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Stochastic analysis of load-transfer mechanism of energy piles by random finite difference model
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作者 Chao Shi Yu Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第4期997-1010,共14页
The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a... The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a promising carbon reduction technology that can stably and effectively exploit subsurface geothermal energy by taking advantage of load-bearing structural elements as heat transfer medium.However,the transformation of conventional geo-structures(e.g.piles)into heat exchangers between the ground and superstructures can potentially induce variable thermal axial stresses and displacements in piles.Traditional energy pile analysis methods often rely on deterministic and homogeneous soil parameter profiles for investigating thermo-mechanical soil-structure interaction,without consideration of soil spatial variability,model uncertainty or statistical uncertainty associated with interpolation of soil parameter profiles from limited site-specific measurements.In this study,a random finite difference model(FDM)is proposed to investigate the thermo-mechanical load-transfer mechanism of energy piles in granular soils.Spatially varying soil parameter profile is interpreted from limited site-specific measurements using Bayesian compressive sensing(BCS)with proper considering of soil spatial variability and other uncertainties in the framework of Monte Carlo simulation(MCS).Performance of the proposed method is demonstrated using an illustrative example.Results indicate that the proposed method enables an accurate evaluation of thermally induced axial stress/displacement and variation in null point(NP)location with quantified uncertainty.A series of sensitivity analyses are also carried out to assess effects of the pile-superstructure stiffness and measurement data number on the performance of the proposed method,leading to useful insights. 展开更多
关键词 Null point(NP)variation Load-transfer mechanism Bayesian compressive sensing(BCS) Heating and cooling Monte Carlo simulation(MCS)
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Capability of discrete element method to investigate the macro-micro mechanical behaviours of granular soils considering different stress conditions and morphological gene mutation
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作者 Wei Xiong Jianfeng Wang Zhuang Cheng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2731-2745,共15页
Discrete element method(DEM)has been widely utilised to model the mechanical behaviours of granular materials.However,with simplified particle morphology or rheology-based rolling resistance models,DEM failed to descr... Discrete element method(DEM)has been widely utilised to model the mechanical behaviours of granular materials.However,with simplified particle morphology or rheology-based rolling resistance models,DEM failed to describe some responses,such as the particle kinematics at the grain-scale and the principal stress ratio against axial strain at the macro-scale.This paper adopts a computed tomography(CT)-based DEM technique,including particle morphology data acquisition from micro-CT(mCT),spherical harmonic-based principal component analysis(SH-PCA)-based particle morphology reconstruction and DEM simulations,to investigate the capability of DEM with realistic particle morphology for modelling granular soils’micro-macro mechanical responses with a consideration of the initial packing state,the morphological gene mutation degree,and the confining stress condition.It is found that DEM with realistic particle morphology can reasonably reproduce granular materials’micro-macro mechanical behaviours,including the deviatoric stressevolumetric straineaxial strain response,critical state behaviour,particle kinematics,and shear band evolution.Meanwhile,the role of multiscale particle morphology in granular soils depends on the initial packing state and the confining stress condition.For the same granular soils,rougher particle surfaces with a denser initial packing state and a higher confining stress condition result in a higher degree of shear strain localisation. 展开更多
关键词 Discrete element method(DEM) Spherical harmonic-based principal component analysis(SH-PCA) Particle morphology Granular so
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Review of advanced road materials, structures, equipment, and detection technologies
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作者 JRE Editorial Office Maria Chiara Cavalli +37 位作者 De Chen Qian Chen Yu Chen Augusto Cannone Falchetto Mingjing Fang Hairong Gu Zhenqiang Han Zijian He Jing Hu Yue Huang Wei Jiang Xuan Li Chaochao Liu Pengfei Liu Quantao Liu Guoyang Lu Yuan Ma Lily Poulikakos Jinsong Qian Aimin Sha Liyan Shan Zheng Tong B.Shane Underwood Chao Wang Chaohui Wang Di Wang Haopeng Wang Xuebin Wang Chengwei Xing Xinxin Xu Min Ye Huanan Yu Huayang Yu Zhe Zeng You Zhan Fan Zhang Henglong Zhang Wenfeng Zhu 《Journal of Road Engineering》 2023年第4期370-468,共99页
