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Hybrid method of limit equilibrium and finite element internal force for analysis of arch dam stability against sliding

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Science china(Technological Sciences) 2011年第4期54卷 793-798页

作者： BAO TengFei1,2.3.XU BaoSong1,2.3.& ZHENG XueQing1,2.3.1State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,hohai university,nanjing 2.0098,china 2.ational Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety,nanjing 2.0098,china 3.ollege of Water conservancy and hydropower Engineering,hohai university,nanjing 2.0098,china State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Nanjing China College of Water conservancy and {2. Engineering Hohai University Nanjing China

A hybrid method of limit equilibrium and finite element internal force for analysis of arch dam stability against sliding is *** finite element internal force method(FEIFM) is used to provide more accurate thrust forces acting on the faces of a slip body,and the limit equilibrium method(LEM) is employed to evaluate the factor of safety of the slip *** method presented can deal with a slip body with large amount of geometrically complex slip *** addition,compared with the traditional LEM,it can meet the balance condition of the forces in the slip *** example shows that the factor of safety obtained by the method presented agrees well with the theoretical solution.A practical example is also presented to demonstrate the application of the method in the stability analysis of an arch dam *** results from the examples show that the method is promising in analysis of arch dam stability against sliding.

关键词： arch dam stability against sliding limit equilibrium method finite element internal force method

THE ALGORITHMS AND APPLICATIONS FOR DETERMINING PERMEABILITY COEFFICIENTS BY PULSE SPECTRUM TECHNIQUE

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Journal of Hydrodynamics 2002年第2期14卷 112-115页

作者： Wang Ling-ling College of Water conservancy and {2. Engineering, {3., nanjing 2.0098, china Coll. of Water conservancy Hohai Univ. Nanjing 210098 China

The determination of inhomogeneous permeability coefficient was studied as a parameter-control inverse problem for parabolic-type equation in this paper. By virtue of PST, the solution of the inverse problem is converted into an iteration procedure of solving a direct problem and solving a Fredholm integral equation of the first kind. Besides, Tikhonov normalization method is introduced to treat the uncertainty caused by the integral equation. Thus an algorithm for determining inhomogeneous permeability coefficient has been formulated and implemented. Numerical results show: (1) The algorithm presented in the paper is suitable to strongly inhomogeneous seepagel; (2. The additional information needed for solution is merely the seepage velocity on partical boundary, so that drill works can be reduced remarkably; (3. The algorithm is applicable to determining inhomogeneous transmission coefficients in groundwater engineering or other engineering.

关键词： inverse problem Pulse Spectrum Technique (PST) permeability coefficient parameter identification

Back analysis of mechanical parameters of roller compacted concrete dam

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Science china(Technological Sciences) 2010年第3期53卷 848-853页

作者： GU ChongShi 1,2.3.LI Bo 1,XU GuangLei 4 &YU Hong 1,2.3.1 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,{2.,nanjing 2.0098,china 2.{3. of Water conservancy hydropower,{2.,nanjing 2.0098,china 3.ational Engineering Research Center of Water Resources Engineering Safety,Efficient Utilization and nanjing 2.0098,china 4 nanjing Hydraulic Research Institute,nanjing 2.002.,china State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing China College of Water conservancy {2. Hohai University Nanjing China National Engineering Research Center of Water Resources Engineering Safety Efficient Utilization and Nanjing Nanjing China nanjing Hydraulic Research Institute Nanjing China

In view of the diversity and complexity of mechanical parameters of roller compacted concrete dam(RCCD),the uniform design method,partial least-squares regression(PLS)and least squares support vector machine(LSSVM)were applied to the back analysis of RCCD with the use of the complex nonlinear relationship between dam mechanical parameters and dam *** the process of back analysis,the initial samples of parameters were designed with uniform design ***,a transversely isotropic model of RCCD was established by *** *** this model,training samples of LSSVM model could be *** then,the complex nonlinear relationship between relative values of hydraulic components of dam displacements and mechanical parameters was ***,actual relative values of dam hydraulic components are isolated from the measured data of dam displacements by using *** inputting the isolated relative values into LSSVM model,the back analysis values of RCCD mechanical parameters can be *** example analysis showed that mechanical parameters obtained by the above-mentioned back analysis method are reasonable,and the back analysis method is feasible.

