Computers and Geotechnics最新文献

{"title":"Morphological variability and its influence on the true triaxial mechanical response of rockfill: A DEM approach","authors":"Chenhui Guan ,&nbsp;Chunshun Zhang ,&nbsp;Qixin Wu ,&nbsp;Wei Wei ,&nbsp;Jie Dong ,&nbsp;Congying Li","doi":"10.1016/j.compgeo.2025.107153","DOIUrl":"10.1016/j.compgeo.2025.107153","url":null,"abstract":"<div><div>The variability in particle morphology significantly impacts the mechanical properties of rockfill materials. To enhance the understanding of this influence, this study collected basalt rockfill particles from 6 different site sources, with their morphology captured by 3D scanning technology, and then the morphological characteristics categorized through cluster analysis. True triaxial tests for these 6 particle groups were simulated using discrete element method (DEM), and the effects of elongation, flatness, convexity, and intermediate principal stress coefficient on the stress-strain relationship and peak strength were qualitatively assessed through principal component analysis (PCA). Further, by controlling the elongation, flatness, and convexity, 3D reconstructed particle models were created by spherical harmonics (SH) analysis, and the true triaxial tests on these models were simulated to quantitatively clarify the influence of morphological parameters on the macroscopic stress-strain relationship, peak strength, microscopic contact, anisotropic evolution, and other characteristics. Considering the size effect in rockfill materials, multi-scale models incorporating particle morphology were further evaluated across four sample scales. The results indicate that, on the macro scale, the three morphological parameters and the middle principal stress coefficient each have substantial effects on peak strength independently, while the interaction among these parameters does not have a notable influence on the strength. With increasing convexity, the peak strength of samples gradually decreases, while an increase in elongation and flatness leads to a trend of initially increasing and then decreasing strength. On the micro scale, the increase in both elongation and flatness results in a more uniform fabric in the main and lateral directions, while the coordination number shows a trend of initially increasing and then decreasing before stabilizing gradually. The influence of elongation on the main direction fabric is slightly smaller than that of flatness, while convexity has minimal effect on these microscopic features. Additionally, the morphological parameters not only impact the deformation capacity of samples but also demonstrate heightened sensitivity to the strength-size relationship of the sample due to interlocking and boundary constraints between particles. This underscores the pivotal role of morphological parameters in governing the mechanical motion of particles during the sample size scaling process, consequently influencing the strength of the material.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107153"},"PeriodicalIF":5.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474914","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":"Tomography-based DEM simulation of Fujian River sand considering multiscale particle morphology","authors":"Wei Xiong ,&nbsp;Zeyu Wang ,&nbsp;Jianfeng Wang","doi":"10.1016/j.compgeo.2025.107151","DOIUrl":"10.1016/j.compgeo.2025.107151","url":null,"abstract":"<div><div>This study conducts tomography-based derivative discrete element method (DEM) simulations of Fujian River sand under triaxial shear. It contains the X-ray μCT experiment for the particle morphology extraction, the digital twin-based model calibration for obtaining the model parameters, the spherical harmonic-based principal component analysis for the morphological gene mutation at different length scales, and the DEM simulations of virtual triaxial tests. 26 DEM samples were generated comprising three degrees of morphological gene mutation at different length scales. In this context, the particle morphology at each length scale can be successfully isolated to highlight its specific contribution to the allocation of external loadings within a given granular assemblage. It is found that particle morphology at different length scales plays a more crucial role in the various aspects of micro–macro mechanical behaviours of granular soils. The results of this study provide a novel viewpoint to systematically connect the micro-scale properties and macro-scale responses of granular soils under triaxial shear.