As a vital and integral component of transportation infrastructure,pavement has a direct and tangible impact on socio-economic sustainability.In recent years,an influx of groundbreaking and state-of-the-art materials,... As a vital and integral component of transportation infrastructure,pavement has a direct and tangible impact on socio-economic sustainability.In recent years,an influx of groundbreaking and state-of-the-art materials,structures,equipment,and detection technologies related to road engineering have continually and progressively emerged,reshaping the landscape of pavement systems.There is a pressing and growing need for a timely summarization of the current research status and a clear identification of future research directions in these advanced and evolving technologies.Therefore,Journal of Road Engineering has undertaken the significant initiative of introducing a comprehensive review paper with the overarching theme of“advanced road materials,structures,equipment,and detection technologies”.This extensive and insightful review meticulously gathers and synthesizes research findings from 39 distinguished scholars,all of whom are affiliated with 19 renowned universities or research institutions specializing in the diverse and multidimensional field of highway engineering.It covers the current state and anticipates future development directions in the four major and interconnected domains of road engineering:advanced road materials,advanced road structures and performance evaluation,advanced road construction equipment and technology,and advanced road detection and assessment technologies. 展开更多
关键词 Road engineering Advanced road material Advanced road structure Advanced road equipment Advanced road detection technology
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Superior and safer lithium sulfur batteries realized by robust polysulfides-retarding dam with high flame retardance
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作者 Junling Wang Yanfang Cao +5 位作者 Zhirong Wang Yinquan Zhao Chuang He Fudong Zhao Chaoling Han Shui Yu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第2期471-486,I0011,共17页
The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive usages.Unfortunately,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite grow... The unparalleled energy density has granted lithium-sulfur batteries(LSBs)with attractive usages.Unfortunately,LSBs still face some unsurpassed challenges in industrialization,with polysulfides shuttling,dendrite growth and thermal hazard as the major problems triggering the cycling instability and low safety.With the merit of convenience,the method of designing functional separator has been adapted.Concretely,the carbon aerogel confined with CoS_(2)(CoS_(2)-NCA)is constructed and coated on Celgard separator surface,acquiring CoS_(2)-NCA modified separator(CoS_(2)-NCA@C),which holds the promoted electrolyte affinity and flame retardance.As revealed,CoS_(2)-NCA@C cell gives a high discharge capacity 1536.9 mAh/g at 1st cycle,much higher than that of Celgard cell(987.1 mAh/g).Moreover,the thermal runaway triggering time is dramatically prolonged by 777.4 min,corroborating the promoted thermal safety of cell.Noticeably,the higher coulombic efficiency stability and lower overpotential jointly confirm the efficacy of CoS_(2)-NCA@C in suppressing the lithium dendrite growth.Overall,this work can provide useful inspirations for designing functional separator,coping with the vexing issues of LSBs. 展开更多
关键词 Lithium-sulfur batteries Thermal safety Flame retardancy SEPARATOR
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Fundamental Study on Response Properties of Structures Constructed on Lunar Regolith
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作者 Yuji Miyamoto Takaharu Nakano Toshio Kobayashi 《Open Journal of Earthquake Research》 2024年第1期27-40,共14页
The Artemis Program, for constructing the lunar base, is in progress. How to design and construct architectural and civil engineering structures in the lunar environment has become an important issue. The lunar surfac... The Artemis Program, for constructing the lunar base, is in progress. How to design and construct architectural and civil engineering structures in the lunar environment has become an important issue. The lunar surface is covered with soft sand, called regolith, and it is required to protect lunar bases and structures, as well as internal precision equipment, against vibrational disturbances such as moonquakes and meteorite collisions. Therefore, in this study, the static and cyclic triaxial compression tests of the regolith simulant were conducted. The reference strain and equivalent damping factor of the regolith simulant were smaller compared to sandy soil on Earth. In addition, a shaking table test using model specimens was conducted on the response properties of regolith ground alone and structures set on regolith ground. The buried foundation and pile foundation notably suppressed the horizontal response attributed to the rocking component compared to a direct foundation. 展开更多
