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Back analysis of mechanical parameters of roller compacted concrete dam

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,hohai university,nanjing 210098,china 2college of water Conservancy hydropower,hohai university,nanjing 210098,china 3National engineering Research Center of water Resources engineering Safety,Efficient Utilization and nanjing 210098,china 4 nanjing Hydraulic Research Institute,nanjing 210029,china State Key Laboratory of Hydrology-water Resources and Hydraulic engineering Hohai University Nanjing China college of water Conservancy hydropower 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

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A new method of estimating the equivalent elastic modulus of RCCD

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Science china(Technological Sciences) 2007年第Z1期50卷 136-143页

作者： GU ChongShi1,2?, WU Yuan1, SU HuaiZhi1,2 & TANG LiHui1 1 college of water Conservancy and hydropower engineering, hohai university, nanjing 210098, china 2 National engineering Research Center of water Resources Efficient Utilization and engineering Safety, nanjing 210098, china college of water Conservancy and hydropower engineering Hohai University Nanjing China National engineering Research Center of water Resources Efficient Utilization and engineering Safety Nanjing China

Based on the composite material mechanic theory, the analysis method for the equivalent elastic moduli which are parallel and vertical to the construction interface of RCCD is studied in this paper. The differences between the equivalent elastic moduli which are vertical to the construction interface of RCCD gotten from different methods are discussed in detail. The variation range of the equivalent elastic modulus which is vertical to the construction interface of RCCD is studied based on the principle of minimum complementary energy and the principle of minimum potential energy. The effect of the related influential factors on the equivalent elastic modulus is analyzed. The estimation formula of the equivalent modulus which is vertical to the construction interface of RCCD is proposed. The feasibility of the approach proposed in this paper is analyzed through an example.

关键词： RCCD equivalent elastic modulus variation range estimation method

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Review on hidden trouble detection and health diagnosis of hydraulic concrete structures

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Science china(Technological Sciences) 2007年第Z1期50卷 34-50页

作者： WU ZhongRu1,2?, LI Ji1, GU ChongShi1,2 & SU HuaiZhi1,2 1 college of water Conservancy and hydropower engineering, hohai university, nanjing 210098, china 2 National engineering Research Center of water Resources Efficient Utilization and engineering Safety, nanjing 210098, china college of water Conservancy and hydropower engineering Hohai University Nanjing China National engineering Research Center of water Resources Efficient Utilization and engineering Safety Nanjing China

A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures.

关键词： hydraulic concrete structure hidden trouble detection health diagnosis

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Thermal Conductivity and Heat Transfer Coefficient of Concrete

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Journal of Wuhan university of Technology(Materials Science) 2011年第4期26卷 791-796页

作者：郭利霞 North china university of water Resources and Electric Power

A very simple model for predicting thermal conductivity based on its definiensis was presented. The thermal conductivity obtained using the model provided a good coincidence to the investigations performed by other authors. The heat transfer coefficient was determined by inverse analysis using the temperature measurements. From experimental results, it is noted that heat transfer coefficient increases with the increase of wind velocity and relative humidity, a prediction equation on heat transfer coefficient about wind velocity and relative humidity is given.

关键词： thermal conductivity heat transfer coefficient relative humidity wind velocity

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NUMERICAL STUDY OF HYDRODYNAMICS OF MULTIPLE TANDEM JETS IN CROSS FLOW

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Journal of Hydrodynamics 2011年第6期23卷 806-813页

作者： XIAO Yang TANG Hong-wu LIANG Dong-fang ZHANG Jiu-ding State Key Laboratory of Hydrology-water Resources and Hydraulic engineering Nanjing 210098 China college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China Department of engineering University of Cambridge Cambridge UK

The hydrodynamics of a single jet and four tandem jets in a cross flow are simulated by using the Computational Fluid Dynamics （CFD） software Fluent. The realizable model is used to close the Reynolds-Averaged equations. The flow characteristics of the jets, including the jet trajectory, the velocity field and the turbulent kinetic energy are obtained with various jet-to-cross flow velocity ratios in the range of 2.38-17.88. It is shown that a single jet penetrates slightly deeper than the first jet in a jet group at the same , although the difference decreases with the decrease of . It is also found that the way in which the velo-city decays along the centerline of the jet is similar for both a single jet and the first jet in a group, and the speed of the decay increases with the decrease of . The downstream jets in a group are found to behave differently due to the sheltering effect of the first jet in the group. Compared with the first jet, the downstream jets penetrate deeper into the cross flow, and the velocity decays more slowly. The circulation zone between the two upstream jets in the front is stronger than those formed between the downstream jets. The Turbulent Kinetic Energy （TKE） sees a distinct double-peak across the cross-sections close to each nozzle, with low values in the jet core and high values in the shear layers. The double-peak gradually vanishes, as the shear layers of the jet merge further away from the nozzle, where the TKE assumes peaks at the jet centerline.

