Article
Physics, Fluids & Plasmas
Ming Yang, Mahdi Taiebat, Patrick Mutabaruka, Farhang Radjai
Summary: By conducting 3D particle dynamics simulations, this study analyzed the microstructure and liquefaction state of granular materials under constant volume cyclic shearing, revealing the periodic jamming-unjamming transition leading to liquefaction. The research found that liquefaction is characterized by partial collapse of force-bearing network, decrease in coordination number and nonrattler fraction, and broadening of contact force probability density function. Additionally, the study showed that jamming transition and contact network percolation threshold are independent of initial conditions, leading to high contact anisotropy and decreased friction mobilization upon unjamming.
Article
Computer Science, Interdisciplinary Applications
Fuguang Zhang, Chaojun Wang, Jianmei Chang, Huaiping Feng
Summary: In cemented sand, with a high cement content or low cyclic stress ratio, there are few bond breakages and the mechanical coordination number remains almost unchanged. The increase in input work mainly contributes to the elastic energies at particle contacts and bond contacts, rather than leading to liquefaction. In liquefied cemented sand, as the cyclic stress ratio increases, bond breakages become more intense, the mechanical coordination number decreases faster, and various energy dissipation mechanisms reach their maximum more promptly. Additionally, the normal orientations for different types of contacts tend to become isotropic more rapidly.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Geological
Jaime A. Mercado, Luis G. Arboleda-Monsalve, Kevin R. Mackie
Summary: This study evaluates the influence of structural modeling assumptions on soil response due to seismic excitations, showing that nonlinear inelastic-degrading structural models significantly affect the seismic response of the entire SSI system.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Pu Yang, Edward Kavazanjian, Narayanan Neithalath
Summary: In this paper, the liquefaction resistance of untreated, MICP-cemented, and reconstituted sands is evaluated through DEM-based simulations of CyDSS tests. The DEM model is shown to accurately represent the cyclic behavior of different types of sands. MICP is found to have a significant effect on liquefaction in CyDSS tests.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Geological
Jiajin Zhao, Zhehao Zhu, Dexuan Zhang, Hao Wang, Xi Li
Summary: This paper studies the fabric properties during sand liquefaction using 3D constant-volume cyclic triaxial DEM tests. The results show good consistency with experimental data. The evolution of fabric characteristics is assessed using the coordination number and mechanical coordination number. The second-order contact normal fabric tensor is introduced to analyze complex inter-particle contacts and the shear strain is used as a bridge to describe the evolution of coordination number and anisotropy degree.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2024)
Article
Engineering, Marine
Leiye Wu, Wei Cheng, Zhehao Zhu
Summary: A new constitutive model incorporating fractional plastic flow rule and multiple hardening rules is proposed and validated with medium-dense sand cyclic test results, demonstrating robustness in capturing non-associativity and cyclic mobility of sandy soils. The model is implemented into a finite element code for a numerical case study on seabed soils under cyclic wave loadings, showcasing its practical applications in structure-seabed interactions.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Geological
Koichi Hashiguchi, Tatsuya Mase, Yuki Yamakawa
Summary: The article discusses the use of the subloading surface model to accurately predict cyclic mobility in geomaterials prior to liquefaction, by formulating translation rules for the similarity center of normal yield and subloading surfaces, as well as mixed hardening rules to describe induced anisotropy. The modification of material functions for elastic modulus, yield function, and isotropic hardening/softening is also emphasized to improve the accuracy of predictions. The validity of the formulation is verified through comparisons with various test data of cyclic mobility.
Article
Computer Science, Interdisciplinary Applications
Ming Yang, Mahdi Taiebat, Farhang Radjai
Summary: This paper investigates the evolution of internal structure during cyclic liquefaction of dense granular media through 3D-DEM simulations. The study reveals a fast transition to a fluid-like shear strain regime upon liquefaction, characterized by low shear modulus, decreasing dilatancy, and reduced shear viscosity. Various micro- and meso-scale descriptors are used to analyze the internal structure, and two possible criteria for exiting the fluid-like state based on excess pore pressure are discussed.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Geological
Aritra Banerjee, Anand J. Puppala, Laureano R. Hoyos
Summary: Liquefaction in soils can occur not only in saturated soils as commonly known, but also in unsaturated soils. Neglecting the importance of evaluating unsaturated soils that are close to saturation in liquefaction assessment can be risky. This study modified a cyclic double-walled triaxial device to conduct tests on suction-equilibrated specimens at a low suction state. Results from a series of tests were analyzed to study and verify the possibility of liquefaction in unsaturated soils. The study also compared stress paths of cyclic triaxial tests with critical state lines to indirectly assess the hypothesis of liquefaction mitigation using induced partial saturation technique.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2022)
Article
Engineering, Geological
Zhijian Qiu, Athul Prabhakaran, Ahmed Elgamal
Summary: This paper presents a three-dimensional multi-surface plasticity model to simulate the behavior of granular soil during seismically-induced liquefaction. The model extends an existing plasticity formulation and includes the Lade-Duncan failure criterion to capture laboratory test data. The model is implemented into the OpenSees framework and calibrated with laboratory tests to predict the seismic response of liquefiable ground.