关键词 Lunar Development REGOLITH Soil-Structure Interaction Triaxial Compression Test Shaking Table Test
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Influence of explosion parameters on wavelet packet frequency band energy distribution of blast vibration 被引量:12
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作者 中国生 敖丽萍 赵奎 《Journal of Central South University》 SCIE EI CAS 2012年第9期2674-2680,共7页
Blast vibration analysis is one of the important foundations for studying the control technology of blast vibration damage.According to blast vibration live data that have been collected and the characteristics of sho... Blast vibration analysis is one of the important foundations for studying the control technology of blast vibration damage.According to blast vibration live data that have been collected and the characteristics of short-time non-stationary random signals,the wavelet packet energy spectrum analysis for blast vibration signal has made by wavelet packet analysis technology and the signals were measured under different explosion parameters(the maximal section dose,the distance of blast source to measuring point and the section number of millisecond detonator).The results show that more than 95% frequency band energy of the signals s1-s8 concentrates at 0-200 Hz and the main vibration frequency bands of the signals s1-s8 are 70.313-125,46.875-93.75,15.625-93.75,0-62.5,42.969-125,15.625-82.031,7.813-62.5 and 0-62.5 Hz.Energy distributions for different frequency bands of blast vibration signal are obtained and the characteristics of energy distributions for blast vibration signal measured under different explosion parameters are analyzed.From blast vibration signal energy,the decreasing law of blast seismic waves measured under different explosion parameters was studied and the wavelet packet analysis is an effective means for studying seismic effect induced by blast. 展开更多
关键词 小波包分析 爆破振动 能量分布 爆炸参量 频带 非平稳随机信号 振动信号 控制技术
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Non-parametric machine learning methods for interpolation of spatially varying non-stationary and non-Gaussian geotechnical properties 被引量:2
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作者 Chao Shi Yu Wang 《Geoscience Frontiers》 SCIE CAS CSCD 2021年第1期339-350,共12页
Spatial interpolation has been frequently encountered in earth sciences and engineering.A reasonable appraisal of subsurface heterogeneity plays a significant role in planning,risk assessment and decision making for g... Spatial interpolation has been frequently encountered in earth sciences and engineering.A reasonable appraisal of subsurface heterogeneity plays a significant role in planning,risk assessment and decision making for geotechnical practice.Geostatistics is commonly used to interpolate spatially varying properties at un-sampled locations from scatter measurements.However,successful application of classic geostatistical models requires prior characterization of spatial auto-correlation structures,which poses a great challenge for unexperienced engineers,particularly when only limited measurements are available.Data-driven machine learning methods,such as radial basis function network(RBFN),require minimal human intervention and provide effective alternatives for spatial interpolation of non-stationary and non-Gaussian data,particularly when measurements are sparse.Conventional RBFN,however,is direction independent(i.e.isotropic)and cannot quantify prediction uncertainty in spatial interpolation.In this study,an ensemble RBFN method is proposed that not only allows geotechnical anisotropy to be properly incorporated,but also quantifies uncertainty in spatial interpolation.The proposed method is illustrated using numerical examples of cone penetration test(CPT)data,which involve interpolation of a 2D CPT cross-section from limited continuous 1D CPT soundings in the vertical direction.In addition,a comparative study is performed to benchmark the proposed ensemble RBFN with two other non-parametric data-driven approaches,namely,Multiple Point Statistics(MPS)and Bayesian Compressive Sensing(BCS).The results reveal that the proposed ensemble RBFN provides a better estimation of spatial patterns and associated prediction uncertainty at un-sampled locations when a reasonable amount of data is available as input.Moreover,the prediction accuracy of all the three methods improves as the number of measurements increases,and vice versa.It is also found that BCS prediction is less sensitive to the number of measurement data and outperforms RBFN and MPS when only limited point observations are available. 展开更多
