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Numerical stress-deformation analysis of cut-off wall in clay-core rockfill dam on thick overburden

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Water Science and Engineering 2016年第3期9卷 219-226页

作者： Si-hong Liu Liu-jiang Wang Zi-jian Wang erich bauer College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China Zhejiang Design Institute of Conservancy and Hydroelectric Power Hangzhou 310002China Institute of Applied Mechanics Graz University of TechnologyGraz 8010Austria

The cut-off wall in a clay-core rockfill dam built on a thick overburden layer is subjected to a large compressive pressure under the action of the loads such as the dead weight of both the dam and the overburden layer, the frictional force induced by the differential settlement between the cut-off wall and surrounding soils, and the water pressure. Thus, reduction of the stress of the cut-off wall has become one of the main problems for consideration in engineering design. In this paper, numerical analysis of a core rockfill dam built on a thick overburden layer was conducted and some factors influencing the stress-strain behaviors of the cut-off wall were investigated. The factors include the improvement of the overburden layer, the modeling approach for interfacial contact between the cut-off wall and surrounding soils, the modulus of the cut-off wall concrete, and the connected pattern between the cut-off wall and the clay core. The result shows that improving the overburden layer,selecting plastic concrete with a low modulus and high strength, and optimizing the connection between the cut-off wall and the clay core of the dam are effective measures of reducing the deformations and compressive stresses of the cut-off wall. In addition, both the Goodman element and the mud-layer element are suitable for simulating the interfacial contact between the cut-off wall and surrounding soils.

关键词： Overburden layer Core rockfill dam Cut-off wall Numerical analysis Stress and deformation analysis

Calibration and performance of two different constitutive models for rockfill materials

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Water Science and Engineering 2016年第3期9卷 227-239页

作者： Lin-ke Li Zhan-jun Wang Si-hong Liu erich bauer Institute of Applied Mechanics Graz University of Technology Changjiang Institute of Survey PlanningDesign and Research College of Water Conservancy and Hydropower Engineering Hohai University

In this paper, two different concepts for the constitutive modeling of the mechanical behavior of creep-sensitive rockfill materials are presented. Specifically, the performance of an extended generalized plasticity model proposed by Wang is compared with a simplified version of the hypoplastic constitutive model for weathered rockfill materials proposed by bauer. Both models can reflect the influence of the mean stress on the incremental stiffness, the peak friction angle, and the dilatancy angle. The so-called solid hardness defined for a continuum description and originally introduced by bauer is embedded in both models. Hydrochemical, thermal, and mechanical weathering are usually caused by environmental changes and are taken into account in a phenomenological description with an irreversible and time-dependent degradation of the solid hardness. A degradation of the solid hardness is usually accompanied by creep deformation of the stressed rockfill material. It is shown that appropriate modeling of creep deformation requires at least a unified description of the interaction between the time-dependent process of degradation of the solid hardness and the stress state. In this context, the solid hardness can be understood as a key parameter for describing the evolution of the state of weathering of the rockfill material. Particular attention is also paid to the necessary procedure for determining the constitutive constants of the two different constitutive models. Finally, the performance of the two different constitutive models is demonstrated by comparing the results obtained from numerical simulations with experimental data from the creep-sensitive rockfill material.

关键词： Rockfill material Creep Generalized plasticity Hypoplasticity Constitutive model

Hypoplastic constitutive modeling of wetting deformation of weathered rockfill materials

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Frontiers of Structural and Civil Engineering 2010年第1期4卷 78-91页

作者： erich bauer Zhongzhi FU Sihong LIU Institute of Applied Mechanics Graz University of TechnologyGrazAustria Institute of Hydraulic Structures Hohai UniversityNanjing 210098China

The wetting deformation of weathered rockfill materials has been attracting growing attention from both engineers and *** importance of realistic predictions of wetting deformations for high earth and rockfill dams is a strong motivation to establish a suitable constitutive ***,the hypoplastic constitutive model by Gudehus and bauer was extended by introducing solid hardness depending on the state of *** extended model takes into account the influence of the current density,the effective stress state,the rate of deformation,and the time dependent process of degradation of the solid *** the present paper,the performance of this model is evaluated by comparing numerical simulations with experiments obtained from a water sensitive rockfill *** particular,triaxial compression paths and creep deformation under deviatoric stress states are ***,the constitutive model proposed is used to study the influence of a degradation of the solid hardness on the long term behavior of a hypothetical fill dam.

关键词： rockfill dams weathered granular materials hypoplasticity solid hardness creep stress relaxation

Preface for special section on long-term behavior of dams

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水科学与水工程：英文版 2016年第3期9卷 173-174页

作者： Si-hong Liu erich bauer College of Water Conservancy and Hydropower Engineering Hohai University Institute of Applied Mechanics Graz University of Technology

When it comes to the long-term operation of hydropowerplants, the service life of mechanical and electrical equipmentand the reliability of hydraulic engineering structures areboth crucial. The loading history and interaction of theconstruction with ground settlements, earthquake activities andflooding, chemical reactions with water, overtopping, and thestate of weathering and aging of the construction material mayplay an important role in the safe operation of hydraulicstructures such as earth, rockfill, and concrete dams, as wellas novel reinforced soil structures. A critical reduction ofthe safety of dams can be caused by the evolution of internalerosion, cracks in the sealing, earthquake-induced deformations,reduction of the slope stability of earth and rockfilldams triggered by heavy rainwater infiltration, or rapid reductionof the water level in the reservoir.

