The application of nonlinear uncoupled K-G model to deformation analysis of high concrete face rockfill dam

GAO Lian-shi, WANG Zhao-hua, SONG Wen-jing
(Tsinghua University)

Abstract: The nonlinear uncoupled K-G model proposed by the author in 1996 is further improved to accommodate the calculation of high CFRD. In this case, the stress path is very complicated since the filling process of the dam is divided into several stages during construction. The basic formula of the model and the incremental regression method for obtaining the parameters are introduced. The calculation result of Shuibuya CFRD is given as an example of the application of the proposed model.

Key words: nonlinear uncoupled K-G model; stress path; CFRD; FEM

Multi-objective optimization of high arch dam shape under the actions of static and dynamic load

XIE Neng-gang¹, SUN Lin-song², WANG De-xin¹
(1.Anhui University of Technology;2.Hohai University)

Abstract: The multi-objective optimization model for high arch dam shape under the actions of static and dynamic load is established according to the principle of safety and principle of economy. The fuzzy theory is applied to deduce the evaluation function. The calculation of Xiaowan arch dam is given as an example to demonstrate the effectiveness of the optimization. The volume of the dam is reduced and the stress state as well as the earthquake resistance of the dam are improved.

Key words: shape of arch dam; multi-objective; optimization; fuzzy

Calculation of hydraulic properties using the data measured by disc infiltrometers

XUE Xu-zhang¹, ZHANG Ren-duo²
(1.China Agriculture University,China;2.University of Wyoming)

Abstract: A new procedure for calculating the hydraulic conductivity and macroscopic capillary length using the data measured by disc infiltrometers is proposed. A quick and accurate iteration method is applied to solve the resultant highly nonlinear equations. The hydrualic properties calculated from this procedure are compared with those from laboratory measurement and other calculation procedures. It shows that the new procedure gives better estimation of hydraulic conductivity and macroscopic capillary length.

Key words: disc infiltrometer; hydrualic conductivity; macroscopic capillary length

Hydrostatic settling velocity of dredged sediment stored in reservoir

YU Ya-nan，YE Pei-lun
(Zhejiang University)

Abstract：The theoretical relationship between suspended concentration and settling velocity of sediment group during the settling procedure is established.The result is verified by experimental data.It is found that the established concentration-settling velocity relationship is reasonable;the settling procedure of sediment group consists of accelerate,uniform and decelerate stages,if the variation of concentration is taken into account;the effects of grain size,density and original concentration on settling velocity are remarkable.

Key words：settling velocity; settling of sediment group; dredged sediment; sludge reservoir

Study on foundation distortion elimination by means of local softening

LIANG Wei min¹, WANG Yan bin¹， DENG Hong-lin²
(1.China University of Mining Technology;2.Shanxi Railway engineering Construction Supervision Co.,)

Abstract: The add ons force acting on the building base due to ground curvature distortion is analyzed. The maximum add ons moment of flexion is related to the contact length between foundation and ground base. The increase of length may enhance the resistance to distortion. Furthermore, the characteristic of loess and the influence of moisture content to soil mechanics are studied. On this basis, the method of distortion correction by means of wetting to form local softening is suggested.

Key words: curvature distortion; wetting；softening of base

The pollutant source control method for network water environment management

HAN Long xi¹, ZHU Dang-sheng²
(1.Hohai University;2.Water Power Planning Institute of the Ministry of Water Resources)

Abstract: The quality limitation for water body in network is based on its function. In the planning of water environment, the permissible discharge amount of pollutant for various sources is calculated according to the quality limitation of the water body. An inverse problem of water pollutant control with restricted conditions is established and the method for calculating the pollution discharge amount is proposed.

Key words: river network; water quality management; quality limitation; pollution source control

Numerical simulation of 2-D hydraulic transients using Lattice Boltzman method

CHENG Yong guang,ZHANG Hui
(Wuhan University)

Abstract: A set of multi scale equations,for characterizing the relations between the lattice Boltzmann equations and their corresponding macroscopic equations is derived by using Chapman Enskog expansion.With these multi scale equations and based on the basic equations for multi dimensional transient flows,a lattice Boltzmann model for 2 D hydraulic transient analysis is established.Numerical simulations of 1 D wave transmission,2 D wave corner diffraction and hydraulic transients in a concrete spiral case show that this method is a feasible and promising approach to simulate multi dimensional hydraulic transients in engineering.

Key words: hydraulic transient;lattice Boltzmann method;simulation;2-D fluid flow

Flow pattern evolution in plunge pools of high dam

LIU Pei qing¹, LI Fu-tian²
(1.Beijing University of Aeronautics and Astronautics;2.China Institute of Water Resource &.Hydropower Research)

Abstract: A systematic study on flow patterns in plunge pools down stream of the high dams is carried out to investigate the mechanism of the energy dissipation.It is found that three patterns may occur to the flow in the pool including free impact jet,submerge impact jet and surface flow according to the downstream water level.The criteria for determining the flow pattern are proposed.

