Pub Date : 2024-11-07DOI: 10.1016/j.compgeo.2024.106873
Haoran Jiang , Jiayan Nie , Opu Chandra Debanath , Yang Li
Understanding the fundamental principles governing granular flow dynamics has been a longstanding problem. The complexity is heightened when diverse particle shapes come into play, which thus necessitates a quantitative assessment of the impact of particle shape and especially, the interplay among multi-scale shape characteristics. In this study, we numerically study the combined effects of the particle’s overall form and surface asperity in dry granular columns, a simplified granular flow model, using spherical harmonics and the level-set discrete element method. Our results reveal that flow mobility for a given column aspect ratio decreases linearly with an adopted shape index known as the rotational resistance angle. This motivates us to propose a simple runout model incorporating shape effects for predicting flow mobility. Additionally, we analyze the energy evolution process and demonstrate that both the maximum kinetic energy and the final accumulated energy dissipation scale linearly with the shape index. Furthermore, column flow mobility is found to be correlated well with the front kinetic energy. Finally, we compare the static deposit angle from column collapse tests with the critical friction angle from triaxial compression tests, finding that they are approximately equal under short column conditions, which correspond to the quasi-static collapse regime. This provides potential alternative protocols to quickly measure the internal friction angle of dry granular materials.
{"title":"Dynamic column collapse of dry granular materials with multi-scale shape characteristics","authors":"Haoran Jiang , Jiayan Nie , Opu Chandra Debanath , Yang Li","doi":"10.1016/j.compgeo.2024.106873","DOIUrl":"10.1016/j.compgeo.2024.106873","url":null,"abstract":"<div><div>Understanding the fundamental principles governing granular flow dynamics has been a longstanding problem. The complexity is heightened when diverse particle shapes come into play, which thus necessitates a quantitative assessment of the impact of particle shape and especially, the interplay among multi-scale shape characteristics. In this study, we numerically study the combined effects of the particle’s overall form and surface asperity in dry granular columns, a simplified granular flow model, using spherical harmonics and the level-set discrete element method. Our results reveal that flow mobility for a given column aspect ratio decreases linearly with an adopted shape index known as the rotational resistance angle. This motivates us to propose a simple runout model incorporating shape effects for predicting flow mobility. Additionally, we analyze the energy evolution process and demonstrate that both the maximum kinetic energy and the final accumulated energy dissipation scale linearly with the shape index. Furthermore, column flow mobility is found to be correlated well with the front kinetic energy. Finally, we compare the static deposit angle from column collapse tests with the critical friction angle from triaxial compression tests, finding that they are approximately equal under short column conditions, which correspond to the quasi-static collapse regime. This provides potential alternative protocols to quickly measure the internal friction angle of dry granular materials.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106873"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660205","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}
Various mathematical formulations have been proposed to model moisture migration coupled with heat transfer in unsaturated soils under non-isothermal conditions. These formulations adopt different assumptions and approaches to incorporating phase change phenomena. This has led to confusion when assessing the performance of ground heat exchangers in unsaturated soils. This research provides insights into the development of fully coupled hydro-thermal numerical models for partially saturated soils under thermal loading. The multiphysics phenomenon involved is clearly discussed, and the governing equations are presented for both the equilibrium phase change (EPC) and non-equilibrium phase change (NEPC) approaches. A parallel comparison is then made between the two approaches through the estimation of variation in the degree of saturation in unsaturated soils when subjected to thermal gradients. The suitability of the two approaches for numerical modeling of unsaturated soils in the context of ground heat exchangers is then discussed. Considering the uncertainties in parameter identification, the results indicate that the EPC approach is sufficiently accurate and is often preferred over the NEPC approach in hydro-thermal modeling of ground heat exchangers in unsaturated soils.
