{"title":"Multiscale wave dispersion in Sand–Gravel mixtures: Insights from micromorphic modeling","authors":"Yang Liu, Pengqiang Yu","doi":"10.1016/j.compgeo.2025.107351","DOIUrl":"10.1016/j.compgeo.2025.107351","url":null,"abstract":"<div><div>This study presents a novel micromorphic continuum model for sand–gravel mixtures with low gravel contents, which explicitly accounts for the influences of the particle size distribution, gravel content, and fabric anisotropy. This model is rigorously formulated based on the principle of macro–microscopic energy conservation and Hamilton’s variational principle, incorporating a systematic analysis of the kinematics of coarse and fine particles as well as macro–microscopic deformation differentials. Dispersion equations for plane waves are derived to elucidate wave propagation mechanisms. The results demonstrate that the model effectively captures normal dispersion characteristics and size-dependent effects on wave propagation in these mixtures. In long-wavelength regimes, wave velocities are governed by macroscopic properties, whereas decreasing wavelengths induce interparticle scattering and multiple reflections, attenuating velocities or inhibiting waves, especially when wavelengths approach interparticle spacing. The particle size, porosity, and stiffness ratio primarily influence the macroscopic average stiffness, exhibiting consistent effects on dispersion characteristics across all wavelength domains. In contrast, the particle size ratio and gravel content simultaneously influence both macroscopic mechanical properties and microstructural organization, leading to opposing trends across different wavelength ranges. Model validation against experiments confirms its exceptional predictive ability regarding wave propagation characteristics, including relationships between low-pass threshold frequency, porosity, wave velocity, and coarse particle content. This study provides a theoretical foundation for understanding wave propagation in sand–gravel mixtures and their engineering applications.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107351"},"PeriodicalIF":5.3,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212776","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}
Zhi Yong Ai, Xin Kai Chen, Zi Kun Ye, Da Shan Wang
{"title":"Analytical study of fractional viscoelastic transversely isotropic media along shallow-buried square tunnels","authors":"Zhi Yong Ai, Xin Kai Chen, Zi Kun Ye, Da Shan Wang","doi":"10.1016/j.compgeo.2025.107378","DOIUrl":"10.1016/j.compgeo.2025.107378","url":null,"abstract":"<div><div>This paper presents an analytical method for calculating the mechanical characteristics of fractional viscoelastic transversely isotropic surrounding rock along a shallow-buried square tunnel. By employing the Schwarz alternating method, in conjunction with the complex function theory and Flamant’s elastic half-space solution, the analytical solution for a shallow-buried square tunnel in a transversely isotropic half-space is iteratively derived. The solution is then extended from the elastic space to the viscoelastic one using the Laplace transform. Finally, the inverse Laplace transform is applied to obtain the viscoelastic solution in the time domain. The presented analytical solution is validated by comparing the results with those from ABAQUS simulations. Subsequently, case studies are conducted to analyze the influence of various parameters on tunnel deformation and stress.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107378"},"PeriodicalIF":5.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205358","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}
{"title":"Macro- and micro-scale investigation of suffusion in gap-graded soils under multiple factors using CFD-DEM","authors":"Zhibin Liu , Haihua Zhang , Jiangu Qian , Chuang Zhou","doi":"10.1016/j.compgeo.2025.107381","DOIUrl":"10.1016/j.compgeo.2025.107381","url":null,"abstract":"<div><div>Internal erosion induces alterations in the initial microstructure of soils, simultaneously affecting physical, hydraulic, and mechanical properties. The initial soil composition plays a crucial role in governing the initiation and progression of seepage-induced suffusion. This study employs the controlled variable method to develop granular soil models with varying particle size ratios, initial fine particle contents, and coarse particle shapes. Seepage suffusion simulations coupled with microstructural analyses are conducted using the CFD-DEM approach. Results demonstrate that particle size ratio, fine particle content, and coarse particle shape exert distinct influences on cumulative erosion mass, fine particle distribution, contact fabric, and mechanical redundancy at both macroscopic and microscopic scales. This numerical investigation advances the fundamental understanding of internal erosion mechanisms and informs the development of micro-mechanical constitutive models. Furthermore, for binary granular media composed of coarse and fine particles, careful control of the particle size ratio and fine content is recommended when utilizing gap-graded soils in embankment and dam construction to improve structural resilience and resistance to internal erosion.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107381"},"PeriodicalIF":5.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212771","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}