Article
Engineering, Geological
Stefania Gobbi, Maria Paola Santisi d'Avila, Luca Lenti, Jean-Francois Semblat, Philippe Reiffsteck
Summary: The main goal of this paper is to assess the reliability of a nonlinear hysteretic model in capturing the behavior of saturated silty sand mixtures under cyclic loading conditions. The parameters governing the liquefaction triggering are identified through laboratory tests, and the numerical results are in good agreement with the experimental ones. The effects of relative density, fine content, and confining pressure on the liquefaction resistance of silty sands are analyzed.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Acoustics
Mehran Tirandazian, Gholamreza Nouri
Summary: This study numerically investigated the effects of wind turbine weight and liquefaction conditions on the seismic response of wind turbine-monopile systems in multilayered soil. It was found that an increase in wind turbine power did not significantly impact the soil-structure interaction response.
SHOCK AND VIBRATION
(2021)
Article
Chemistry, Multidisciplinary
Xing Dong, Jiaping Li, Yao Li, Zhe Wang, Ruida Han
Summary: Loose sand samples under bi-directional simple shear DEM models were simulated to study the liquefaction characteristics and meso-mechanisms. Results showed that bi-directional cyclic shear stress accelerated the drop in vertical stress and decreased the contact force between particles. An increased ? led to sample instability, increased floating particles, and easier liquefaction. The mechanical coordination number decreased at the beginning and end of shearing and was stable in the middle. The anisotropy tensor magnitude and disturbance to the skeleton structure increased under bi-directional shear paths.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Geological
Weibin Mo, Rui Wang, Jian-Min Zhang, Yannis F. Dafalias
Summary: This study investigates and quantifies the evolution of fabric tensors under cyclic loading using discrete element method (DEM) tests. Two different continuum evolution rate equations are used for simulations, and the results show that the novel Combined Fabric Evolution (CFE) equation can accurately simulate fabric evolution under different conditions.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2023)
Article
Engineering, Geological
Q. X. Wu, Z. X. Yang
Summary: The undrained response of sand under principal stress rotation (PSR) has been studied using the discrete element method, providing insights into the fabric evolution and macroscopic mechanical behavior of granular materials under rotational shear.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2022)
Article
Engineering, Geological
Bence Kato, Gang Wang
Summary: Understanding site-city interaction (SCI) is crucial for sustainable urban development in seismic regions. This study quantifies the effects of SCI at a congested transport hub in Hong Kong, demonstrating that building layout, inertia, and interaction between underground structures through the soil govern SCI, causing ground motion perturbations and wave trapping between buildings. Notable effects include amplification of short-period acceleration spectra and PGA in the center plaza, excess maximum story accelerations, and increased destructive kinetic energy. SCI effects may significantly increase seismic demand on short structures, requiring an adjustment in the seismic design of super-tall and low-rise buildings.
BULLETIN OF EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Chengzeng Yan, Dasheng Wei, Gang Wang
Summary: This paper introduces a three-dimensional heat transfer model considering contact heat transfer and thermal cracking in continuous-discontinuous media, coupled with 3D FDEM for thermo-mechanical calculation. The model's capability is validated through examples and key influencing parameters are discussed in the paper.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Huo Fan, Duruo Huang, Gang Wang
Summary: This study reveals the intrinsic shortcomings of NMM based on quadrilateral isoparametric mapping for the first time, leading to the establishment of a new NMM using a quadrilateral area coordinate system to overcome these drawbacks. The proposed method allows for analytically determining the stiffness matrix without the need for cumbersome Jacobian inversion and numerical integration, while also formulating a conecomplementary-based contact model to accurately determine frictional and cohesive contact forces. This new NMM framework eliminates the need for artificial penalty and open-close iteration, showing excellent performance in several benchmark examples.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Geological
Kewei Feng, Duruo Huang, Gang Wang, Feng Jin, Zhengwei Chen
Summary: A multiscale framework based on the spectral element method and material point method is developed for the analysis of large-deformation coseismic landslides. The proposed SEM-MPM model is able to reproduce the entire process of coseismic landslides and shows good agreement with field data and previous numerical studies.
