Aplication of two new methods for determining the parameters
of solute transport in soils
Ren Li， Li Baoguo， Zeng Fan， Xing Weiling |
(China Agricultural University) |
Abstract Based on the theory of the solute transport in soils,the experimental data of in filtration in three kinds of soil texture are analyzed.The slope method and equal-slope method developed by Yamguchi et al are applied to determine the average pore flow velocity and hydrodynamic dispersion coefficient.The calculation results are compared with the measured data,analytical solution and moment method.In addition,the efficiency of the parabolic interpolation technique in determining the parameters and the accuracy of the new approaches for different values of Brenner number are also investigated.
Key words solute transport, breakthrough curve, pore flow velocity,hydrodynamic dispersion coefficient,Brenner number,slope method,equal-slope method.
Study on influence of probe rod bending on flow field measurement
Qiu Baoyun Liu Chao |
(Yangzhou University) |
Abstract In this paper, a method for correcting the deviations of measuring position, flow direction and flow components due to probe rod bending caused by flow drag is suggested. Based on the quoins of the probe determined by the measured velocity distributions, the deviations can be calculated accordingly. This method is successfully applied to the estimation and correction of the measuring errors of a 3 D flow field. The result shows that the error of the flow component in the direction along the rod length is evident and not negligible. An approximate method for practical use is proposed.
Key words probe rod, bending, flow measurement, flow drag, measuring error, error correction.
Sediment prevention measures for the Tianshengqiao
Second Cascade Hydropower Station
Luo Fuan， Xu Yongnian， Liang Zhiyong |
(China Institute of Water Resources and Hydropower Research) |
Wang Bole， Yan Jun |
(Guiyang Hydroelectric Investigation Design and Research Institute) |
Wei Shanqi， Liu Zejun |
(Tianshengqiao Hydropower Plant) |
Abstract The inlet of the Tianshengqiao Second Cascade Hydropower Station is located at a river bend. To prevent sediment particles from entering the canal of the power station comprehensive measures including utilization of circulation flow in river bend, construction of submerged guide dike to form an artificial circulation, establish of settling basin as well as the operation scheme to reasonably control the water level are adopted. The measures are effective in prevent from the entering of coarse sand and reducing the wearing of the turbines.
Key words sediment prevention, hydropower station, river bend, submerged guide dike, settling basin.
The isotope tracer method for study on seepage flow in fissured rock
Chen Jiansheng, Wang Yuan, Zhao Weibing |
(Hohai University) |
Abstract The principle for measuring the seepage flow in fissured rock and effective mechanical fissured width in coupled well is developed.A method for determining the seepage coefficient by means of isotope tracer based on the measurement of seepage flow velocity,flow direction, discharge and recharge is proposed.
Key words isotope tracer, coupled well, fissured rock,seepage flow, dilute principle.
Application of LDV to measure the flow fields in complicated bifurcated conduits
Wang Xiuying, Cao Wenhong, Tan Dexin, Fu Lingyan, Chen Dong |
(China Institute of Water Resources and Hydropower Research) |
Abstract The 2-D back scattered LDV system is adopted to measure the flow field in a manifold,The velocity distributions and turbulent intensity of the flow are obtained.
Key words velocity, turbulent intensity, LDV, bifurcated conduit.
Analysis on structural shape of sea dyke and its sliding stability
Mao Changxi, Duan Xiangbao, Mao Peiyu |
(Nanjing Hydraulic Research Institute) |
Zhang Shijun,Zhou Ji |
(Water Resources Bureau of Zhejiang Province) |
Abstract The non-steady seepage flow analysis and sliding stability analysis for existing dykes in southeast coast of China are carried out. The comparisons of computational results of FEM analysis for different types of sliding show that it is more reasonable to use the composite circular arc sliding mode for sliding analysis. The results also show that the stability of dykes in sloping shape is better than that of vertical shape.
Key words dyke, structural shape, stability analysis, seepage flow, FEM.
