Abstract: An optimized operation scheme called double flood control levels scheme is proposed to reduce the deposition and enhance the flood control capacity of the reservoir in the Three Gorges Project. It is suggested that the water level of the reservoir should be additionally lowered to 135m before the emergence of the flood higher than 45，000 m3/s, on the basis of the reservoir is controlled at a certain level in the flood season. Thereby, the sediment transport capacity of the reservoir can be enhanced and the deposition can be reduced. In the meantime, the reservoir capacity for flood control is expanded.
Key words: Three Gorges Project; flood control level; deposition reduction; flood control capacity.
WU Xiao-feng1,
TANG Jie1, Yukihisa Fujima2
(1.Tsinghua University; 2.Nagoya University, Japan)
Abstract: The simulation study of diesel-water two-phase flow in 1-D sandy trough is presented. The experimental results show that residual diesel saturation is in proportion to the particle size of the medium, whereas water saturation is in inverse proportion to the size of medium. Because of the interfacial tension, a transition zone exists in the porous media(d>0.5mm) and obvious abrupt change occurs at the upper edge. Image analyzing technology is applied to measure the oil saturation by using a CCD camera. The measurement result is in good agreement with the observation.
Key words: non-aqueous phase liquids; two-phase flow; residual saturation; image analysis; transition one.
HAO Ju-tao, YUE
Yao-zhen, LU Xiao-bin, JIA Jin-sheng
(China Institute of Water Resources and Hydropower Research)
Abstract: Fundamental properties of copper waterstop used in CFRD slab joints are experimentally studied. The bond strength between copper plate and concrete with different buried depth from 20mm to 200mm is measured by using the pull-out method. Furthermore, the mechanical characteristics of copper waterstop in a form of thin shell are investigated by means of strain gage, in order to understand the strain of copper waterstop under the condition of complicated stress state.
Key words: copper waterstop; CFRD; bond strength; deformation characteristics.
SUN Shuang-ke, LIU Zhi-ping, ZHOU Sheng
(China Institute of Water Resources and Hydropower Research)
Abstract: Unfavorable hydraulic phenomena might occur to the diversion tunnel if being reconstructed as a permanent vortex shaft spillway, in case of high tail water level. The phenomena include flow pattern changing from free surface flow to pressure flow, hydraulic jump and unsteady air bags etc. To solve these problems a vertical plate followed by a perforated cover panel installed at the end of the tunnel is proposed to control the flow pattern and release the air entrained. The functions and the principle of this vertical plate are theoretically and experimentally studied.
Key words: diversion tunnel; reconstruction; permanent vortex shaft spillway; vertical plate; perforated cover.
KOU Xiao dong2,
ZHOU Wei yuan1
(1.Tsinghua University)
Abstract：An approximate method for tackling the problem of arch dam fracture is presented. By this method the arch dam is divided into several sections in the arch dam direction. Nodes are distributed and the crack propagation is solely considered in each section. All sections are combined through interfaces to form the whole arch dam. In the example, the lateral constraint stiffness is estimated from the result obtained from FEM, then the crack propagation is simulated for the crest section of the arch dam and the failure length along the base of the dam is estimated. The result shows that element free method(EFM) is convenient and effective in simulation calculation of arch dam fracture.
Key words：element free method; arch dam; crack propagation
CHEN Wen hua1,
CUI Jie2, MEN Fu lu2, ZHAO Cheng gang1
(1.Northern Jiaotong University; 2.Institute of Engineering Mechanics)
Abstract: Based on the total stress method, the cone model theory is introduced to calculate the dynamic stress field of subsoil, so that the pore water pressure under the building can be evaluated directly. The effective stress method is suggested to evaluate the liquefaction potential of inhomogeneous building's subsoil. With the help of the theory for multi phased medium, a method is given to analyze the complex layered and inhomogeneous soil foundation.
Key words: liquefaction; inhomogeneous building;s subsoil; layered soil; cone model; total stress; ffective stress
GONG Xiao nan,
XIONG Chuan xiang, XIANG Ke xiang, HOU Yong feng
(1.Zhejiang University)
Abstract：A review on the study of influence of clay structure on its mechanical characteristics is presented. The classification and the causes of clay structure formation are investigated.
Key words：structure of clay; mechanical characteristics; cause of formation; classification
YANG Wan bin1,
XUE Xi cheng2
(1.Hebei Institute of Architectural Science and Technology;2.Tianjin University)
Abstract: A review of optimization method and its application is presented. The total area of failure zones in adjoining rock is set as the objective function to optimize the spacing and cross sections of double line tunnels for water transfer project. The restraint conditions are determined in line with the cross section required according to the operation of the project.
