A neural network model with dynamic characteristics
LI Yi-tian1, LI Rong2
(1.Wuhan University;2.Pudong Bureau of Water Resources,Shanghai)
Abstract: The neural network model is combined with conservation equations of flow and sediment for river network to establish a new neural network model with dynamic characteristics. The model can be used for real time prediction of flow and sediment transport in multiple connected river channels and is suitable for the area where topography map is not sufficient. The model is applied to simulate the flow and sediment transport in Jingjiang River and Dongting Lake and good agreement between computational results and field measurements is obtained.
Key words: multiple connected channels; neural network; flow and sediment transport.
Study on the reduction of concrete compressive strength due to triaxial compressive loading history
LU Jing-zhou1, LIN
Gao1, XIAO Shi-yun1, WANG Zhe2
(1.Dalian University of Technology;2.Northern Jiaotong University)
Abstract: Based on the continuum damage mechanics theory, the damage of concrete cubes experienced monotonic and cyclic triaxial compressive load is studied experimentally. The loading history is denoted by the combination of lateral stress and maximum longitudinal strain, the damage of the concrete is denoted by the reduction of compressive strength. By curve fitting of the experimental data, the evolution equation of damage is obtained. The main factors that affect the damage development are examined and the causes are expounded. It is demonstrated that the method is convenient and applicable to estimate the damage of concrete in engineering practice.
Key words: concrete; damage; reduction of compressive strength; loading history.
System model for online analytical processing and data mining of hydrological data
AI Ping1, WANG Zhi
jian1,SUO Li sheng1,NI Wei xin2
(1.Hohai University;2.Hydrological Bureau of MWR)
Abstract: Both online analytical processing(OLAP)and knowledge discovery in database(KDD)are advanced modes of information resources exploitation.A system model for online analytical processing and data mining(DM)of hydrological data is proposed to acquire the knowledge of the laws of water movement and its effect on environment.The layered construction of the combination of OLAP and DM is presented in detail and the key technology to be applied in establishing the model is introduced.
Key words: online analytical processing; data mining; knowledge discovery in database; system model; intelligent analysis of hydrological data
Mathematical model for movement of high concentrated sediment in reservoirs
ZHANG Hong yi,YANG Ming,ZHANG
Jun-hua,DENG Hong liang
(Beijing University of Aeronautics and Astronautics)
Abstract: Based on the modified movement equation for sediment and new findings of sediment transport capacity,riverbed roughness as well as density flow,a quasi 2 D mathematical model for movement of high concentrated sediment in reservior is established.The validity of this model is verified by field observation data from Sanmenxia Reservoir and Bajiazui Reservoir.The model is applied to forecast the deposition and sluice effect of Dongzhuang Reservoir,Jing River¡£The computational result is in good agreement with the physical model data.
Key words: high concentrated sediment; mathematical model; equation of movement
Semi-structural decision-making theory and approach for flood control and dispatching system
CHEN Shou-yu
(Dalian University of Technology)
Abstract: This paper points out that the decision-making for flood control and dispatching systems is a multi-objective and semi-structural decision-making including qualitative objectives and quantitative objectives.On the basis of pair-wise comparison,a theory and approach for calculating the relative membership degree of quantitative objectives is develped.Furthermore,the formula for calculating the quantitative objectives that has the same calculating standards as the formula of relative membership degree of quantitative objectives is established.The relative membership degree matrix of all objectives can be integrated.Through multi-objective and multi-level fuzzy optimal model,the optimal or satisfactory decision can be obtained.The practical case shows that the approach takes the influence of all objectives and experience and knowledge of decision-makers into account,so it is rational and reliable.