Kehao Chen , Yang Zhou , Rui Pang , Xingliang Wang , Bin Xu
{"title":"Bounding Surface Model for Cyclic Clay Behavior and Its Application in Dynamic Response Analysis of Monopile Offshore Wind Turbines","authors":"Kehao Chen , Yang Zhou , Rui Pang , Xingliang Wang , Bin Xu","doi":"10.1016/j.compgeo.2025.107383","DOIUrl":"10.1016/j.compgeo.2025.107383","url":null,"abstract":"<div><div>The cyclic behavior of clay significantly influences the dynamic response of offshore wind turbines (OWTs). This study presents a practical bounding surface model capable of describing both cyclic shakedown and cyclic degradation. The model is characterized by a simple theoretical framework and a limited number of parameters, and it has been numerically implemented in ABAQUS through a user-defined material (UMAT) subroutine. The yield surface remains fixed at the origin with isotropic hardening, while a movable projection center is introduced to capture cyclic hysteresis behavior. Cumulative plastic deviatoric strain is integrated into the plastic modulus to represent cyclic accumulation. Validation against undrained cyclic tests on three types of clay demonstrates its capability in reproducing stress–strain hysteresis, cyclic shakedown, and cyclic degradation. Additionally, its effectiveness in solving finite element boundary value problems is verified through centrifuge tests on large-diameter monopiles. Furthermore, the model is adopted to analyze the dynamic response of monopile OWTs under seismic loading. The results indicate that, compared to cyclic shakedown, cyclic degradation leads to a progressive reduction in soil stiffness, which diminishes acceleration amplification, increases settlement accumulation, and results in higher residual excess pore pressure with greater fluctuation. Despite its advantages, this model requires a priori specification of the sign of the plastic modulus parameter <em>c</em><sub>d</sub> to capture either cyclic degradation or shakedown behavior. Furthermore, under undrained conditions, the model leads <em>p</em>-stabilization of the effective stress path, which subsequently results in underestimation of the excess pore pressure.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107383"},"PeriodicalIF":5.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205370","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}
{"title":"Phase-field modeling of CO2 fracturing: effects of natural fractures and formation interlayer contrast","authors":"L. Li , X.L. Yang , T. Yu , N. Guo","doi":"10.1016/j.compgeo.2025.107386","DOIUrl":"10.1016/j.compgeo.2025.107386","url":null,"abstract":"<div><div>CO<sub>2</sub> fracturing has been recognized for its significant advantages in enhancing petroleum recovery. In this study, we establish a finite volume method (FVM)-based phase-field model to simulate CO<sub>2</sub> fracturing in poroelastic media, accounting for fluid property variations with temperature and pressure. The porous medium is modeled using classical Biot poroelasticity theory, while fracture behavior is described through a phase-field framework. The phase field acts as an interpolation function to smoothly transition properties between the fracture and reservoir regions. The governing equations are discretized using an implicit cell-centered FVM and solved via an iterative staggered scheme. CO<sub>2</sub> thermophysical properties are updated via the Peng–Robinson equation of state and the Lohrenz–Bray–Clark viscosity model. The framework is verified through a 2D notched specimen subjected to injection of water and CO<sub>2</sub>. It is then applied to investigate fracture propagation in both homogeneous and heterogeneous shale reservoirs. For the homogeneous cases, we analyze the effects of horizontal principal stress differences and natural fracture approach angles. For the heterogeneous reservoirs, we examine how natural fracture orientation and interlayer elastic modulus contrast affect fracture morphology and propagation. This study demonstrates the robustness of the proposed framework in capturing complex fracture behavior, offering insights into optimizing CO<sub>2</sub> fracturing for unconventional gas and oil extraction.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107386"},"PeriodicalIF":5.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195987","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}
Cheng Chen , Lei Yan , Xianwei Zhang , Yong Wang , Zhonghua Sun , Mengbing Xu
