions. The initiation and growth of ice lenses is the core issue to understand the process of frost heave. But this process has not been well modelled in previous studies. It is hard to accurately model the formation of ice lenses and the contribution of the vapour phase during the freezing process. This study presents a novel frost heave model that accounts for the effects of vapour migration in unsaturated soils, which is implemented in a C++ simulation programme with an interactive user interface. The model reveals periodic frost heave variations due to cooling gradients and highlights the impact of vapour on ice lens formation under low moisture conditions. It also demonstrates the relative importance of liquid and vapour fluxes with moisture content, with vapour migration playing a key role in frost heave in coarse‐grained soils. These new findings provide new insights into frost heave mechanisms and challenge traditional ice lens formation criteria. In addition, the model effectively simplifies boundary conditions and improves computational stability and efficiency. These advancements can improve frost heave prediction and deepen the understanding of soil freezing mechanisms, offering valuable insights for infrastructure applications.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"18 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145203160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}