Key words: flood control; semi-structural decision-making; qualitative objective; quantitative objective
MA Xiu-feng1, RUAN
Ben-qing2
(1.Hydrologic Bureau, YRCC;2. China Institute of Water Resources and Hydropower)
Abstract: A numerical integral approach arithmetic using weighting function is proposed.It can solve the coefficients of sampling variation and skewness simultaneously.The solution procedures of exponential and variation single weighting functions are introduced in detail.The numerical integral arithmetic of double weighting function is also improved.An example solved by using Mathcad 7.0 is given for demonstration.The calculation result is compared with those using arithmetic of double weighting function and moment method of numerical integral.
Key words: arithmetic of weighting function; P-¢ó distribution; coefficient of standard variation; coefficient of skewness
Characteristics of inferior variation of water environment in Hutuohe River dried up area
FEI Yu hong1, CHEN
Shu-e2£¬LIU Ke yan3
(1.Institute of Hydrogeology and Engineering Geology, CAGS£»
2.Information Center of MWR;3.Bureau of Water
Resources, Hebei Province)
Abstract£ºThe effects of surface water retaining and excess pumping of groundwater on environment in Hutuohe River dried up area is expounded by analyzing the characteristics of inferior variation of surface water and groundwater environment. The possibility of utilizing the aquifer to regulate the water resources is suggested. The potential capacity of the underground reservoir is introduced. This may be used as a regulation reservoir in the Water Transfer from South to North Project¡£
Key words£ºHutuohe River; dried up; excess pumping; ground water; funnel; water resources regulation
Stability and seepage analysis of dredge filled embankment
ZHANG Feng-zhan1, LIU
Run2, YAN Shu wang2, GUO Lian ying3
(1.Tianjin Harbor Bureau,China;2.Tianjin University;3.Tianjin Hydraulic Survey and Design
Institute)
Abstract£ºOn the basis of stability analysis, it was proved that with the self weight consolidation and moisture vaporization the hydraulic filled deposit could be used as the foundation of embankment. By performing the finite element analysis, it was found that after the completion of embankment the stress level inside the foundation was not higher than the yield stress and the uneven settlement did not exceed the allowable value. Permeability tests were carried out for the hydraulic filled soil and the failure hydraulic gradients were measured. By comparing the measured failure hydraulic gradients with those from calculation, the safety of the embankment during flooding period was evaluated
Key words£ºflood control work£»hydraulic filling£»embankment; slope stability; permeability; displacement
Effect of plasticity index of saturated soft clay on its deformation parameters
BAI Bing1, ZHOU Jian2,
ZHANG Guang1
(1.Institute of Rock and Soil Mechanics, Chinese Academy of Sciences;
2.Dept.of Geatechnical Engineering, Tongji University)
Abstract£ºThe physical meanings of plasticity index of cohesive soils and its influencing mechanism on the mechanical properties of saturated soft clays are analyzed. Based on the research findings of predecessors and combining with the experimental data accumulated by the authors, the quantitative relationships between some deformation parameters of saturated soft clays and plasticity index are established. Theses parameters include compression index, expansion index, coefficient of secondary consolidation and initial coefficient of re consolidation volume compressibility, et al. The results can be used in engineering practice.
Key words£ºplasticity index; mechanical properties; deformation parameters
Sduty on the rule of wave decaying on silt seabed
BAI Yu-chuan1,HU
Shi-xiong2, JIN Yu-shi1
(1.Tianjin University;2.International Research and Training Center for Sedimentation and
Erosion)
Abstract: The experimental research was carried out to study the wave decaying on silt seabed. A formula for calculation of wave decaying is established by using dimensional analysis and step-by-step multiple regressive statistics method. It is found that a critical condition of mud exists. When mud is not yielded the wave decaying parameter is very small, but it becomes very big when mud is yielded. The rate of decay is inversely proportional to the stiffness of mud.
Key words: sediment; wave decaying; silt seabed; regressive statistics method
Study on p-version adaptive finite element method for analysis of hydraulic structure
CHEN Sheng-hong, CHENG Zhao
(Wuhan University)
Abstract: The 2-D p-version adaptive finite element method is presented.The Legendre and Jacobi polynomial functions are used to construct the basic function of hierarchical element.Based on the discrete error estimation theory three types of strategy of p-version adaptivity,namely homogeneous p-adaptivity,element p-adaptivity and DOF p-adaptivity, are proposed.The advantages of the proposed method and its application to calculation of hydraulic structures are demonstrated by example.
