Computers and Geotechnics最新文献

Tunable discrete fracture network for dynamic analyses of rock landslides by material point method

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-19 DOI: 10.1016/j.compgeo.2025.107154

Jingsong Yan , Yawen Wu , Qirui Gao , Yuxia Kong , Shuxin Deng , Zhu Song

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.

{"title":"Tunable discrete fracture network for dynamic analyses of rock landslides by material point method","authors":"Jingsong Yan , Yawen Wu , Qirui Gao , Yuxia Kong , Shuxin Deng , 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}

引用次数: 0

Insights into particle breakage induced macroscopic and microscopic behavior of railway ballast via DEM

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-19 DOI: 10.1016/j.compgeo.2025.107135

Pan Tan , Yuanjie Xiao , Meng Wang , Tao Yang , Chongchong Zhang , Wenqi Li

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.

{"title":"Insights into particle breakage induced macroscopic and microscopic behavior of railway ballast via DEM","authors":"Pan Tan , Yuanjie Xiao , Meng Wang , Tao Yang , Chongchong Zhang , 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}

引用次数: 0

A unified transport-velocity formulation for SPH simulation of cohesive granular materials

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-18 DOI: 10.1016/j.compgeo.2025.107139

Shuaihao Zhang , Feng Wang , Xiangyu Hu , Sérgio D.N. Lourenço

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.

{"title":"A unified transport-velocity formulation for SPH simulation of cohesive granular materials","authors":"Shuaihao Zhang , Feng Wang , Xiangyu Hu , 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}

引用次数: 0

Interpretation of free-fall piezocone tests in clay using a simplified cylindrical cavity expansion solution

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-17 DOI: 10.1016/j.compgeo.2025.107132

Minsheng Zhang , George Kouretzis , Changfa Li , Lubao Luan

This paper presents the derivation of a simplified closed-form expression for the interpretation of the undrained shear strength of clay soil from free-fall piezocone tests measurements, based on an undrained cylindrical cavity expansion solution. The cavity expansion solution employs an elastic-viscoplastic constitutive model to describe the rate-dependent behavior of clay upon loading. The derived expression correlates the measured tip resistance and pore pressure with the undrained shear strength by using a cone factor and a power function to account for strain rate effects. Unlike existing formulas that entail calibration of empirical parameters, the proposed expression requires as input only the constitutive model parameters and the cone geometry, which all have direct physical meaning. The cavity expansion solution, on which the interpretation expression is based on, is validated via comparison of its results against published studies, and accordingly the accuracy of the proposed expression is benchmarked against centrifuge test measurements. We show that, despite the simplifications introduced in the derivation, the proposed expression is capable of reproducing results of centrifuge tests with reasonable accuracy.

{"title":"Interpretation of free-fall piezocone tests in clay using a simplified cylindrical cavity expansion solution","authors":"Minsheng Zhang , George Kouretzis , Changfa Li , Lubao Luan","doi":"10.1016/j.compgeo.2025.107132","DOIUrl":"10.1016/j.compgeo.2025.107132","url":null,"abstract":"<div><div>This paper presents the derivation of a simplified closed-form expression for the interpretation of the undrained shear strength of clay soil from free-fall piezocone tests measurements, based on an undrained cylindrical cavity expansion solution. The cavity expansion solution employs an elastic-viscoplastic constitutive model to describe the rate-dependent behavior of clay upon loading. The derived expression correlates the measured tip resistance and pore pressure with the undrained shear strength by using a cone factor and a power function to account for strain rate effects. Unlike existing formulas that entail calibration of empirical parameters, the proposed expression requires as input only the constitutive model parameters and the cone geometry, which all have direct physical meaning. The cavity expansion solution, on which the interpretation expression is based on, is validated via comparison of its results against published studies, and accordingly the accuracy of the proposed expression is benchmarked against centrifuge test measurements. We show that, despite the simplifications introduced in the derivation, the proposed expression is capable of reproducing results of centrifuge tests with reasonable accuracy.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107132"},"PeriodicalIF":5.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427822","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}

