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Centrifuge model tests on pile-reinforced slopes subjected to drawdown

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1290-1300页

作者： Sujia Liu Fangyue Luo ga zhang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China

Piles are generally an effective way to reduce the risk of slope ***,previous approaches for slope stability analysis did not consider the effect of the piles coupled with the decrease of the water level(drawdown).In this study,a series of centrifuge model tests was performed to understand the deformation and failure characteristics of slopes reinforced with various pile *** the centrifuge model tests,the pile-reinforced slopes exhibited two typical failure modes under drawdown conditions:across-pile failure and through-pile *** the through-pile slope failure,a discontinuous slip surface was observed,implying that the assumption of the slip surface in previous stability analysis methods was *** test results showed that drawdown led to instability of the piles in cohesive soil,as the saturated cohesive soil failed to provide sufficient constraint for *** slope exhibited progressive failure,from top to bottom,during *** deformation of the piles was reduced by increasing the embedment depth and row number of *** addition,the deformation of soils outside the piles was influenced by the piles and showed a similar distribution shape as the piles,and the similarity degree weakened as the distance from the piles *** study also found that the failure mechanism of unreinforced and pile-reinforced slopes induced by drawdown could be described by coupling between the deformation localization and local failure,and it revealed that pile-reinforced slopes could reduce slope deformation localization during drawdown.

关键词： Slope Pile Drawdown Failure Reinforcement Centrifuge model test

Simplified method for analyzing soil slope deformation under cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第6期14卷 1967-1976页

作者： ga zhang Yaliang Wang Fangyue Luo State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China

Reasonable assessment of slope deformation under cyclic loading is of great significance for securing the safety of slopes. The observations of centrifuge model tests are analyzed on the slope deformation behavior under cyclic loading conditions. The potential slip surface is the key for slope failure and follows two rules:(i) the relative horizontal displacement along the potential slip surface is invariable at an elevation, and(ii) the soil along the slip surface exhibits the same degradation pattern. These rules are effective regardless of the location of the potential slip surface throughout the entire deformation process of a homogeneous slope, ranging from the initial deformation stage to the failure process and to the post-failure stage. A new, simplified method is proposed by deriving the displacement compatibility equation and unified degradation equation according to the fundamental rules. The method has few parameters that can be determined through traditional element tests. The predictions from the proposed method agree with the centrifuge test results with vertical loading and shaking table loading. This result confirms that the proposed method is effective in predicting the full deformation process of slopes under different cyclic loading conditions.

关键词： Soil slope Cyclic load Deformation Centrifuge model test Slice method

A novel sulfidization system for enhancing hemimorphite flotation through Cu/Pb binary metal ions

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International Journal of Mining Science and Technology 2024年第12期34卷 1741-1752页

作者： Qicheng Feng Yingchao zhang ga zhang Guang Han Wenjuan Zhao State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunming 650093China

The low reactivity of hemimorphite surfaces hinders the effective action of sulfidizing agents and xanthate,resulting in unsatisfactory flotation *** enhance the surface reactivity of hemi-morphite with sulfidizing agents and xanthate,Cu/Pb binary metal ions were introduced into the sul-fidization flotation system to enhance the sulfidization process and thereby promote hemimorphite *** flotation results demonstrated a remarkable improvement in the hemimorphite flotation recovery when Cu/Pb binary metal ions were added prior to *** flotation recovery of hemi-morphite increased from less than 5%to over 80%.After strengthening the sulfidization of hemimorphite with Cu/Pb binary metal ions,the mineral surface formed multicomponent sulfide products composed of zinc,copper,and lead *** reactivity of the copper-lead sulfide components exceeds that of the zinc sulfide component;thus,the enhancement by Cu/Pb binary metal ions not only increases the content of sulfide products on the hemimorphite surface but also augments their *** angle and adsorption experiments indicated that after enhanced sulfidization with Cu/Pb binary metal ions,the hemimorphite surface adsorbed a greater amount of xanthate,significantly increasing the mineral sur-face ***,the enhanced sulfidization by Cu/Pb binary metal ions effectively improved the flotation behavior of hemimorphite,presenting an innovative sulfidization system for the flotation recovery of zinc silicate minerals in zinc oxide ores.

关键词： Hemimorphite Enhanced sulfidization Cu/Pb binary metal ions Flotation

Tribological properties of polyimide composites reinforced with fibers rubbing against Al_(2)O_(3)

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Friction 2021年第2期9卷 301-314页

作者： Huimin QI ga zhang Zhiqin ZHENG Jiaxin YU Chao HU Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education State Key Laboratory of Environment-friendly Energy MaterialsSouthwest University of Science and TechnologyMianyang 621010China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Qingdao Center of Resource Chemistry&New Materials Qingdao 266071China Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory Southwest University of Science and TechnologyMianyang 621010China

Reinforcing fillers are of great importance in tribological performance and tribofilm formation of polymeric *** this study,the tribological properties of aramid particle(AP)and short carbon fiber(SCF)reinforced polyimide(PI)composites were added to hexagonal boron nitride(h-BN),and silica(SiO_(2))nanoparticles sliding against alumina were comprehensively *** sliding occurred with AP-reinforced PI composites,the tribological properties were not closely depended on the pressure×velocity(p×v)factors and the *** interactions between AP and its counterpart could not induce tribo-sintering of the transferred wear *** such,the tribofilm seemed to be in a viscous state,leading to higher friction and ***,the inclusion of hard SCF into the PI matrix changed the interfacial interactions with alumina.A robust tribofilm consisting of a high fraction of silica was generated when the SCF-reinforced PI was added to the SiO_(2) *** exhibited a high load-carrying capability and was easily *** caused a significant decrease in the friction and wear of the PI composite at 8 MPa·1m/***,due to their high melting point,few h-BN nanoparticles were observed in the tribofilm of the SCF-reinforced PI when hexagonal boron nitride was added.

