Pub Date : 2026-01-30DOI: 10.1016/j.compgeo.2026.107957
Zhenjie Tang, Li He
Characterizing spatially variable hydraulic properties in geotechnical subsurface systems is a high-dimensional and ill-posed inverse problem, particularly in unsaturated flow conditions. We introduce TKLE-BPINN, a novel Bayesian framework that integrates Bayesian physics-informed neural networks (B-PINNs) with truncated Karhunen–Loève expansion (KLE) to address these challenges efficiently. By representing unknown fields with latent KLE coefficients and employing Ensemble Kalman Inversion (EKI) for posterior inference, TKLE-BPINN achieves accurate parameter estimation and robust uncertainty quantification. We validate the framework on three subsurface flow and transport test cases: (i) a linear diffusion–reaction problem with unknown diffusivity, (ii) a nonlinear diffusion–reaction problem with unknown reaction coefficients, and (iii) a multi-parameter inversion of diffusivity and contaminant source locations, where TKLE-BPINN consistently outperforms standard B-PINNs in accuracy and stability. We further apply TKLE-BPINN to a realistic hydrogeotechnical scenario, inverting saturated hydraulic conductivity in nonlinear unsaturated flow for heterogeneous soils, yielding reliable parameter estimates and uncertainty quantification essential for subsurface flow modeling. These results indicate that TKLE-BPINN provides a flexible and robust alternative for geotechnical subsurface characterization.
{"title":"TKLE-BPINN: A Bayesian physics-informed inversion framework for high-dimensional parameter identification in geotechnical subsurface systems","authors":"Zhenjie Tang, Li He","doi":"10.1016/j.compgeo.2026.107957","DOIUrl":"10.1016/j.compgeo.2026.107957","url":null,"abstract":"<div><div>Characterizing spatially variable hydraulic properties in geotechnical subsurface systems is a high-dimensional and ill-posed inverse problem, particularly in unsaturated flow conditions. We introduce TKLE-BPINN, a novel Bayesian framework that integrates Bayesian physics-informed neural networks (B-PINNs) with truncated Karhunen–Loève expansion (KLE) to address these challenges efficiently. By representing unknown fields with latent KLE coefficients and employing Ensemble Kalman Inversion (EKI) for posterior inference, TKLE-BPINN achieves accurate parameter estimation and robust uncertainty quantification. We validate the framework on three subsurface flow and transport test cases: (i) a linear diffusion–reaction problem with unknown diffusivity, (ii) a nonlinear diffusion–reaction problem with unknown reaction coefficients, and (iii) a multi-parameter inversion of diffusivity and contaminant source locations, where TKLE-BPINN consistently outperforms standard B-PINNs in accuracy and stability. We further apply TKLE-BPINN to a realistic hydrogeotechnical scenario, inverting saturated hydraulic conductivity in nonlinear unsaturated flow for heterogeneous soils, yielding reliable parameter estimates and uncertainty quantification essential for subsurface flow modeling. These results indicate that TKLE-BPINN provides a flexible and robust alternative for geotechnical subsurface characterization.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107957"},"PeriodicalIF":6.2,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30DOI: 10.1016/j.compgeo.2026.107951
Yuanping Li , Ruyang Yu , Xiaolong Yin , Huanquan Pan , Bin Gong , Lifeng Chen , Jingwei Huang
Particle clogging in porous media is a critical phenomenon with significant implications for geotechnical engineering, subsurface flow, and underground carbon storage. However, existing studies are limited to single-scale analysis, lacking multi-scale insights into the connections between simplified models and real porous media. To address these limitations, this study conducts a multi-scale investigation spanning single pores, homogeneous porous media, and digital rocks to elucidate clogging mechanisms. In the single-pore, three clogging regimes were identified: non-clogging, unstable clogging, and stable clogging. The critical thresholds of the three regimes were determined. In homogeneous porous medium, the clogging process could undergo three stages. Firstly, particles only blocked the dominant flow paths. Secondly, the new preferential pathways experience an increase in velocity and particle flux, leading to secondary clogging. Thirdly, the primary and secondary paths were mostly blocked, and a network of blockages was formed. The three clogging modes were summarized: selective channel clogging, localized bridging, and network-scale blockage, which are controlled by particle-to-throat size ratio, flow velocity and particle concentration. Network-scale blockages result in the most significant decline in permeability, while selective channel clogging leads to the least. In digital rocks, clogging exhibited the similar clogging behaviors observed in homogeneous porous media, but it exhibited distinct permeability loss due to the heterogeneity of realistic pore structures. This multi-scale study quantifies the regulatory effects of key parameters on clogging across scales, and identifies scale-specific patterns and mechanisms.