关键词： hydropowerplants equipmentand

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堆石料的亚塑性本构建模及其应用研究

岩石力学与工程学报 2007年第2期26卷 312-322页

作者：岑威钧王修信 erich bauer 朱岳明东南大学土木工程学院江苏南京210096 格拉茨技术大学应用力学研究所河海大学水利水电工程学院江苏南京210098

亚塑性本构理论是20世纪中晚期发展起来的一类基于有理力学的新型的连续介质本构建模理论,主要用于刻画无黏性散粒型土体的非弹性、非线性及剪胀(剪缩)性等主要应力应变特性。较详细地介绍了该本构理论的起源、发展和本构方程的一般表... 详细信息

亚塑性本构理论是20世纪中晚期发展起来的一类基于有理力学的新型的连续介质本构建模理论,主要用于刻画无黏性散粒型土体的非弹性、非线性及剪胀(剪缩)性等主要应力应变特性。较详细地介绍了该本构理论的起源、发展和本构方程的一般表述形式,并做相应的数学力学特性分析。在对散粒型土体孔隙比与平均压力及孔隙比与体积应变关系分析研究的基础上,扼要介绍了新近发展的亚塑性模型的重要的建模改进思想。结合分析堆石料的主要工程特性,将能够反映当前亚塑性研究水平的Gudehus-bauer亚塑性模型做适当改进后首次引入到堆石料的本构建模中,并将其应用到一典型混凝土面板堆石坝的应力变形数值分析中。理论分析和算例应用表明,所改进的Gudehus-bauer亚塑性模型能够合理反映堆石料的非弹性、非线性、剪胀剪缩性等主要应力、应变特性,且具有本构参数适用范围广的优点。

关键词：岩土力学亚塑性本构理论率型孔隙比堆石料本构建模面板堆石坝

考虑湿化效应的堆石料Gudehus-bauer亚塑性模型应用研究

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岩土力学 2009年第12期30卷 3808-3812页

作者：岑威钧 erich bauer Sendy F.Tantono 河海大学水利水电工程学院南京210098 Institute of Applied Mechanics Graz University of TechnologyGraz8010Austria Petra Christian University SurabayaIndonesia

在扼要分析堆石料主要力学特性的基础上,在亚塑性理论框架内,采用扩展的Gudehus-bauer亚塑性模型对堆石料因含水率发生变化引起的湿化行为进行建模预测。扩展模型除能考虑含水率对颗粒硬度的影响外,还能反映土体密实度、应力状态和含水... 详细信息

在扼要分析堆石料主要力学特性的基础上,在亚塑性理论框架内,采用扩展的Gudehus-bauer亚塑性模型对堆石料因含水率发生变化引起的湿化行为进行建模预测。扩展模型除能考虑含水率对颗粒硬度的影响外,还能反映土体密实度、应力状态和含水率等对堆石料非线性和非弹性变形的影响。将该模型应用于心墙坝初次蓄水时应力变形的亚塑性计算分析中。结果表明,扩展模型能较合理地反映心墙堆石坝的湿化变形规律。

关键词：堆石料湿化亚塑性 Gudehus-bauer模型数值验证心墙坝

Influence of pressure and density on the rheological properties of rockfills

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Frontiers of Structural and Civil Engineering 2012年第1期6卷 25-34页

作者： erich bauer Zhongzhi FU Sihong LIU Institute of Applied Mechanics Graz University of TechnologyGrazAustria Geotechnical Engineering Department Nanjing Hydraulic Research InstituteNanjing210029Ch Institute of Hydraulic Structures Hohai UniversityNanjing 210098China

Long-term deformations of rockfill dams can be related to the type of dam,the pre-compaction achieved during the construction of the dam,the history of loading events,the rheological properties of the rockfill material used,the seepage behavior caused by defects of the sealing,the interactions of the dam building with the foundation,and the hydrothermal phenomena of the stressed rockfill *** present paper investigates the theological propcrtics of coarse grained rockfill materials using a hypoplastic constitutive *** attention is paid to wetting deformation under different deviatoric loading states and *** quantify the state of weathering a so-called“solid hardness”is used in the sense of a continuum *** is shown that an appropriate modeling of wetting deformations requires a unified description of the interaction at least between the state of weathering,the stress state,the density and the rate of *** results obtained from the numerical simulations are compared with available experimental data for a rockfill material used in Xiaolangdi earth dam.

