Yang Luo, Yusheng Shen, Haifeng Huang, Sensen Song, Chao Wang, Shengwen Zhan, Hang Yang
Buried pipelines are susceptible to earthquake‐induced damage when crossing soft‐hard rock strata in high‐intensity seismic regions. In mitigation, pipelines are usually installed within tunnels and buried under backfill materials. The existing seismic calculation method for pipelines does not consider the effects of tunnels. In this study, the pipeline‐tunnel system crossing soft‐hard rock strata is longitudinally simplified to an elastic foundation double‐beam. Green's function is employed to derive the analytical solution for the longitudinal seismic response of the pipeline‐tunnel system, whose validity is verified through numerical models and literature data. A parametric analysis is conducted through the control variable method. As the elastic modulus ratio between the hard and soft rocks increases, the peak internal forces of the pipeline and tunnel near the interface increase significantly. Specifically, the peak bending moments display a double‐peak pattern, while the peak shear forces present a single‐peak one. With the increase in the lining elastic modulus and thickness, the peak internal forces of the pipeline near the interface decrease, while those of the tunnel increase significantly. The peak internal forces of the pipeline increase sharply with the pipeline thickness, whereas those of the tunnel are hardly affected. The shaking table test results demonstrate that the tunnel crossing the interface sustained more severe damage than that in other segments, with oblique shear cracks appearing. This indicates that the sudden increase of the shear forces near the interface is one of the vital reasons for the structural damage, which verifies the rationality of the analytical solution.
{"title":"Analytical Solution for Longitudinal Seismic Responses of Pipelines and Tunnels Crossing Soft‐Hard Rock Strata Based on Double‐Beam Model","authors":"Yang Luo, Yusheng Shen, Haifeng Huang, Sensen Song, Chao Wang, Shengwen Zhan, Hang Yang","doi":"10.1002/nag.70177","DOIUrl":"https://doi.org/10.1002/nag.70177","url":null,"abstract":"Buried pipelines are susceptible to earthquake‐induced damage when crossing soft‐hard rock strata in high‐intensity seismic regions. In mitigation, pipelines are usually installed within tunnels and buried under backfill materials. The existing seismic calculation method for pipelines does not consider the effects of tunnels. In this study, the pipeline‐tunnel system crossing soft‐hard rock strata is longitudinally simplified to an elastic foundation double‐beam. Green's function is employed to derive the analytical solution for the longitudinal seismic response of the pipeline‐tunnel system, whose validity is verified through numerical models and literature data. A parametric analysis is conducted through the control variable method. As the elastic modulus ratio between the hard and soft rocks increases, the peak internal forces of the pipeline and tunnel near the interface increase significantly. Specifically, the peak bending moments display a double‐peak pattern, while the peak shear forces present a single‐peak one. With the increase in the lining elastic modulus and thickness, the peak internal forces of the pipeline near the interface decrease, while those of the tunnel increase significantly. The peak internal forces of the pipeline increase sharply with the pipeline thickness, whereas those of the tunnel are hardly affected. The shaking table test results demonstrate that the tunnel crossing the interface sustained more severe damage than that in other segments, with oblique shear cracks appearing. This indicates that the sudden increase of the shear forces near the interface is one of the vital reasons for the structural damage, which verifies the rationality of the analytical solution.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"115 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145664967","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}
Gao Liang Liu, Jie Hu, Jia Qing Chen, Chang Jie Chen, Yun Min Chen
Accurately describing slurry diffusion in fracture remains challenging due to the complexity of fracture roughness and the non‐linear rheological properties of slurry. This study presents an analytical solution for the single‐hole grouting in rough fractures considering the time‐dependent viscosity of Bingham fluid. Fracture roughness is described by introducing two parameters, the fractal dimension D and the characteristic scale parameter G . The accuracy of the analytical solution is validated by comparing the slurry flow and diffusion radius from experimental results with predicted results. The corresponding slurry flow Q calculated from the analytical solution is used to delineate different areas. Variations in D and G shift the slurry flow resistance from rough ( Q < 0.1 L) to transitional (0.1–0.8 L) and smooth ( Q > 0.8 L) areas under constant other parameter conditions. Variations in yield stress and viscosity shift the slurry flow areas among low, medium, and high sensitivity areas. Additionally, numerical analysis of two‐hole grouting in rough fractures is performed to determine optimal grouting hole spacing based on the percentage of the area covered by the slurry relative to the total fracture area. During two‐hole grouting, mutual squeezing effect between slurry alternately promotes and impedes flow. The optimal grouting hole spacing of Bingham fluids with varying water‐to‐cement ratios decreases with fracture roughness and increases with grouting pressure. Bingham fluids with water‐to‐cement ratios of 1.0–2.0 exhibit greater sensitivity to grouting pressure in wide fractures due to complex flow characteristics, providing a reference for simplifying grouting process across varying geological conditions.