关键词 Spatial interpolation Multiple point statistics Bayesian compressive sampling Compressive sensing Sparse measurement
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Influence of anisotropic stress path and stress history on stiffness of calcareous sands from Western Australia and the Philippines 被引量:2
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作者 Huan He Siyue Li +2 位作者 Kostas Senetakis Matthew Richard Coop Songyu Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2022年第1期197-209,共13页
Investigation of dynamic properties of carbonate/calcareous soils is important in earthquake and offshore engineering as these soils are commonly encountered in large-scale projects related with energy geomechanics an... Investigation of dynamic properties of carbonate/calcareous soils is important in earthquake and offshore engineering as these soils are commonly encountered in large-scale projects related with energy geomechanics and land reclamation.In this study,the stiffness and stiffness anisotropy of two types of calcareous sands(CS)from the Western Australia and the Philippines were examined using bender elements configured in different directions in stress path setups.Stiffness measurements were taken on specimens subjected to constant p’compression/extension and biaxial stress paths and additional tests were performed on three types of silica sands with different geological origins and particle shapes,which were used as benchmark materials in the study.Compared with the three brands of silica sands,the stiffness of the CS was found to be more significantly influenced by anisotropic loading;an important observation of the experimental results was that stress anisotropy had different weighted influences on the stiffness in different directions,thus influencing stiffness anisotropy.Comparisons were made between the specimens subjected to complex loading paths,and respected model parameters as suggested from published expressions in the literature.These comparisons further highlighted that calcareous soils have different responses in terms of stiffness,stiffness anisotropy and loading history,compared with that of silica-based sands. 展开更多
关键词 Calcareous soils Dynamic properties Shear stiffness Stress anisotropy Stress history
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Experimental and FEM Modal Analysis of a Deployable-Retractable Wing 被引量:4
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作者 P. Jia S. K. Lai +1 位作者 W. Zhang C. W. Lim 《Modern Mechanical Engineering》 2014年第4期183-197,共15页
The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was c... The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was conducted in order to determine the free vibration characteristics. Natural frequencies and vibration mode shapes were obtained via measurement in LMS Test. Lab. The frequency response functions were identified and computed by force and acceleration signals, and then mode shapes of this morphing wing structure were subsequently identified by PolyMAX modal parameter estimation method. FEM modal analysis was also implemented and its numerical results convincingly presented the mode shape and natural frequency characteristics were in good agreement with those obtained from experimental modal analysis. Experimental study in this paper focuses on the transverse response of morphing wing as its moveable part is deploying or retreating. Vibration response to different rotation speeds have been collected, managed and analyzed through the use of comparison methodology with each other. Evident phenomena have been discovered including the resonance on which most analysis is focused because of its potential use to generate large amplitude vibration of specific frequency or to avoid such resonant frequencies from a wide spectrum of response. Manufactured deployable-retractable wings are studied in stage of experimental modal analysis, in which some nonlinear vibration resulted should be particularly noted because such wing structure displays a low resonant frequency which is always optimal to be avoided for structural safety and stability. 展开更多
关键词 Deployable-Retractable WING EXPERIMENTAL MODAL Analysis FEM Mode SHAPES Natural Frequency LMS Test. Lab
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Harmonic Analyses of Hydrodynamic Characteristics for Gap Resonance Between Fixed Box and Vertical Wall 被引量:1
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作者 HE Zhi-wei GAO Jun-liang +3 位作者 CHEN Hong-zhou ZANG Jun LIU Qian WANG Gang 《China Ocean Engineering》 SCIE EI CSCD 2021年第5期712-723,共12页