引用次数: 0

Analytical solution of heat transfer for energy soldier piles considering convection at the ground surface and internal wall of underground space 考虑地表和地下空间内壁对流的能源兵桩传热解析解

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-17 DOI: 10.1016/j.compgeo.2025.107150

Guohao Dai , Gangqiang Kong , Qing Yang

This paper presents a new 2-D heat transfer model for the energy soldier pile wall-internal structural wall during the operation and maintenance period of the internal building. Both the convection at the ground surface and the internal wall boundary convection effects are considered. The analytical solution to the problem is obtained by using the separation variable method and is compared with numerical solutions and an existing analytical solution to verify the correctness of the solution. The effects of the convection coefficient, thickness of overlying soil, and soil thermal conductivity on heat transfer are analyzed. Results show that the dimensionless temperature rise decreases with increasing internal/external convection heat transfer coefficient, increasing thickness of overlying soil, and decreasing soil thermal conductivity. For different times of operation, the temperature below the dimensionless depths of 2.1/6.6/9.5 (for the soil side) and 3.4/7.5/10.0 (for the underground space side) is mainly controlled by the heat source. For the summer conditions, the average air temperature is higher than the average pile-soil temperature, it is the ambient temperature that dominates, not the convection coefficient. The depths of ground convection effects corresponding to thicknesses of less than 1.0 m on the 30th day of operation are concentrated at depths of about 10.0. Under the premise of ensuring structural and engineering safety, using the smaller thickness of overlying soil has a better effect on both heat flux and temperature rise.

{"title":"Analytical solution of heat transfer for energy soldier piles considering convection at the ground surface and internal wall of underground space","authors":"Guohao Dai , Gangqiang Kong , Qing Yang","doi":"10.1016/j.compgeo.2025.107150","DOIUrl":"10.1016/j.compgeo.2025.107150","url":null,"abstract":"<div><div>This paper presents a new 2-D heat transfer model for the energy soldier pile wall-internal structural wall during the operation and maintenance period of the internal building. Both the convection at the ground surface and the internal wall boundary convection effects are considered. The analytical solution to the problem is obtained by using the separation variable method and is compared with numerical solutions and an existing analytical solution to verify the correctness of the solution. The effects of the convection coefficient, thickness of overlying soil, and soil thermal conductivity on heat transfer are analyzed. Results show that the dimensionless temperature rise decreases with increasing internal/external convection heat transfer coefficient, increasing thickness of overlying soil, and decreasing soil thermal conductivity. For different times of operation, the temperature below the dimensionless depths of 2.1/6.6/9.5 (for the soil side) and 3.4/7.5/10.0 (for the underground space side) is mainly controlled by the heat source. For the summer conditions, the average air temperature is higher than the average pile-soil temperature, it is the ambient temperature that dominates, not the convection coefficient. The depths of ground convection effects corresponding to thicknesses of less than 1.0 m on the 30th day of operation are concentrated at depths of about 10.0. Under the premise of ensuring structural and engineering safety, using the smaller thickness of overlying soil has a better effect on both heat flux and temperature rise.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107150"},"PeriodicalIF":5.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420833","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}

引用次数: 0

Machine Learning-guided Observational Method for Prediction of Preloading-induced Consolidation Settlement

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-16 DOI: 10.1016/j.compgeo.2025.107140

