{"title":"Molecular Dynamics Simulation and Lab‐Scale Experimental Testing of Water Migration in Unsaturated Expansive Clay","authors":"Qiuyan Liu, Liuqun Dong, Genli Tang","doi":"10.1002/nag.70004","DOIUrl":"https://doi.org/10.1002/nag.70004","url":null,"abstract":"The mechanical performances of expansive clay in semi‐arid areas deteriorate with the change in humidity and temperature due to its characteristics of water‐swelling and drying shrinkage. So, investigating the moisture migration in expansive clays is of great significance. This study employs molecular dynamics (MD) simulations to elucidate microscale water transport mechanisms in clay mineral pores, complemented by experimental validation using a novel horizontal migration apparatus across temperature gradients (5°C, 20°C, 40°C). Quantitative analysis reveals that temperature significantly influenced water migration, with the migration rates at 5°C and 20°C accounting for approximately 30% to 60% of the rate observed at 40°C. Based on the MD simulation results obtained, a modified Kozeny–Carman equation is presented to simulate the hydraulic conductivity at various temperatures. The microscopic flow behavior of clay minerals was compared with the macroscopic characteristics of clay. The results demonstrate that hydraulic conductivity varies non‐linearly with changes in matric suction. Under the same matric suction, the computed hydraulic conductivity obtained from MD is higher than that of the experimental simulation. The arrangement and connectivity of soil pores at a higher suction have a more pronounced impact on soil permeability. These results elucidate the moisture migration mechanisms in unsaturated expansive clay at the microscale.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"23 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144513146","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":"Three‐Dimensional Seismic Response Analysis of Tunnels in Layered Media Using Modified Domain Reduction Method","authors":"Bhavesh Banjare, Gauri Ranjan Krishna Chand Avatar, Goudappa Ramanagouda Dodagoudar","doi":"10.1002/nag.70006","DOIUrl":"https://doi.org/10.1002/nag.70006","url":null,"abstract":"Fault inclination and complex geological soil features significantly impact the seismic response of underground unlined tunnels. Modeling fault rupture mechanisms necessitates spanning the computational domain over several kilometers, thus making the approach computationally inefficient. In this study, an efficient modeling algorithm, named as multi‐layer Modified Domain Reduction Method (MDRM), has been proposed to analyze the Soil‐Fault‐Tunnel (SFT) system in layered soil media. The study has demonstrated the effectiveness of the MDRM for modeling the SFT system in layered soil media, considering the seismic source, wave propagation path, and local site effects for realistic seismic response assessment of the tunnels. The MDRM algorithm is implemented in an open‐source finite element package, MASTODON (Multi‐hazard Analysis for STOchastic time‐DOmaiN phenomena), based on the MOOSE numerical framework. Using the MDRM approach, parametric simulations for four different fault rupture mechanisms and three distinct tunnel cross‐sections (all having the same opening area) are being performed to capture the overall seismic response of the tunnels. The results provide insights into the influence of fault inclination angle, surface wave generation, and local site effects on the response. The transfer function profiles for the considered soil layers are contrasted, and their influence on different tunnel cross‐sections is investigated. The findings are useful in the efficient and reliable design of underground tunnels in multi‐layered media subjected to different fault rupture mechanisms.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"10 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144500766","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":"Effects of Consolidation Stress and Chemical Compatibility on Contaminant Transport Through Soil‐Bentonite Cutoff Walls","authors":"Lin‐Feng Cao, Bo Huang, Yu‐Chao Li","doi":"10.1002/nag.70003","DOIUrl":"https://doi.org/10.1002/nag.70003","url":null,"abstract":"The soil‐bentonite (SB) cutoff wall is commonly utilized at contaminated sites to delay the contaminant transport. Current research typically assumes that their transport parameters are constant, ignoring the non‐uniform distribution of these parameters with depth caused by consolidation stress, and performance degradation due to contaminants (i.e., chemical compatibility). A two‐dimensional contaminant transport model was developed in an SB wall system, for the first time, simultaneously considering consolidation stress and chemical compatibility. A computational framework was established to obtain the numerical solution, which was then compared with analytical solutions and centrifuge tests to verify its effectiveness. Subsequently, existing models were compared, and the impact of relevant parameters on SB wall performance was analyzed. The results indicate that neglecting consolidation stress and chemical compatibility can overestimate SB wall performance, with a maximum overestimation of 139.76% for breakthrough time and a maximum underestimation of 96.25% for total flux. The spatial distribution of contaminant source and concentrations of Na<jats:sup>+</jats:sup> and Ca<jats:sup>2+</jats:sup> significantly impact the breakthrough time. Additionally, the bentonite content should be increased on the original standard to compensate for performance declines caused by contaminants. The thickness and position design should consider contaminant source in the shallow part, and choose a more economical combination. The proposed model can provide more comprehensive and accurate guidance for SB wall construction.