Computers and Geotechnics最新文献

{"title":"The effect of particle elongations on incremental behavior of granular materials using discrete element method","authors":"Minyi Zhu ,&nbsp;Guobin Gong ,&nbsp;Shiva Prashanth Kumar Kodicherla ,&nbsp;Kai Li ,&nbsp;Yu Huang ,&nbsp;Hu Zheng","doi":"10.1016/j.compgeo.2024.106948","DOIUrl":"10.1016/j.compgeo.2024.106948","url":null,"abstract":"<div><div>This study offers a novel investigation into the incremental behavior of granular materials by focusing on the effects of particle elongation on mechanical properties and microstructural evolution. Through a series of Discrete Element Method (DEM) simulations, samples with varying elongation coefficients (<span><math><mrow><mi>η</mi></mrow></math></span>) are systematically analyzed using two strain decomposition methods: the energy dissipation constraint method and the loading cycle method. The results show that as <span><math><mrow><mi>η</mi></mrow></math></span> increases, the strain envelope size decreases, indicating greater stiffness. A ‘memory effect’ is observed in the elastic strain envelope, suggesting internal rearrangement and partial microstructural recovery in later stages. The plastic strain envelope exhibits distinct patterns that vary with loading conditions, with magnitude decreasing as <span><math><mrow><mi>η</mi></mrow></math></span> increases. Despite identical initial stress states, the orientation of the plastic strain envelope shifts significantly, highlighting the impact of loading history and anisotropy. Notably, the misalignment between the normal direction of the yield surface and the incremental plastic flow direction indicates a non-associated flow rule for the generated granular materials. This misalignment varies with <span><math><mrow><mi>η</mi></mrow></math></span> and loading conditions. The study also reveals a transition from contraction to dilation behavior across different probing states, with increasing <span><math><mrow><mi>η</mi></mrow></math></span> leading to a denser packing of particles with a lower void ratio. As <span><math><mrow><mi>η</mi></mrow></math></span> increases, the anisotropy within the granular assembly becomes more pronounced, leading to a stronger directional dependence of the mechanical response.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106948"},"PeriodicalIF":5.3,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745100","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 simplified interpolation algorithm for the numerical simulation of the consolidation in composite foundation containing group of stone columns","authors":"Li Yuan ,&nbsp;Qiankun Liu ,&nbsp;Tongchun Li ,&nbsp;Fei Wang","doi":"10.1016/j.compgeo.2024.106941","DOIUrl":"10.1016/j.compgeo.2024.106941","url":null,"abstract":"<div><div>Based on Biot consolidation theory, a simplified interpolation algorithm under the finite element method and a corresponding modeling method for group of stone columns are proposed to solve the consolidation simulation problem of composite foundation containing group of stone columns. The correctness of the modeling method and computational program is confirmed by comparing the results from the unit cell model with those from axisymmetric model and analytical solution. Subsequently, the composite foundation model is used to verify the accuracy of this method in calculating the settlement change and consolidation time under load for composite foundation containing group of stone columns. Compared to detailed modeling, this method gets satisfactory results with simpler modeling and less computation time. In comparison to homogenization method, this method offers better computational accuracy and enables the stress analysis of stone column. Additionally, discussions on mesh sensitivity, number of stone columns and the influence of the upper structure provide guidelines for the application of this method in practical engineering projects.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106941"},"PeriodicalIF":5.3,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745101","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":"Mechanical behavior of clayey methane hydrate-bearing sediment: Effects of pore size and physicochemical characteristics using a novel DEM contact model","authors":"Xudong Zhang ,&nbsp;Mingjing Jiang ,&nbsp;Zhenyu Yin ,&nbsp;An Zhang","doi":"10.1016/j.compgeo.2024.106943","DOIUrl":"10.1016/j.compgeo.2024.106943","url":null,"abstract":"<div><div>The mechanical behavior of Methane Hydrate-Bearing Sediment (MHBS) is essential for the safe exploitation of Methane Hydrate (MH). In particular, the pore size and physicochemical characteristics of MHBS significantly influence its mechanical behavior, especially in clayey grain-cementing type MHBS. This study employs the Distinct Element Method (DEM) to investigate both the macroscopic and microscopic mechanical behavior of clayey grain-cementing type MHBS, focusing on variations in pore size and physicochemical characteristics. To accomplish this, we propose a Thermo-Hydro-Mechanical-Chemical-Soil Characteristics (THMCS) DEM contact model that incorporates the effects of pore size and physicochemical characteristics on the strength and modulus of MH. This THMCS model is validated using experimental data available in the literature. Using the proposed contact model, we conducted a series of investigations to explore the mechanical behavior of MHBS under conventional loading paths, including isotropic and drained triaxial tests using the DEM. The numerical results indicate that smaller pore sizes and lower water content—key physicochemical characteristics resulting from variations in electrochemical properties and the intensity of the electric field—can lead to reduced shear strength and stiffness due to the increased breakage of aggregates and weakened cementation. Additionally, heating was found to further accelerate the process of structural damage in MHBS.