{"title":"Analytical and Numerical Analysis of Bingham Fluid Grouting in Rough Fracture","authors":"Gao Liang Liu, Jie Hu, Jia Qing Chen, Chang Jie Chen, Yun Min Chen","doi":"10.1002/nag.70160","DOIUrl":"https://doi.org/10.1002/nag.70160","url":null,"abstract":"Accurately describing slurry diffusion in fracture remains challenging due to the complexity of fracture roughness and the non‐linear rheological properties of slurry. This study presents an analytical solution for the single‐hole grouting in rough fractures considering the time‐dependent viscosity of Bingham fluid. Fracture roughness is described by introducing two parameters, the fractal dimension <jats:italic>D</jats:italic> and the characteristic scale parameter <jats:italic>G</jats:italic> . The accuracy of the analytical solution is validated by comparing the slurry flow and diffusion radius from experimental results with predicted results. The corresponding slurry flow <jats:italic>Q</jats:italic> calculated from the analytical solution is used to delineate different areas. Variations in <jats:italic>D</jats:italic> and <jats:italic>G</jats:italic> shift the slurry flow resistance from rough ( <jats:italic>Q</jats:italic> < 0.1 L) to transitional (0.1–0.8 L) and smooth ( <jats:italic>Q</jats:italic> > 0.8 L) areas under constant other parameter conditions. Variations in yield stress and viscosity shift the slurry flow areas among low, medium, and high sensitivity areas. Additionally, numerical analysis of two‐hole grouting in rough fractures is performed to determine optimal grouting hole spacing based on the percentage of the area covered by the slurry relative to the total fracture area. During two‐hole grouting, mutual squeezing effect between slurry alternately promotes and impedes flow. The optimal grouting hole spacing of Bingham fluids with varying water‐to‐cement ratios decreases with fracture roughness and increases with grouting pressure. Bingham fluids with water‐to‐cement ratios of 1.0–2.0 exhibit greater sensitivity to grouting pressure in wide fractures due to complex flow characteristics, providing a reference for simplifying grouting process across varying geological conditions.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657533","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}
Tunnel excavation induces stress redistribution and deformation in the surrounding soil, weakening the lateral bearing capacity of adjacent piles and potentially resulting in engineering failures. Therefore, accurately evaluating the mechanism of lateral pile‐soil interaction induced by tunnelling is important. This study numerically investigated the pile‐soil interaction pt ‐ yt curves of a pile adjacent to tunnelling in sand (where pt denotes the soil force per unit pile length induced by tunnelling and yt represents the corresponding lateral pile displacement), clarifying the evolution mechanisms of the passive‐side (away from the tunnel), the active‐side (adjacent to the tunnel), and the resultant pt ‐ yt curves, and examining the effects of excavation parameters on the evolution of pt ‐ yt curves. The results showed that the evolution of the passive pile pt ‐ yt curves can be divided into two stages: the excavation‐induced unloading stage and the pile‐soil deformation stage. Both the passive‐side and active‐side pt ‐ yt curves evolved synchronously: the passive‐side soil force initially increased and subsequently decreased with increasing lateral pile displacement, whereas the active‐side soil resistance initially decreased and then increased. Moreover, both the passive‐side soil force and active‐side soil resistance exhibited opposite trends in response to changes in tunnel diameter, volume loss, tunnelling speed, and the pile‐tunnel distance, but exhibited similar trends in response to changes in cover depth and pile diameter.