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107151"},"PeriodicalIF":5.3,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471145","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":"Seismic bearing capacity of rectangular foundations near slopes using the upper bound method","authors":"Sheng Xu ,&nbsp;Xiao-Li Yang ,&nbsp;Zhen-Yu Yin","doi":"10.1016/j.compgeo.2025.107133","DOIUrl":"10.1016/j.compgeo.2025.107133","url":null,"abstract":"<div><div>When the upper load of a rectangular foundation exceeds its ultimate bearing capacity, its failure mechanism is typically an irregular three-dimensional (3D) geometry. By constructing this 3D failure mechanism, this article introduces a theoretical framework for evaluating the seismic bearing capacity of rectangular foundations adjacent to slopes. This 3D mechanism’s profile is the classical multi-block mechanism, and the construction of the end faces follows strict associated flow rule. Additionally, the pseudo-static method is utilized to calculate the action of seismic loads. Finally, an energy balance equation is constructed, from which the upper bound solution for seismic bearing capacity is derived. To facilitate practical design, a simple superposition method is provided to calculate the seismic bearing capacity. The effects of aspect ratio, slope inclination, and distance to the slope edge on the seismic bearing capacity are extensively explored. A shape factor is introduced to investigate the differences in bearing capacity between rectangular and strip foundations, with results indicating that a smaller aspect ratio yields a larger shape factor. The investigation into critical 3D failure mechanisms indicates that an increase in seismic intensity reduces the overall size of the mechanism, while an increase in internal friction angle enlarges it.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107133"},"PeriodicalIF":5.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A numerical solution for unsteady permeation grouting of Bingham grout in saturated porous media considering the threshold pressure gradient","authors":"Zhengyu Wang ,&nbsp;Guangsi Zhao ,&nbsp;Yang Zhou ,&nbsp;Minghui Ren","doi":"10.1016/j.compgeo.2025.107138","DOIUrl":"10.1016/j.compgeo.2025.107138","url":null,"abstract":"<div><div>To overcome the limitations of steady-state analysis in traditional permeation theory, this study presents an unsteady-state permeation model for Bingham grout flow in saturated porous media under high confining pressures. The model incorporates the threshold pressure gradient (TPG) for Bingham fluid dynamics, which is grounded in two-phase flow principles, to provide a more accurate representation of grout behaviour under these conditions. By utilizing the finite volume method, the fluid partial differential governing equations are discretized, and a custom-designed program is developed to obtain numerical solutions. The program dynamically monitors the pressure gradient at the Bingham grout front, and upon reaching the TPG, adjusts the calculations to accurately track the movement of the grout. The research results indicate the following: (1) The accuracy of numerical solutions depends on the time and spatial step sizes. A time step below 0.1 s limits the errors in the grouting volume and diffusion radius to 2.000 % and 4.32 %, respectively. A spatial step of 0.02 m reduces errors to 4.21 % and 3.85 %, balancing accuracy and efficiency. (2) The numerical solution reveals a nonlinear decrease in grout pressure, with a sharp decrease of up to 74.14 % within 2 m of the grouting pipe before stabilizing near the diffusion front. (3) The slow dissipation of pore water in high-pressure saturated porous media hinders the diffusion and transmission of grouting pressure, thereby limiting the grouting rate. (4) Larger TPGs and smaller pressure ratios hinder grout diffusion, whereas a pressure ratio greater than 2 significantly enhances diffusion, and increasing the TPG from 0.1 MPa/m to 10 MPa/m reduces the maximum diffusion distance by up to 8.11 times. These findings enhance the understanding of grout permeation and diffusion in highly confining pressure-saturated porous media, providing valuable insights for optimizing grouting strategies.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107138"},"PeriodicalIF":5.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444683","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":"Effect of particle shape on the mechanical behavior of methane hydrate-bearing sediments: A DEM study","authors":"Chengkai Xu ,&nbsp;Pei Wang ,&nbsp;Zhen-Yu Yin ,&nbsp;Yuxuan Wen ,&nbsp;Changjie Xu","doi":"10.1016/j.compgeo.2025.107141","DOIUrl":"10.1016/j.compgeo.2025.107141","url":null,"abstract":"<div><div>Methane hydrate-bearing sediments (HBS) have emerged as a promising energy source, and an in-depth understanding of their mechanical properties is critical for safe exploration and utilization. Previous studies have demonstrated the significant effect of microstructures, such as hydrate distribution patterns and sediment particle-hydrate interactions, on the mechanical behavior of HBS. However, as one of the most important factors determining both particle–particle and particle-hydrate interaction behaviors, particle shape has been insufficiently explored in previous studies. This study employs the Discrete Element Method (DEM) to simulate HBS with various particle angularity, focusing on the effect of particle shape on mechanical behavior of HBS with different hydrate distribution patterns (often referred to as pore habits). By simulating a set of triaxial tests, we found that the particle angularity (defined by sphericity, roundness, and convexity) exerts a significant influence on the strength and stiffness of HBS. Moreover, an anti-rotation effect imposed by particle angularity at the initial loading stage is observed, and the evolution of deviatoric fabric and contact distribution is also influenced by particle shape. This comprehensive analysis underscores the importance of particle shape in modeling HBS and unravels the complex particle–particle and particle-hydrate interaction mechanisms in HBS, offering valuable insights for reservoir exploitation.