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106943"},"PeriodicalIF":5.3,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probabilistic analysis of progressive slope retreats due to weathering: An improved discretized-UBLA approach","authors":"Zhibin Sun ,&nbsp;Juncao Ding ,&nbsp;Guoxian Huang ,&nbsp;Daniel Dias","doi":"10.1016/j.compgeo.2024.106945","DOIUrl":"10.1016/j.compgeo.2024.106945","url":null,"abstract":"<div><div>Slope retreat phenomena have been a persistent area of interest for researchers; however, the majority of these studies have been conducted within a deterministic framework, thereby overlooking the numerous geotechnical uncertainties inherent in these scenarios. This study addresses this gap by considering the initial slope strength and its degradation rate as random variables, thereby enabling a probabilistic analysis of the progressive sliding behavior of a slope subjected to weathering. An upper-bound limit analysis (UBLA)-based discretized mechanism was established to serve as the deterministic model. This mechanism employs a ’point-to-point’ technique for generating the discretized sliding surface, effectively circumventing the limitations and complexity associated with the classic log-spiral mechanism. When integrated with time-varying slope strength, this model is capable of predicting the occurrence of each sliding event with remarkable accuracy and efficiency. To assess the likelihood of specific sliding events occurring at any given time, a reliability analysis was conducted using Monte Carlo simulation. The framework proposed in this study was validated through two case studies: one involving a homogeneous slope and the other a two-layered slope. These case studies produced a variety of reliability results of great value, including the time-varying failure probability (<em>P</em>_f) for each slide, the distance of slope retreat, and the probabilistic collapse within the slope. Additionally, this study also conducted a system reliability analysis. It is demonstrated that the variability in initial strength and degradation rate exerts contrasting effects on the time-varying slope strength. The variability in initial strength constricts the strength distribution, while the variability in degradation rate tends to expand it. Homogeneous and heterogeneous slopes exhibit distinct characteristics of slip surface degradation. These results provide novel insights into how the probabilistic characteristics of initial strength and degradation rate influence progressive failure. The proposed methodology provides a powerful tool for conducting probabilistic analysis of slope retreat resulting from weathering, and it has significant implications for regions that are prone to landslides.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106945"},"PeriodicalIF":5.3,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Macro- and micro-scopic suffusion behavior of gap-graded soils under cyclic hydraulic gradient reversal","authors":"Yi Zhao ,&nbsp;Qixin Wu ,&nbsp;Zheng Hu ,&nbsp;Yafei Jia ,&nbsp;Yewei Zheng","doi":"10.1016/j.compgeo.2024.106950","DOIUrl":"10.1016/j.compgeo.2024.106950","url":null,"abstract":"<div><div>Wave surging, fracking operations, and tides can cause seepage flow with hydraulic gradient reversals, resulting in complex hydraulic conditions. These complex hydraulic conditions can lead to more intricate suffusion processes, affecting the movement and loss of fine particles, and thereby weakening the internal stability of hydraulic structures. In this study, the coupled computational fluid dynamics and discrete element method (CFD-DEM) was employed to investigate the suffusion behavior of gap-graded soils under cyclic hydraulic gradient reversal. The suffusion behavior of gap-graded soil under constant hydraulic gradient and cyclic hydraulic gradient reversal conditions were first compared. Then, the influences of cyclic frequencies and reversal ratios on the suffusion behavior of gap-graded soils were analyzed. The simulation results show that the fine particle loss of gap-graded soils under cyclic hydraulic gradient reversal is greater than that under constant hydraulic gradient conditions. A higher reversal ratio or lower frequency can lead to a more significant fines loss. During suffusion, the evolution of micro-scale quantities such as fines migration, coordination number, and particle force characteristics is tracked, offering a more insightful explanation for the observed macroscopic behavior of gap-graded soils under cyclic hydraulic gradient reversal.