隧道开挖引起周围土体应力重分布和变形，削弱了邻近桩的侧向承载能力，可能导致工程失效。因此，准确评价隧道开挖引起的桩土横向相互作用机理具有重要意义。本研究通过数值模拟研究了沙中隧道邻近桩的桩土相互作用p t - y - t曲线（其中p t表示隧道开挖引起的单位桩长土力，y t表示相应的桩侧位移），阐明了被动侧（远离隧道）、主动侧（靠近隧道）以及由此产生的p t - y - t曲线的演化机制。考察了开挖参数对p - t - y - t曲线演化的影响。结果表明：被动桩p - t - y - t曲线的演化可分为两个阶段：开挖诱发卸荷阶段和桩土变形阶段。被动侧和主动侧p - t - y - t曲线同步演化：随着桩侧位移的增加，被动侧土力先增大后减小，而主动侧土阻力先减小后增大。此外，被动侧土力和主动侧土阻力对隧道直径、体积损失、隧道掘进速度和桩隧距离的响应趋势相反，但对覆盖深度和桩径的响应趋势相似。
{"title":"Numerical Analysis of Tunnelling‐Induced Lateral Pile‐Soil Interactions of Adjacent Piles in Sand","authors":"Mingqun Zhu, Songyu Liu, Hongjiang Li, Liyuan Tong","doi":"10.1002/nag.70154","DOIUrl":"https://doi.org/10.1002/nag.70154","url":null,"abstract":"Tunnel excavation induces stress redistribution and deformation in the surrounding soil, weakening the lateral bearing capacity of adjacent piles and potentially resulting in engineering failures. Therefore, accurately evaluating the mechanism of lateral pile‐soil interaction induced by tunnelling is important. This study numerically investigated the pile‐soil interaction <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> ‐ <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> curves of a pile adjacent to tunnelling in sand (where <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> denotes the soil force per unit pile length induced by tunnelling and <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> represents the corresponding lateral pile displacement), clarifying the evolution mechanisms of the passive‐side (away from the tunnel), the active‐side (adjacent to the tunnel), and the resultant <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> ‐ <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> curves, and examining the effects of excavation parameters on the evolution of <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> ‐ <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> curves. The results showed that the evolution of the passive pile <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> ‐ <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> curves can be divided into two stages: the excavation‐induced unloading stage and the pile‐soil deformation stage. Both the passive‐side and active‐side <jats:italic>p</jats:italic> <jats:sub>t</jats:sub> ‐ <jats:italic>y</jats:italic> <jats:sub>t</jats:sub> curves evolved synchronously: the passive‐side soil force initially increased and subsequently decreased with increasing lateral pile displacement, whereas the active‐side soil resistance initially decreased and then increased. Moreover, both the passive‐side soil force and active‐side soil resistance exhibited opposite trends in response to changes in tunnel diameter, volume loss, tunnelling speed, and the pile‐tunnel distance, but exhibited similar trends in response to changes in cover depth and pile diameter.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"43 11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657535","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}
The shear behavior of intermittently jointed rock masses is crucial in engineering geology, yet the widely used Jennings criterion still lacks a systematic evaluation regarding its accuracy when applied to rock with various joint geometries. This study combines physical experiments and Particle Flow Code (PFC) simulations to investigate how joint geometries influence shear strength and to further assess whether the Jennings criterion can effectively capture these influences. Both approaches reveal similar trends: peak shear stress and cohesion decrease with higher joint connectivity and number, but increase with steeper dip angles. In the present experimental conditions, no clear trend was observed between the friction angle and variations in discontinuity geometrical features, which is likely related to the relatively limited range of geometrical configurations considered in the tests. A further comparison between measured and Jennings‐derived equivalent cohesion shows a widespread discrepancy: on average, equivalent cohesion exceeds measured values by 31.4% in physical tests and 10% in numerical simulations. This overestimation, due to stress concentration and altered failure paths introduced by different joint geometries, is most significant in low‐connectivity, high‐joint‐number, and gentle‐dip‐angle scenarios. These findings suggest that the Jennings criterion's applicability is limited, as significantly overestimated equivalent parameters could lead to overly optimistic stability assessments under certain conditions. Additionally, the impact of joint geometrical features on shear strength is both systematic and potentially quantifiable, offering a valuable reference for incorporating such features into equivalent parameter estimation methods to improve the accuracy of strength assessments.