{"title":"Coupled heat and moisture migration in unsaturated soils subjected to thermal gradients","authors":"Arvind Kumar , Asal Bidarmaghz , Arman Khoshghalb , Kenichi Soga","doi":"10.1016/j.compgeo.2024.106893","DOIUrl":"10.1016/j.compgeo.2024.106893","url":null,"abstract":"<div><div>Various mathematical formulations have been proposed to model moisture migration coupled with heat transfer in unsaturated soils under non-isothermal conditions. These formulations adopt different assumptions and approaches to incorporating phase change phenomena. This has led to confusion when assessing the performance of ground heat exchangers in unsaturated soils. This research provides insights into the development of fully coupled hydro-thermal numerical models for partially saturated soils under thermal loading. The multiphysics phenomenon involved is clearly discussed, and the governing equations are presented for both the equilibrium phase change (EPC) and non-equilibrium phase change (NEPC) approaches. A parallel comparison is then made between the two approaches through the estimation of variation in the degree of saturation in unsaturated soils when subjected to thermal gradients. The suitability of the two approaches for numerical modeling of unsaturated soils in the context of ground heat exchangers is then discussed. Considering the uncertainties in parameter identification, the results indicate that the EPC approach is sufficiently accurate and is often preferred over the NEPC approach in hydro-thermal modeling of ground heat exchangers in unsaturated soils.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106893"},"PeriodicalIF":5.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660204","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}
Pub Date : 2024-11-06DOI: 10.1016/j.compgeo.2024.106856
Huidong Wang , Zhen Qu , Guowei Ma
Linear and nonlinear fluid flow in fractured rock masses often co-occurs because of the hydraulic pressure gradient discrepancy and significant permeability difference between fractures and rock matrixes. In the current Darcy-Forchheimer coupled theory, the linear and nonlinear fluid flow is often artificially and strictly confined to rock matrixes and fractures, respectively. In this study, we conducted a numerical study on linear and nonlinear unified fluid flow in fractured porous media, considering flow pattern adaptive conversions instead of artificial constraints. The flow pattern adaptive conversion is realized by a conversion factor of linear and nonlinear fluid flow. A numerical linear and nonlinear unified fluid flow method was proposed using the unified pipe-network method. The accuracy and correctness of the proposed method were validated by comparing it with the result of both linear and nonlinear fluid flow. This method can effectively describe the linear and nonlinear mixed fluid flow and calculate the distributions of linear and nonlinear flow regions in fractured porous media. Characteristics of the unified fluid flow in fractured porous media were analyzed in detail by parametric discussions based on the developed numerical method.
{"title":"Linear and nonlinear unified fluid flow in fractured porous media considering flow pattern adaptive conversions","authors":"Huidong Wang , Zhen Qu , Guowei Ma","doi":"10.1016/j.compgeo.2024.106856","DOIUrl":"10.1016/j.compgeo.2024.106856","url":null,"abstract":"<div><div>Linear and nonlinear fluid flow in fractured rock masses often co-occurs because of the hydraulic pressure gradient discrepancy and significant permeability difference between fractures and rock matrixes. In the current Darcy-Forchheimer coupled theory, the linear and nonlinear fluid flow is often artificially and strictly confined to rock matrixes and fractures, respectively. In this study, we conducted a numerical study on linear and nonlinear unified fluid flow in fractured porous media, considering flow pattern adaptive conversions instead of artificial constraints. The flow pattern adaptive conversion is realized by a conversion factor of linear and nonlinear fluid flow. A numerical linear and nonlinear unified fluid flow method was proposed using the unified pipe-network method. The accuracy and correctness of the proposed method were validated by comparing it with the result of both linear and nonlinear fluid flow. This method can effectively describe the linear and nonlinear mixed fluid flow and calculate the distributions of linear and nonlinear flow regions in fractured porous media. Characteristics of the unified fluid flow in fractured porous media were analyzed in detail by parametric discussions based on the developed numerical method.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106856"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593778","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 : 2024-11-06DOI: 10.1016/j.compgeo.2024.106894
Rong-Sheng Deng , Bao Chen , Wei-Min Ye , Yong-Gui Chen , Qiong Wang
Low-density zones generated during the bentonite blocks/voids homogenization process in the repository may serve as potentially preferential paths for radionuclide leakage. More importantly, void closure during homogenization process involves complex contact problems, where the stiffness at the contact interface typically undergoes significant fluctuations. In this work, with contact interface stiffness addressed through a step function approach, a modified penal.
ty-based contact model was proposed to simulate the contact behavior involved at the gap closure stage of the bentonite/gap assemblage homogenization process. Then, unsaturated infiltration swelling tests on bentonite block (1.7 Mg/m3)/gap (width: 2 mm) assemblages were performed, and the variation of dry density at different hydrated times (0, 24, 72, 168, and 720 h) in specific areas were measured. Based on the results, time-dependent swelling pressure profiles of the assemblage were acquired, while the homogenization process was evaluated. Results reveal that after approximately 40 h of hydration, the gap is completely closed, and the radial stress condition of the compacted bentonite transits progressively from the initial free swelling into a constant volume expansion state. The swelling pressure correspondingly develops quickly to a peak value at 1.8 MPa once the hydration starts, then decreases to a valley value of 1.4 MPa at the complete gap closure, and subsequently begins to increase to the final stable value of 1.8 MPa. Further examination reveals that as hydration advances, dry density of the assemblage converges to the expected final dry density with a maximum residual inhomogeneity of about 2 %. Finally, validations demonstrate that the proposed model can accurately reproduce deformations of the assemblage during the free swelling stage, and the swelling pressure profiles. A comparative analysis was made with the previous approach of identifying gaps as highly deformable materials, revealing that the proposed model overcomes the traditional limitations associated with the separation or penetration behavior occurring between the compacted bentonite and contact boundaries during the gap closure.