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106950"},"PeriodicalIF":5.3,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745098","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":"Scaling law for correcting the gravel content effect due to scalping techniques by DEM investigations","authors":"Peng Xia ,&nbsp;Dai-Guang Yu ,&nbsp;Hai-Dong Luo ,&nbsp;Zhuo-Feng Li ,&nbsp;Qiang Ma ,&nbsp;Yu-Feng Gao","doi":"10.1016/j.compgeo.2024.106954","DOIUrl":"10.1016/j.compgeo.2024.106954","url":null,"abstract":"<div><div>Scalping techniques are commonly employed to handle oversized particles in gravelly soils for performing laboratory tests, which will cause significant gravel content (<em>GC</em>) effect on the predicted mechanical behaviors of prototype soils. To solve this obstacle, this study tries to establish the scaling law for correcting the <em>GC</em> effect, which controls the same equivalent skeleton void ratio between the prototype and model soils. The proposed scaling law characterizes the mechanical parameters using the newly introduced indexes including the degree of heterogeneity and the scaling factor for parameter <em>A</em> of the Harding equation. Then a series of DEM simulations of element tests were performed on sand-dominant gravelly soils to parameterize and check the applicability of the proposed scaling law. The simulation results show that both the converted shear responses and shear modulus reduction curves through the proposed scaling law are highly consistent with that of the prototype soils. This suggests that in dealing with deformation problems from small to medium strains, Rocha’s assumption is highly applicable for correcting the <em>GC</em> effect. When the adopted scalping techniques control the change in <em>GC</em> (Δ<em>GC</em>) below 20 %, the predicted liquefaction resistance will be very close to that of the prototype soils regardless of the earthquake magnitudes. However, when Δ<em>GC</em> is larger than 40 %, the prediction error in liquefaction resistance will be larger. Based on these simulation results, it is recommended that when selecting scalping techniques for laboratory tests on gravelly soils containing oversized particles, it is preferred that Δ<em>GC</em> be kept below 20 %.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106954"},"PeriodicalIF":5.3,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745148","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":"Rate-dependent FDEM numerical simulation of dynamic tensile fracture and failure behavior in frozen soil","authors":"Taiyu Zhang ,&nbsp;Zhiwu Zhu ,&nbsp;Yue Ma ,&nbsp;Zhengqiang Cheng ,&nbsp;Tao Li","doi":"10.1016/j.compgeo.2024.106916","DOIUrl":"10.1016/j.compgeo.2024.106916","url":null,"abstract":"<div><div>Considering that the dynamic fracture and failure behaviors of frozen soil play a crucial role in the safety and stability of engineering foundations in cold regions, this study aimed to reveal the dynamic tensile mechanical properties and damage failure mechanisms of frozen soil under impact loading. Dynamic Brazilian disk (BD) tests were conducted on frozen soil at different temperatures and loading velocities using a split Hopkinson pressure bar (SHPB) apparatus, followed by numerical simulations using the finite discrete element method (FDEM), focusing on the dynamic tensile deformation characteristics, failure patterns, tensile strength, and energy dissipation mechanisms of the frozen soil. The experimental results indicated that the dynamic tensile mechanical properties of frozen soil were influenced by both temperature and loading velocity. As the temperature decreased and loading velocity increased, the tensile strength of frozen soil significantly increased and showed a linear correlation with the loading velocity. At lower loading velocities, the cracks tended to propagate along the paths of least resistance, forming fewer but longer macrocracks. With increasing loading velocities, the number of cracks markedly increased, and their distribution became more diffuse, leading to a greater extent of failure in the frozen soil. An exponential damage cohesive interface model that considers rate effects was proposed to describe the dynamic tensile fracture mechanical behavior of frozen soil accurately. This model addresses the rate sensitivity of frozen soil and effectively accounts for the temperature effect by considering the volume of ice content and cryogenic suction. A comparison of the FDEM numerical simulation results with the experimental data indicated a good consistency in the overall trends, thus validating the effectiveness and applicability of the FDEM in simulating the dynamic tensile mechanical behavior of frozen soil.