Key words: hydraulic structure; finite element method; hierarchical element; p-version; adaptivity
The influence of capacity decrease on flood stages in Dongting Lake and in Yangtze River
FANG Chun ming,ZHONG Zheng qing
(China Institute of Water Resources and Hydropower Research)
Abstract: In the recent years,the flood stage of Yangtze River is elevated due to the decrease of the capacity in Dongting Lake.A method is presented to analyze the flood stage increment,Using the lake's capacity curve in 1954 and 1995,the influence of capacity variation on flood stage is calculated.
Key words: Dongting Lake;capacity decrease;outflow capacity;flood stage;stage discharge relationship
Finite element analysis for thermal stress of concrete slabs with friction constraint
ZHANG Guo-xin, PENG Jing
(China Institute of Water Resources and Hydropower Research)
Abstract: This paper presents the procedure for simulating the contact friction by using FEM. The effect of frictional constraint of rock dump on thermal slabs is analyzed. The result shows that the maximum value of the average tensile stress occurs to the lower part of the dam. Penetrating tensile stress will not be yield when the friction angle is less than the dam slope, whereas a maximun value of the tensile stress exists when the friction angle is larger than the dam slope. When the tensile stress reaches the maximum value the tensile stress in the slabs keeps unchanged in spite of the temperature drop. It is an effective measure to avoid the occurence of penetrating carck by enhancing the flatness of the dam slope and reducing the restriction of the rock dump to the slabs.
Key words: concrete face rockfill dam; friction constraint; concrete slab; thermal stress
Controlled root-divided alternative irrigation --Theory and Experiments
KANG Shao-zhong1, PAN
Ying-hua1,2, SHI Pei-ze3, ZHANG Jian-hua4
(1.Northwest Sci-Tech University of Agriculture and Forestry;2.Institute of Soil and Water
Conservation,CAS & MWR;
3.Wuwei Institute of Water Resources;4.Hong Kong Baptist University,Kowloon Tong)
Abstract£ºThis paper discussed the conception and theoretical basis of controlled root-divided alternative irrigation(CRDI) and studied it systematically through potted maize,field maize and peach roots-divided irrigation.The results show that CRDI could save irrigation water under the condition of not to reduce the yield but the luxury water used,since the evapor-transpiration can be reduced greatly.At the same time,the irrigation water use efficiency is also decreased.It demonstrates that CRDI is a feasible irrigation technique suitable for arid area.
Key words£ºroot system; CRDI; water use efficiency
Simulation of regional soil water and nitrogen behaviors in agricultural field
HUANG Yuan-fang1, LI
Yun-zhu1, LI Bao-guo1, CHEN De-li2
(1.China Agricultural University; 2.University of Melbourne)
Abstract£ºThe North China Plain was selected as the research region of this paper.Based upon the data of the Second General Soil Survey,a simplified distribution map of soil types in this region was obtained with geographic information system(GIS)method (ARC/INFO).There were 72 types of soil with representative profiles.Based on the simplified parameters of crop growth,development,regional soil and meteorology,the soil water-nitrogen-heat joint model was employed to simulate the regional water and nitrogen behaviors.When the simulation model combined with GIS,it was easy to evaluate regional soil nitrogen behaviors under different treatments of water and nitrogen.The simulating results indicated that water use efficiency(WUE) was obviously different between different types of hydrologic year,high in dry year,low in wet year.The nitrogen use efficiency (NUE) possessed the similar characteristics but not obviously.The distributions of WUE and NUE in the North China Plain were closely dependent upon the soil and meteorological conditions.
Key words£ºregional; soil water and nitrogen behaviors; simulation; GIS