{"title":"Simulation of homogenization behavior of compacted bentonite containing technological voids using modified penalty-based contact model","authors":"Rong-Sheng Deng , Bao Chen , Wei-Min Ye , Yong-Gui Chen , Qiong Wang","doi":"10.1016/j.compgeo.2024.106894","DOIUrl":"10.1016/j.compgeo.2024.106894","url":null,"abstract":"<div><div>Low-density zones generated during the bentonite blocks/voids homogenization process in the repository may serve as potentially preferential paths for radionuclide leakage. More importantly, void closure during homogenization process involves complex contact problems, where the stiffness at the contact interface typically undergoes significant fluctuations. In this work, with contact interface stiffness addressed through a step function approach, a modified penal.</div><div>ty-based contact model was proposed to simulate the contact behavior involved at the gap closure stage of the bentonite/gap assemblage homogenization process. Then, unsaturated infiltration swelling tests on bentonite block (1.7 Mg/m<sup>3</sup>)/gap (width: 2 mm) assemblages were performed, and the variation of dry density at different hydrated times (0, 24, 72, 168, and 720 h) in specific areas were measured. Based on the results, time-dependent swelling pressure profiles of the assemblage were acquired, while the homogenization process was evaluated. Results reveal that after approximately 40 h of hydration, the gap is completely closed, and the radial stress condition of the compacted bentonite transits progressively from the initial free swelling into a constant volume expansion state. The swelling pressure correspondingly develops quickly to a peak value at 1.8 MPa once the hydration starts, then decreases to a valley value of 1.4 MPa at the complete gap closure, and subsequently begins to increase to the final stable value of 1.8 MPa. Further examination reveals that as hydration advances, dry density of the assemblage converges to the expected final dry density with a maximum residual inhomogeneity of about 2 %. Finally, validations demonstrate that the proposed model can accurately reproduce deformations of the assemblage during the free swelling stage, and the swelling pressure profiles. A comparative analysis was made with the previous approach of identifying gaps as highly deformable materials, revealing that the proposed model overcomes the traditional limitations associated with the separation or penetration behavior occurring between the compacted bentonite and contact boundaries during the gap closure.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106894"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593780","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 : 2024-11-06DOI: 10.1016/j.compgeo.2024.106859
Shuvankar Das, Debarghya Chakraborty
To examine the heterogeneous behavior of spatially random rock mass, the probabilistic bearing capacity of strip footing subjected to eccentric loading is computed in the present study. The lower bound finite element limit analysis in combination with the power conic optimization technique is employed by assuming the rock mass to follow the generalized Hoek-Brown (GHB) failure criterion at collapse. Geological Strength Index (GSI) is modeled as a spatially random variable. The rock mass material constant (mi) and uniaxial compressive strength ratio (σci/γB) are modeled as spatially random fields. Correlation-controlled Latin hypercube sampling (LHS) is implemented to create the spatially random discretized rock mass domain. With the help of the Monte Carlo simulation technique, the stochastic responses are determined. The obtained values of bearing capacity factor are found to follow the gamma distribution. The failure probability and mean bearing capacity factor for different ranges of practical cases of rock mass heterogeneity and loading eccentricity conditions are presented in design charts. With the increase in the eccentricity values, the mean bearing capacity factor reduces in all probabilistic cases. The target probability is expressed in terms of the desired factor of safety based on the acquired results for different rock mass and loading parameters.