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106916"},"PeriodicalIF":5.3,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745147","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":"An efficient dense discs packing method in complex domains for DEM simulations","authors":"Ming Xia ,&nbsp;Liu He ,&nbsp;Longjun Dong ,&nbsp;Tongming Qu ,&nbsp;Y.T. Feng","doi":"10.1016/j.compgeo.2024.106947","DOIUrl":"10.1016/j.compgeo.2024.106947","url":null,"abstract":"<div><div>Efficiently assembling densely packed discs in complex domains remains an unresolved challenge for discrete element simulations. This study develops an efficient dense disc packing method based on the advancing front method (AFM) with closed form version. The new method enables a unified and efficient generation of intricate packings incorporating not just interior boundaries with multiple cavities, but also convex or non-convex external boundaries with complex geometric shapes. Furthermore, the new method can eliminate potential discontinuity encountered in certain DEM assemblies, such as the <em>one-sided lifting problem</em> that arises during discs packing using AFM with open form version. Several examples with complex geometries are presented to showcase the versatility, capability and performance of the proposed method. The proposed approach not only offers an efficient means of generating DEM packings, but also empowers DEM for enhanced simulations with complex geometric boundaries. Specifically, it takes only 70.92 s to generate 675.3 million discs on a 2 GHz laptop.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106947"},"PeriodicalIF":5.3,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745165","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":"Analytical solution for calculating three-dimensional responses due to dynamic loads acting on an underwater tunnel in stratified soil","authors":"Chao He,&nbsp;Yanrui Liu,&nbsp;Shunhua Zhou,&nbsp;Yuanping Jia,&nbsp;Xiaohui Zhang","doi":"10.1016/j.compgeo.2024.106924","DOIUrl":"10.1016/j.compgeo.2024.106924","url":null,"abstract":"<div><div>Hydroacoustic noise generated by trains running in underwater tunnels significantly impacts aquatic ecosystems, particularly fish breeding grounds and the habitats of endangered species. This underscores the necessity of investigating the characteristics of wave propagation and noise radiation emanating from underwater tunnels. This study proposes a novel analytical method for calculating 3D responses due to a dynamic point load acting on an underwater tunnel in stratified soils that considers dynamic tunnel–soil–fluid interactions. Stratified soils consist of multiple sediment layers, which are simulated as saturated porous media, overlying substrate layers, which are modeled as phase elastic media. The transfer matrix method is applied to simulate wave propagation in a layered fluid–solid system. The functions describing various types of waves scattered at the layer interfaces and the tunnel–soil interface are unified by wave transformation, thereby deriving an analytical solution for dynamic tunnel–soil–fluid interactions. A comparison with existing methods via numerical cases confirms the accuracy of the proposed method. Vibrations and hydroacoustic noise owing to dynamic loads acting on an underwater tunnel buried either in a saturated sediment layer or a single-phase substrate layer are investigated. The influences of tunnel burial depth, layering, as well as the porosity and permeability of saturated sediment are systematically analyzed. This research enhances the understanding of wave propagation and noise radiation in water emanating from underwater tunnels, facilitating the development of vibration isolation measures and protecting aquatic ecosystems.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106924"},"PeriodicalIF":5.3,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745167","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 new pile-soil interface and its application in battered mini piles under monotonic lateral load in cohesive soil","authors":"Haran Gananathan,&nbsp;Mahdi Disfani,&nbsp;Yinghui Tian,&nbsp;Guillermo Narsilio","doi":"10.1016/j.compgeo.2024.106922","DOIUrl":"10.1016/j.compgeo.2024.106922","url":null,"abstract":"<div><div>Numerical modelling of laterally loaded piles requires a robust pile-soil interface model. The conventional Coulomb friction model has limitations when predicting the soil-structure interaction at shallow depths for battered mini piles (BMPs) in cohesive (fine-grained) soils. This paper proposes an efficient pile-soil interface model to simulate laterally loaded BMPs in cohesive soils using three-dimensional finite element models (FEM). BMP systems have been commonly used to support lateral load-dominated lightweight superstructures. They are hybrid foundations with BMPs oriented at different inclinations and directions, mimicking tree root systems. FEM results indicate that the Coulomb model is unsuitable for simulating the pile-soil interface at shallow depth due to underprediction of shear resistance. The proposed interface model comprising a surface-to-surface cohesive damage interface with friction captures the lateral performance of BMPs accurately. The proposed model was implemented for a range of pile and soil properties to verify its suitability in understanding the behaviour of BMPs. The ultimate lateral capacity of BMPs increases with penetration length up to 1.5 m. While an increase in diameter and undrained shear strength increases the capacity, the lateral load eccentricity negatively impacts it. Interaction diagrams are developed to serve engineers estimate the ultimate lateral capacity of BMPs.</div></div>","PeriodicalId":55217,"journal":{"name":"Computers and Geotechnics","volume":"178 ","pages":"Article 106922"},"PeriodicalIF":5.3,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745166","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}