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107141"},"PeriodicalIF":5.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452860","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":"Post-failure stage analysis of flow-type landslides using different numerical techniques","authors":"Antonello Troncone,&nbsp;Luigi Pugliese,&nbsp;Andrea Parise,&nbsp;Pietro Mazzuca,&nbsp;Enrico Conte","doi":"10.1016/j.compgeo.2025.107152","DOIUrl":"10.1016/j.compgeo.2025.107152","url":null,"abstract":"<div><div>The analysis of the post-failure stage of landslides is of great interest for the geotechnical community (researchers and practitioners), especially for the case of flow-type landslides that are generally characterized by very high velocity and very long distance of run-out. This interest has increased in recent years thanks to the development of numerical methods able to solve successfully problems involving large deformations. Although such methods were employed in several studies for the analysis of the post-failure stage of landslides, only few of them have compared the numerical performance of the available techniques in dealing with real case studies. In the present study, three methods recognised as very effective numerical techniques for solving large deformation problems are considered: the Coupled Eulerian-Lagrangian (CEL) method, the Material Point Method (MPM) and the Smoothed Particle Hydrodynamics (SPH) method. These methods are used herein to simulate the post-failure stage of some well-documented landslides that evolved in a flow after failure. The predictive capacity of the considered methods and the associated computational costs are discussed with a view to their use for practical purposes.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107152"},"PeriodicalIF":5.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pore-network modeling of polymer flow in porous media","authors":"Si Suo ,&nbsp;Sajjad Foroughi ,&nbsp;Martin J. Blunt ,&nbsp;Catherine O’Sullivan","doi":"10.1016/j.compgeo.2025.107142","DOIUrl":"10.1016/j.compgeo.2025.107142","url":null,"abstract":"<div><div>Non-Newtonian fluid flows in porous media are critical in various subsurface and geotechnical engineering applications. However, accurately predicting such flows remains challenging due to the complex fluid rheology and intricate pore structures. This study focuses on polymer fluids with shear-thinning rheology with the motivation of advancing understanding of polymer support fluids for ground engineering applications. To address the limitations of existing models, we derive a theoretical conductance model for polymer flow in a capillary tube, based on which a customized pore-network method is developed. Our simulations reveal three distinct flow regimes, highlighting the impact of the rheology on flow dynamics. Notably, flow heterogeneity amplifies as the shear-thinning feature directs more flow through wider pores, where the effective viscosity decreases more significantly compared to narrower ones. A generalized Darcy’s law is formulated for non-Newtonian fluids, validated through pore-network modeling on 60 distinct sphere packings. The proposed framework is adaptable to a broad range of non-Newtonian fluids, offering valuable insights for scaling up to field-scale applications.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107142"},"PeriodicalIF":5.3,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable discrete fracture network for dynamic analyses of rock landslides by material point method","authors":"Jingsong Yan ,&nbsp;Yawen Wu ,&nbsp;Qirui Gao ,&nbsp;Yuxia Kong ,&nbsp;Shuxin Deng ,&nbsp;Zhu Song","doi":"10.1016/j.compgeo.2025.107154","DOIUrl":"10.1016/j.compgeo.2025.107154","url":null,"abstract":"<div><div>The discrete fracture network (DFN) significantly influences the failure mechanisms of rock slopes. However, the integration of DFN within the hybrid mesh-particle material point method (MPM) remains ambiguous when juxtaposed with the frictional contact interfaces inserted in mesh-based methods and the degradation of contact bonds in particle-based approaches. This research introduces a tunable DFN adaptable to the MPM, employing hybrid congruence and normal probability algorithms to generate rock fractures with specific inclination angles and trace lengths. These fractures are then superimposed onto the computational domain of material points by image processing techniques, and the mechanical properties of fractures are assigned to the corresponding material points. The developed method effectively captures the critical features of rockslide, and the newly proposed parameter for intersection patterns of rock fractures allows for the examination of intricate slope failure modes, including slide-buckling-toppling, sliding-secondary toppling, and toppling-circular slope failure. This research further presents a comprehensive probability analysis of jointed slopes, where the mean sliding surface and deposit configuration can offer valuable insights for site characterization and risk assessment of rock slope engineering. This research contributes to a more nuanced understanding of complex interactions within rock slopes and enhances the predictive capabilities of slope stability models.