关键词： roller compacted concrete dam mechanical parameters back analysis

Numerical simulation of two-phase turbulent flow in hydraulic and hydropower engineering

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Science china(Technological Sciences) 2007年第Z1期50卷 79-89页

作者： DAI HuiChao1,2., WANG LingLing1, GAO JiZhang3. ZHANG XiaoDong3.& YANG ZhongHua2.1 C{2. of Water conservancy and hydropower Engineering, {3., nanjing 2.0098, china 2.china Yangtze River Three Gorges Project Development Corporation, Yichang 443.02. china 3.china Institute of Water Resources and hydropower Research, Beijing 100044, china College of Water conservancy and {2. Engineering Hohai University Nanjing China china Yangtze River Three Gorges Project Development Corporation Yichang China china Institute of Water Resources and hydropower Research Beijing China

In connection with the specific features of high velocity aerated flow generated by hydraulic engineering structures, the mathematical model is developed for high turbulence air-water two-phase flow with the use of twin flow theoretical model in this paper. Furthermore the numerical method is proposed to treat bubbled flows. In addition, on the basis of air-water stratified twin flow model, the new calculation methods and free surface tracking technique are proposed to describe complicated movements of the free surface. Finally, the proposed model is used to calculate artificial aerated flows. The computed results coincide quite well with experimental results. This means that the proposed method can provide solid basis for practical engineering design.

关键词： high turbulence two-phase flow twin flow model aerated flow free surface

Research on stability of the accumulated rock-soil body of reservoir bank under rainfall condition

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Science china(Technological Sciences) 2009年第9期52卷 2528-2535页

作者： GU ChongShi1,2.WU HaiZhen1,2.& SU HuaiZhi1,2.1 College of Water Resources and hydropower Engineering,{2.,{3.,china 2.National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety,{2.,{3.,china 3.Jiangxi Water conservancy Research Institute,Nanchang 3.002.,china College of Water Resources and hydropower Engineering Hohai University Nanjing China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Hohai University Nanjing China Jiangxi Water conservancy Research Institute Nanchang China

The shear strength parameters property of rock-soil aggregates in embankment slope of reservoir,that is,the relationship between cohesion and gravel content,between friction angle and gravel content,and the relationship between cohesion and water content,between friction angle and water content,is studied based on the direct shear test results,the shear strength change law of the rock-soil aggregates is given,and the unsaturated shear strength formulation of rock-soil aggregates that could consider suction and saturation degree influence is put forward in this paper,through which the sliding or failure physical mechanism of this type of slope under the condition of rainfall infiltration is studied. Also the 3. unsteady saturated-unsaturated seepage field and its FEM resolving mode are established based on the analysis of the slope rainfall infiltration process. Case study with this method indicates that the minimum safety factor of the accumulated rock-soil aggregates dose not arrive at the moment of rainfall cessation,but appears several hours after the rainfall cessation,this phenomenon is in accordance with the practical slope engineering's failure process and could explain appropriately the slope failure caused by rainfall infiltration. Research results in this paper have an important reference value for the research on stability of the accumulated rock-soil aggregates in embankment slope of reservoir,and can enrich the stability analysis method and relevant theory of reservoir embankment slope.

