Journal of Hydraulic Engineering No.12 1998

Journal

Abstract　The relationship between ice cover thickness of reservoir and its frozen duration is studied and the growing process of the ice cover is simulated in consideration of the density flow caused by temperature difference.The analysis on the ice pressure acting on the gate measured in the field test helps to explain why the history curves of ice pressure differs from that in reservoir.The forced lifting height of the radial gate due to ice action is estimated.The result is in accordance with the field observation.
Key words　ice cover,reservoir,ice pressure,forced lifting of gate.

　Research on law of sediment movement agitated by dredger and

mathematical modelong of the dredging benefit

Bai Yuchuan   Gu Yuanyan    (Tianjing University)

Zhu Baoliang ,Yu Tianyi    (Haihe River Conservancy Commission)

Abstract  The movement of the sediments agitated by dredger is simulated mathematically . The process of the sediments carried by the river flow and ebb tide is studied in detail . The effect of agitation on mitigation of silting in Haihe river estuary is quantitatively estimated .

Key words　setuary , sediment movement , mathematical model , agitating dredger

Abstract　The rheologic data of two phase mixtures obtained by the author has been analyzed to find out the stresses constitutive relation of two-phase flows.The stresses in two-phase flows is the sum of the stresses created by internal action of each phase and the interactions between the liquid-phase and solid-phase.According to the tensor analysis,a quadratic polynomial of shear-rate is adopted as the stress constitutive equation.Each term in the polynomial reflects the action of differsnt mechanism.The coefficients of terms in polynomial depend on the characteristics of two-phase mixtures,and determined by nonlinear regression empirically.In the case of natural debris flow,in which the restitution coefficient of grains and shear rate are lower,the collision actions of grains can be neglected,its stress constitutive relation can be simplified as a linear equation with a yield value.
Key words　debris flow, two-phase flow, rheology, stress constitutive relation.

Abstract　Through theoretical analysis,this paper proposes the formula for diffusion coefficient in shear turbulent flow,which is described by F-distribution function over the flow depth.The vertical distribution of relative sediment concentration calculated by this formula is in agreement with Rouse′s formula and Zhang Hongwu′s formula.So it also can be used for computation for turbulent model.
Key words　turbulence diffusion, Reynolds stress, F-distribution.

Abstract　In this paper,the analysis results of prototype observation data for high lift ship lock in Wuqiangxi hydro project is presented.Emphases are laid on the distribution of hydrodynamic pressure acting on the wall of filling-emptying system and flow-induced vibration of the reversed tainter gate.The possibility of cavitation and the safety of the gate are assessed.
Key words　high lift ship lock, filling-emptying system, hydrodynamic pressure, reversed tainter gate, flow-induced vibration, prototype observation.

Abstract　A current large scale LP model is developed for operation of complicated flood control system.For solving forced flood diversion constraints containing 0—1 factor,this paper presents a simplified method-separate-phase algorithm of judging flood diversion point of demarcation.According to super-sparse characteristics of this generalized model,a large common and efficient computational software package is developed.Case study verifies that this model is satisfactory for practical uses.
Key words　flood control system, large scale LP, Forced flood diversion, separate-phase algorithm, optimal strategy.

Abstract　The structural earthquake resistance characteristics of the ship-lifter tower in Geheyan project are studied in model test on a 3-D six freedoms shaking table. The filling depth of the tower foundation and the coupling of the aqueduct with tower structure are simulated. Three typical operation conditions are considered respectively: the ship tank is clipped at the top position of the tower, the ship tank is moving in the process of lifting, the balance mass is locked at the top position. The dynamic characteristics and seismic responses of the tower structure are obtained.
Key words　ship-lifter, tower structure, dynamic test.

Abstract　An elasto-plastic model of saturated sands under cyclic loading is presented. Every point of this model is in a state of loading or neutral loading by the usage of relative stress ratio. The model does not define yield surface and potential surface explicitly but consists of failure envelope, flow direction, loading direction, original loading surface and plastic modulus. Parameters of this model are relatively fewer and easy to be determined. The feasibility of this model is verified by comparing the results predicted by this model with those of experiment.
Key words　cyclic loading, elasto-plastic model, relative stress ratio.

Abstract　Based on the theory of reaction kinetics this paper discusses the relations among gelling time, reactant concentration and primer concentration of acrylic calcium grouting material. A quantitative formula is proposed. An example is provided to verify the proposed formula.
Key words　chemical grouting, gelling time, reaction kinetics.

Abstract　According to the results of field investigation and model test, this article discusses the filling law of fly ash. It involves the ditch position and cross section, hydraulic properties of the fluid, geographic characteristics of the fly ash reservoir, filling slope and critical velocity.
Key words　fly ash, ditch, filling slope, critical velocity.

Abstract　The stability of high rock-fill dam is greatly influenced by the non-linear relation ship between the rock shear strength and the normal stress. This paper reveals some conclusions through theoretical analysis and calculation: (1)The reasonable shape of a high rock-fill dam slope could be taken as a exponential curved surface; (2)In analyging the stability of high rock-fill dam, it is more reasmalle to use the curved-sliding curface method. (3)The three types of reasonable shope presented the paper are all fit to the shape design of high rock-fill dam.
Key words　limiting stability, side slope, rock-fill dam.

Abstract　In this paper,an universal mathematical model is proposed for simulating steady flows in complicated water supply networks.In this model,the network is divided into some elements and similar equations for each element is deduced.Then the equations for elements are combined with the boundary conditions.The general equations for the system can be obtained and to be solved by using a nodes group method.The model possesses the advantages of high computational speed and high accuracy.
Key words　steady flows, equations for the element, the nodes group method.

Abstract　This paper presents a dynamic response model of crop to water-salinity, The method for solving model coefficient are analyzed. Based on the experimental data the salt sensitive index and water sensitive index in different stage of winter wheat are given. It helps to promote the management of poor quality irrigation water for high yield of crops.
Key words　crop, salt sensitive index, water sensitive index, dynamic response.

Abstract　By means of the combination of multi-stratum recursive prediction and regression analysis, a multi-stratum recursive regression analysis model for formulation of reservoir operation function is established. As a case study, the calculation result of Danjiangkou reservoir is given. It shows that the model is feasible and practical.
Key words　Dynamic system, regressive analysis, operation function.