{"title":"CFD-DEM investigation on particle clogging in porous media at different scales: From single pore to digital rock","authors":"Yuanping Li , Ruyang Yu , Xiaolong Yin , Huanquan Pan , Bin Gong , Lifeng Chen , Jingwei Huang","doi":"10.1016/j.compgeo.2026.107951","DOIUrl":"10.1016/j.compgeo.2026.107951","url":null,"abstract":"<div><div>Particle clogging in porous media is a critical phenomenon with significant implications for geotechnical engineering, subsurface flow, and underground carbon storage. However, existing studies are limited to single-scale analysis, lacking multi-scale insights into the connections between simplified models and real porous media. To address these limitations, this study conducts a multi-scale investigation spanning single pores, homogeneous porous media, and digital rocks to elucidate clogging mechanisms. In the single-pore, three clogging regimes were identified: non-clogging, unstable clogging, and stable clogging. The critical thresholds of the three regimes were determined. In homogeneous porous medium, the clogging process could undergo three stages. Firstly, particles only blocked the dominant flow paths. Secondly, the new preferential pathways experience an increase in velocity and particle flux, leading to secondary clogging. Thirdly, the primary and secondary paths were mostly blocked, and a network of blockages was formed. The three clogging modes were summarized: selective channel clogging, localized bridging, and network-scale blockage, which are controlled by particle-to-throat size ratio, flow velocity and particle concentration. Network-scale blockages result in the most significant decline in permeability, while selective channel clogging leads to the least. In digital rocks, clogging exhibited the similar clogging behaviors observed in homogeneous porous media, but it exhibited distinct permeability loss due to the heterogeneity of realistic pore structures. This multi-scale study quantifies the regulatory effects of key parameters on clogging across scales, and identifies scale-specific patterns and mechanisms.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107951"},"PeriodicalIF":6.2,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.compgeo.2026.107941
Juntao Wu , Weikai Zhao , Kuihua Wang , M. Hesham El Naggar
Traditional analytical and numerical methods for dynamic pile-soil interaction (PSI) have limitations in solving the problem’s partial differential equations (PDEs). To address some of these limitations, a transfer learning enhanced progressive multi-physics-informed neural networks (TLP-mPINNs) framework is developed in this paper. The improved PINNs model utilizes customized independent deep neural networks (DNNs) for pile and soil to adapt to different material domains. First, a pre-trained pile vibration network is transferred to a more sophisticated pile-soil coupled vibration network to accelerate the training process. Second, the parameters of pile and soil DNNs are progressively trained through alternating learning to improve the model stability. The predictions of the TLP-mPINNs are verified using existing solutions of the pile-half space soil coupled vibration system. The validated model is then employed to investigate the dynamic PSI problem under different cases. The results demonstrate that the improved PINN framework can provide a new solution for the dynamic PSI problems, and highlight its potential as an optimization methodology for applying PINN to complex multi-media coupled vibration problems.