{"title":"Theoretical solution for drained cylindrical cavity expansion in sands incorporating fabric anisotropy using the SANISAND-F model","authors":"Cheng Chen , Lei Yan , Xianwei Zhang , Yong Wang , Zhonghua Sun , Mengbing Xu","doi":"10.1016/j.compgeo.2025.107380","DOIUrl":"10.1016/j.compgeo.2025.107380","url":null,"abstract":"<div><div>This paper presents a rigorous, semi-analytical solution for the drained cylindrical cavity expansion in transversely isotropic sand. The constitutive model used for the sand is the SANISAND-F model, which is developed within the anisotropic critical state theory framework that can account for the essential fabric anisotropy of soils. By introducing an auxiliary variable, the governing equations of the cylindrical expansion problem are transformed into a system of ten first-order ordinary differential equations. Three of these correspond to the stress components, three are associated with the kinematic hardening tensor, three describe the fabric tensor, and the last one represents the specific volume. The solution is validated through comparison with finite element analysis, using Toyoura sand as the reference material. Parametric analyses and discussion on the impact of initial void ratio, initial mean stress level, at-rest earth pressure coefficient and initial fabric anisotropy intensity are presented. The results demonstrate that the fabric anisotropy of sand significantly influences the distribution of stress components and void ratio around the cavity. When fabric anisotropy is considered, the solution predicts lower values of radial, circumferential and vertical stresses near the cavity wall compared to those obtained without considering fabric anisotropy. The proposed solution is expected to enhance the accuracy of cavity expansion predictions in sand, which will have significant practical applications, including interpreting pressuremeter tests, predicting effects of driven pile installation, and improving the understanding of sand mechanics under complex loading scenarios.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107380"},"PeriodicalIF":5.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189584","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}
Xinying Shen , Jie Wu , Zhenzhen Song , Tingshuo Jia
{"title":"Automatic simulation of soil-rock mixture seepage using image model directly","authors":"Xinying Shen , Jie Wu , Zhenzhen Song , Tingshuo Jia","doi":"10.1016/j.compgeo.2025.107341","DOIUrl":"10.1016/j.compgeo.2025.107341","url":null,"abstract":"<div><div>Meso-structures in soil-rock mixtures (SRM) exhibit complex geometries that significantly impact their seepage characteristics. The simulation of these structures through conventional methods, such as the Finite Element Method (FEM), necessitates the development of CAD (computer-aided design) models and the generation of conforming meshes. This process is often labor-intensive and can be cumbersome.</div><div>In this work, a seepage analysis that employs image models and structured grids, thus owning high automatic level, is first developed for SRM. Compared to traditional boundary (2D) or surface models (3D), image models can sincerely and efficiently capture the <em>meso</em>-structure of SRM. Using structured grids significantly alleviates the preprocessing workload associated with generating conforming meshes. The element size of the structured grid is completely independent of the pixel size of the image model, facilitating a flexible trade-off between computational accuracy and time efficiency. Weak discontinuities in the seepage field at the soil-rock interfaces are accurately represented using continuous-discontinuous (C-D) trial functions using the Numerical Manifold Method (NMM), enforced through penalty methods. Numerical examples investigate the computational accuracy and efficacy of the proposed method. More promisingly, the direct use of image models and structured grids in simulating SRM greatly reduces manual intervention, demonstrating the new method’s outstanding automation advantage and providing a methodological foundation for the development of related unmanned hardware devices.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107341"},"PeriodicalIF":5.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189585","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}
{"title":"Numerical evaluation of the dynamic performance of recommissioned offshore wind turbines under service life extension and repowering strategies","authors":"Yikang Wang , Fayun Liang , Hao Zhang , Hanbo Zheng","doi":"10.1016/j.compgeo.2025.107370","DOIUrl":"10.1016/j.compgeo.2025.107370","url":null,"abstract":"<div><div>This study addresses the recommissioning needs of offshore wind farms facing foundation degradation and equipment aging after years of operation. Service Life Extension (SLE) and Repowering, as key strategies to reduce decommissioning costs and enhance asset value, have been successfully applied to multiple wind farms. Based on advanced 3D finite element (FE) simulations, this study systematically analyzes the dynamic response of sand-monopile-offshore wind turbine (OWT) system under long-term service and scour effects, focusing on the impact of recommissioning strategies, including upper structure replacement (Repowering) and cement-solidified soil foundation remediation (SLE). The analysis reveals that long-term service and scour effects significantly reduce the natural frequency of OWTs, increasing the risk of resonance and exacerbating the dynamic response and deformation of the tower. Replacing the upper structure with a lower-power OWT can effectively enhance the tower’s resistance to deformation but may lead to increased dynamic response at the nacelle. When replacing with a higher-power OWT, cement- solidified soil remediation significantly restores the turbine’s service performance by suppressing displacement and strain accumulation in shallow soils, though its effectiveness diminishes as the remediation height increases. These findings provide valuable insights for selecting and evaluating recommissioning strategies for OWTs.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107370"},"PeriodicalIF":5.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195986","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}