Hua-Ming Tian , Siew-Wei Lee , Yu Wang

The Asaoka’s method, established in the late 1970 s and based on an assumption of one-dimensional (1D) consolidation, has been used worldwide for prediction of reclamation-induced consolidation settlement with the aid of field monitoring data. In the last several decades, the state of the practice in geotechnical engineering has advanced significantly. For example, numerical modeling (e.g., 2D finite element method, FEM) is now commonly used for geotechnical analysis and design of reclamations. The 1D consolidation assumption in the Asaoka’s method is not compatible with 2D FEM analysis for predicting consolidation settlement and its variation in a 2D spatial domain. To tackle this challenge, this study proposes a machine learning-guided observational method for improving prediction of consolidation settlement from 2D FEM models using field monitoring data. It uses random FEM to incorporate various uncertainties and generate many sets of FEM analysis outcomes (e.g., time-varying settlement in a 2D space). Then, these outcomes are adopted as basis functions, or dictionary atoms, under a sparse dictionary learning (SDL) framework and used together with the field monitoring data sequentially acquired to continuously improve predictions of consolidation settlement. A ground improvement project using combined vacuum and surcharge preloading is adopted to illustrate the efficacy of the proposed approach.

{"title":"Machine Learning-guided Observational Method for Prediction of Preloading-induced Consolidation Settlement","authors":"Hua-Ming Tian , Siew-Wei Lee , Yu Wang","doi":"10.1016/j.compgeo.2025.107140","DOIUrl":"10.1016/j.compgeo.2025.107140","url":null,"abstract":"<div><div>The Asaoka’s method, established in the late 1970 s and based on an assumption of one-dimensional (1D) consolidation, has been used worldwide for prediction of reclamation-induced consolidation settlement with the aid of field monitoring data. In the last several decades, the state of the practice in geotechnical engineering has advanced significantly. For example, numerical modeling (e.g., 2D finite element method, FEM) is now commonly used for geotechnical analysis and design of reclamations. The 1D consolidation assumption in the Asaoka’s method is not compatible with 2D FEM analysis for predicting consolidation settlement and its variation in a 2D spatial domain. To tackle this challenge, this study proposes a machine learning-guided observational method for improving prediction of consolidation settlement from 2D FEM models using field monitoring data. It uses random FEM to incorporate various uncertainties and generate many sets of FEM analysis outcomes (e.g., time-varying settlement in a 2D space). Then, these outcomes are adopted as basis functions, or dictionary atoms, under a sparse dictionary learning (SDL) framework and used together with the field monitoring data sequentially acquired to continuously improve predictions of consolidation settlement. A ground improvement project using combined vacuum and surcharge preloading is adopted to illustrate the efficacy of the proposed approach.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107140"},"PeriodicalIF":5.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420830","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}

引用次数: 0

Experimental and numerical investigation of the granular column collapse under different initial water-saturation conditions

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-16 DOI: 10.1016/j.compgeo.2025.107136

Shu-San Hsiau , Weihang Sun , Li-Tsung Sheng , Shih-Hao Chou , Jun-Yi Wang , Yongqi Wang

This paper investigates experimentally and numerically the collapse of granular columns under different initial water-saturation conditions. The results show that the collapse dynamics of water-granular mixture columns strongly depend on the initial saturation condition. With the increase of initial water content of the column, both the particle runout distance and the particle velocity increase. During the collapse, different flow regimes, e.g., water-saturated, over-saturated, under-saturated or pure granular, pure water regions, can develop. Differences in particle velocities between the upper pure granular layer and the lower mixture layer in an under-saturated mixture, and the effect of the interaction between the upper pure water layer and the lower mixture layer in an over-saturated mixture are observed in the experiments. To describe such flow behaviours, a recently developed depth-averaged model with a two-layer structure is adopted, which is able to capture the dynamics with different flow regimes simultaneously, as well as their occurrence, transition, and disappearance. Comparisons between experimental and numerical results demonstrate good agreement. Additionally, the effects of the initial solid volume fraction and the initial column aspect ratio are analysed and quantified by numerical investigations, providing further insights into the mechanisms governing the flow dynamics.