{"title":"Physics-informed neural networks (PINNs) for dynamic pile-soil interaction problems","authors":"Juntao Wu , Weikai Zhao , Kuihua Wang , M. Hesham El Naggar","doi":"10.1016/j.compgeo.2026.107941","DOIUrl":"10.1016/j.compgeo.2026.107941","url":null,"abstract":"<div><div>Traditional analytical and numerical methods for dynamic pile-soil interaction (PSI) have limitations in solving the problem’s partial differential equations (PDEs). To address some of these limitations, a transfer learning enhanced progressive multi-physics-informed neural networks (TLP-mPINNs) framework is developed in this paper. The improved PINNs model utilizes customized independent deep neural networks (DNNs) for pile and soil to adapt to different material domains. First, a pre-trained pile vibration network is transferred to a more sophisticated pile-soil coupled vibration network to accelerate the training process. Second, the parameters of pile and soil DNNs are progressively trained through alternating learning to improve the model stability. The predictions of the TLP-mPINNs are verified using existing solutions of the pile-half space soil coupled vibration system. The validated model is then employed to investigate the dynamic PSI problem under different cases. The results demonstrate that the improved PINN framework can provide a new solution for the dynamic PSI problems, and highlight its potential as an optimization methodology for applying PINN to complex multi-media coupled vibration problems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107941"},"PeriodicalIF":6.2,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.compgeo.2025.107860
Yangping Yao , Yu Tian , Zijun Yao , Dechun Lu , Xiuli Du
The small-strain Unified Hardening (SSUH) model considers the high initial stiffness and rapid stiffness degradation of soils during the loading process. When its stress integration is implemented by an implicit algorithm in the finite element analysis, a key issue lies in how to solve the highly nonlinear constitutive equations. This paper proposes multistage Homotopy continuation method (MHCM), which progressively optimizes the initial guess by several stages of Homotopic deformation, to ensure the successful solution of the constitutive equations using Newton-Raphson iteration. An adaptive Homotopic deformation rate is introduced to prevent the subsequent stage of Homotopic deformation from repeating the previous failure. Compared with the original single-stage Homotopy continuation method, MHCM improves the convergence and efficiency without compromising the accuracy. Based on the SSUH model and the proposed stress integration algorithm, the ground displacement induced by the excavation of Crossrail tunnels can be reasonably predicted.
{"title":"Stress integration algorithm of the small-strain Unified Hardening model for soils based on multistage Homotopy continuation method","authors":"Yangping Yao , Yu Tian , Zijun Yao , Dechun Lu , Xiuli Du","doi":"10.1016/j.compgeo.2025.107860","DOIUrl":"10.1016/j.compgeo.2025.107860","url":null,"abstract":"<div><div>The small-strain Unified Hardening (SSUH) model considers the high initial stiffness and rapid stiffness degradation of soils during the loading process. When its stress integration is implemented by an implicit algorithm in the finite element analysis, a key issue lies in how to solve the highly nonlinear constitutive equations. This paper proposes multistage Homotopy continuation method (MHCM), which progressively optimizes the initial guess by several stages of Homotopic deformation, to ensure the successful solution of the constitutive equations using Newton-Raphson iteration. An adaptive Homotopic deformation rate is introduced to prevent the subsequent stage of Homotopic deformation from repeating the previous failure. Compared with the original single-stage Homotopy continuation method, MHCM improves the convergence and efficiency without compromising the accuracy. Based on the SSUH model and the proposed stress integration algorithm, the ground displacement induced by the excavation of Crossrail tunnels can be reasonably predicted.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107860"},"PeriodicalIF":6.2,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.compgeo.2026.107939
Wentao Yang, Shaobo Jin, Qiuhua Rao, Wei Yi, Zelin Liu
The seepage-stress coupling effect is critical to the stability of engineering structures, but existing models have certain limitations: the equivalent continuum model neglects seepage differences between pores and fractures; the discrete fracture network model overlooks pore permeability and involves complex calculations; and the dual medium model fails to account for non-Darcy seepage effects and the spatiotemporal evolution of physical parameters. Consequently, solving the seepage-stress coupling problem of spatially heterogeneous pore-fracture dual media remains challenging. In this study, we incorporate two key effects into the modeling framework: the non-Darcy seepage and the nonlinear seepage-stress coupling (including the spatiotemporal evolution of seepage parameters, solid deformation parameters, and effective stress coefficients). The model is developed via self-programming in COMSOL Multiphysics, and its reliability is validated through lab experiments. Results show that both effects suppress the dissipation of fluid pressure, the consolidation rate, and the final settlement of the soil. The degree of such suppression is governed by fracture permeability, pore permeability, and their ratio. Additionally, the practicality of this model is verified through a 3D engineering case. The model can be further extended to a multi-scale fracture network model (explicitly characterizing main fractures and implicitly describing randomly distributed secondary fractures and pores) with consideration of permeability anisotropy.