关键词： multiple tandem jets jet in cross flow realizable model flow dynamics

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DISTRIBUTION OF BIOAVAILABLE PHOSPHORUS BETWEEN OVERLYING water AND SPM UNDER ABRUPT EXPANSION CONDITION

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Journal of Hydrodynamics 2011年第3期23卷 398-406页

作者： WAN Jun WANG Ze QIAN Shu-qin college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China college of Mechanics and Materials Hohai University Nanjing 210098 China Institute of Pearl River water Research Guangzhou 510611 China

Experiments on Phosphorus （P） fraction characteristics in sediment resuspension were performed under adequate hydrodynamic conditions. It is found that the concentration of Suspended Particulate Matter （SPM） in the eddy current region exhibits the ＂Matthew effect＂. Velocity is an impact factor of the Equilibrium Phosphate Concentration （EPC）, which is related to other hydraulic conditions. Overall bioavailable dissolved P in the SPM causes migration to overlying water and sediment, eventually being converted into a chemical speciation of P. Conditions of resuspension promote A1-P of SPM that migrated to the sediment and water. Concentrations of A1-P in SPM are reduced. P is released from SPM to water bodies, mainly through conversion into particulate P and dissolved total P. Meanwhile, exchange between SPM and sediments occur mainly through Ca-P migration. A1-P and BD-P possess similar geochemical characteristics or source. Ca-P and A1-P exhibit a negative correlation between migration and conversion.

关键词： bioavailable phosphorus Suspended Particulate Matter (SPM) abrupt expansion flow resuspension

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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 Conservancy and hydropower engineering,hohai university,nanjing 210098,china 2 National engineering Research Center of water Resources Efficient Utilization and engineering Safety,nanjing 210098,china 3 Department of Computer engineering,nanjing Institute of Technology,nanjing 210013,china college of water Conservancy and hydropower 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

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HYDRAULIC CHARACTERISTICS OF water-WINGS FOR THE MIDDLE-PIER OF A DISCHARGE TUNNEL

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Journal of Hydrodynamics 2006年第5期18卷 567-571页

作者： WU Jian-hua CAI Chang-guang JI Wei RUAN Shi-ping college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China china hydropower Mid-South Design and Research Institute Changsha 410014 China

water-wings, induced by the middle-pier placed in the inlet of a discharge tunnel, have harmful effects on the operation of the discharge tunnel. Based on dimensional analysis and physical model tests, the hydraulic characteristics of water-wings were investigated and their causes were analyzed in this study. The results show that the height and length of the water-wings increased with the increase of three factors, i.e., the Froude number Frd of the outlet of the pressure section, the depth Hc of the water surface concave at the end of the middle-pier, and the impact length Li of the two flows after this end.

关键词： water-wing dimensional analysis discharge tunnel middle-pier

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FLOWS THROUGH ENERGY DISSIPATERS WITH SUDDEN REDUCTION AND SUDDEN ENLARGEMENT FORMS

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Journal of Hydrodynamics 2010年第3期22卷 360-365页

作者： WU Jian-hua AI Wan-zheng college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China

The energy dissipation of flood discharges has been one of important problems that affect directly the safety of hydropower projects. The energy dissipater with sudden reduction and sudden enlargement forms, used widely in large-scale projects has been a kind of effective structure for energy dissipation. The concept of critical thickness was defined, which is related to both the geometric parameters and the hydraulic parameters of the energy dissipater, and the factors affecting the critical thickness, were analzsed by means of dimensional analysis. The empirical expression about the critical thickness was obtained and could be used as the criterion to distinguish the flows through the energy dissipater, i.e., the plug flow and the orifice plate flow. The error analysis showed that the critical thickness calculated by the expression has the errors of smaller than 10% in the estimation of the flows for the energy dissipater mentioned above.

关键词： critical thickness energy dissipater orifice plate plug reduction ratio sudden reduction sudden enlargement

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HYDRAULIC CHARACTERISTICS OF BOTTOM UNDERLAY-TYPE PIER FOR water-WING CONTROL

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Journal of Hydrodynamics 2008年第6期20卷 735-740页

作者： WU Jian-hua YAN Zhong-min college of water Conservancy and hydropower engineering Hohai University Nanjing 210098 China

The pier, placed at the outlet of the pressure flow section, is an effective design to deal with the problems of the manufacture and operation of the gates fbr a discharge tunnel with high water head. It is crucial to control the water-wing, induced by this type of the pier. Through observing the phenomena of the water-wing, the reason of the water-wing inception, i.e., the concave of the flow surface, was presented, and a type of the new pier with bottom underlay was designed. The hydraulic characteristics of the pier, including the variations of the water-wing features, both length and height, with the water head, as well as with the concave depth, and with the height of the bottom underlay, and the variations of the concave depth with the height of the bottom underlay, were investigated by physical model experiments. The results show that the approach of the modification of the concave through the structures with the bottom underlay-type pier is remarkably effective in the water-wing control.

关键词： bottom underlay-type pier concave of flow surface discharge tunnel water-wing

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