{"title":"Measured and Equivalent Shear Strength Parameters for Intermittently Jointed Rock Masses: Insights From Physical and Numerical Tests","authors":"Jiali Han, Wen Zhang, Jia Wang, Donghui Chen","doi":"10.1002/nag.70178","DOIUrl":"https://doi.org/10.1002/nag.70178","url":null,"abstract":"The shear behavior of intermittently jointed rock masses is crucial in engineering geology, yet the widely used Jennings criterion still lacks a systematic evaluation regarding its accuracy when applied to rock with various joint geometries. This study combines physical experiments and Particle Flow Code (PFC) simulations to investigate how joint geometries influence shear strength and to further assess whether the Jennings criterion can effectively capture these influences. Both approaches reveal similar trends: peak shear stress and cohesion decrease with higher joint connectivity and number, but increase with steeper dip angles. In the present experimental conditions, no clear trend was observed between the friction angle and variations in discontinuity geometrical features, which is likely related to the relatively limited range of geometrical configurations considered in the tests. A further comparison between measured and Jennings‐derived equivalent cohesion shows a widespread discrepancy: on average, equivalent cohesion exceeds measured values by 31.4% in physical tests and 10% in numerical simulations. This overestimation, due to stress concentration and altered failure paths introduced by different joint geometries, is most significant in low‐connectivity, high‐joint‐number, and gentle‐dip‐angle scenarios. These findings suggest that the Jennings criterion's applicability is limited, as significantly overestimated equivalent parameters could lead to overly optimistic stability assessments under certain conditions. Additionally, the impact of joint geometrical features on shear strength is both systematic and potentially quantifiable, offering a valuable reference for incorporating such features into equivalent parameter estimation methods to improve the accuracy of strength assessments.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"244 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651028","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}
Zhang Keqin, Wu Wei, Kang Yanfei, Hao Yongtao, Wang Xi, Zhu Hehua
Discontinuous deformation analysis (DDA) is a numerical method that is extensively utilized for simulating discrete blocks. Nevertheless, its implicit calculation approach brings in a multitude of control parameters that lack physical significance, and proper handling of these parameters is essential for obtaining accurate results. To tackle this issue, this study proposes a surrogate model‐driven parameter calibration framework that incorporates interpretability analysis. First, a Kriging surrogate model is constructed to establish an efficient substitute for DDA computations, thus accelerating forward calculations. Subsequently, the SHapley Additive exPlanations (SHAP) method is introduced to quantify global parameter sensitivity. Finally, an intelligent optimization algorithm is integrated to develop a parameter inversion mechanism, thereby forming a complete calibration system of “surrogate modeling–sensitivity analysis–parameter optimization.” Numerical examples demonstrate that this framework can effectively identify the optimal combination of key control parameters. The average errors are 1.39% in the two‐slider model and 1.63% in the elastic foundation model. This approach offers an automated parameter calibration process that doesn't require manual intervention, providing a reliable theoretical tool for DDA engineering applications in tunneling, slope stability, and rock engineering.