{"title":"A modified nonlinear seepage-stress coupling model of heterogeneous pore-fracture dual medium for engineering geomaterials","authors":"Wentao Yang, Shaobo Jin, Qiuhua Rao, Wei Yi, Zelin Liu","doi":"10.1016/j.compgeo.2026.107939","DOIUrl":"10.1016/j.compgeo.2026.107939","url":null,"abstract":"<div><div>The seepage-stress coupling effect is critical to the stability of engineering structures, but existing models have certain limitations: the equivalent continuum model neglects seepage differences between pores and fractures; the discrete fracture network model overlooks pore permeability and involves complex calculations; and the dual medium model fails to account for non-Darcy seepage effects and the spatiotemporal evolution of physical parameters. Consequently, solving the seepage-stress coupling problem of spatially heterogeneous pore-fracture dual media remains challenging. In this study, we incorporate two key effects into the modeling framework: the non-Darcy seepage and the nonlinear seepage-stress coupling (including the spatiotemporal evolution of seepage parameters, solid deformation parameters, and effective stress coefficients). The model is developed via self-programming in COMSOL Multiphysics, and its reliability is validated through lab experiments. Results show that both effects suppress the dissipation of fluid pressure, the consolidation rate, and the final settlement of the soil. The degree of such suppression is governed by fracture permeability, pore permeability, and their ratio. Additionally, the practicality of this model is verified through a 3D engineering case. The model can be further extended to a multi-scale fracture network model (explicitly characterizing main fractures and implicitly describing randomly distributed secondary fractures and pores) with consideration of permeability anisotropy.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107939"},"PeriodicalIF":6.2,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 presents a multiphysics model and the corresponding algorithm for the numerical simulation of millimetre-wave ablation of geological materials. Simulations of this process are particularly challenging due to the low thermal conductivity and limited melt mobility of rock, as well as the high latent heat of evaporation and melt-to-vapour density ratio (exceeding 2500:1), which induce strong velocity divergence effects at the melt–vapour interface. Specifically, the model introduced in this work addresses the low-intensity, volumetric heating of rocks, taking place over significantly larger spatial and temporal scales (approximately 300 and 100 times greater, respectively) compared to similar processes encountered in laser drilling of metals. A comprehensive description is provided of the mathematical formulation, beam model, and numerical algorithm employed to perform robust, fully three-dimensional simulations lasting up to 25 s. These demanding computations are made tractable through MPI parallelisation and hierarchical Adaptive Mesh Refinement. Following the presentation of the model and solution methodology, an experiment is introduced which was devised specifically to produce data for model calibration and validation purposes. Comparison of the numerical results against the experimental reference test case and a parametric study of varying beam intensity demonstrate that the model can make good predictions of the penetration depth and the volume of material removed. The bounds and limitations of the model are also explored through the parametric study, with desirable future extensions identified to improve the accuracy of the model predictions.
{"title":"Multiphysics modelling of millimetre-wave ablation of geological materials","authors":"Nandan Gokhale , Candace Gilet , Franck Monmont , Nikos Nikiforakis","doi":"10.1016/j.compgeo.2026.107946","DOIUrl":"10.1016/j.compgeo.2026.107946","url":null,"abstract":"<div><div>This study presents a multiphysics model and the corresponding algorithm for the numerical simulation of millimetre-wave ablation of geological materials. Simulations of this process are particularly challenging due to the low thermal conductivity and limited melt mobility of rock, as well as the high latent heat of evaporation and melt-to-vapour density ratio (exceeding 2500:1), which induce strong velocity divergence effects at the melt–vapour interface. Specifically, the model introduced in this work addresses the low-intensity, volumetric heating of rocks, taking place over significantly larger spatial and temporal scales (approximately 300 and 100 times greater, respectively) compared to similar processes encountered in laser drilling of metals. A comprehensive description is provided of the mathematical formulation, beam model, and numerical algorithm employed to perform robust, fully three-dimensional simulations lasting up to 25 s. These demanding computations are made tractable through MPI parallelisation and hierarchical Adaptive Mesh Refinement. Following the presentation of the model and solution methodology, an experiment is introduced which was devised specifically to produce data for model calibration and validation purposes. Comparison of the numerical results against the experimental reference test case and a parametric study of varying beam intensity demonstrate that the model can make good predictions of the penetration depth and the volume of material removed. The bounds and limitations of the model are also explored through the parametric study, with desirable future extensions identified to improve the accuracy of the model predictions.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107946"},"PeriodicalIF":6.2,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dynamics of embankment considering elastoplasticity is investigated using the coupled seepage–deformation finite element analysis with the full Biot formation in the u–v–p format, where the solid displacement, relative fluid velocity respect to solid, and pore fluid pressure are taken as the primary variables. The seismic response of embankment is first evaluated using the centrifuge experiment, based on which the typical seepage and deformation characteristics of embankment are investigated. The validation against the centrifuge experimental result demonstrates the capability of the coupled finite element analysis using the full formulation and elastoplasticity to predict embankment responses during seismic loading such as the horizontal acceleration, surface settlement, and pore water pressure, thus proving a robust tool to investigate the porous media dynamics. Regarding the dynamics of embankment during seismic loading with various combinations of soil permeability and loading frequency, the predicated embankment responses such as solid acceleration, pore fluid pressure, and soil deformation based on the full analysis tend to show more significant difference in comparison with those predicted by the simplified analysis that neglects the relative fluid acceleration respect to solid acceleration when the soil permeability or loading frequency increases to a high level. Based on the numerical simulation with elastoplasticity, the difference in various dynamic responses of the embankment especially the soil deformation using the full and simplified analysis approaches can mainly be divided into two distinct zones in the – space ( and are the permeability and frequency ratios), where the significant difference is found in scenarios with or generally larger than 100 m or 100 Hz.