{"title":"Probabilistic bearing capacity of eccentrically loaded strip footing on spatially random rock mass using correlation-controlled LHS sampling","authors":"Shuvankar Das, Debarghya Chakraborty","doi":"10.1016/j.compgeo.2024.106859","DOIUrl":"10.1016/j.compgeo.2024.106859","url":null,"abstract":"<div><div>To examine the heterogeneous behavior of spatially random rock mass, the probabilistic bearing capacity of strip footing subjected to eccentric loading is computed in the present study. The lower bound finite element limit analysis in combination with the power conic optimization technique is employed by assuming the rock mass to follow the generalized Hoek-Brown (GHB) failure criterion at collapse. Geological Strength Index (<em>GSI</em>) is modeled as a spatially random variable. The rock mass material constant (<em>m<sub>i</sub></em>) and uniaxial compressive strength ratio (<em>σ<sub>ci/</sub>γB</em>) are modeled as spatially random fields. Correlation-controlled Latin hypercube sampling (LHS) is implemented to create the spatially random discretized rock mass domain. With the help of the Monte Carlo simulation technique, the stochastic responses are determined. The obtained values of bearing capacity factor are found to follow the gamma distribution. The failure probability and mean bearing capacity factor for different ranges of practical cases of rock mass heterogeneity and loading eccentricity conditions are presented in design charts. With the increase in the eccentricity values, the mean bearing capacity factor reduces in all probabilistic cases. The target probability is expressed in terms of the desired factor of safety based on the acquired results for different rock mass and loading parameters.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106859"},"PeriodicalIF":5.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593777","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 : 2024-11-05DOI: 10.1016/j.compgeo.2024.106870
Xiaofeng Dou , Zhichao Liu , Dianheng Yang , Yingjie Zhao , Yanlong Li , Deli Gao , Fulong Ning
Sand production is one of the bottlenecks restricting the safe, efficient, and controllable production of hydrates. Enhancing the understanding of mesoscopic sand production responses is essential for sand production risk management. Yet, existing mesoscopic sand production models inadequately capture the effects of hydrate cementation, resulting in an incomplete assessment of the mechanical impacts of hydrates on sand production. Herein, we developed a new three-dimensional model for sand production in gas hydrate-bearing sediments (GHBSs) with gravel packing well completion, utilizing the coupled computational fluid dynamics and discrete element method (CFD-DEM). The model considers the coupled interactions of mechanical weakening and permeability variation in GHBSs caused by hydrate cementation reduction. Simulations are analyzed to clarify the responses of sand production and reservoir compaction under the coupled mechanical, hydraulic, and sand control completion in GHBSs during depressurization. The high fluid flow rate induced by a high production pressure differential can promote sand production and reservoir compaction. Additionally, the high effective stress and high hydrate dissociation rate induced by a high production pressure differential are beneficial for initial sand production, but they can also prematurely lead to gravel packing layer obstruction, inhibiting the final sand production. This also results in a dual impact on compaction deformation, enhancing it through compaction while decelerating it by inhibiting sand production. This work provides a viable simulation idea and preliminary insights into the mechanism of sand production from GHBSs.
{"title":"3D CFD-DEM modeling of sand production and reservoir compaction in gas hydrate-bearing sediments with gravel packing well completion","authors":"Xiaofeng Dou , Zhichao Liu , Dianheng Yang , Yingjie Zhao , Yanlong Li , Deli Gao , Fulong Ning","doi":"10.1016/j.compgeo.2024.106870","DOIUrl":"10.1016/j.compgeo.2024.106870","url":null,"abstract":"<div><div>Sand production is one of the bottlenecks restricting the safe, efficient, and controllable production of hydrates. Enhancing the understanding of mesoscopic sand production responses is essential for sand production risk management. Yet, existing mesoscopic sand production models inadequately capture the effects of hydrate cementation, resulting in an incomplete assessment of the mechanical impacts of hydrates on sand production. Herein, we developed a new three-dimensional model for sand production in gas hydrate-bearing sediments (GHBSs) with gravel packing well completion, utilizing the coupled computational fluid dynamics and discrete element method (CFD-DEM). The model considers the coupled interactions of mechanical weakening and permeability variation in GHBSs caused by hydrate cementation reduction. Simulations are analyzed to clarify the responses of sand production and reservoir compaction under the coupled mechanical, hydraulic, and sand control completion in GHBSs during depressurization. The high fluid flow rate induced by a high production pressure differential can promote sand production and reservoir compaction. Additionally, the high effective stress and high hydrate dissociation rate induced by a high production pressure differential are beneficial for initial sand production, but they can also prematurely lead to gravel packing layer obstruction, inhibiting the final sand production. This also results in a dual impact on compaction deformation, enhancing it through compaction while decelerating it by inhibiting sand production. This work provides a viable simulation idea and preliminary insights into the mechanism of sand production from GHBSs.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106870"},"PeriodicalIF":5.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587157","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 paper presents a three-phase two-point formulation of the material point method (MPM) for modeling unsaturated soils involving large deformation. In the formulation, solid phase material is represented by one layer of material points while liquid and gas phases are modeled by another layer of material points. The formulation is a u-U formulation. It eliminates advection term between solid and liquid phases and is capable to address large relative deformations between the two phases. The advection term between liquid and gas phases are assumed to be small and not considered. The proposed formulation is validated with numerical models for small and finite deformation problems. The capacity of the method for study of geomechanics problems is demonstrated with simulation of seismic-induced ground liquefaction with an unsaturated embankment. The method is able to simulate large ground deformation due to soil liquefaction and generation of excess pore pressure, and captures pore pressure dissipation through the rapid water drainage through high-permeable soils.