{"title":"A Framework for Parameter Calibration in Discontinuous Deformation Analysis Based on Interpretable Surrogate Models","authors":"Zhang Keqin, Wu Wei, Kang Yanfei, Hao Yongtao, Wang Xi, Zhu Hehua","doi":"10.1002/nag.70166","DOIUrl":"https://doi.org/10.1002/nag.70166","url":null,"abstract":"Discontinuous deformation analysis (DDA) is a numerical method that is extensively utilized for simulating discrete blocks. Nevertheless, its implicit calculation approach brings in a multitude of control parameters that lack physical significance, and proper handling of these parameters is essential for obtaining accurate results. To tackle this issue, this study proposes a surrogate model‐driven parameter calibration framework that incorporates interpretability analysis. First, a Kriging surrogate model is constructed to establish an efficient substitute for DDA computations, thus accelerating forward calculations. Subsequently, the SHapley Additive exPlanations (SHAP) method is introduced to quantify global parameter sensitivity. Finally, an intelligent optimization algorithm is integrated to develop a parameter inversion mechanism, thereby forming a complete calibration system of “surrogate modeling–sensitivity analysis–parameter optimization.” Numerical examples demonstrate that this framework can effectively identify the optimal combination of key control parameters. The average errors are 1.39% in the two‐slider model and 1.63% in the elastic foundation model. This approach offers an automated parameter calibration process that doesn't require manual intervention, providing a reliable theoretical tool for DDA engineering applications in tunneling, slope stability, and rock engineering.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651029","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}
Debris flows, characterized by a heterogeneous mixture of solid, liquid, and gas phases, exhibit complex mechanical behavior and pose substantial threats to infrastructure and human lives in mountainous regions. This study presents a novel three‐dimensional material point method (MPM), integrating a geographic information system (GIS) and Perlin noise functions, to model the debris flow over complex terrain as a coupled liquid‐solid system. The digital elevation models in GIS are mapped directly onto the MPM computational domain and preserve realistic terrain features. The irregular rock blocks generated by Perlin noise function in Houdini software are embedded into the source zone of debris flow to explicitly represent fluid‐solid interactions. In addition, to maintain the computational accuracy and efficiency, the sparse paged grid structure (SPGrid) is introduced to provide an efficient computational framework for large‐scale 3D hazard analysis. The proposed MPM framework is validated firstly by comparing numerical results and experimental data from previous studies, including saturated soil leakage, rockslide‐induced wave generation, and debris dam break flow. The dynamic behavior and deposition patterns of debris flows are then analyzed, revealing that these factors are significantly influenced by rock block content and the basal friction coefficient. Results show that the proposed two‐phase two‐point MPM is an effective tool to reproduce the realistic propagation of debris flows and provides a scientific reference for hazard assessment and disaster prevention in debris flow‐prone regions.