{"title":"Coupled seepage–deformation analysis of the dynamics of embankment with elastoplasticity based on the full formulation","authors":"Jiawei Xu , Ryosuke Uzuoka , Kyohei Ueda , Yoshikazu Tanaka","doi":"10.1016/j.compgeo.2026.107950","DOIUrl":"10.1016/j.compgeo.2026.107950","url":null,"abstract":"<div><div>The dynamics of embankment considering elastoplasticity is investigated using the coupled seepage–deformation finite element analysis with the full Biot formation in the <strong><em>u</em></strong>–<strong><em>v</em></strong>–<em>p</em> format, where the solid displacement, relative fluid velocity respect to solid, and pore fluid pressure are taken as the primary variables. The seismic response of embankment is first evaluated using the centrifuge experiment, based on which the typical seepage and deformation characteristics of embankment are investigated. The validation against the centrifuge experimental result demonstrates the capability of the coupled finite element analysis using the full formulation and elastoplasticity to predict embankment responses during seismic loading such as the horizontal acceleration, surface settlement, and pore water pressure, thus proving a robust tool to investigate the porous media dynamics. Regarding the dynamics of embankment during seismic loading with various combinations of soil permeability and loading frequency, the predicated embankment responses such as solid acceleration, pore fluid pressure, and soil deformation based on the full analysis tend to show more significant difference in comparison with those predicted by the simplified analysis that neglects the relative fluid acceleration respect to solid acceleration when the soil permeability or loading frequency increases to a high level. Based on the numerical simulation with elastoplasticity, the difference in various dynamic responses of the embankment especially the soil deformation using the full and simplified analysis approaches can mainly be divided into two distinct zones in the <span><math><mrow><mi>k</mi><mo>/</mo><mi>f</mi></mrow></math></span>–<span><math><msup><mrow><mi>f</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span> space (<span><math><mi>k</mi></math></span> and <span><math><mi>f</mi></math></span> are the permeability and frequency ratios), where the significant difference is found in scenarios with <span><math><mrow><mi>k</mi><mo>/</mo><mi>f</mi></mrow></math></span> or <span><math><mi>f</mi></math></span> generally larger than 100 m or 100 Hz.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107950"},"PeriodicalIF":6.2,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.compgeo.2026.107925
Zhonghao Li , Xiaofeng Li , Haibo Li , Qi Zhao , Giovanni Grasselli
The combined finite–discrete element method (FDEM) has proven effective for simulating crack initiation, propagation, and coalescence in brittle solids. However, existing FDEM frameworks remain limited to constant-strain elements, leading to restricted capability in representing complex stress fields, pronounced sensitivity to shear and volumetric locking, and a strong tendency toward numerical dispersion in dynamic problems. To overcome these limitations, this study develops a high order element-based framework incorporating a novel quadratic cohesive element to enhance model accuracy and continuity. The proposed quadratic cohesive element ensures uniform traction distribution along edges, avoiding the mid-node stress concentrations that typically lead to mesh incompatibility and artificial strength reduction. Three quasi-static loading tests and one wave propagation test are performed to compare quadratic and linear models. The results show that the quadratic model consistently outperforms the linear counterpart in stress path, crack propagation, and mitigating numerical dispersion. In quasi-static loading, the new quadratic model exhibits a lower error in stress, predicts a more precise crack initiation load, and provides more reliable crack path predictions compared with previous models. In dynamic conditions, it can effectively mitigate the numerical dispersion of high-frequency wave components that low-order elements struggle with and provide more stable wave propagation simulations. Moreover, the quadratic elements FDEM framework offers an economical alternative for enhancing the fidelity of crack simulations: compared to mesh refinement, quadratic elements achieve comparable accuracy in crack initiation load prediction with only 50–60% of the computational cost.