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107154"},"PeriodicalIF":5.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436669","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":"Insights into particle breakage induced macroscopic and microscopic behavior of railway ballast via DEM","authors":"Pan Tan ,&nbsp;Yuanjie Xiao ,&nbsp;Meng Wang ,&nbsp;Tao Yang ,&nbsp;Chongchong Zhang ,&nbsp;Wenqi Li","doi":"10.1016/j.compgeo.2025.107135","DOIUrl":"10.1016/j.compgeo.2025.107135","url":null,"abstract":"<div><div>Particle breakage greatly affects the stability of ballast beds and safe operation of train traffic. Existing particle breakage simulation methods suffer from shortcomings including non-breakable sub-particles and the low computational efficiency. To tackle this challenge, this paper first simulated the particle breakage by using the particle cutting method and then studied the evolution law of particle breakage of ballast specimens subjected to monotonic triaxial compression loading. The breakage-related macroscopic and microscopic behaviors including the stress–strain relation, particle rotation, and fabric anisotropy were simulated and analyzed accordingly. The results show that the rate of ballast particle breakage is the fastest at the initial loading stage, and then decreases with increasing axial strain. The ballast particle breakage mainly occurs within the shearing bands, and the severity of particle breakage increases with increasing confining pressure. The ballast particle breakage reduces the dilation, peak strength, and the degree of anisotropy of the normal contact forces, the long axes of ballast particles, and the contact normals. Such trends become more significant as confining pressure increases. An improved inter-particle contact system lags behind the particle breakage. The greater the confining pressure, the faster the inter-particle contact system stabilizes after the particle breakage.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"182 ","pages":"Article 107135"},"PeriodicalIF":5.3,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436677","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":"A unified transport-velocity formulation for SPH simulation of cohesive granular materials","authors":"Shuaihao Zhang ,&nbsp;Feng Wang ,&nbsp;Xiangyu Hu ,&nbsp;Sérgio D.N. Lourenço","doi":"10.1016/j.compgeo.2025.107139","DOIUrl":"10.1016/j.compgeo.2025.107139","url":null,"abstract":"<div><div>When simulating cohesive granular materials using smoothed particle hydrodynamics (SPH), tensile instability often arises, characterized by particle clustering and non-physical fractures. In two-dimensional scenarios, this issue is typically addressed by the artificial stress method, which introduces repulsive forces between particle pairs. However, extending this approach to three dimensions is considered complex due to the requirements of matrix diagonalization and coordinate system rotation. In this study, we introduce the transport-velocity formulation (TVF), a numerical technique widely used in SPH simulation of fluids to remove tensile instability, to address this issue. Furthermore, rather than being limited to inner particles alone as in the previous TVF, we develop a unified transport-velocity formulation (UTVF) that encompasses both free-surface and inner particles, by applying corrections to surface particles only in the tangential direction. This unified approach is tailored for large deformation and failure flow problems in cohesive granular materials, which often involve free surfaces. The proposed approach is first validated through benchmark cases of both fluids and elastic materials with known analytical solutions, demonstrating its convergence, stability, and accuracy. Comparisons with the artificial stress and particle shifting methods highlight the advantages of the UTVF in terms of momentum conservation and low dissipation. Subsequently, the developed UTVF is applied to the simulation of cohesive granular material failure and flows in both two-dimensional and three-dimensional settings. The results indicate that the proposed method effectively eliminates tensile instability, regardless of dimensionality. An open-source code is provided for further comparison and in-depth study.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107139"},"PeriodicalIF":5.3,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}