{"title":"Three‐Dimensional Dynamic Analysis of Debris Flows Over Complex Terrain","authors":"Yawen Wu, Shanyong Wang, John P. Carter","doi":"10.1002/nag.70184","DOIUrl":"https://doi.org/10.1002/nag.70184","url":null,"abstract":"Debris flows, characterized by a heterogeneous mixture of solid, liquid, and gas phases, exhibit complex mechanical behavior and pose substantial threats to infrastructure and human lives in mountainous regions. This study presents a novel three‐dimensional material point method (MPM), integrating a geographic information system (GIS) and Perlin noise functions, to model the debris flow over complex terrain as a coupled liquid‐solid system. The digital elevation models in GIS are mapped directly onto the MPM computational domain and preserve realistic terrain features. The irregular rock blocks generated by Perlin noise function in Houdini software are embedded into the source zone of debris flow to explicitly represent fluid‐solid interactions. In addition, to maintain the computational accuracy and efficiency, the sparse paged grid structure (SPGrid) is introduced to provide an efficient computational framework for large‐scale 3D hazard analysis. The proposed MPM framework is validated firstly by comparing numerical results and experimental data from previous studies, including saturated soil leakage, rockslide‐induced wave generation, and debris dam break flow. The dynamic behavior and deposition patterns of debris flows are then analyzed, revealing that these factors are significantly influenced by rock block content and the basal friction coefficient. Results show that the proposed two‐phase two‐point MPM is an effective tool to reproduce the realistic propagation of debris flows and provides a scientific reference for hazard assessment and disaster prevention in debris flow‐prone regions.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"22 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651027","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}
Composite piles are a promising technique that improve the stability and loading capacity of soft ground, offering superior performance over traditional methods. Natural soft clays often tend to exhibit pronounced anisotropy, which can substantially affect the consolidation behavior of composite ground. This study presents an analytical consolidation model for composite ground that explicitly incorporates the anisotropic behavior of surrounding soft clay. The model is developed under the equal strain assumption, which is well‐suited for conditions beneath rigid loading platforms such as embankments or raft foundations. The annular equivalent method is employed to accommodate various practical geometries of composite piles. The mechanical behavior of the soft clay is characterized using a yield surface consistent with the S‐CLAY1 model, represented by an inclined ellipse to account for inherent anisotropy. The model integrates both size hardening and rotational hardening laws to describe the evolution of anisotropy under progressive loading. Comparative verification against existing analytical solutions confirms the accuracy of the proposed model. A detailed parametric study is conducted to investigate the influence of key anisotropic parameters, including the critical‐state friction angle , the evolution rate of rotational hardening , and the volumetric‐shear strain weighting factor , on the nonlinear consolidation behavior of the composite ground. Results indicate that higher accelerates consolidation due to increased soil stiffness, while lower values enhance system stiffness and excess pore pressure dissipation. Conversely, increasing reduces the effect of volumetric strain on rotational hardening, leading to greater compressibility and slower consolidation.
{"title":"Effect of Anisotropic Behavior of Soft Clay on the Nonlinear Consolidation of Composite Pile‐Improved Soft Ground Considering Size and Rotational Hardening","authors":"Jisen Shi, Xibin Li, Ruiqi Guo, Dengguo Li, Shilin Gong, Daosheng Ling","doi":"10.1002/nag.70181","DOIUrl":"https://doi.org/10.1002/nag.70181","url":null,"abstract":"Composite piles are a promising technique that improve the stability and loading capacity of soft ground, offering superior performance over traditional methods. Natural soft clays often tend to exhibit pronounced anisotropy, which can substantially affect the consolidation behavior of composite ground. This study presents an analytical consolidation model for composite ground that explicitly incorporates the anisotropic behavior of surrounding soft clay. The model is developed under the equal strain assumption, which is well‐suited for conditions beneath rigid loading platforms such as embankments or raft foundations. The annular equivalent method is employed to accommodate various practical geometries of composite piles. The mechanical behavior of the soft clay is characterized using a yield surface consistent with the S‐CLAY1 model, represented by an inclined ellipse to account for inherent anisotropy. The model integrates both size hardening and rotational hardening laws to describe the evolution of anisotropy under progressive loading. Comparative verification against existing analytical solutions confirms the accuracy of the proposed model. A detailed parametric study is conducted to investigate the influence of key anisotropic parameters, including the critical‐state friction angle , the evolution rate of rotational hardening , and the volumetric‐shear strain weighting factor , on the nonlinear consolidation behavior of the composite ground. Results indicate that higher accelerates consolidation due to increased soil stiffness, while lower values enhance system stiffness and excess pore pressure dissipation. Conversely, increasing reduces the effect of volumetric strain on rotational hardening, leading to greater compressibility and slower consolidation.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"111 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651030","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}
The study of water retention and strength characteristics in unsaturated soils is an underexplored topic yet significant challenge in geotechnical engineering. This paper proposes a simplified computational model for the soil‐water characteristic curve (SWCC), incorporating the novel proposed void optimization parameters l1 and l2 . This model can predict SWCC under various initial void ratios and is applicable across a wide suction range. Additionally, we suggest an adjustment parameter m , which can reflect soil type, and then develop a three‐dimensional strength criterion for unsaturated soil. The strength criterion inherently allows for three expansion trends of the failure surface as the matrix suction s increases: parallel, outward non‐parallel, and inward non‐parallel. Furthermore, based on the novel SWCC model, a predictive formula for the shear strength qf of unsaturated soils is established. This formula is then applied to accurately estimate the strength of unsaturated soils under drained true triaxial conditions.