{"title":"A three-phase two-point MPM for large deformation analysis of unsaturated soils","authors":"Yosuke Higo , Yudai Takegawa , Fan Zhu , Daichi Uchiyama","doi":"10.1016/j.compgeo.2024.106860","DOIUrl":"10.1016/j.compgeo.2024.106860","url":null,"abstract":"<div><div>This paper presents a three-phase two-point formulation of the material point method (MPM) for modeling unsaturated soils involving large deformation. In the formulation, solid phase material is represented by one layer of material points while liquid and gas phases are modeled by another layer of material points. The formulation is a u-U formulation. It eliminates advection term between solid and liquid phases and is capable to address large relative deformations between the two phases. The advection term between liquid and gas phases are assumed to be small and not considered. The proposed formulation is validated with numerical models for small and finite deformation problems. The capacity of the method for study of geomechanics problems is demonstrated with simulation of seismic-induced ground liquefaction with an unsaturated embankment. The method is able to simulate large ground deformation due to soil liquefaction and generation of excess pore pressure, and captures pore pressure dissipation through the rapid water drainage through high-permeable soils.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106860"},"PeriodicalIF":5.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587156","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}
Evaluating the seismic resistance of embankments using crushed mudstone as a geomaterial is an urgent and crucial requirement. In this study, a ground investigation was conducted on the actual embankment. Based on the results, the seismic response of the embankment, simulating progressed slaking, was conducted by elastoplastic finite deformation analysis using two major types of earthquake motion: epicentral and subduction zone earthquakes. Based on the results of the geotechnical investigation, the embankment could be divided into three layers owing to differences in physical properties, and slaking progressed below the groundwater level in the embankment. The embankment did not exhibit large deformation during the epicentral earthquake owing to the short duration. For the subduction zone earthquake, the developed shear strain was from the two large acceleration groups and the subsequent smaller accelerations, resulting in large deformation. Seismic loading caused the gradual loss of the overconsolidation and decay of the structure which reduced the embankment strength. This analysis revealed that shear strain developed at the slope toe and the lower part of the embankment. Furthermore, the analysis after the earthquake was also conducted to examine whether or not countermeasure method is feasible for emergency restoration. The seismic resistance was greatly improved when a combination of ground improvement and replacement/counterweight fill methods were used to reinforce these areas, which is not only during but also after the earthquake. This study can contribute to the understanding of the seismic behavior of soil structures using materials undergoing internal deterioration and to the development of countermeasure methods for such structures.