Two marine structures arranged side by side with a narrow gap may suffer from violent free-surface resonance,which would cause green water on deck,dramatically raise hydrodynamic loads on structures and seriously thre... Two marine structures arranged side by side with a narrow gap may suffer from violent free-surface resonance,which would cause green water on deck,dramatically raise hydrodynamic loads on structures and seriously threaten the operation safety.The CFD-based open-sourced software,OpenFOAM?,is employed to simulate the twodimensional fluid resonance inside a narrow gap between a fixed box and a vertical wall induced by regular waves with different wave heights.The topographies with various plane slopes are placed in front of the wall.The focus of this article is on the influences of the incident wave height and the topographic slope on the nonlinear characteristics of various hydrodynamic parameters(including the wave height in the gap,the vertical wave force,and the horizontal wave force on the box)during gap resonance.The ratios of their high-order to the corresponding 1 st-order components under different sets of the incident wave height and the topographic slope are analyzed.It is found that the relative importance of all the high-order components increases gradually with the incident wave height for all the three parameters.The topographic influence on them closely depends on the type of the parameters and the incident wave height.In addition,the occurrence of the 2 nd-order gap resonance phenomenon can cause the 2 nd-order wave height and horizontal force to be significantly larger than the corresponding 1 st-order components. 展开更多
关键词 gap resonance harmonic analyses resonant wave height wave loads OPENFOAM
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In-situ Characterization of Non-aqueous Nano-dispersion Systems by Freeze-etching TEM and Comparative Study with Laser Scattering Method
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作者 欧忠文 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期432-436,共5页
In-situ characterization of non-aqueous nano-dispersion systems(NANDS) by freeze-etching transmission electron microscope(FETEM) was reported.To improve just-for-once successive rate of specimen preparation and get go... In-situ characterization of non-aqueous nano-dispersion systems(NANDS) by freeze-etching transmission electron microscope(FETEM) was reported.To improve just-for-once successive rate of specimen preparation and get good characterization results,an improving specimen preparation method of freezing etching was developed.Size,distribution and morphology of NANDS were directly visualized.Some information of particle dispersion feature and particle density can also be obtained.Reproductivity of the FETEM characterization is excellent.Comparing with laser scattering method,which is liable to give positive error especially for small size particle anchoring disperser,FETEM characterization can give more accurate measurement of particle size.Moreover,FETEM can give dispersion feature of nanoparticle in non-aqueous medium. 展开更多
关键词 冷冻蚀刻透射电子显微镜 激光散射法 分散系统 纳米颗粒 原位表征 非水介质 粒子密度 样品制备
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Game theory model of exit selection in pedestrian evacuation considering visual range and choice firmness
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作者 王维莉 万芳芳 卢兆明 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第8期355-362,共8页
Exit choice is one of the most important pedestrian behaviors during evacuation.Distance to the exit is a generally recognized factor influencing expected moving time to the exit.Visual range determines how much infor... Exit choice is one of the most important pedestrian behaviors during evacuation.Distance to the exit is a generally recognized factor influencing expected moving time to the exit.Visual range determines how much information a pedestrian can perceive,thus the number of pedestrians within the visual field can be used to estimate waiting time at the exit.Besides,the choice firmness that reflects the degree to which a pedestrian would persist in his/her previous choice of exit is proposed.By integrating game theory into a cellular automata simulation framework,the pedestrian exit choice mechanism is investigated and explicitly modeled in this paper.A systematic analysis of the key factors influencing pedestrian evacuation is conducted,including visual radius and choice firmness of a pedestrian,initial crowd distribution of the room,exit layout as well as exit width.It is found that low choice firmness level can lead to unnatural pedestrian behavior such as wandering,which is adverse to evacuation.The longer the pedestrian's visual radius,the earlier the pedestrian can determine his/her final selection of the exit.Compared with the scenario where the pedestrians are randomly distributed,pedestrians clustered together in a corner of the room lead to high crowd density and imbalanced use of exits.Furthermore,the exit layout and exit width also have a certain influence on pedestrian evacuation process.The results of this paper may be of benefit to the formulation of behavioral rules in other pedestrian simulation models. 展开更多