关键词： rockfills solid hardness wetting deformation hypoplasticity creep

An inverted triplesalen ligand by a convergent synthesis and its influence on trinuclear Fe_3~Ⅲ complexes

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Science China Chemistry 2012年第6期55卷 951-966页

作者： FELDSCHER Bastian KRICKEMEYER erich MOSELAGE Marc THEIL Hubert HOEKE Veronika KAISER Yvonne STAMMLER Anja BGGE Hartmut GLASER Thorsten Lehrstuhl für Anorganische Chemie I Fakultt für Chemie Universitt Bielefeld Universittsstr. 25 D-33615 Bielefeld Germany

The inverted triplesalen ligand H 6 feld Me has been synthesized from 2,4,6-triformyl-phloroglucinol and a ketimine salen half-unit in a convergent synthesis. NMR, IR, and UV-vis spectroscopy reveal that this ligand is not in the O-protonated tautomer but in the N-protonated tautomer with substantial heteroradialene contribution. This ligand and the conventional triplesalen ligand H 6 talen t-Bu 2 have been used to synthesize the trinuclear Fe III complexes [(feld Me )(FeCl) 3 ] and [(talen t-Bu 2 )(FeCl) 3 ], respectively. The molecular structures of these complexes were obtained by single-crystal X-ray diffraction. Two trinuclear Fe III complexes of [(feld Me )(FeCl) 3 ] dimerize via two Fe-phenolate bonds, whereas due to steric hindrance no dimerization is observed for [(talen t-Bu 2 )(FeCl) 3 ]. The structural data also reveal some heteroradialene contribution in the trinuclear complexes. Whereas UV-vis and M bauer spectroscopy are not suitable to distinguish between the two complexes, FT-IR spectra show characteristic features due to the different substitution patterns of the conventional and the inverted triplesalen ligands. Another handle is provided by electrochemistry. Whereas both complexes exhibit an irreversible oxidation wave (0.94 V vs. Fc + /Fc for [(feld Me )(FeCl) 3 ] and 0.84 V vs. Fc + /Fc for [(talen t-Bu 2 )(FeCl) 3 ]), which is assigned to the oxidation of the central backbone, higher potential oxidations are reversible for [(talen t-Bu 2 )(FeCl) 3 ]) but irreversible for [(feld Me )(FeCl) 3 ]. This is attributed to the reversible oxidation of the terminal phenolates in the di-tert-butyl substituted [(talen t-Bu 2 )(FeCl) 3 ] in contrast to the mono-methyl-substituted phenolates in [(feld Me )(FeCl) 3 ]. The magnetic properties of [(talen t-Bu 2 )(FeCl) 3 ] reveal a very small ferromagnetic coupling with significant zero-field splitting of the FeⅢ S = 5/2 ions. In contrast, the dimerization of two trinuclear complexes in [(feld Me )(FeCl) 3 ] r

关键词：三核配合物氯化铁复合物合成收敛反铁磁相互作用单晶X-射线衍射紫外可见光谱

An inverted triplesalen ligand by a convergent synthesis and its influence on trinuclear FeXII3 complexes

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中国科学：化学 2012年第6期42卷 897-900页

作者： Bastian FELDSCHER erich KRICKEMEYER Marc MOSELAGE Hubert THEIL Veronika HOEKE Yvonne KAISER Anja STAMMLER Hartmut BGGE Thorsten GLASER Lehrstuhl f黵 Anorganische Chemie I Fakult鋞 f黵 Chemie Universit鋞 Bielefeld Universit鋞sstr. 25 D-33615 Bielefeld Germany

The inverted triplesalen ligand H6feldMehas been synthesized from 2,4,6-triformyl-phloroglucinol and a ketimine salen half-unit in a convergent synthesis. NMR, IR, and UV-vis spectroscopy reveal that this ligand is not in the O-protonated tautomer but in the N-protonated tautomer with substantial heteroradialene contribution. This ligand and the conventional triplesalen ligand H6talent-Bu2 have been used to synthesize the trinuclear FeⅢcomplexes [(feldMe)(FeCl)3] and [(talent-Bu2)(FeCl)3], respectively. The molecular structures of these complexes were obtained by single-crystal X-ray diffraction. Two trinuclear FeⅢcomplexes of [(feldMe)(FeCl)3] dimerize via two Fe-phenolate bonds, whereas due to steric hindrance no dimerization is observed for [(talent-Bu2)(FeCl)3]. The structural data also reveal some heteroradialene contribution in the trinuclear complexes. Whereas UV-vis and M??bauer spectroscopy are not suitable to distinguish between the two complexes, FT-IR spectra show characteristic features due to the different substitution patterns of the conventional and the inverted triplesalen ligands. Another handle is provided by electrochemistry. Whereas both complexes exhibit an irreversible oxidation wave (0.94 V vs. Fc+/Fc for [(feldMe)(FeCl)3] and 0.84 V vs. Fc+/Fc for [(talent-Bu2)(FeCl)3]), which is assigned to the oxidation of the central backbone, higher potential oxidations are reversible for [(talent-Bu2)(FeCl)3]) but irreversible for [(feldMe)(FeCl)3]. This is attributed to the reversible oxidation of the terminal phenolates in the di-tert-butyl substituted [(talent-Bu2

关键词：三核配合物合成收敛反铁磁相互作用复合物单晶X-射线衍射紫外可见光谱铁配合物