{"title":"Prediction of huge earthquake-induced deformation of in-service embankments using crushed mudstone as a soil material with slaking and proposal of countermeasures","authors":"Shogo Inukai , Takayuki Sakai , Masashi Nagata , Toshihiro Noda , Masaki Nakano","doi":"10.1016/j.compgeo.2024.106855","DOIUrl":"10.1016/j.compgeo.2024.106855","url":null,"abstract":"<div><div>Evaluating the seismic resistance of embankments using crushed mudstone as a geomaterial is an urgent and crucial requirement. In this study, a ground investigation was conducted on the actual embankment. Based on the results, the seismic response of the embankment, simulating progressed slaking, was conducted by elastoplastic finite deformation analysis using two major types of earthquake motion: epicentral and subduction zone earthquakes. Based on the results of the geotechnical investigation, the embankment could be divided into three layers owing to differences in physical properties, and slaking progressed below the groundwater level in the embankment. The embankment did not exhibit large deformation during the epicentral earthquake owing to the short duration. For the subduction zone earthquake, the developed shear strain was from the two large acceleration groups and the subsequent smaller accelerations, resulting in large deformation. Seismic loading caused the gradual loss of the overconsolidation and decay of the structure which reduced the embankment strength. This analysis revealed that shear strain developed at the slope toe and the lower part of the embankment. Furthermore, the analysis after the earthquake was also conducted to examine whether or not countermeasure method is feasible for emergency restoration. The seismic resistance was greatly improved when a combination of ground improvement and replacement/counterweight fill methods were used to reinforce these areas, which is not only during but also after the earthquake. This study can contribute to the understanding of the seismic behavior of soil structures using materials undergoing internal deterioration and to the development of countermeasure methods for such structures.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106855"},"PeriodicalIF":5.3,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587228","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 : 2024-11-04DOI: 10.1016/j.compgeo.2024.106865
Xudong Zhang , Tianwen Huang , Zhuan Ge , Teng Man , Herbert E. Huppert
Slurry infiltration clogging commonly occurs in porous media with fine pores. This infiltration leads to changes in the mechanical properties of the matrix, causing challenges such as material drainage difficulties and uneven force distributions. To investigate the clogging behavior of slurries under various pressure conditions, this study employs a simulation approach with corresponding theoretical analyses. Specifically, it utilizes the discrete element method (DEM) in conjunction with the lattice-Boltzmann method (LBM) to simulate the microscopic infiltration test of slurries in porous media. The findings reveal that fine soil particles exhibit greater mobility compared to their larger counterparts. Furthermore, statistical analysis demonstrates that the degree of pore-clogging is not always positively correlated with pressure. Higher pressures can also lead to the unclogging of the pore space. These observations indicate that particle sizes and pressure conditions are key factors influencing the potential for particle clogging. Based on the analysis, a clogging mechanism is proposed to elucidate the dynamics of particles in porous media. This study provides insights into clogging formation within porous media, leading to a better understanding of both slurry filtration in geotechnical engineering and hyporheic exchange phenomena in stream bed ecosystems.
{"title":"Infiltration characteristics of slurries in porous media based on the coupled Lattice-Boltzmann discrete element method","authors":"Xudong Zhang , Tianwen Huang , Zhuan Ge , Teng Man , Herbert E. Huppert","doi":"10.1016/j.compgeo.2024.106865","DOIUrl":"10.1016/j.compgeo.2024.106865","url":null,"abstract":"<div><div>Slurry infiltration clogging commonly occurs in porous media with fine pores. This infiltration leads to changes in the mechanical properties of the matrix, causing challenges such as material drainage difficulties and uneven force distributions. To investigate the clogging behavior of slurries under various pressure conditions, this study employs a simulation approach with corresponding theoretical analyses. Specifically, it utilizes the discrete element method (DEM) in conjunction with the lattice-Boltzmann method (LBM) to simulate the microscopic infiltration test of slurries in porous media. The findings reveal that fine soil particles exhibit greater mobility compared to their larger counterparts. Furthermore, statistical analysis demonstrates that the degree of pore-clogging is not always positively correlated with pressure. Higher pressures can also lead to the unclogging of the pore space. These observations indicate that particle sizes and pressure conditions are key factors influencing the potential for particle clogging. Based on the analysis, a clogging mechanism is proposed to elucidate the dynamics of particles in porous media. This study provides insights into clogging formation within porous media, leading to a better understanding of both slurry filtration in geotechnical engineering and hyporheic exchange phenomena in stream bed ecosystems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"177 ","pages":"Article 106865"},"PeriodicalIF":5.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578983","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 : 2024-11-03DOI: 10.1016/j.compgeo.2024.106868
Wenhao Li , Guotao Ma , Mingjing Jiang , Mohammad Rezania , Haitao Zhu
This study presents an innovative adversarial multi-source transfer learning approach to enhance submarine hydrate slope stability predictions in the face of small and varied datasets. Integrating terrestrial and submarine data, our method significantly improves knowledge transfer and model generalization. Utilizing hydrate triaxial tests and pore pressure models, we construct a comprehensive dataset that bridges the gap between diverse geological environments. Employing the novel Walrus Optimizer and adversarial training techniques, the model substantially outperforms traditional regression methods. It achieves a correlation coefficient of 0.9936 and a mean absolute error of 0.094, indicating high predictive accuracy and robust handling of data anomalies and distribution inconsistencies. These advancements provide crucial insights into slope stability factors and offer potential enhancements for geological hazard monitoring and early warning systems. Our research demonstrates a substantial improvement in slope stability analysis and opens new avenues for intelligent geological hazard assessments in environments characterized by data scarcity.
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