Key words: plunge pool;flow pattern; criteria

Characteristics and chemical suffosion of the environment water around the dam site

MA Xiao-hui, PENG Han-xing, YANG Guang-zhong, ZENG Kai-hua
(Hohai University)

Abstract: Generally,great change of the environment around the dam will take place after the impounding of the reservoir.It is in favor of the enrichment of organic materials in water which containing erosive CO₂.In the process of erosive water transferring towards the dam foundation,physicochemical reaction takes place in rock,grout curtain and concrete forming chemical suffosion.The transferring of great amount of kalium,sodium, silicon and aluminum into water is the signal of strong chemical suffosion.This effect is limited by the geochemical environment of the dam foundation.In the process of suffosion the clay powder in rock may deposit at the outlet of drainage orifice due to coagulating migration of colloidal particles.Consequently,the chemical suffosion is always accompanied by seepage.

Key words: dam; water quality; water-rock action; chemical suffosion

Study and application of multi-objective optimization for arch dam design

WANG Shu-yu¹, LIU Guo-hua¹, DU Wang-gai¹, MA Yi-chao²
(1.Zhejiang University; 2.Institute of Investigation Design and Research for Water Resources and Hydropower, Zhejiang Province)

Abstract: The modeling,calculation method and application of multi-objective optimization for arch dam design are investigated.The economic index(concrete volume of the dam) and safety indices (stress level,probability of failure,area of high stress zone) are adopted as objective functions for optimization.The formula for probability of strength failure is deduced.The weight ideal point method is used to solve the problem.By adjusting the weight coefficient of objective functions,many efficient solutions (Pareto-optimal set) are obtained whch will reflect the decision-maker's personal favor and value.The paper also introduces a flexible modeling and corresponding implementation using computer.The different types of optimal model(single objective or multi-objective) can be easily formed by man-machine interaction in this modeling framework.A preliminary application to some large dams is presented.The results are reasonable and reliable.It shows that the model and method are desirable.

Key words: optimal design; arch dam; multi-objective function; probability of strength failure; flexible modeling

A mesoscopic approach for the size effect on fracture energy of concrete

ZHENG Jian jun, ZHOU Xin zhu
(Zhejiang University of Technology)

Abstract: A mesoscopic approach for the size effect on fracture energy of concrete is presented. Based on the wall effect on mesostructure of concrete, the fractal dimension of the macro crack in a concrete specimen is determined, which is found to change with the distance from the specimen boundaries. To calculate the length of the main macro crack with variable fractal dimension, a differential relationship between the fractal length of a curve and the corresponding Euclidian length is put forward by extending the definition of the fractal length of a curve. By applying the principle of energy equivalence, the nominal fracture energy of concrete is expressed in terms of the fractal fracture energy, the fractal dimension, some mesostructural dimensions and the cross sectional dimension of the specimen. A further theoretical analysis reveals that the basic mechanical characteristics of the nominal fracture energy agree with the observed macroscopic experimental phenomena of concrete. The theoretical prediction is compared with experiment data to confirm the effectiveness of the approach.

Key words: concrete; fracture energy; size effect; mesocopic approach; fractal; wall effect

Study on empirical transfer function of gorge free field ground motion

CUI Jiang yu¹, DU Xiu li²
(1.Northern Jiaotong University;2.Beijing Polytechnic University)

Abstract: An empirical transfer function for gorge free field ground motion is proposed and field special parameters are determined using explicit finite element method. The calculation of transfer function matrix of free field for the arch dam in Xiaowan Project is given as an example for demonstration. The field special parameters are fitted by least square method.

Key words: gorge ground motion; empirical transfer function matrix; arch dam parameters

Study on environmental management and monitoring planning of hydro projects

PENG Sheng hua¹, WENG Li da²
(Beijing Normal University;2.Research Institute for Yangtze Water Resources Protection)

Abstract: This paper discusses the characteristics of environmental impacts of hydro projects and highlights the role of environmental management and monitoring in construction and operation periods of the project. It is pointed out that emphases should be placed on the contents of environmental management and monitoring, feasibility of environmental protection measures, easiness of implementation of the environmental management and monitoring plan(EMMP), organization and implementation of environmental management and monitoring activities in EMMP prepared in EIA. An example is given for demonstration of the outline, approach and major contents of EMMP.