ENGINEERING GEOLOGY
(2022)
Article
Engineering, Geological
Chengzeng Yan, Xin Xie, Yuhang Ren, Wenhui Ke, Gang Wang
Summary: A coupled thermal-hydro-mechanical (THM) model based on the combined finite-discrete element method (FDEM) is proposed for simulating rock cracking driven by multi-physics. By simulating the interaction between thermal, hydraulic, and mechanical processes, the study shows that branching fractures can be produced in addition to the primary fracture during hydraulic fracturing.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Computer Science, Interdisciplinary Applications
Zhihao Shen, Gang Wang, Duruo Huang, Feng Jin
Summary: A resolved coupling model was developed in this paper to simulate the interaction between two-phase fluids and irregularly shaped particles using CFD and DEM. The model calculates meso-scale flow around particles and directly computes the fluid forces on multi-sphere particles without relying on empirical drag force models. Benchmark cases and a case study on dambreak wave impact on a rock pile demonstrate the accuracy and potential application of the model in coastal engineering.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Construction & Building Technology
Wei Wang, Feng Jin, Bohao Wang, Gang Wang, Duruo Huang, Chunyang Cui
Summary: The deposition morphology of cement grout in granular materials is studied, and it is found that the morphology varies with the yield stress of the grout.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Ting Liang, Feng Jin, Duruo Huang, Gang Wang
Summary: This study models rock-filled concrete using a mesoscopic finite element approach, revealing the evolution of its elastic modulus and providing important research results to fill the gaps in RFC research in the numerical computational field.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Construction & Building Technology
Tie Wang, Chengzeng Yan, Gang Wang, Yuchen Zheng, Wenhui Ke, Yu-Yong Jiao
Summary: In this paper, the deformation and failure process of soft rock roadway in high humidity environment are simulated using the humidity diffusion-deformation-fracture coupling model based on the finite-discrete element method (FDEM). The numerical results provide a better understanding of the deformation and failure behavior of soft rock roadway in high humidity environment.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Computer Science, Interdisciplinary Applications
Tie Wang, Chengzeng Yan, Hong Zheng, Yuchen Zheng, Gang Wang
Summary: This study investigates the microcrack behavior and energy evolution of mudstone during moisture diffusion by introducing the Weibull distribution function into the FDEM-based moisture diffusion-fracture coupling model. The results show that nonuniform swelling deformation is the main cause of microfractures, and the evolution of kinetic energy and strain energy is related to the storage rate of swelling deformation and the release rate of microfractures.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Geological
Chengzeng Yan, Tie Wang, Yakun Gao, Wenhui Ke, Gang Wang
Summary: In this study, a three-dimensional grouting model based on the combined finite-discrete element method is proposed. The model successfully simulates rock cracking and the effect of hydromechanical coupling. The validation example and parameter study demonstrate the accuracy of the model in simulating grout migration, pressure distribution, grout-rock mass interaction, and crack evolution.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Zhihao Shen, Duruo Huang, Gang Wang, Yuntian Zhao, Feng Jin
Summary: A mesoscale bond model to study the mechanical behavior of cemented granular particles was developed in this study. The numerical results were consistent with the experimental results, indicating that the model can accurately simulate the behavior of cemented granular materials with different cement ratios.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Civil
Zhengwei Chen, Duruo Huang, Gang Wang
Summary: A large-scale physics-based simulation was conducted to investigate the ground motion distribution in the 2016 Kumamoto earthquake in Japan with a magnitude of M-w 7.0. The simulation considered fault rupture, wave propagation, and localized site response, taking into account the combined effect of soil nonlinearity and topographic amplification. The obtained ground motion time histories were compared satisfactorily with recorded data. The study presented the ground motion distribution considering nonlinear soil response and topographic amplification, and developed a 3D equivalent linear model to mimic soil nonlinearity. Neglecting soil nonlinearity could result in overestimating peak ground acceleration (PGA) and underestimating peak ground velocity (PGV) near the fault. The study also found topographic amplification factors (TAFs) of PGA and PGV between 0.5 and 2.0, with a correlation coefficient of 0.7 between them. Predictive equations were proposed to correlate TAFs of PGA and PGV with topographic features.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Chemistry, Multidisciplinary
Du Han, Hongwei Fan, Chengzeng Yan, Tie Wang, Yu Yang, Sajid Ali, Gang Wang
Summary: This paper analyzes the heat transfer processes of functionally graded materials (FGMs) using MultiFracS software and a coupled thermo-mechanical model. The study verifies the model for handling the heat transfer problem in heterogeneous materials. The advantages and disadvantages of FGMs and composite materials under thermal shock loads are compared, and the geometric characteristics of double-edge cracks in the gradient material plate on crack propagation are analyzed.
APPLIED SCIENCES-BASEL
(2022)
Article
Automation & Control Systems
Lin Li, Feng Jin, Duruo Huang, Gang Wang
Summary: This study proposes deep learning models to predict soil seismic response based on recorded ground motions. These models achieve better accuracy and higher efficiency compared to conventional physics-based models like finite element method (FEM).
ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE
(2023)