关键词 game theory exit selection visual range choice firmness
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Investigation of Shoreline and Topographic Change on the West Side of the Imagire-Guchi Inlet, Japan
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作者 Andi Subhan Mustari Shigeru Kato +1 位作者 Takumi Okabe Mieko Kataoka 《Journal of Shipping and Ocean Engineering》 2013年第1期30-39,共10页
关键词 地形变化 海岸线 固齿 GPS测量 西岸 海峡 进口 日本
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Constitutive modelling of idealised granular materials using machine learning method
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作者 Mengmeng Wu Zhangqi Xia Jianfeng Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第4期1038-1051,共14页
Predicting the constitutive response of granular soils is a fundamental goal in geomechanics.This paper presents a machine learning(ML)framework for the prediction of the stress-strain behaviour and shearinduced conta... Predicting the constitutive response of granular soils is a fundamental goal in geomechanics.This paper presents a machine learning(ML)framework for the prediction of the stress-strain behaviour and shearinduced contact fabric evolution of an idealised granular material subject to triaxial shearing.The MLbased framework is comprised of a set of mini-triaxial tests which provide a benchmark for the setup and validation of the discrete element method(DEM)model of the granular materials,a parametric DEM simulation programme of virtual triaxial tests which provides datasets of micro-and macro-mechanical information,as well as a multi-layer perceptron(MLP)neural network which is trained and tested using the DEM-based datasets.The ML model only requires the initial void ratio of the granular sample as the input for predicting its constitutive response.The excellent agreement between the ML model prediction and experimental test and DEM simulation results indicates that the MLebased modelling approach is capable of capturing accurately the effects of initial void ratio on the constitutive behaviour of idealised granular materials,bypassing the need to incorporate the complex micromechanics underlying the macroscopic mechanical behaviour of granular materials.Lastly,a detailed comparison between the used MLP model and long short-term memory(LSTM)model was made from the perspective of technical algorithm,prediction accuracy,and computational efficiency. 展开更多
关键词 Machine learning(ML) Multi-layer perceptron(MLP) Contact fabric Granular material Discrete element method(DEM)
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How Generative Adversarial Networks Promote the Development of Intelligent Transportation Systems:A Survey
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作者 Hongyi Lin Yang Liu +1 位作者 Shen Li Xiaobo Qu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第9期1781-1796,共16页
In current years,the improvement of deep learning has brought about tremendous changes:As a type of unsupervised deep learning algorithm,generative adversarial networks(GANs)have been widely employed in various fields... In current years,the improvement of deep learning has brought about tremendous changes:As a type of unsupervised deep learning algorithm,generative adversarial networks(GANs)have been widely employed in various fields including transportation.This paper reviews the development of GANs and their applications in the transportation domain.Specifically,many adopted GAN variants for autonomous driving are classified and demonstrated according to data generation,video trajectory prediction,and security of detection.To introduce GANs to traffic research,this review summarizes the related techniques for spatio-temporal,sparse data completion,and time-series data evaluation.GAN-based traffic anomaly inspections such as infrastructure detection and status monitoring are also assessed.Moreover,to promote further development of GANs in intelligent transportation systems(ITSs),challenges and noteworthy research directions on this topic are provided.In general,this survey summarizes 130 GAN-related references and provides comprehensive knowledge for scholars who desire to adopt GANs in their scientific works,especially transportation-related tasks. 展开更多
关键词 driving TRANSPORTATION DIRECTIONS
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Influence of rock property correlation on reliability analysis of rock slope stability: From property characterization to reliability analysis 被引量:5
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作者 Adeyemi Emman Aladejare Yu Wang 《Geoscience Frontiers》 SCIE CAS CSCD 2018年第6期1639-1648,共10页