{"title":"The performance of quadratic finite-discrete element method (qFDEM) and its potential advantages","authors":"Zhonghao Li , Xiaofeng Li , Haibo Li , Qi Zhao , Giovanni Grasselli","doi":"10.1016/j.compgeo.2026.107925","DOIUrl":"10.1016/j.compgeo.2026.107925","url":null,"abstract":"<div><div>The combined finite–discrete element method (FDEM) has proven effective for simulating crack initiation, propagation, and coalescence in brittle solids. However, existing FDEM frameworks remain limited to constant-strain elements, leading to restricted capability in representing complex stress fields, pronounced sensitivity to shear and volumetric locking, and a strong tendency toward numerical dispersion in dynamic problems. To overcome these limitations, this study develops a high order element-based framework incorporating a novel quadratic cohesive element to enhance model accuracy and continuity. The proposed quadratic cohesive element ensures uniform traction distribution along edges, avoiding the mid-node stress concentrations that typically lead to mesh incompatibility and artificial strength reduction. Three quasi-static loading tests and one wave propagation test are performed to compare quadratic and linear models. The results show that the quadratic model consistently outperforms the linear counterpart in stress path, crack propagation, and mitigating numerical dispersion. In quasi-static loading, the new quadratic model exhibits a lower error in stress, predicts a more precise crack initiation load, and provides more reliable crack path predictions compared with previous models. In dynamic conditions, it can effectively mitigate the numerical dispersion of high-frequency wave components that low-order elements struggle with and provide more stable wave propagation simulations. Moreover, the quadratic elements FDEM framework offers an economical alternative for enhancing the fidelity of crack simulations: compared to mesh refinement, quadratic elements achieve comparable accuracy in crack initiation load prediction with only 50–60% of the computational cost.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107925"},"PeriodicalIF":6.2,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.compgeo.2026.107911
Srinivas Vivek Bokkisa , Jorge Macedo , Pedro Arduino
Anisotropic critical state theory (ACST) provides a framework for incorporating fabric effects in constitutive models. However, most previous efforts have focused on constitutive aspects with comparatively limited attention to numerical implementations. This study presents a comprehensive assessment of explicit and implicit implementations of the ACST-based bounding surface model, SANISAND-F. Assessments are conducted in terms of stability, accuracy, computational efficiency, and both local and global performance.
In the implicit implementation, the critical importance of accurate gradient calculations is highlighted, introducing a verification procedure that enables quadratic convergence. The explicit and implicit implementations exhibit stability, producing smooth and bounded responses across a wide range of strain increments and numerical tolerances. However, their accuracy differs significantly. The implicit implementation is sensitive to the initial loading state, strain increment, and loading direction, showing minor dependence on the solver tolerance. In contrast, the explicit implementation is influenced by both strain increment and substepping tolerance, and at practical tolerance and strain increment levels, it often outperforms the implicit scheme in accuracy. Regarding efficiency, the explicit implementation proves more efficient at the local integration level. However, at the global level, the implicit implementation with the consistent tangent exhibits a faster rate of convergence in global equilibrium iterations. Nonetheless, the overall computational cost at the global level is not definitive when comparing explicit and implicit schemes; it varies with simulations and loading-specific parameters, as demonstrated through the included boundary-value problems.