关键词： reservoir bank slope rock-soil aggregates rainfall infiltration saturated/unsaturated seepage

Game model of safety monitoring for arch dam deformation

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Science china(Technological Sciences) 2008年第S2期51卷 76-81页

作者： SU HuaiZhi1,2.WU ZhongRu1,2.GU YanChang1,2.HU Jiang1 & WEN ZhiPing3.1 College of Water {2. and hydropower Engineering,{3.,nanjing 2.0098,china 2.National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety,nanjing 2.0098,china 3.Department of Computer Engineering,nanjing Institute of Technology,nanjing 2.0013.china College of Water conservancy and {2. Engineering Hohai University Nanjing China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Nanjing China Department of Computer Engineering Nanjing Institute of Technology Nanjing China

Arch dam deformation is comprehensively affected by water pressure,temperature,dam's structural behavior and material properties as well as other *** them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam's structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance ***,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of *** the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

关键词： arch dam deformation monitoring model flexibility coefficient game theory

Influence of fractality of fracture surfaces on stress and displacement fields at crack tips

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Science china(Technological Sciences) 2008年第S2期51卷 95-100页

作者： BAO TengFei,WU ZhongRu,GU ChongShi & GU YanLing College of Water conservancy and {2. Engineering,{3.,nanjing 2.0098,china College of Water conservancy and {2. Engineering Hohai University Nanjing China

In the classic theory of fracture mechanics,expressions for calculating the stresses and displacements in the vicinity of the crack tip are deduced on the basis of the assumption that a fracture surface is a smooth surface or that a crack is a smooth *** fact,the surface of a crack formed during the fracture is usually very *** the real asymptotic form of the stress and displacement fields at the crack tip is different from the classic *** the irregularity of a real fracture surface or a real crack profile,the crack is taken as a fractal one,and then the real asymptotic form at the crack tip is developed by applying Griffith's energy balance principle and fractal *** the developed asymptotic form,it is discovered that the fractality of the crack reduces the stress singularity at the crack tip.

关键词： fracture surface crack fractal stress and displacement fields

EFFECTS OF HYDRAULIC AND GEOMETRIC PARAMETERS ON DOWNSTREAM CAVITY LENGTH OF DISCHARGE TUNNEL SERVICE GATE

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Journal of Hydrodynamics 2009年第6期21卷 774-778页

作者： MOHAGHEGH A College of Water conservancy and {2. Engineering Hohai University

Aerators on discharge tunnel outlets may be regarded as an effective protection against cavitation erosion. The air entrainment of aerators is governed by a number of independent parameters, including the bottom slope of releasing free-surface flow tunnel downstream of service gate, the end top slope of pressure tunnel, the height of step, and the Froude number at take-off. During eight phases of experiments, the effects of above-mentioned parameters were observed on the cavity length downstream of the fully open operating service gate of a discharge tunnel. The results show that, the bottom slope of releasing free-surface flow tunnel has obvious effect on the cavity length as well as the Froude number at gate take-off. The effect of the step height variations on the cavity length could be considered for higher discharges and steeper tunnel top slope, particularly in higher discharges, resulting in shorter cavity length downstream of service gate.

关键词： cavitation erosion cavity length discharge tunnel service gate

AN IMPROVED ALGORITHM FOR DPIV CORRELATION ANALYSIS

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Journal of Hydrodynamics 2007年第1期19卷 62-67页

作者： WU Long-hua College of Water conservancy and {2. Engineering Hohai University Nanjing 210098 China

In a Digital Particle Image Velocimetry （DPW） system, the correlation of digital images is normally used to acquire the displacement information of particles and give estimates of the flow field. The accuracy and robustness of the correlation algorithm directly affect the validity of the analysis result. In this article, an improved algorithm for the correlation analysis was proposed which could be used to optimize the selection/determination of the correlation window, analysis area and search path. This algorithm not only reduces largely the amount of calculation, but also improves effectively the accuracy and reliability of the correlation analysis. The algorithm was demonstrated to be accurate and efficient in the measurement of the velocity field in a flocculation pool.

关键词： Digital Particle Image Velocimetry (DPIV),correlation analysis improved algorithm