Article
Engineering, Environmental
Pei Zuan, Liu Yang, Luo Fei
Summary: It is well known that particle breakage in frozen sands occurs throughout the triaxial shearing process and is accompanied by irreversible energy dissipation. In this study, the contact relationships between particles in frozen sands were investigated, and a modified energy equation was developed to consider the continuous variation in the internal friction angle. Cryogenic triaxial compression tests were conducted to explore the particle breakage behaviors, and it was found that the degree of particle breakage is most severe when the axial strain ranges from 1.5% to 2.5%. The results also showed that the energy dissipation increases with higher confining pressure, shear stress, or lower temperature.
COLD REGIONS SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Shiyu Wei, Han Wei, Henrik Saxen, Yaowei Yu
Summary: This paper uses the discrete element method (DEM) to study the effects of rolling and static friction coefficients on the repose angle. The results show that the repose angle increases with increasing coefficients of rolling and static friction, although the rate of increase diminishes. The coefficient of static friction has a greater impact on the repose angle than the coefficient of rolling friction, and the roughness of the base surface affects the repose angle.
Article
Engineering, Ocean
Fenghui Hu, Xiangwei Fang, Zhihua Yao, Huanran Wu, Chunni Shen, Yitao Zhang
Summary: This study investigates the particle breakage characteristics of coral sand through experimental and numerical simulation methods. The results indicate that the overall behavior of coral sand transitions from strain softening to strain hardening with increasing confining pressure, and overall breakage gradually becomes the dominant mechanism. Microscopic analysis reveals that higher confining pressure increases the overall contact force and coordination number of the coral sand.
MARINE GEORESOURCES & GEOTECHNOLOGY
(2023)
Article
Engineering, Chemical
Yanjie Li, Qi Zhang, Xia Hua, Yu Guo, Jennifer S. Curtis
Summary: This study simulates the triaxial compressions of spherical granular beds reinforced by immersed flexible fibers using the discrete element method (DEM). The results show that the yield stresses of the particle beds increase with higher fiber concentration or aspect ratio, but are not affected by fiber flexibility. The configuration of the immersed fibers significantly impacts the compressive strength of the beds.
Article
Engineering, Chemical
Tong Deng, Vivek Garg, Hamid Salehi, Michael S. A. Bradley
Summary: Bulk solids often segregate on inclined surfaces, especially when particles of different shapes and sizes move differently on the surface. Studies have shown that segregation levels increase with higher particle sphericity and sphericity ratio, and are higher at low angles of repose but minimal at angles higher than 32 degrees. It is important to note that this 32 degree angle of repose should not be generalized to indicate susceptibility of blends to free-surface rolling segregation for materials other than the one tested.
Article
Engineering, Geological
Iman Rostamsowlat, Brian Evans, Joel Sarout, Jamal Rostami, Hyock-Ju Kwon
Summary: This paper provides experimental evidence that the internal friction angle of rocks can be determined using a scratch test with a blunt polycrystalline diamond compact (PDC) cutter. The study shows that the apparent friction angle at the wear flat-rock interface of the blunt cutter is influenced by the wear flat roughness and material properties.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Geological
Mathias Tolomeo, Glenn R. McDowell
Summary: This paper assesses two different methods for modeling real particle shapes in 3D discrete element method (DEM) simulations and applies them to triaxial tests on railway ballast. The results show that using clumps can achieve higher shear strength closer to the experimental response. A micromechanical analysis reveals the influence of particle shape on the mechanics, particularly the concave shape. Additionally, the combined effect of particle shape and interparticle friction coefficient on shear strength is evaluated.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Geological
Yaohui Gao, Kezhong Wang, Chang Zhou
Summary: By using 3D discrete element method (DEM) to conduct simulated true triaxial compression tests on jointed marble, this study investigated the influence of intermediate principal stress and joint inclined angle on the macroscopic mechanical characteristics of rock mass. The study found a strong dependency of strength and failure mechanism on the intermediate principal stress, and significant influence of joint inclined angle on the strength and failure characteristics.
Review
Construction & Building Technology
Haohui Ding, Zheng Han, Yange Li, Wendou Xie, Bangjie Fu, Changli Li, Lianheng Zhao
Summary: Granular soils are extensively used in engineering and understanding the correlation between particle breakage and mechanical response is crucial. This study reviews the up-to-date research from four perspectives: statistical analysis, experimental investigation, numerical simulation, and theoretical analysis. Future research should focus on exploring the microstructure of particle systems to gain a deeper understanding of particle breakage.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Computer Science, Interdisciplinary Applications
Zhiren Zhu, Jianfeng Wang, Mengmeng Wu
Summary: This paper aims to simulate particle crushing events in triaxial tests using the three dimensional discrete element method, considering irregular particles and coordination numbers. By reproducing irregular particle shapes and modeling the flexible membrane in triaxial tests, the study successfully models particle crushing events by replacing crushed particles with generated fragments while maintaining mass conservation.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Chemical
Zhuo Cui, Dou Huang, Chao Dang, Li Jia
Summary: The pressure drop in wicks significantly impacts the heat transfer rates of heat pipes. This study found that wicks made of spherical particles had lower pressure drops, while the pressure drop in wicks made of irregular particles decreased with increasing porosity. Different correlations were used to predict pressure drops in wicks, with the Morcom correlation providing accurate predictions for spherical particle wicks and the Meyer and Smith correlations being better for irregular particle wicks.