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"26 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144488444","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}
Qi Zhang, Haiyi Zhong, Haowen Guo, Charles Wang Wai Ng, Arezoo Rahimi
{"title":"Analytical Solutions for Calculating Pore‐Water Pressure and Stability of Infinite Slope With Cracks and Vegetation Under Rainfall","authors":"Qi Zhang, Haiyi Zhong, Haowen Guo, Charles Wang Wai Ng, Arezoo Rahimi","doi":"10.1002/nag.4019","DOIUrl":"https://doi.org/10.1002/nag.4019","url":null,"abstract":"The presence of desiccation cracks can affect rainfall‐induced slope stability through both hydraulic and mechanical ways. Despite the valuable insights gained from physical tests in literature, there still lacks understanding how crack characteristics impact water flow dynamics and slope stability, especially considering the coexistence of vegetation. In this study, new analytical solutions were derived for calculating pore‐water pressure and slope stability for an infinite unsaturated slope with cracks and vegetation. Both enhanced infiltration from water‐filled cracks and water uptake by plant roots are considered. Using the newly developed solutions, two series of parametric analyses were carried out to improve understanding of the factors affecting crack water infiltration and hence the stability of vegetated slope. The calculated results show that slope failure at shallow depths is governed by the surface crack ratio, whereas deeper failures typically occur with greater crack depths. The surface crack ratio primarily influences the hydraulic response at shallow depths not exceeding 1.5 m, hence affecting the factor of safety for slip surfaces within the crack zone. Moreover, increasing the crack‐to‐root depth ratio from 0.5 to 1.5 results in a 25% reduction in suction at 1.5 m, threatening slope safety in deeper depth after 10‐year rainfall.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"232 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144311568","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}
Jinwei Fu, Jiaxin Wei, Hadi Haeri, Vahab Sarfarazi, Ali Reza Masoomi, Kaveh Asgari, Erfan Zarrin Ghalam
{"title":"Effects of the Shapes of Surrounded Cracks on the Failure Behavior of Rock‐Like Samples","authors":"Jinwei Fu, Jiaxin Wei, Hadi Haeri, Vahab Sarfarazi, Ali Reza Masoomi, Kaveh Asgari, Erfan Zarrin Ghalam","doi":"10.1002/nag.4022","DOIUrl":"https://doi.org/10.1002/nag.4022","url":null,"abstract":"The research employed laboratory and numerical simulation methods to examine how the shapes and sizes of surrounding cracks influence the compressive breakage properties of concrete samples. The notches examined were of various shapes, including semicircle, semi‐ellipse, triangle, rectangle, square, and trapezoid, with an angle of 45° between the notch and the horizontal axis. Additionally, numerical models were created that included 15 embedded rectangular notches. The investigation focused on different notch angles (0°, 30°, 45°, 60°, and 90°) and notch lengths (3, 6, and 9 cm). A consistent displacement loading rate of 0.01 mm/s was maintained throughout the experiment. In the intact specimens tested, the measured uniaxial compressive strength was 16 MPa, while the tensile strength was found to be 1.2 MPa. Tests on different crack types revealed that both the surface area and shape significantly influenced the fracture and failure of rock mass specimens. A correlation was established between the strength of the specimens and crack propagation. As the angle of the joints decreased and the surface area of the cracks increased, tensile cracks developed, ultimately leading to the fracturing and final breakage of the specimens. The modeled specimens exhibited the lowest tensile strength at a 30‐degree inclination angle. Semicircular cracks displayed the highest tensile strength, whereas rectangular cracks had the lowest. In comparing the laboratory and numerical outcomes, the breakage patterns, failure mechanisms, and strengths of the geomaterial samples were found to be similar.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"37 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144311569","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}
Jinwei Fu, Jiaxin Wei, Hadi Haeri, Vahab Sarfarazi, Mohammad Mehdi Chehrepak, Mohammad Fatehi Marji