{"title":"Three‐dimensional Shear Strength Prediction of Unsaturated Soil Based on a Novel Soil‐water Characteristic Curve (SWCC) Model","authors":"Rui Wang, Xuefeng Li, Guowei Fan","doi":"10.1002/nag.70185","DOIUrl":"https://doi.org/10.1002/nag.70185","url":null,"abstract":"The study of water retention and strength characteristics in unsaturated soils is an underexplored topic yet significant challenge in geotechnical engineering. This paper proposes a simplified computational model for the soil‐water characteristic curve (SWCC), incorporating the novel proposed void optimization parameters <jats:italic>l</jats:italic> <jats:sub>1</jats:sub> and <jats:italic>l</jats:italic> <jats:sub>2</jats:sub> . This model can predict SWCC under various initial void ratios and is applicable across a wide suction range. Additionally, we suggest an adjustment parameter <jats:italic>m</jats:italic> , which can reflect soil type, and then develop a three‐dimensional strength criterion for unsaturated soil. The strength criterion inherently allows for three expansion trends of the failure surface as the matrix suction <jats:italic>s</jats:italic> increases: parallel, outward non‐parallel, and inward non‐parallel. Furthermore, based on the novel SWCC model, a predictive formula for the shear strength <jats:italic>q</jats:italic> <jats:sub>f</jats:sub> of unsaturated soils is established. This formula is then applied to accurately estimate the strength of unsaturated soils under drained true triaxial conditions.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"29 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145651031","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}
This study investigates the bearing capacity of tension piles and pile‐soil interaction during loading. Discrepancies between predicted and measured bearing capacities in previous tests motivated the study, where analytical methods showed considerable scatter and uncertainties in design. A large‐scale field test was conducted on three additional adjacent tension piles (Pile 1, 2 and 3), featuring extensive fibre‐optic strain measurements. Concurrently, a numerical Class‐A prediction was developed beforehand to analyse pile‐soil interaction and predict bearing capacity, utilising hypoplastic and visco‐hypoplastic models for the thinly inter‐layered subsoils. The fibre‐optic measurements revealed significant locked‐in bending strains post‐installation, prior to loading. The results showed a correlation between pronounced bending strains and lower load‐bearing capacity. Numerical predictions were compared with the field measurements, providing good agreement with Pile 1, which exhibited minimal installation‐induced bending and thus represented an idealised case. This comparison offered valuable insights into tension pile failure mechanisms and load capacity. This research enhances understanding of tension pile behaviour in complex soils and underscores the necessity of optimising installation methods to improve load‐bearing capacities.