Study on rational determination of specific yield in aquifer of loess areaLi
Li Peicheng |
(Xian Engineering University) |
Abstract In this paper,the field experiment result using neutron moisture meter in loess area is presented.The process of water release and variation of specific yield in aquifer are described.The inherent mechanism in the process is analyzed.The relationship between time-dependent specific yield and time history is found to be a hyperbola and accordingly an empirical formula is derived.Using this formula,the rational specific yield can be determined based on the variation of measured soil moisture content.
Key words specific yield, aquifer, water release mechanism.
Guo Xingwen ,Wang Dexin, Cai Xin, Dong Lichuan |
(Hohai University) |
Abstract In this paper,a rheological model for rock-fill material is proposed and a method for solving is suggested.Based on the 3-D FEM,the computation of a concrete rock-fill dam is carried out.The results show that the rheology of rock-fill material has effects on the dam,especially on the concrete faced slab.It is necessary to consider the rheology of rock-fill material in large dam design in various stages including construction and reservoir impounding period.
Key words rheological analysis, concrete faced rock-fill dam, FEM.
The comparison o soft clay slope stability using 2-D and 3-D FEM
Yan Shuwang |
(Tianjin University) |
Sun Wanhe |
(Tianjin Port and Harbor Engineering Institute) |
Abstract In this paper, 2-D and 3-D FEM based on elastoplastic model are used to alculate the stress and displacement of the soft clay slope. The stress distribution shows that the 3-D boundary effect varies with the stress level of the whole slope. Accordingly, a failure standard is established. At the same time, it is found that the failure is in different mode if the slope is under different stress state.
Key words slope stability, soft clay, FEM.
Mathematical model for sediment motion and optimization
of dredging scheme for Duliu river estuary
Bai Yuchuan Gu Yuanyan |
(Tianjin University) |
Xing Huanzhen |
(Haihe River Conservancy Commission) |
Abstract The sediment mathematical model is established for muddy estuary having short diversion canal. The sediment motion rule is studied and the optimization calculation for dredging scheme is carried out. The multiple hybridization finite element method is applied in the calculation.
Key words muddy estuary, dredging scheme, multiple hybridization finite element method.
Study on cracks at the heel of the arch dam of Shimen Project
Li Zan |
(North China Hydroelectric Investigation Design and Research Institute) |
Key words crack, dam heel, arch dam.
Finite element analysis for slope stability of earth-rock dam under
the action of stochastic seismic
Shao Longtan, Tang Hongxiang, Kong Xianjin, Han Guocheng |
(Dalian University of Technology) |
Abstract The response of earth-rock dam under the action of stochastic seismic is calculated by using the definite computation method. Thus, based on the finite element analysis method, the slope stability analysis method under the action of stochastic seismic is developed. The effectiveness and reasonableness of this method are verified by model test and corresponding analysis under the excitation of sine wave.
Key words stochastic seismic, response, finite element analysis, slope stability.
The simplified mathematical model of nitrogen losses in tile effluent from
the drained field of winter wheat
Liu Peibin |
(Beijing Hydraulic Research Institute) |
Zhang Yufang |
(Wuhan University of Hydraulic and Electrical Engineering) |
Abstract A simplified Mathematical model of nitrogen transport and transformation is established for field condition. A 1 D model of saturated unsaturated flow is applied when water table is above the drain pipes and a 2 D simplified travel time model is adopted for the flow field below the pipes. The advantage of these methods is that both drainage rate and concentration of nitrogen drained from each stream tube can be calculated and consequently the weighted average concentration of drainage effluent is derived. The field experiments are carried out to demonstrate the validity of the model.
Key words drained field, winter wheat, nitrogen leaching losses, stream net, mathematical model.
Experimental study on cavitation erosion resistance of IPN material
Liang Chuan Ru Shuxun |
(Sichuan University) |
Abstract The experimental study on interpenetrating polymer network (IPN) material is carried out by using the rotating disk testing device. The result shows that the polymer structure, the flexibility of material and the iterpenetrating level are the major factors affecting the cavitaion erosion resistance of the material. The IPN possesses the “double spring” cushion effect when two kinds of polymer have been interpenetrated. Thus, the fatigue limit of IPN is raised and the material is strengthened.
Key words interpenetrating polymer network material,cavitation erosion resistance, experiment.