Cohesion(c) and friction angle(φ) of rock are important parameters required for reliability analysis of rock slope stability. There is correlation between c and φ which affects results of reliability analysis of roc... Cohesion(c) and friction angle(φ) of rock are important parameters required for reliability analysis of rock slope stability. There is correlation between c and φ which affects results of reliability analysis of rock slope stability. However, the characterization of joint probability distribution of c and φ through which their correlation can be estimated requires a large amount of rock property data, which are often not available for most rock engineering projects. As a result, the correlation between c and φ is often ignored or simply assumed during reliability studies, which may lead to bias estimation of failure probability. In probabilistic rock slope stability analysis, the influence of ignoring or simply assuming the correlation of the rock strength parameters(i.e., c and φ) on the reliability of rock slopes has not been fully investigated. In this study, a Bayesian approach is developed to characterize the correlation between c and φ, and an expanded reliability-based design(RBD) approach is developed to assess the influence of correlation between c and φ on reliability of a rock slope. The Bayesian approach characterizes the sitespecific joint probability distribution of c and φ, and quantifies the correlation between c and φ using available limited data pairs of c and φ from a rock project. The expanded RBD approach uses the joint probability distribution of c and φ obtained through the Bayesian approach as inputs, to determine the reliability of a rock slope. The approach gives insight into the propagation of the correlation between c and φ through their joint probability into the reliability analysis, and their influence on the calculated reliability of the rock slope. The approaches may be applied in practice with little additional effort from a conventional analysis. The proposed approaches are illustrated using real c and φ data pairs obtained from laboratory tests of fractured rock at Forsmark, Sweden. 展开更多
关键词 Reliability-based design ROCK SLOPE CORRELATION Failure PROBABILITY BAYESIAN approach Joint PROBABILITY distribution
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An analytical symplectic approach to the vibration analysis of orthotropic graphene sheets 被引量:4
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作者 Xinsheng Xu Dalun Rong +2 位作者 C.W.Lim Changyu Yang Zhenhuan Zhou 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2017年第5期912-925,共14页
A nonlocal continuum orthotropic plate model is proposed to study the vibration behavior of single-layer graphene sheets(SLGSs) using an analytical symplectic approach. A Hamiltonian system is established by introduci... A nonlocal continuum orthotropic plate model is proposed to study the vibration behavior of single-layer graphene sheets(SLGSs) using an analytical symplectic approach. A Hamiltonian system is established by introducing a total unknown vector consisting of the displacement amplitude, rotation angle, shear force, and bending moment.The high-order governing differential equation of the vibration of SLGSs is transformed into a set of ordinary differential equations in symplectic space. Exact solutions for free vibration are obtianed by the method of separation of variables without any trial shape functions and can be expanded in series of symplectic eigenfunctions. Analytical frequency equations are derived for all six possible boundary conditions. Vibration modes are expressed in terms of the symplectic eigenfunctions. In the numerical examples, comparison is presented to verify the accuracy of the proposed method. Comprehensive numerical examples for graphene sheets with Levy-type boundary conditions are given. A parametric study of the natural frequency is also included. 展开更多
关键词 HAMILTONIAN system ANALYTICAL method NONLOCAL ELASTICITY theory ORTHOTROPIC graphene SHEET Natural frequency
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Effects of Free Heave Motion on Wave Forces on Two Side-by-Side Boxes in Close Proximity Under Wave Actions 被引量:2
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作者 HE Zhi-wei GAO Jun-liang +3 位作者 ZANG Jun CHEN Hong-zhou LIU Qian WANG Gang 《China Ocean Engineering》 SCIE EI CSCD 2021年第4期490-503,共14页