{"title":"Bearing Capacity of Tension Steel Piles in Thinly Inter‐Layered Soils: Numerical Class‐A Prediction vs. Field Measurements","authors":"Diaa Alkateeb, Jürgen Grabe","doi":"10.1002/nag.70132","DOIUrl":"https://doi.org/10.1002/nag.70132","url":null,"abstract":"This study investigates the bearing capacity of tension piles and pile‐soil interaction during loading. Discrepancies between predicted and measured bearing capacities in previous tests motivated the study, where analytical methods showed considerable scatter and uncertainties in design. A large‐scale field test was conducted on three additional adjacent tension piles (Pile 1, 2 and 3), featuring extensive fibre‐optic strain measurements. Concurrently, a numerical Class‐A prediction was developed beforehand to analyse pile‐soil interaction and predict bearing capacity, utilising hypoplastic and visco‐hypoplastic models for the thinly inter‐layered subsoils. The fibre‐optic measurements revealed significant locked‐in bending strains post‐installation, prior to loading. The results showed a correlation between pronounced bending strains and lower load‐bearing capacity. Numerical predictions were compared with the field measurements, providing good agreement with Pile 1, which exhibited minimal installation‐induced bending and thus represented an idealised case. This comparison offered valuable insights into tension pile failure mechanisms and load capacity. This research enhances understanding of tension pile behaviour in complex soils and underscores the necessity of optimising installation methods to improve load‐bearing capacities.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"25 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145613987","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}
Investigating the cumulative thermal damage of rocks under prolonged high‐temperature exposure is crucial for the stability of deep rock engineering. This study investigates the temporal effects of thermal exposure (1–32 h) on granite's physico‐mechanical properties and damage mechanisms through experiments at 150°C, 550°C, and 950°C, combined with uniaxial compression tests, acoustic emission (AE), and numerical simulation. The results show that: (1) the mass loss rate, volume expansion rate, P‐wave velocity reduction rate, and porosity increase exponentially with the duration of high temperature. The proportion of large pores increases. (2) Uniaxial compressive strength and elastic modulus decay exponentially, while peak strain grows exponentially. AE dominant frequency shifts from 120–140 kHz to 260–320 kHz, reflecting microcrack‐dominated fracture. (3) Numerical simulations show thermal crack density positively correlates with temperature/duration. Over 80% of cracks are intergranular shear fractures, with orientations transitioning from directional to random, accompanied by brittle‐to‐ductile failure mode evolution. (4) Microscopic analyses identify mineral phase transitions, grain‐boundary cracking, and interconnected pores as primary damage mechanisms, where temperature governs physico‐chemical reactions and duration amplifies cumulative damage. This work provides reference and suggestions for evaluating the long‐term thermal stability of rocks in deep, high‐temperature geotechnical engineering applications.
{"title":"The Influence of High Temperature Duration on the Thermal Mechanical Properties and Damage Mechanism of Granite: Experimental and Numerical Study","authors":"Congming Li, Peng Zeng, Kui Zhao, Cong Gong, Liangfeng Xiong, Zhen Huang","doi":"10.1002/nag.70183","DOIUrl":"https://doi.org/10.1002/nag.70183","url":null,"abstract":"Investigating the cumulative thermal damage of rocks under prolonged high‐temperature exposure is crucial for the stability of deep rock engineering. This study investigates the temporal effects of thermal exposure (1–32 h) on granite's physico‐mechanical properties and damage mechanisms through experiments at 150°C, 550°C, and 950°C, combined with uniaxial compression tests, acoustic emission (AE), and numerical simulation. The results show that: (1) the mass loss rate, volume expansion rate, P‐wave velocity reduction rate, and porosity increase exponentially with the duration of high temperature. The proportion of large pores increases. (2) Uniaxial compressive strength and elastic modulus decay exponentially, while peak strain grows exponentially. AE dominant frequency shifts from 120–140 kHz to 260–320 kHz, reflecting microcrack‐dominated fracture. (3) Numerical simulations show thermal crack density positively correlates with temperature/duration. Over 80% of cracks are intergranular shear fractures, with orientations transitioning from directional to random, accompanied by brittle‐to‐ductile failure mode evolution. (4) Microscopic analyses identify mineral phase transitions, grain‐boundary cracking, and interconnected pores as primary damage mechanisms, where temperature governs physico‐chemical reactions and duration amplifies cumulative damage. This work provides reference and suggestions for evaluating the long‐term thermal stability of rocks in deep, high‐temperature geotechnical engineering applications.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"29 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145613966","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}
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