Key words: hydro project；environmental management; environmental monitoring; planning

Study on the interactive effects of water quality in upper and lower pools of pumped storage power plant

LI Jia, LI Ke-feng, DENG Yun
(Sichuan University)

Abstract: The interactive effect of water quality in upper and lower pools of a pumped storage power plant is studied through field measurement and numerical approach. The mathematical models adopted are partly verified by measured data. The predicted results show that the operation of power plant may influence the water in local area of the pools. However, both the area and degree being affected are limited in a small range.

Key words: pumped storage power plant; upper and lower pools; water quality; interaction; mathematical model; field measurement

Numerical study on 3-D deposition patterns of sand dumping in flowing water

MA Fu-xi¹, LI Zhi-wei²
(1.North China Institute of Water Conservancy and Hydroelectric Power;2.Hong Kong Polytechnic University)

Abstract: The 3-D buoyancy extended K-ε turbulence model is employed in the study of deposition patterns for sand dumping in flow water. This model consists of one continuity equation, three momentum equations, two turbulence-modeling equations, one concentration equation and one deposition equation. In the model, the governing equations are split into three parts in the finite difference solution namely advection, dispersion and propagation. The advection part is solved by the QUICKEST scheme. The dispersion part is solved by the central difference method and the propagation part is solved implicitly by using the Gauss-Seidel iteration method. By using this model, 8 numerical sample runs have been conducted. Two different deposition patterns are obtained. One is oblong and the other is horseshoe shape depending on hydraulic conditions and sediment parameters. The computer results are in satisfactory agreement with experiment. The reasons for the formation of the horseshoe shape have been investigated with the concept of bifurcation of buoyant plumes.

Key words: deposition pattern; sand dumping; turbulence model; plume; bifurcation

Distribution characteristics of solid grains in spiral pipe flow

PENG Long-sheng,ZHANG Yu, LU Zhun-wei,REN Wan-shen
(Taiyuan University of Technology)

Abstract: The non-uniform distribution of solid grains with the characteristic of "low up and high down" is formed in 2-D natural sand-laden flow due to the action of gravity. While in spiral flow, the distribution is symmetric about its center and horizontal axis. The solution of differential equations of equilibrium equations shows that in this case the flow carries much more grains than that in normal straight pipe flow. It might be explained by disappear of settling velocity. Instead of settling velocity an expanding velocity with magnitude of two orders less than the settle velocity occurs and leads to the more uniform distribution of grains along the rotating radius. The characteristics of symmetric and uniform distribution leads to the high concentration of grains carried in spiral pipe flow.

Key words: spiral pipe flow; spin floating grain; concentration distribution; trace of grain

1-D and 2-D nesting sediment transport model for rivers and estuaries

ZHANG Xiu-zhong, WANG Guang-qian
(Tsinghua University)

Abstract: A 1-D and 2-D combined sediment transport model for rivers and estuaries is presented.The basic equation,the numerical method,the coupling conditions and the treatments for non-uniform sediment are studied.The model is based on unsteady non-uniform and non-equilibrium sediment transport theory.The finite element method is abopted to solve the governing equations for its capability of accepting complex geometry.The model is verified by the simulations of the flow and sediment transport in the estuaries of the Zhangweixin River,in which the river area is treated as 1-D and the sea area is treated as 2-D.By transferring the water level,discharge and sediment concentration at the interface,the coupling calculations are conducted in each iterative step.The results are in good agreement with the measured data and a lot of CPU time is saved,which shows that the proposed model is reliable and high efficiency in solving practical engineering problems.

Key words: estuary; sediment transport; nesting linking; finite element discretization

Study on spatial variation of infiltration rates for small watershed in loess plateau

YUAN Jian-ping¹, LEI Ting-wu², GUO Suo-yan¹, JIANG Ding-sheng²
(1.Soil and Water Conservation Monitoring Center, MWR;2.Institute of soil and Water Conservation,CAS)

Abstract: According to the observation data the infiltration rate in the watershed is divided into four grades on the basis of different land using models and different topography and landforms features.It is found that infiltration rate possesses the law of spatial variation,the bigger the slope degree,the higher the soil infiltration rate.Different land use types have different infiltration rates.

Key words: soil erosion; infiltration rate; spatial variation; land use model

Design of vibrating burrow excavator

CHEN Fu-kun, WANG Zhi-yi, SUN Song-huai, DAI Yong
(Bureau of Water Resources,Gaoyou County,Jiangsu Province)

Abstract: The excavator consists of three main components:mechanism of vibration,mechanism of drive transmission and mechanism for burrow formation.The working principles and design of these mechanisms are introduced.The excavator possesses the advantages of easy to be used,high quality of burrow formation and low noise.It is suitable for the farming in China.With the application of this excavator,the farming land can be saved and the yield of the crop will be increased.

Key words: burrow excavator; vibrationg; drive transmission; water saving