The basic principle of water pollution synergetic control
LI Jia1,ZHANG Jian
gao2
(1.Sichuan University;2.Chongqing University)
Abstract: On the basis of 1 D river water pollution synergetic control model for single contamination,the general principles of river pollution synergetic control are suggested.For achieving the designated water quality standard,the characteristics of pollution source,the capacity of corporation,competition mentality and correlative rules of law or policies are all taken into consideration. The meaning and role of these principles in water pollution control are expounded.
Key words: water pollution; synergetic control; group rationality; individual rationality
Characteristics of loess slope evolution based on concept of self-organization
NI Jin-ren, HAN Peng, ZHANG Jian
(Peking University)
Abstract: Based on the model presented in companion paper, slope evolution under different slopes is simulated. The relation between sheet erosion and rill erosion, the mechanism of transformation, which is hardly to establish in previous studies, are examined. It is shown that the ratio of sheet erosion to total erosion yield decreases substantially with the increase of slope. For the given slope, sheet erosion decreases while rill erosion increases in the slope evolution. The slope plays an important role in the transformation of sheet erosion into rill erosion. The critical time needed for the transformation altered by the slope. The critical time is much shorter during the slope is greater than 20¡ã¡£
Key words: loess slope; rill evolution; self-organization model; sheet erosion; rill erosion
REN Jian-xi1,2
(1.Xi'an University of Science and Technology;2.Shanghai Jiaotong University)
Abstract: The meso-mechanism of creep damage propagation in rock under uniaxial compression is experimentally studied using the computerized tomograhpy(CT) real-time testing facility developed by the authors. Clear images of the failure process, including micro-cracks initiation, crack development and bifurcation and fracture are attained. Based on the change of the CT value and CT image obtained from scanning test, the propagation law of the meso-damage in rock is deduced. The change law of crack width and length related to creeping time has been quantitatively analyzed.
Key words: creep meso-damage of rock; CT real-time testing; damage evolution law
Study on numerical simulation of river sink
PENG Wen-qi1, XUE Hai2,
SUN Dong-po2, HE Shu-hui3
(1.China Institute of Water Resources and Hydropower Research;2.North China Institute of
Water Conservancy and Hydropowe£»3.The Second Hebei
Province's Survey and Design Institute of Water Resources and Hydropower)
Abstract: A coupled model composed of 1-D and 2-D model for simulation of flood and tide current in river sink area is developed. The basic theory for establishment of the model is presented. Interface conditions and the coupling modes are discussed in detailed. The 1-D model is applied to calculate the upstream section of the river mouth area, while the 2-D model is used for the calculation of the area including the tide lock and estuary. The validity of the model is verified by using the historical recorded flood and measured tide. The calculated results are in good agreement with the observation data.
Key words: tide current; numerical simulation; river sink; coupled model
Study on algorithm of trace length estimation for discontinuities for sideslip surface
FAN Liu-ming1,2,
HUANG Run-qiu3, DING Xiu-mei3
(1.Xi'an University of Technology; 2.Changan University;3.Chengdu University of
Technology)
Abstract: Sideslip surface is one of the important mechanical boundaries that control the arch dam stability against sliding.Those steep discontinuities constituting sideslip surface are called discontinuities for sideslip surface.In order to analyze the boundary conditions of sideslip surface,it is necessary that trace length of discontinuities for sideslip surface should be studied if they are random jointed.In this paper,several conventional methods for trace length estimation,such as H-H algorthm,Laslett algorithm,2L0.5 algorithm,etc,are studied first.On this basis,a new algorithm,generalized H-H algorithm of trace length estimation,is established according to probability methods and assured methods.It is successfully applied to trace length estimation of discontinuities for sideslip surface in a hydro project.
Key words: sideslip surface; discontinuities for sideslip; trace length estimation; generalized H-H algorithm
LI Jiu-sheng1,2, RAO
Min-jie1
(1.Agrometeorology Institute,Chinese Academy of Agriculture Sciences;2.China Institute of
Water Resources and Hydropower Research)
Abstract: Field experiments were conducted in growing seasons to evaluate the influence of uniformity of sprinkler applying water and fertilizer on winter wheat yield.The seasonal mean Christiansen uniformity coefficient(CU) obtained is ranging from 62% to 82%.The results demonstrate that winter wheat canopy has significant potential to modify the water distribution of sprinkler¡£The uniformity coefficient below the canopy is higher than that above the canopy,if the coefficient above the canopy is lower than 76%.The Christiansen uniformity coefficients calculated from the cumulative depth caught above the canopy are larger than the averages of individual CU value during the irrigation season.Measurement of individual CU during the irrigation season will therefore underestimate the cumulative CU.Fertilizer irrigation experiment showed that distributions of both fertilizer and water applied through sprinkler system can be represented by an approximate similar normal distribution function.Field experiments also demonstrated that the uniformity of sprinkler-applied water and fertilizer has significant effect on winter wheat yield grown in North China plains.