{"title":"Experimental and numerical investigation of the granular column collapse under different initial water-saturation conditions","authors":"Shu-San Hsiau , Weihang Sun , Li-Tsung Sheng , Shih-Hao Chou , Jun-Yi Wang , Yongqi Wang","doi":"10.1016/j.compgeo.2025.107136","DOIUrl":"10.1016/j.compgeo.2025.107136","url":null,"abstract":"<div><div>This paper investigates experimentally and numerically the collapse of granular columns under different initial water-saturation conditions. The results show that the collapse dynamics of water-granular mixture columns strongly depend on the initial saturation condition. With the increase of initial water content of the column, both the particle runout distance and the particle velocity increase. During the collapse, different flow regimes, e.g., water-saturated, over-saturated, under-saturated or pure granular, pure water regions, can develop. Differences in particle velocities between the upper pure granular layer and the lower mixture layer in an under-saturated mixture, and the effect of the interaction between the upper pure water layer and the lower mixture layer in an over-saturated mixture are observed in the experiments. To describe such flow behaviours, a recently developed depth-averaged model with a two-layer structure is adopted, which is able to capture the dynamics with different flow regimes simultaneously, as well as their occurrence, transition, and disappearance. Comparisons between experimental and numerical results demonstrate good agreement. Additionally, the effects of the initial solid volume fraction and the initial column aspect ratio are analysed and quantified by numerical investigations, providing further insights into the mechanisms governing the flow dynamics.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107136"},"PeriodicalIF":5.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420831","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}

引用次数: 0

Microscopic analysis of granular material behaviour from small to large strains

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-16 DOI: 10.1016/j.compgeo.2025.107126

Qing Chen , Chao Zhou

The Discrete Element Method (DEM) has been widely used to study the macro–micro behaviour of granular materials at large strains (>1%). However, investigations over a wider strain range are lacking. This study conducts DEM triaxial tests on specimens with different particle physical properties to examine their influence on macro–micro behaviour from small strains (below 1 %) to large strains. Small-strain behaviour is characterised by the maximum shear modulus, elastic range and stiffness degradation rate. Large-strain behaviour is analysed through the peak stress ratio, critical state stress ratio and void ratio. Then, the micro-mechanisms underlying these results are examined using the Stress-Force-Fabric (SFF) relationship, which links the (macro) stress ratio and (micro) anisotropy source. This study is the first to apply the SFF relationship to small strain behaviour. Results reveal the qualitative relationship between particle physical properties and macro-behaviour at different strains: increasing particle Young’s modulus enhances the maximum shear modulus but accelerates stiffness degradation; increasing shearing and rolling friction significantly reduces the stiffness degradation at small strains and enhances strength and dilation at large strains. This study also highlights the limitation of the Hertz contact model in capturing both small-strain and large-strain behaviour quantitatively using a single set of parameters. Hence, modellers should calibrate model parameters based on whether their focus is on large-strain or small-strain behaviour. For micro-behaviour, the relative importance of anisotropy sources depends on strain level rather than particle physical properties. At small strains, the mechanical anisotropy source (both normal and tangential forces) primarily controls stiffness and its degradation. At large strains, material strength is influenced by both mechanical and geometrical anisotropy sources, with anisotropy from the normal force being the most significant, followed by contact normal, tangential forces, and branch vector.

{"title":"Microscopic analysis of granular material behaviour from small to large strains","authors":"Qing Chen , Chao Zhou","doi":"10.1016/j.compgeo.2025.107126","DOIUrl":"10.1016/j.compgeo.2025.107126","url":null,"abstract":"<div><div>The Discrete Element Method (DEM) has been widely used to study the macro–micro behaviour of granular materials at large strains (>1%). However, investigations over a wider strain range are lacking. This study conducts DEM triaxial tests on specimens with different particle physical properties to examine their influence on macro–micro behaviour from small strains (below 1 %) to large strains. Small-strain behaviour is characterised by the maximum shear modulus, elastic range and stiffness degradation rate. Large-strain behaviour is analysed through the peak stress ratio, critical state stress ratio and void ratio. Then, the micro-mechanisms underlying these results are examined using the Stress-Force-Fabric (SFF) relationship, which links the (macro) stress ratio and (micro) anisotropy source. This study is the first to apply the SFF relationship to small strain behaviour. Results reveal the qualitative relationship between particle physical properties and macro-behaviour at different strains: increasing particle Young’s modulus enhances the maximum shear modulus but accelerates stiffness degradation; increasing shearing and rolling friction significantly reduces the stiffness degradation at small strains and enhances strength and dilation at large strains. This study also highlights the limitation of the Hertz contact model in capturing both small-strain and large-strain behaviour quantitatively using a single set of parameters. Hence, modellers should calibrate model parameters based on whether their focus is on large-strain or small-strain behaviour. For micro-behaviour, the relative importance of anisotropy sources depends on strain level rather than particle physical properties. At small strains, the mechanical anisotropy source (both normal and tangential forces) primarily controls stiffness and its degradation. At large strains, material strength is influenced by both mechanical and geometrical anisotropy sources, with anisotropy from the normal force being the most significant, followed by contact normal, tangential forces, and branch vector.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"181 ","pages":"Article 107126"},"PeriodicalIF":5.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420832","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}