Wave forces on two side-by-side boxes in close proximity under wave actions were analyzed using the OpenFOAM package.The upstream box heaved freely under wave actions,whereas the downstream box remained fixed.For comp... Wave forces on two side-by-side boxes in close proximity under wave actions were analyzed using the OpenFOAM package.The upstream box heaved freely under wave actions,whereas the downstream box remained fixed.For comparison,a configuration in which both boxes were fixed was also considered.The effects of the heave motion of the upstream box on the wave loads,including the horizontal wave forces,vertical wave forces,and moments on the boxes,were the focus of this study.Numerical analyses showed that all frequencies at which the maximum horizontal wave forces,maximum vertical wave forces,and maximum moment appeared are dependent on the heave motion of the upstream box and that the effects of the heave motion on these frequencies are different.Furthermore,these frequencies were observed to deviate from the corresponding fluid resonant frequency.Moreover,the heave motion of the upstream box reduced the wave forces acting on both boxes and altered the variation trends of the wave forces with the incident wave frequency. 展开更多
关键词 fluid resonance wave forces narrow gap heave motion OPENFOAM
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An Efficient Model for Transient Surface Waves in Both Finite and Infinite Water Depths 被引量:1
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作者 宁德志 滕斌 +1 位作者 臧军 柳淑学 《China Ocean Engineering》 SCIE EI 2009年第3期459-472,共14页
A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Eulerian-Lagrangian formulation is adopted and a higher-order boundary element metho... A numerical model is developed to simulate fully nonlinear extreme waves in finite and infinite water-depth wave tanks. A semi-mixed Eulerian-Lagrangian formulation is adopted and a higher-order boundary element method in conjunction with an image Green function is used for the fluid domain. The boundary values on the free surface are updated at each time step by a fourth-order Runga-Kutta time-marching scheme at each time step. Input wave characteristics are specified at the upstream boundary by an appropriate wave theory. At the downstream boundary, an artificial damping zone is used to prevent wave reflection back into the computational domain. Using the image Green function in the whole fluid domain, the integrations on the two lateral walls and bottom are excluded. The simulation results on extreme wave elevations in finite and infinite water-depths are compared with experimental results and second-order analytical solutions respectively. The wave kinematics is also discussed in the present study. 展开更多
关键词 有限和 瞬态面波 水深 完全非线性波 格林函数 时间推进 边界波 数值模型
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Laboratory-scale model of carbon dioxide deposition for soilstabilisation 被引量:1
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作者 Mohammad Hamed Fasihnikoutalab Afshin Asadi +3 位作者 Bujang Kim Huat PaulWestgate Richard JBall Shahram Pourakbar 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第2期178-186,共9页
Olivine sand is a natural mineral,which,when added to soil,can improve the soil's mechanical properties while also sequester carbon dioxide(CO_2)from the surrounding environment.The originality of this paper stems... Olivine sand is a natural mineral,which,when added to soil,can improve the soil's mechanical properties while also sequester carbon dioxide(CO_2)from the surrounding environment.The originality of this paper stems from the novel two-stage approach.In the first stage,natural carbonation of olivine and carbonation of olivine treated soil under different CO_2 pressures and times were investigated.In this stage,the unconfined compression test was used as a tool to evaluate the strength performance.In the second stage,details of the installation and performance of carbonated olivine columns using a laboratory-scale model were investigated.In this respect,olivine was mixed with the natural soil using the auger and the columns were then carbonated with gaseous CO_2.The unconfined compressive strengths of soil in the first stage increased by up to 120% compared to those of the natural untreated soil.The strength development was found to be proportional to the CO_2 pressure and carbonation period.Microstructural analyses indicated the presence of magnesite on the surface of carbonated olivinetreated soil,demonstrating that modified physical properties provided a stronger and stiffer matrix.The performance of the carbonated olivine-soil columns,in terms of ultimate bearing capacity,showed that the carbonation procedure occurred rapidly and yielded a bearing capacity value of 120 k Pa.Results of this study are of significance to the construction industry as the feasibility of carbonated olivine for strengthening and stabilizing soil is validated.Its applicability lies in a range of different geotechnical applications whilst also mitigates the global warming through the sequestration of CO_2. 展开更多
关键词 OLIVINE Soil stabilisation CO2 DEPOSITION CLIMATE change Unconfined COMPRESSIVE strength Microstructure analysis
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