{"title":"Investigation of Failure Mechanism of Geogrid Reinforced Porous Concrete Based on Experimental Test","authors":"Jinwei Fu, Jiaxin Wei, Hadi Haeri, Vahab Sarfarazi, Mohammad Mehdi Chehrepak, Mohammad Fatehi Marji","doi":"10.1002/nag.70002","DOIUrl":"https://doi.org/10.1002/nag.70002","url":null,"abstract":"The breakage behavior and damage mechanisms of geogrid‐reinforced porous concrete (GRPC) were evaluated through uniaxial compressive loading tests. Cubic samples measuring 15 cm × 15 cm × 15 cm were constructed with layered aggregates, incorporating 1 to 3 geogrids positioned at angles of 0°, 45°, and 90°. Testing was conducted in a rock mechanics laboratory, and strain‐stress curves were analyzed to examine mechanical behavior and fracture mechanisms. The breakage process of the GRPC was categorized into three stages: crack initiation, propagation, and final breakage. Results indicated that the mechanics and failure stages of GRPC differed significantly from those of ordinary concrete. In GRPC specimens, failure was primarily attributed to the sliding of aggregates and geogrid bonding layers, with cracks tending to propagate in stress concentration areas formed by connected or unconnected pores. Increasing the number of geogrids resulted in fewer fractures and reduced damage area. In tests with a consistent number of geogrids and concrete age, the horizontal geogrid configuration demonstrated a higher young modulus and failure stress compared to the vertical arrangement. Additionally, horizontal geogrid reinforcement caused delayed failure, while vertical reinforcement led to rapid breakage. A reduction in the number of geogrids led to a shift in breakage type, resulting in a more rapid and abrupt failure.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"17 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296142","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":"Molecular Dynamics Study on Quartz‐Indenter Shape and Depth Effects in Epoxy Interfacial Mechanics","authors":"Pengchang Wei, Zhen‐Yu Yin, Pierre‐Yves Hicher, Yuanyuan Zheng","doi":"10.1002/nag.4021","DOIUrl":"https://doi.org/10.1002/nag.4021","url":null,"abstract":"The interfacial mechanical behavior between epoxy and quartz at the microscale remains inadequately understood. The quartz‐indenter shape and indentation depth (<jats:italic>h</jats:italic><jats:sub>c</jats:sub>) effect on epoxy interfacial mechanical behavior has been investigated through molecular dynamics (MD) simulation of nanoindentation and nanoscratching. This work employs two Vickers‐type and four spherical indenters with varying radii (<jats:italic>R</jats:italic>) under different <jats:italic>h</jats:italic><jats:sub>c</jats:sub> conditions, revealing the fundamental deformation mechanisms at the microscale. The reduced modulus and Young's modulus of epoxy resin obtained from MD simulations align well with experimental results. Key findings include: (1) during MD nanoindentation, the elastic‐plastic deformation of epoxy and the indentation force increased with rising <jats:italic>R</jats:italic> and <jats:italic>h</jats:italic><jats:sub>c</jats:sub>, due to the enhanced interfacial interactions between epoxy and quartz. (2) A negative indentation force was observed during the unloading stage, attributed to adhesion effects. (3) In MD nanoscratching, the forces in the <jats:italic>y</jats:italic>‐ and <jats:italic>z</jats:italic>‐directions increased with rising <jats:italic>R</jats:italic> and <jats:italic>h</jats:italic><jats:sub>c</jats:sub>, which was due to a greater contact zone and elastic–plastic deformation. (4) The friction coefficient could increase with rising indentation depth, exceeding 1.0 at <jats:italic>h</jats:italic><jats:sub>c</jats:sub>/<jats:italic>R</jats:italic> > 0.75. (5) The classic Coulomb's law of friction was not applicable at the microscale or nanoscale. These results provide a foundation for developing interfacial models at the macroscopic scale for engineering applications.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"604 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144304455","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}
Lingfeng Zhao, Zengguang Xu, Xican Cui, Cheng Cao, Fan Zhang
{"title":"Study on Spherical Diffusion Mechanism of Bingham Fluid Slurry Infiltration Grouting Considering Tortuous Effect of Porous Media","authors":"Lingfeng Zhao, Zengguang Xu, Xican Cui, Cheng Cao, Fan Zhang","doi":"10.1002/nag.4013","DOIUrl":"https://doi.org/10.1002/nag.4013","url":null,"abstract":"Current studies on soil tortuosity models typically assume a single particle size, neglecting the impact of particle gradation and spatial arrangement on pore channels and structures. To address this limitation, we develop a tortuosity model that incorporates multiple factors by assuming ellipsoidal particles and accounting for their arrangement and gradation. This model, combined with the Bingham fluid flow equation in porous media, elucidates the spherical penetration grouting mechanism of Bingham fluids, considering both tortuosity and time‐varying viscosity. Using COMSOL Multiphysics, we simulate seepage to create a numerical program for Bingham fluid spherical seepage grouting that accounts for tortuosity and time‐varying