引用次数: 0

DEM modelling of shaft load transfer behavior of rock-socketed piles

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-14 DOI: 10.1016/j.compgeo.2025.107149

J.G. Gutiérrez-Ch , S. Melentijevic , S. Senent , R. Jimenez

The behavior of rock-socketed piles (RSPs) has been the aim of extensive research through field load tests, centrifuge tests, numerical simulations, etc. In this work, the Distinct Element Method (DEM) is employed to study the load transfer behavior at the shaft of rough rock-socketed piles (RSPs) and the effect of socket roughness on their load capacity and on their complex load transfer mechanisms (LTMs). DEM numerical results indicate that socket roughness crucially affects the load transfer behavior of RSPs, as illustrated by the investigation of the following aspects: (i) load-settlement response, (ii) inter-particle force distributions obtained by the DEM model of RSP tests, (iii) the evolution of stresses at the pile-rock interface (PRI) as a function of socket head settlement, (iv) the distribution of axial load and shaft resistance mobilized with depth, and (v) the failure mechanism. Numerical results highlight that an “arching effect” controls the shaft LTM of rough RSPs. This behavior occurs because the pile load is not uniformly distributed along its length, but transferred through the front of asperities at the PRI. Additionally, this work identifies that “measurement slices” rather than “measurement spheres”, provide a more accurate force distributions along the pile in DEM simulations. Furthermore, DEM results are compared with experimental and numerical published in the literature and good agreement is found. Finally, based on DEM results, an idealized shaft LTM for axially loaded RSPs is proposed. This mechanism enhances the understanding of the fundamental physical processes governing the shaft LTM of RSPs.

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引用次数: 0

Assessing highway resilience subjected to rainfall-induced slope failure

IF 5.3 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers and Geotechnics

Pub Date : 2025-02-14 DOI: 10.1016/j.compgeo.2025.107134

Jie Zhang , Xiangyu Ma , Meng Lu , Atma Sharma , Lulu Zhang

Resilience assessment of the highway under rainfall-induced slope failure can support landslide hazard mitigation effectively. However, this direction is rarely studied. This study proposes a novel probabilistic method to assess highway resilience subjected to rainfall-induced slope failure, where the residual functionality of highways is quantified based on the landslide runout and the recovery process of blocked highways is modelled by a step function. First, a physically based model is built using a two stage FEM-MPM approach to simulate landslide runout under rainfall, and three types of uncertainties involved in resilience assessment of highways are explicitly modelled. To improve computational efficiency, a surrogate model is then created to predict the residual functionality of blocked highways. Finally, the mean value and the coefficient of variation of the highway resilience are estimated via Monte Carlo simulation. A four-lane highway next to a sandy slope is employed to perform the proposed method. The results show that the highway resilience is most sensitive to the strength parameter of the slope. As the variability of the slope strength parameter increases, the mean resilience of the highway decreases and the resilience variability increases. Overall, this study provides a useful tool for assessing highway resilience subjected to rainfall-induced slope failure.

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引用次数: 0