Article
Chemistry, Multidisciplinary
Lan Cui, Wenzhao Cao, Qian Sheng, Mingxing Xie, Tao Yang, Ping Xiao
Summary: By experiment and simulation, the performance of layered geogrid-sand-clay reinforced structures was studied, showing that laying sand layers and embedding geogrids in sand layers can improve the mechanical properties of the structure and increase the shear strength index.
APPLIED SCIENCES-BASEL
(2021)
Article
Computer Science, Interdisciplinary Applications
Penghai Deng, Quansheng Liu, Haifeng Lu
Summary: In this paper, a random parameter assignment method based on the combined finite-discrete element method is proposed to simulate the mechanical properties and failure behavior of heterogeneous rock. The simulation results show that with an increase in the heterogeneity m value, the strength parameters, elastic modulus, and tensile strength of the rock increase exponentially and approach those of the homogeneous rock sample. The simulation results of tunnel excavation indicate that the overall fracture morphology of the surrounding rock remains unchanged, but the failure degree and maximum fracture propagation range decrease exponentially with an increase in the m value.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Chemistry, Multidisciplinary
Sun-Hoon Kim, Kwang-Jin Kim
Summary: This study presents numerical parametric studies on the stress distribution in the surrounding rocks of an underground silo using a 2D axial symmetric finite element model. The analysis includes different ratios of in situ stress and provides detailed stress states and safety factor distributions in the key locations of the underground silo.
APPLIED SCIENCES-BASEL
(2022)
Article
Computer Science, Interdisciplinary Applications
Jia-Yan Nie, Yi-Fei Cui, Zhi-Yong Yang, Yan-Zhou Yin, Zi-Jun Cao, Dian-Qing Li
Summary: The study investigates the variability of soil deformation and strength properties for the same type of soil samples at the same density and stress states using the random discrete element method. By incorporating a random field model and Monte Carlo simulations, the study explores the underlying microscopic mechanisms and provides insights into the cross-scale understanding of sandy soil properties in the laboratory.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Geological
Sixia Gong, Tao Zhao, Jidong Zhao, Feng Dai, Gordon G. D. Zhou
Summary: Slit dams are open-check barrier structures widely used in mountainous regions to resist the destructive impacts of granular flows. A numerical study using DEM showed that by adjusting relative post spacing and particle clump aspect ratio, the design of slit dams can be optimized to increase trapping efficiency.
Article
Construction & Building Technology
Ang Li, Feng Dai, Yi Liu, Hongbo Du, Ruochen Jiang
Summary: A novel dynamic method is proposed for evaluating the stability of high sidewalls subjected to flexural-toppling by integrating derived criterion, continuum modelling and microseismic data. The study defines a geo-mechanical model for analyzing toppling rock strata on high sidewalls and deduces potential energies equations using the Rayleigh-Ritz method. A quantitative stability evaluation methodology is presented considering progressive failure and the influence of fractures along bedding planes.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2021)
Article
Mining & Mineral Processing
Wei You, Feng Dai, Yi Liu, Hongbo Du, Ruochen Jiang
Summary: This study introduces a numerical servo triaxial Hopkinson bar (NSTHB) to investigate the dynamic responses of rocks under a true triaxial stress state. The results indicate that the increase in intermediate principal stress leads to an increase in dynamic strength and elastic modulus of rocks, while the dynamic elastic modulus remains independent of the dynamic strain rate. Additionally, the study shows that the intermediate principal stress significantly affects the dynamic failure modes of rocks.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2021)
Article
Environmental Sciences
Li Qian, Jianhai Zhang, Xianliang Wang, Yonghong Li, Ru Zhang, Nuwen Xu, Zhiguo Li
Summary: In this study, the creep behavior of granite in Shuangjiangkou underground powerhouse was investigated, and a new parameter DPR, the ratio of deviatoric stress to peak strength, was proposed. Based on the test results, an improved generalized Kelvin creep model was introduced to accurately describe the primary and secondary creep behavior of granite under given deviatoric stresses and confining pressures.