{"title":"Probabilistic analysis of tunnel deformation and ground surface settlement induced by surcharge in spatially variable soil","authors":"Han Han , Wengang Zhang , Zhihao Wu , Weixin Sun","doi":"10.1016/j.compgeo.2025.107369","DOIUrl":"10.1016/j.compgeo.2025.107369","url":null,"abstract":"<div><div>Existing tunnels are inevitably influenced by surrounding environments, with ground surface surcharge being one of the most significant factors affecting tunnel deformations and ground surface settlement. At the same time, the spatial variability of soils also plays a crucial role in these outcomes. However, many studies rely on deterministic analyses that overlook the spatial variability of soils, which can lead to inaccurate predictions of tunnel behavior and surface settlement. Furthermore, there is limited research that simultaneously considers the effects of both surcharge and the spatial variability of soil on these responses in a three-dimensional space. In this study, the impact of surcharge and uncertain soil properties on surface settlement and tunnel deformations was investigated based on random fields combined with the finite element method. The influence of surcharge positions <em>L</em>, eccentricities <em>e</em>, heights <em>h</em>, as well as the coefficient of variation of Young's modulus (<em>COV<sub>E</sub></em>) and scales of fluctuation (SOF) of Young's modulus on surface settlement and tunnel deformations were investigated. As <em>L</em> increases, with the surcharge shifting from the center towards the boundaries, the maximum tunnel deformations and surface settlement, along with the corresponding probability of failure (<em>P<sub>f</sub></em>) intensify, due to the limited space for dissipation of the surcharge. As <em>e</em> increases, these effects decrease. In contrast, an increase in <em>h</em> amplifies them. The larger the <em>COV<sub>E</sub></em>, the greater the impact of the surcharge on tunnel deformations, surface settlement, and the corresponding <em>P<sub>f</sub></em>. This is because a larger <em>COV<sub>E</sub></em> increases the probability of extreme realizations. Similar to the effect of <em>COV<sub>E</sub></em>, a larger SOF increases the impact of soil spatial variability.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107369"},"PeriodicalIF":5.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185504","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}
Liang Wang , Qiang Xue , Yong Wan , Jingjing Meng , Xiang Sun , Tao Zhao , Houzhen Wei , Xue Zhang
{"title":"An implicit nodal integration-based three-dimensional particle finite element model for simulating dynamic saturated porous media","authors":"Liang Wang , Qiang Xue , Yong Wan , Jingjing Meng , Xiang Sun , Tao Zhao , Houzhen Wei , Xue Zhang","doi":"10.1016/j.compgeo.2025.107372","DOIUrl":"10.1016/j.compgeo.2025.107372","url":null,"abstract":"<div><div>Large deformation analysis of dynamic saturated porous media holds significant importance in accurately describing the life of various geotechnical and geological applications, since they can seamlessly capture the continuous variation of geomaterials with extreme changes in configurations and properties. Many numerical models have been developed, while most of them are limited to two-dimensional scenarios and explicit time integration schemes, which therefore compromise their accuracy and efficiency in studying low- and medium-frequency practical problems. In addition, different stabilisation techniques with tunable parameters are often required when using the efficient linear elements for dynamic analysis. To overcome these hurdles, this work introduces an implicit three-dimensional nodal integration-based particle finite element method (N-PFEM) that combines the advantages of a mixed variational principle, a nodal-based strain smoothing technique, mathematical programming, and the particle finite element method, ensuring the accuracy and robustness in analysing dynamic saturated media. The three-dimensional N-PFEM is thoroughly examined against four numerical benchmarks, for which numerical solutions agree well with reference solutions or experimental data. The model is further applied to simulate earthquake-induced slope failures, which characterises the effect of material property on the initiation and propagation of landslides in a three-dimensional space. The developed model holds important implications for developing numerical approaches and demonstrates strong potential as an effective and practical tool in analysing the hydro-mechanical behaviour of geomaterials in real applications.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"186 ","pages":"Article 107372"},"PeriodicalIF":5.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185423","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}