Shen Zhujiang Zhao Kuizhi

(Nanjing Hydraulic Research Institute)

Abstract In this paper a creep model with 3 parameters has bee n proposed for rockfill materials and it is emphasized that parameters are hardly can be determined from the laboratory test because of the requirement of long duration. Four rockfill dams with different materials recently constructed in Chin a have been analyzed with this model to get the model parameters through the comparison between measured and computed increments of displacement. Finally, four typical sets of creep parameters for rockfill material from very soft (mud stone)to very hard(granite)are recommended for design of rockfill dams.

Key words rockfill dam, creep deformation, constitutive model, back analysis.

Abstract In this paper the flow-sliding property of the fine-silty sand in the Three Gorges Project cofferdam has been studied by CU test on these tress-controlled triaxial apparatus. From the experimental results the steady state lines and the steady state strength lines of two kinds of the sands with different initial void ratio and different consolidation ratio are obtained. The main factors determining the loose sand to get into the steady state under dynamic loading are expounded. On this basis the shear strength parameters of saturated loose sand are classified as effective stress friction angle at large strain ¦µ',effective stress friction angle at peak value ¦µp',total stress friction angle at peak value ¦µp and friction angle at steady state ¦µr, provided for different working condition of soil mass. As an instance, the flow-sliding region in an earth cofferdam during 7¡ã seismic intensity is estimated and the friction angles at steady state ¦µr of each elements in flow-sliding region are give n.

Key words saturated loose sand, flow-sliding property, steady state, shear strength at steady state.

A simplified hydraulic calculation method for flaring gate pier stilling basin

Ni Hangen

(Dalian University of Technology)

Abstract In this paper a new concept named equivalent spatial flow ratio for the flaring gate pierª²stilling basin is suggested. From analyzing some engineering experimental results an empirical relationship between the value of ¦Á_e and the ratio E₀/h_k and B'/B₀ was obtained. The numerical examples show that the simplified method proposed is very convenient for calculation.

Key words energy dissipation, flaring gate pier, equivalent spatial flow ratio.

Water hammer simulation by the Lattice Boltzmann method

Cheng Yongguang     Zhang Shihua    Chen Jianzhi

Study on Water-saving irrigation of wheat in Fenqiu region

Zhou Lingyun Chen Zhixiong

Co¡ªKriging estimation on the spatial variability of soil salt
solute and ions grade

Abstract¡¡According to the demand of the spatial variability research of soil characteristics and soil watersalt monitoring in a large irrigation district, the Co-Kriging estimation of soil salt solute and its major ions grade in a So^2-₄-Cl^- kind of the saline and under two scales in the Hetao irrigation district, China, are done by Co-Kriging of the multi-variable geostastics (MVG). Three kinds of single variable and a group of multi-variable are used to forecast main variable information. The result show that grade of cl^- can be estimated accurately by EC which is easy to be measured in the field, the grade of K⁺+Na⁺ can be estimated by using multi-variable group of EC&Cl^-, the MVG model of the small-scale can be accurately estimated in the middle-scale. The solution method of CK equation is studied in this paper.
Key words¡¡soil salt solute; ion grade, Co-Kriging, estimation, multi-variable geostatics, spatial variability.

Modeling approach for optimal operation planning of Sihu drainage system

Abstract¡¡This paper is a part of results of optimal operation of the Sihu drainage system by cooperative study between China and Canada.The optimal operation planning modeling approach of the large scale drainage systems in plain polder areas has been developed by using various system analysis technique in this paper.The authors put forward the whole modeling system including operation models and basic data models.The structures.properties and functions of the optimization model,statistics model and simulation model are introduced emphatically.Application of the modeling approach to Sihu Drainage system in the middle and lower zones shows that the models are realistic and the approach is available.
Key words¡¡drainage system in plain polder area,modeling approach, system analysis.