viscosity. Theoretical analysis and simulations validate our proposed tortuosity model and diffusion mechanisms. Additionally, we examine the sensitivity of the diffusion radius to Bingham grout rheology, grouting pressure, groundwater pressure, and grouting pipe radius. The research results demonstrate that the established tortuosity theoretical model is in excellent agreement with numerical simulations, with a maximum error of less than 3%. The spherical permeation grouting diffusion mechanism of Bingham fluid, which accounts for the tortuosity effect of porous media, more closely matches the experimental test values, achieving an average error of 10.13% and a minimum error of 3%. Grouting pressure and groundwater pressure are key factors, and their interaction with the grouting pipe radius has the strongest effect. These research findings provide valuable theoretical support for designing construction controls related to restoration projects involving porous medium earth‐rock dams.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"8 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144288196","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":"Effect of the Variation of Compressibility and Permeability Characteristics of Clogged Stone Column on Drainage Performance of Column During Liquefaction","authors":"Suravi Pal","doi":"10.1002/nag.70001","DOIUrl":"https://doi.org/10.1002/nag.70001","url":null,"abstract":"Installation of a stone column (SC) is an effective way to promote radial drainage and reduce the risk of liquefaction. However, the clogging effects caused during the service life of SC result in degradation of the performance of SC. Clogging of SC develops when the water flow force fines to release from soil and migrate with it. These fines may become trapped in the pores of gravel and cause the clogging of SC. The fines accumulation within SC over time not only decrease the permeability of SC, but also increases the compressibility of SC due to the reduction of inter‐particle contact between gravels. The present paper demonstrates a mathematical model to determine the pore pressure of SC‐improved soil during liquefaction by considering the change in permeability and compressibility of clogged SC. The model is validated with the available experimental data. Detail parametric studies are conducted to enhance the understanding of various parameters of soil and SC on the effectiveness of SC due to change in permeability and compressibility of the clogged SC. The results obtained from the present model shows that in the case of multiple earthquakes, for the second earthquake, the pore pressure ratio of SC‐improved ground may increase by more than 36% due to consideration of the compressibility effect of clogged SC.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"91 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144289780","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":"Seismic Displacement Analysis of Jointed Rock Slopes Considering Topographic Amplification and Joint Strength Degradation","authors":"Hui Shen, Xinping Li, Tingting Liu, Yaqun Liu, Haibo Li, Wenxu Huang","doi":"10.1002/nag.4017","DOIUrl":"https://doi.org/10.1002/nag.4017","url":null,"abstract":"Accurately estimating seismically induced permanent displacement is essential for evaluating the dynamic stability of rock slopes. This study presents an enhanced model aimed at better evaluating the seismic displacement of jointed rock slopes by incorporating topographic amplification effects and the dynamic strength degradation of joints. A pseudodynamic analysis was utilized to model the amplified seismic force acting on the slope. The dynamic degradation law of the joint strength was characterized through the cyclic shear tests and integrated into the proposed model. Seismic displacement for the jointed slopes was obtained by solving the equations of motion, with sliding governed by the Mohr–Coulomb joint strength criterion. The performance of the prediction model was evaluated by comparing its results with those derived from the Newmark method and existing methods. Subsequently, the impact of amplified ground motions and joint strength degradation dependent on displacement and velocity on seismic displacement of jointed rock slopes was examined numerically. The results indicate that the proposed model can directly estimate reasonable seismic displacements of jointed slopes without explicitly specifying the yield acceleration, and it produces more conservative displacements compared to the Newmark method. Findings also emphasize that the amplified ground motion and the dynamic shear strength of joints significantly increase the seismic displacements, implying that neglecting them may lead to an underestimation of the permanent displacement of slopes. This study offers an alternative approach for estimating the permanent displacement of jointed rock slopes, which may provide valuable insights for the seismic design of slope engineering.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"10 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144288201","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}