Key words: sprinkler irrigation; fertigation; uniformity; North China Plains; winter wheat; yield
Study on the setting motion of the long bag filled with sand
SUN Dong-po1, PENG
Cheng-shan1, GENG Ming-quan2, LI Guo-qing1
(1.North China Institute of Water Conservancy and Hydroelectric Power;2. Yellow River
Affair Bureau of Henan Province)
Abstract: The logn bag filled with sand is a new type material for dam building and emergency harnessing of river.In this paper,the mechanics and numerical simulation of the setting motion of the long bag are studied.The dynamic properties and setting process of the long bag in the river are analyzed and mathematical model is established.The formulas for calculation of displacement and angle of deflection are deduced.Parameters of the formulas are determined by prototype observation data.
Key words: spur dike; bag filled with sand; setting velocity; displacement; angle of deflection
Basic performance of cracking and permeability resistance concrete and reinforced concrete pipe
TIAN Wen ling1, HUANG
Cheng kui2, LI Shi chun2, LI Zi xiang1
(1.Hebei University of Technology;2.Dalian University of Technology)
Abstract: A new type of cracking and permeability resistance concrete is introduced. This kind of concrete is made of steel fibers and expansive concrete. It possesses good mechanical performance and permeability performance. The experimental results show that the expansion deformation is restricted by the steel fibers distributed disorderly. Ths mechanical performance of the concrete is greatly improved by the reinforced steel fibers.
Key words: steel fiber reinforced concrete; expansive concrete; mechanical performance; shrinkage deformation
Optimal choice of water saving irrigation mode
ZHANG Qing hua, BAI Yu hui, NI
Hong zheng
(Shangdong Agriculture University)
Abstract: The method for synthetical evaluation of optimal choice on water saving irrigation mode is presented. The analytic hierarchy process(AHP) theory is applied and the following factors are taken into account:the national economic evaluation, the technical evaluation and the social evaluation of a project, internal rate of return; net present value, benefit to cost ratio, period of investment return, the uniformity of irrigation, the intensity of irrigation, rate of irrigation water used, the security and reliability of the water saving irrigation mode, the adaptability of landforms, the adaptability of crops, the popularity with the farmers and the difficulty in construction. This paper also deals with the general compositor and the single compositor of evaluating the mode of water saving irrigation and calculating method of the weights of the correlated factors.
Key words: water saving irrigation; optimal choice; synthetical evaluation£»analytical hierarchy process(AHP)
The application of GIS in regional water resources systematic evaluation
LIU Ming-zhu1,CHEN
Hong-han1,YE Nian-jun2,HU Li-qin3
(1.China University of Geosciences;2.Institute of Hydraulic Science,Huai River Water
Resources Committee;3.Haidian University)
Abstract: A groundwater resources evaluation system(GRES) is established on the basis of GIS platform.The system can evaluate different spatial objects through different spatial analysis methods,discovers the relationship among subsystems of groundwater resource system and then evaluates the groundwater resources in the whole area.
Key words: GIS;spatial analysis;groundwater resoures
Effective stress and liquefaction of seabed under the action of standing waves
WU Meng-xi, LOU Zhi-gang
(Institute of Mechanics, CAS)
Abstract: Stability and liquefaction are important to the design of offshore structures. A practical elastoplastic constitutive model for cohesionless soil under cyclic load is proposed. The parameters of the model for a kind of silt are obtained from un-drained dynamic triaxial test. The plastic strain increment of soil under cyclic load can be calculated according to the initial stress states, magnitude of cyclic stress and duration. No elastoplastic matrix related to stress and strain is needed. Biot's consolidation equation is applied to the FEM computation program developed by the authors. Variation of effective stress of seabed response to standing waves indicates that the location of greatest potential liquefaction is in the area beneath the wave anti-node. There is a densification effect to the seabed under the wave action.
Key words: standing wave; effective stress; pore water pressure; liquefation
Entropy method for estimating the parameters of Nash model
ZHANG Ming
(Water Conservancy Department of Yunnan Province)
Abstract: An entropy method for estimating the parameters of Nash model is proposed.Based on the mathematical expression of the relationship between Nash model and Gamma distribution and using the maximum information entropy principle,the equation for estimating the parameters is established.The formula for calculation can be deduced from the logarithmic expected value if it is expanded into Taylor's series and the terms higher than second order are neglected. The verification using ideal hydrographic data shows that the proposed method is better than the moment method.