关键词： reinforcing filler polyimide composite tribofilm Al_(2)O_(3)

Three-dimensional seismic response analysis of a concrete-faced rockfill dam on overburden layers

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Frontiers of Structural and Civil Engineering 2010年第2期4卷 258-266页

作者： Dakuo FENG ga zhang Jianmin zhang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing 100084China

Reasonable seismic response analysis of a high rockfill dam is of great engineering significance in guiding its design and ensuring its seismic safety during operation,especially of a concrete-faced rockfill dam(CFRD)on overburden *** three-dimensional seismic behavior of the Miaojiaba CFRD is simulated and analyzed by the finite element method(FEM).The results indicate that:1)the amplification coefficient along the dam axis gradually increases with the altitude,and reaches maximum at the dam crest;2)the vertical residual deformation mainly exhibits downwards and reaches maximum near the dam crest;3)the earthquake significantly aggravates the deformation of peripheral joints;4)the impounding condition and overburden characteristics have great effects on the dam's seismic response.

关键词： concrete-faced rockfill dam(CFRD) overburden layer dynamic analysis finite element method(FEM)

EXPERIMENTAL STUDY ON THE MECHANISM OF THE RICHTMYERMESHKOV INSTABILITY AT A gaS-LIQUID INTERFACE

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Journal of Hydrodynamics 2009年第3期21卷 423-428页

作者： SHI Hong-hui zhang ga DU Kai JIA Hui-xia College of Mechanical Engineering and Automation Zhejiang University of Science and Technology Hangzhou 310018 China

The mechanism of the Richtmyer-Meshkov instability was experimentally studied in a vertical rectangular shock tube. The velocity of the interface driven by the shock wave was measured by a self-designed measurement system, which consists of semiconductor lasers, signal amplification circuits, digital oscilloscope and computer. Tests were carded out at several shock wave Mach numbers. In addition, the movement of the interface and the variation of the mixed zone width with time were recorded by high-speed photography. The experimental results show that the interface velocity increases with the increase of the Mach number, and the distance of the interface＇s movement and the width of the mixed zone vary with time in a linear relationship.

关键词： Richtmyer-Meshkov instability shock wave shock tube laser interface

Recent progress on lanthanide complexes/clay minerals hybrid luminescent materials

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Journal of Rare Earths 2022年第9期40卷 1360-1370,I0001页

作者： ga zhang Lefu Mei Junjie Ding Ke Su Qingfeng Guo Guocheng Lv Libing Liao Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of GeosciencesBeijing 100083China School of Gemmology China University of GeosciencesBeijing 100083China

The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent *** not only retains the excellent luminescent characteristics of lanthanide complexes but also improves the poor stability of the *** this article,we introduce the luminescence mechanism of lanthanide complexes and point out the necessity of their combination with clay *** the analysis of the structure and interlayer environment differences of 1:1-type and 2:1-type clay minerals,the intercalation methods(covalent grafting and ion exchange)appropriate for different clay minerals are summarized with *** on the luminescence characteristics of the hybrid materials,the applications of these materials as luminescent probes in recognition of specific metal cations and molecules,detection of pH value,and temperature are ***,the current problems in the preparation of lanthanide complexes/clay minerals hybrid luminescent materials and shortcomings that need improvement in their performance are analyzed,and the application prospect is forecast.

关键词： Luminescence Hybrid materials Lanthanide complexes Clay minerals Luminescent probes Rare earths

State of the art:Mechanical behavior of soil-structure interface

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Progress in Natural Science:Materials International 2009年第10期19卷 1187-1196页

作者： ga zhang,Jianmin zhang State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China

The monotonic and cyclic behavior of a soil-structure interface has a significant effect on the mechanical response of a soil-structure interaction ***,the behavior of the interface should be investigated with focusing on the individual characters different from other geomaterials.A brief introduction and critical review are presented on the state of the art of monotonic and cyclic behavior of soil- structure interface,including the test device and measurement techniques,fundamental rules and deformation mechanism,constitutive models and their applications in the numerical *** tendencies of the investigation on the interface are also predicted in this paper.

关键词： Interface Soil Mechanical behavior Test Constitutive model Numerical analysis

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水库区边坡群稳定性耦联分析概念性模型

清华大学学报（自然科学版） 2015年第6期55卷 612-615页

作者：张嘎清华大学水沙科学与水利水电工程国家重点实验室北京100084

为了更准确评价边坡稳定性,提出了岩土域的概念,定义为处于同一地域、具有内在联系的多个岩土体构成的系统。构建了一个耦联分析概念性模型,包括数据层(输入层和响应层)和分析层(模型层和计算层)这2大类。模型以数据驱动为主。数据是模... 详细信息

为了更准确评价边坡稳定性,提出了岩土域的概念,定义为处于同一地域、具有内在联系的多个岩土体构成的系统。构建了一个耦联分析概念性模型,包括数据层(输入层和响应层)和分析层(模型层和计算层)这2大类。模型以数据驱动为主。数据是模型的核心和基础,其来源不再是统一格式的,而且是开放的,可以接受分析层提供的数据以及其他来源的信息。各岩土体的模型和响应是彼此独立的,其相互耦联通过输入层和计算层实现,通过利用其他岩土体数据提高特定岩土体的分析精度。采用岩土域耦联分析理论分析了某库区边坡群的稳定性,分析结果表明水位变化对边坡稳定性影响显著。

关键词：边坡岩土域耦联水库稳定性