{"title":"On the integration of an ACST-based bounding surface model","authors":"Srinivas Vivek Bokkisa , Jorge Macedo , Pedro Arduino","doi":"10.1016/j.compgeo.2026.107911","DOIUrl":"10.1016/j.compgeo.2026.107911","url":null,"abstract":"<div><div>Anisotropic critical state theory (ACST) provides a framework for incorporating fabric effects in constitutive models. However, most previous efforts have focused on constitutive aspects with comparatively limited attention to numerical implementations. This study presents a comprehensive assessment of explicit and implicit implementations of the ACST-based bounding surface model, SANISAND-F. Assessments are conducted in terms of stability, accuracy, computational efficiency, and both local and global performance.</div><div>In the implicit implementation, the critical importance of accurate gradient calculations is highlighted, introducing a verification procedure that enables quadratic convergence. The explicit and implicit implementations exhibit stability, producing smooth and bounded responses across a wide range of strain increments and numerical tolerances. However, their accuracy differs significantly. The implicit implementation is sensitive to the initial loading state, strain increment, and loading direction, showing minor dependence on the solver tolerance. In contrast, the explicit implementation is influenced by both strain increment and substepping tolerance, and at practical tolerance and strain increment levels, it often outperforms the implicit scheme in accuracy. Regarding efficiency, the explicit implementation proves more efficient at the local integration level. However, at the global level, the implicit implementation with the consistent tangent exhibits a faster rate of convergence in global equilibrium iterations. Nonetheless, the overall computational cost at the global level is not definitive when comparing explicit and implicit schemes; it varies with simulations and loading-specific parameters, as demonstrated through the included boundary-value problems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107911"},"PeriodicalIF":6.2,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-27DOI: 10.1016/j.compgeo.2026.107937
Wei CHENG , Zhen-Yu YIN
Stable integration schemes are critically important for rate-dependent constitutive models, serving as a cornerstone for ensuring accuracy, efficiency, and robustness in finite element implementations. This paper investigates the numerical performance of explicit stress integration schemes with adaptive substepping for integrating a newly proposed fractional consistency two-surface viscoplastic model for saturated clays. The incremental stress–strain-strain rate relation of the model can be linearized following the consistency condition of the rate-dependent loading surface and subsequently integrated using four distinct explicit Runge-Kutta substepping integration algorithms (i.e., RK12, RK23, RK34, RK45) with automatic error control and stress drift correction techniques. The overall numerical performance of the algorithms in terms of accuracy and efficiency is evaluated at both the material point level (i.e., isotropic, oedometric, and triaxial compression tests) and the boundary-value problem level (i.e., piezocone penetration and underground gallery excavation), which demonstrates that the RK23 and RK34 algorithms perform excellently in balancing accuracy and computational cost. The proposed algorithms provide a versatile and adaptive framework for integrating time-dependent constitutive equations, particularly those based on the consistency viscoplastic approaches commonly used in advanced rate-dependent modeling, allowing for a wide range of geotechnical engineering applications.
{"title":"Extension of explicit Runge-Kutta substepping stress integration for viscoplastic model of saturated soils","authors":"Wei CHENG , Zhen-Yu YIN","doi":"10.1016/j.compgeo.2026.107937","DOIUrl":"10.1016/j.compgeo.2026.107937","url":null,"abstract":"<div><div>Stable integration schemes are critically important for rate-dependent constitutive models, serving as a cornerstone for ensuring accuracy, efficiency, and robustness in finite element implementations. This paper investigates the numerical performance of explicit stress integration schemes with adaptive substepping for integrating a newly proposed fractional consistency two-surface viscoplastic model for saturated clays. The incremental stress–strain-strain rate relation of the model can be linearized following the consistency condition of the rate-dependent loading surface and subsequently integrated using four distinct explicit Runge-Kutta substepping integration algorithms (i.e., RK12, RK23, RK34, RK45) with automatic error control and stress drift correction techniques. The overall numerical performance of the algorithms in terms of accuracy and efficiency is evaluated at both the material point level (i.e., isotropic, oedometric, and triaxial compression tests) and the boundary-value problem level (i.e., piezocone penetration and underground gallery excavation), which demonstrates that the RK23 and RK34 algorithms perform excellently in balancing accuracy and computational cost. The proposed algorithms provide a versatile and adaptive framework for integrating time-dependent constitutive equations, particularly those based on the consistency viscoplastic approaches commonly used in advanced rate-dependent modeling, allowing for a wide range of geotechnical engineering applications.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"193 ","pages":"Article 107937"},"PeriodicalIF":6.2,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}