Key words: Nash model;parameter estimation;principle of maximum information entropy;entropy method
LIN Shao-zhong, SU Hai-dong
(Yangtze River Scientific Research Institute)
Abstract: The surrounding concrete of steel spiral case in the power station of Three Gorges Project is constructed by means of keeping a specific level of internal pressure during construction.For analyzing the contact behavior of the interface between the steel spiral case and its surrounding concrete,the numerical simulations of the construction process during winter or summer season are carried out with 3-D FEM separately.The variation of the gap and the interaction force between the steel spiral case and its surrounding concrete in different opeation stages and different seasons are studied.The calculation result shows that the effect of temperature on the interacting force is significant.The effect of reducing the interacting force in the summer season during high impounding water level by means of elevating the internal water temperature in case of concreting in winter season and the effect of reducing the gap in winter during low impounding level by means of reducing the internal pressure in the case of concreting in summer season are studied.
Key words: spiral case; surrounding concrete; keeping the internal pressure during constructing; temperature effect; 3-D FEM simulation analysis
Random seismic response analysis of large scale underground caverns
CHEN Jian yun, HU Zhi qiang, LIN
Gao
(Dalian University of Technology)
Abstract: The seismic analysis of large scale underground caverns is complicated because of the interaction between structure and surrounding rocks and the uncertainty of earthquake excitation. Besides, the spatial variation characteristics of earthquake excitation have great effects on seismic response of the structures. In this paper, the dynamic impedance of surrounding rocks is evaluated using the damping solvent method. On this basis, the effect of the uncertainty of seismic input on dynamic random response of large scale underground caverns is studied using pseudo excitation random method. The results show that the seismic spatial coherence loss, wave travelling and scattering around the caverns may significantly affect the seismic response of underground caverns. The seismic wave travelling effect and spatial coherence loss will reduce the seismic response of underground structures, whereas the wave scattering effect can greatly improve the dynamic response of the underground structures. These factors must be taken into accoun in seismic analysis of the structures.
Key words: underground structure; random analysis£»interaction; travelling effect; wave scattering; coherence loss
Effect of fracture path on fracture energy of concrete
YAN An, WU Ke ru,YAO Wu, ZHANG
Dong
(Tongji University)
Abstract: The fractal theory is applied to quantitatively study the fracture surface and the relationship between fracture energy and fracture characteristics. The experimental results show that fractal dimension increases with the increase of maximum aggregate size and the increment for high water binder ratio concrete is much higher than that of low ratio; fracture energy of concrete increases with the increase of fractal dimension for a constant water binder ratio and the increment for low water binder concrete is much higher than that of high ratio. Good linear correlation between ductility index and fractal dimension is attained if the ductility index is used to assess the brittleness of concrete. It is concluded that a direct relationship between fracture energy may not exist.
Key words: concrete£»fracture energy£»strength; fractal dimension; brittleness
Database construction for regional scale soil loss assessment on the whole Loess Plateau
HU Liang-jun, Zhang Xiao-ping,
YANG Qin-ke1, LI Rui
(Institute of Soil and Water Conservation, CAS & MWR)
Abstract: The construction of database is fundamental to assess the soil and water loss of a region. In this paper, taking the whole Loess Plateau of China as an example, the factors affecting the soil and water loss and the data necessary to assess the soil and water loss in the region are analyzed. By using GIS, the fundamental database to assess the soil and water loss of this region is setup.
Key words: database; soil and water loss; region; the Loess Plateau of China; GIS
Analysis on the flow characteristics of long distance pipeline equipped with ventilation valve
HOU Jian-guo1, GUO
Ya-jie2, YAN Qing-fu3
(1.Hydraulic Engineering Quality Supervisory Station of Shanxi Province;2.Hydraulic
Science Institution of Shanxi Province£»
3.Taiyuan University of Technology)
Abstract: Air valve is necessary for long distance pipeline. The flow in the vicinity of valve within the pipe is very complicated. Cavity may occur and oscillating flow may happen. A method is proposed to analysis the characteristics of this kind of transient flow. The assumptions of constant entropy and constant temperature are adopted. The unsteady flow in the pipeline system can be calculated. An example is given for demonstration.
Key words: ventilation valve; water conveyer system; flow characteristics; unsteady flow
ZHENG Ji-yong, SHAO Ming-an
(Institute of Water and Soil Conservation,CAS & MWR)
Abstract: The movement of solute front in soil is detected by means of time domain reflectometry(TDR).The comparison of the parameters obtained from boundary layer theory method(BLTM) and break-through curve fitting shows that the former method is better than the later.But the value of retardation factor R determined by BLTM is greater than that from break-through curve fitting,due to the sensitivity limitation of TDR.A lag deviation of the solute front judged by TDR is always occurred.The solution profiles calculated with the BLTM and the analytical solution using the parameters identified by BLTM prove that the dynamic distribution of pollutants can be accurately forecasted by BLTM in a certain time.
Key words: porous medium; solute transport; BLTM; solute front