ENVIRONMENTAL EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Quanfu Ding, Biao Li, Haijian Su, Nuwen Xu, Xuehua Li, Xingyang Deng
Summary: High geo-stresses and complicated geological conditions are typical characteristics in the traffic tunnel of the tailrace surge chamber at the Shuangjiangkou hydropower station. Microseismic monitoring technology helped evaluate rock mass stability and reveal rock fracturing mechanisms. Weak structures and the multi-cavern effect exacerbated rock mass damage during excavation-unloading, with tensile failure being the main fracturing type.
GEOMATICS NATURAL HAZARDS & RISK
(2022)
Article
Engineering, Geological
Xiao Huang, Nuwen Xu, Wei Wu, Peiwei Xiao, Linlu Dong, Biao Li
Summary: This study uses microseismic monitoring and numerical modeling to investigate the stability of intersecting discontinuities in rock masses. The results suggest that the stability is influenced by geological features and mechanical properties, emphasizing the importance of paying attention to key properties favorable for rock instability.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Metallurgy & Metallurgical Engineering
Biao Li, Quan-fu Ding, Nu-wen Xu, Feng Dai, Yuan Xu, Hong-lue Qu
Summary: Rock mass large deformation in underground powerhouse caverns is a significant hazard in hydropower engineering in Southwest China. Microseismic monitoring techniques can be used to detect the fractures generated during the development of rock mass large deformation. The study analyzes the MS b-values associated with rock mass large deformation and their temporal variation, and provides valuable information for understanding the fracturing characteristics of MS sources and early warning of rock mass large deformation in underground powerhouse caverns.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
Article
Engineering, Geological
Kang Yan, Tao Zhao, Yong Liu
Summary: This research examined the influence of spillway section shape on the breaching process of landslide dams through flume tests, and the results showed that the triangle spillway had the best performance.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Engineering, Geological
Peiwei Xiao, Haoyu Mao, Bo Qian, Biao Li, Xingguo Yang, Nuwen Xu
Summary: A high-precision microseismic monitoring system was established to monitor surrounding rock micro-fractures in the underground powerhouse of Shuangjiangkou Hydropower Station. Qualitative analysis of the damage mechanism of surrounding rock microfractures was conducted based on the source parameters of microseismic events. Numerical analysis using FLAC3D showed that considering microseismic damage can better reflect the actual situation of the field. The microfractures in the surrounding rock mainly exhibited mixed failure characteristics, with shear failures localized in certain areas and large fractures in the vault section.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2022)
Article
Engineering, Geological
Tao Zhao, Gordon G. D. Zhou, Qicheng Sun, Giovanni B. Crosta, Dongri Song
Summary: The study conducted field observations and experiments in Southwest China to explore debris flow dynamics, sediment transportation, and slope erosion. It found that heavily jointed, weathered, and sparsely vegetated areas are more prone to debris flows, with the characteristics of debris flow influenced by erodible sediments and water sources.
Article
Engineering, Geological
Tao Zhao, Giovanni B. Crosta, Yong Liu
Summary: Earthquakes can cause rock fracturing, which is crucial for assessing the risks of slope failures and rock avalanches in seismic prone areas. This study used a 2D discrete element method to simulate the fracturing of an intact rock slope, considering material heterogeneity. The results showed that earthquakes triggered significant ground motion and slope damage, resulting in densely spaced fractures that split the slope into rock fragments with varied shapes. The size distribution of these fragments followed the Weibull's cumulative distribution.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Construction & Building Technology
Zhonghua Hu, Bangbiao Wu, Nuwen Xu, Kai Wang
Summary: This study investigates the failure mechanism of rock masses in the underground powerhouse caverns of the Baihetan hydropower station and finds that discontinuities significantly affect the stability of rock masses. A risk boundary, affected by discontinuities, is proposed to evaluate roof stability. The study provides valuable insights for the design of excavation and support systems in underground engineering projects.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Construction & Building Technology
Jinyong Zhang, Nuwen Xu, Wei Wu, Peiwei Xiao, Biao Li, Linlu Dong
Summary: This study explores the application of the fast marching method (FMM) to improve the accuracy of microseismic source location in faulted rock masses, showing the potential to enhance location accuracy for P-wave propagation and indicating the need for further improvement.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Engineering, Geological
Kang Yan, Tao Zhao, Yong Liu
Summary: This study simulated the plane breach of cohesionless dikes induced by overtopping flow using the discrete-element method coupled with computational fluid dynamics. The influence of three important factors on the dike breach process was investigated. The results show that the inflow discharge per unit width and convergence area length have significant impacts on the breach process, and the particle size is linearly related to the breach process.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Jiayu Lin, Tao Zhao, Mingjing Jiang
Summary: This study investigates the dynamics of projectile penetration into a granular bed immersed in a fluid using a coupled computational fluid dynamics and discrete element method. The results show that the final penetration depth follows an empirical relation derived from experimental observations and the interstitial fluid enhances the effective drag force of the granular bed.