Key words: double line tunnels; water tunnel; optimization design; bolting reinforcement; failure zone; non linear analysis
CHEN Hu-xing1,
WANG Shang-xian2, WANG Shu-yin2, WU Chao-huan2
(1.Zhejiang University;2.Yangtze River Scientific Research Institute)
Abstract: The properties of concrete composed of double expansive moderate heat Portland cement as well as the double expansive low heat protland slag cement are experimentally studied respectively. The autogenous volume deformation, prestress and strength are tested. The result shows that these kinds of concrete expand both in early and later stage, stable prestress can be obtained in condition of restricted by reinforcement.
Key words: double expansive concrete; autogenous volume deformation; prestress
SUN Jian-sheng
(Taiyuan University of Technology)
Abstract: Based on the nonlinear hyperbolic model for load-deformation of earth filling, the finite element analysis method for simulation the earth filling load increments in the process of construction and the interaction between soil and liner is proposed. The internal stress and earth filling pressure acting on culvert liner with extended bottom plate laid on soft foundation as well as the edge load distribution on the excavation base are determined.
Key words: culvert liner; extended bottom plate; earth-fill pressure; nonlinear FEM
GAO Lang, XIE
Kang-he
(Institute of Geotechnical Engineering, Zhejing University)
Abstract: This paper presents the results of inspection and prediction of the stress of nails for soil nailing.The time series neural network based model is proposed for predicting the stress of the nails. Genetic algorithm is employed to solve the local minimum problem of back-propagation learning algorithm.The calculation results are compared with the observation data and good agreement is attained.
Key words: Deep excavation;soil nailing; stress;inspection;prediction;artificial neural network;genetic algorithm
CHEN Xin-min1,
XIA Jia1, LUO Guo-yu2
(1.Nanjing Architectural and Civil Engineering Institute;2.Nanjing University)
Abstract: The theory and relevant method of risk analysis are applied to assess the risk of dike breach in the lower reaches of Yellow River within the territory of Henan Province. The most dangerous river section is found. The result provides the basis of river harnessing planning for river sections in which river bed is higher than the adjacent land behind the dike.
Key words: lower Yellow River;dike breach; risk assessment; hazard degree
YIN Ming wan,
GAN Hong, WANG Dang xian, LI Ling yue
(China Institute of Water Resources and Hydropower Research)
Abstract：An intelligent model for balancing the demand and supply of water resources is presented.The concept,main functions and characteristics as well as the establishment of the model are demonstrated.The important aspects including time,space,water resources and water demands are concretely and systematically reflected in the model.The intelligent functions of the model elevate the calculation speed and make a breakthrough in the optimal analysis of vast water resources system.The application of the model to the reasonable allocation of water resources in Xinjian Autonomous is introduced in brief.
Key words：system analysis; water balance model; demand and supply;intelligent
HUANG Cai an, XI
Bin
(Yangzhou University)
Abstract：The effective shear stress of sediment transport is analyzed theoretically and tested by experimental data. The result shows that the effective shear stress is neither the overall shear stress nor the sand grain shear stress, but the geometric mean of these two stresses. The effective shear stress not only generalizes the flow intensity but also summarizes the flow intensities of mean flow velocity, stream power and unit stream power.
Key words：sediment transport; effective shear stress; sand grain shear stress; sediment transport rate; stream power.
SUN Zhi lin
(Zhejiang University)
Abstract：Based on the stochastic mechanistic model for exchange of non uniform sediment near the river bed,a theoretical formula is developed for the equilibrium bed concentration of the kth fraction of non uniform sediment defined at the bed surface.The bed concentration is the function of incipient motion probability,non ceasing probability,pick up probability and the ratio of single step motion time to repose time.The result calculated from the proposed formula is in good agreement with the measured data.Therefore,the present formula can be used to the bottom boundary condition for the differential equation of suspended load motion.
Key words：equilibrium bed concentration; non uniform sediment; sediment exchange; stochastic mechanistic model; concentration profile; gray system model.
WANG Kang, SHEN
Rong kai, HUANG Jie sheng
(Wuhan University of Hydraulic and Electric Engineering)
Abstract：The transpiration calculation of crop with transparent polyethylene mulch layer by using Penman Monteith model and the effect of transparent polyethylene mulch are studied in this paper.The field experiment dataare used to verify the model.Transpiration of winter wheat both for mulched field and non mulched field is calculated.The result is discussed.
Key words：transparent polyethylene mulch; transpiration; winter wheat; Penman Monteith model.