The water quality multi-parameter identification and inverse algorithm

Li Lan
(Wuhan University of Hydraulic and Electric Engineering)

Abstract¡¡The water quality respond relation of input-output measurements are established by systematic theory in this paper.According to the peculiarity of hydrology and the necessity of water quality inverse problem the multi-parameter inverse problem model based on ordinary differential equation is developed.The existence and uniqueness of the solution of the ordinary differential equation about two parameters or multi-parameter are to be proved.The unstability depending on errors between monitoring data and interpolation approximate data are analyzed and demonstrated.Cubic spline interpolation function,the least two multiply and positive rule method are conjoined for obtained solution of multi-parameter.The results from this algorithm indicats its efficient to the multi-parameter identification in water quality modeling.
Key words¡¡water quality, multi-parameter identification, inverse algorithm.

A methodology for modeling sand-drain ground in plain strain analysis

Zhao Weibing Chen Yonghu Gong Youpin
(Hohai University)

Abstract¡¡A new method is described for consolidation analysis of modelling sand-drain ground in plain strain finite element analyses. First this paper presents two-way seepage consolidation solutions of sand-wall ground, based on the assumption of equal strain boundary conditions. Second, comparisons of the solutions and Baron's axisymmetric consolidation theoretical solutions are conducted to find an equivalent and matching method for plane strain analyses and axisymmetric analyses of sand-drained ground. The effects of both the horizontal deformation and smear are considered in the matching procedure. The method introduced can be applied conveniently and accurately to analyze sand-drain ground by plane strain FEM.
Key words¡¡Sand-drain, consolidation, plane strain FEM, sand-wall.

Experimental research of open high specific speed axial
flow pump model device

Shi Weidong
(Jiangsu University of Science and Technology)

Abstract¡¡Some new design methods of high specific speed axial flow pump model are put forward. The characteristics of structure type, the design of flow path and the experimental research of model device on open axial flow pump are introduced. It is found that this model device are characterized by large discharge, high efficiency, wide high efficiency range and can be used in low-lift ranges.
Key words¡¡high specific speed, axial flow pump, model, device experiment, characteristic curve.

The fluid displacement finite elements method for arch dam-reservoir
interaction analysis

Chen Hequn Qian Xiangdong Cui Aihua
(Hohai University)

Abstract¡¡On the basis of the basic equation for fluid, the analysis model of dynamic finite element for dam-reservoir interaction is established. Typical analysis are presented for Ertan arch dam and reservoir system. Comparisons are made with other standard modeling techniques.
Key words¡¡the finite element method, displacement fluid element, arch dam-reservoir dynamic interaction, earthquake response.

Study on water uptake by the winter wheat's roots with
the application of Microlysimeter

Zuo Qiang Sun Yanxin Yang Peiling
(China Agricultural University)

Abstract¡¡Based on the theory of soil water dynamics and more practical and rational upper boundary condition of one dimensional vertical unsaturated flow,a new approach to modeling water uptake rates by roots S(z,t) is put forward in this paper by using the evaporation data from the soil surface measured in situ by Microlysimeter.The accuracy of the modeling result depends on the value of averaging time step ¦Ät,in the earlier growth stages of plants£¬¦Ät can be set bigger than that in the later stages due to the fact of weaker transpiration.As for the winter wheat,the simulated soil moisture content profiles are in reasonable agreement with the measured if ¦Ät is selected as 10d in the earlier stages and 5d in the later growth periods respectively.The winter wheat's S(z,t)in the stages between jointing and harvest has been simulated with the application of the new proposed numerical model about water uptake by roots.The results have shown that:1,the maximum water uptake rate of the winter wheat appears in the stages between milking and milky maturity,2,the roots of the winter wheat grow towards the soil layer with abundant and easier to be absorbed water,namely,if water is sufficient near the soil surface,the water absorbing peak of roots will appear in the upper soil profile,otherwise,the roots will stretch deeper,and the peak move to the lower layer accordingly.
Key words¡¡water uptake by roots,model,numerical simulation,Microlysimeter,evaporation,transpiration.

Computation of stress intensity factors for bimaterial V-notch
and heel of concrete dam on rock foundation

Jian Zheng Huang Songmei Hu Liming
(Xian University of Technology)

Abstract¡¡The eigen values and the fields of stress and displacement for the bimaterial V-notch tip have been calculated by using complex potential theory.A numerical method is constructed to calculate the stress intensity factors for the bimaterial V-notch and the heel of concrete dam on rock foundation.The soluation is highly accurate.
Key words V-notch,stress intensity factors,gravity dam.