Abstract: Some outliers usually are found in the process of analyzing the characteristics of soil and water resources. The universal Kriging method is not suitable to such data processing to obtain a steady solution. For this reason, a geostatistical method-indicator Kriging method(a nonparamtric method) is introduced in this paper. Samples collected from 139 observation points of 667Km² in Quzhou County, North China Plain, are analyzed. Outliers are found in the nitrate content of groundwater. The indicator Kriging method is applied to analyze the data and form the distribution map of nitrate content and the probability map of its content exceeded a maximum allowed value. The proposed method provides a new way for assessing the risk of utilizing soil and water resources in regional scale. It also can be used as the guide for decision making and management of regional soil and water resources.

Key words: indicator Kriging method; groundwater; nitrate; geostatistics

Abstract: The slices method and FEM are integrated in the analysis of slope stability. The principle of combination and the process of implementation are introduced in detail. An example is given to demonstrate the calculation and the result is compared with that derived from conventional simplified method. It is found that the safe factor calculated based on the later method is always much higher. Consequently, the calculation result of conventional method is not safe enough. The integrated method possesses the advantage of fully utilizing the experience of engineering practice and is applicable to the seepage flow with complicated boundary conditions.

Key words: slices method; FEM; seepage flow; slope stability

Calculation methods for reference evapotranspiration with limited weather data

Abstract: The alternative methodologies for calculation of reference evapotranspiration ETª­0 are tested and evaluated when some of the weather data are missing,using daily data from Xiongxian and Wangdu,Hebei province.The sensitivity of the climate factors for ETª­0 is analyzed.The alternative methods for calculation of reference evaportranspiration according to limited weather data appropriate to North China are proposed.

Experimental study on debris flow head and the energy theory

Abstract: The initiation and development of debris flow are experimentally studied with various kinds of gravel and flows in a debris flow test flume. The study indicates that the critical slope for initiation of debris flow is closely related to the diameter of the bed material and the height of debris flow head is proportional to the diameter of the gravel composing the head. The mechanism of collision and momentum exchange explains the high instantaneous but low average velocities of small gravel and relatively stable velocity of large gravel. The energy theory of debris flow is established and a theoretical formula of debris flow velocity is derived. The formula is in good agreement with the experimental and field data.

Key words: debris flow; average velocity; critical slope; initiation of debris flow; collision and momentum exchange; height of debris flow head

Estimation of cofferdam real time water retaining risk using daily stream-flow simulation

Abstract: This paper presents a method for estimating the water retaining real time risk of cofferdam using stream flow simulation.Based on the measured hydrologic series,a stochastic model for daily stream flow has been established by means of system identification technique.The model is used to estimate the real time risk according to the actual flood and construction schedule.It is helpful for adjustment of the construction schedule and decision making of flood control.

Key words: diversion;real time water retaining risk;adjustment of construction schedule;daily stream flow simulation

Analysis on coupled system of pile group and strip type footing

Abstract: The coupled system of pile group and strip type footing is assumed as an integrated structure.Based on the assumption on steelement mode,the principle of energy variation is applied to analyze the coupled system. Parameters of the settlement mode are deduced by using principle of minimum potential energy.Consequently the distribution of settlement is obtained.By this method the moment and shear stress of the strip footing at any position as well as the stress and settlement of the piles can be calculated.

Key words: plie group;strip type footing;energy variation principle;principle of minimum potential energy

Quantitative analysis on income and livelihood level restoration of Shanxi Reservoir resettlement

Abstract: Through monitoring and evaluation of livelihood arrangement and production development of the pilot and first stage of resettlement,this paper gives a quantitative analysis on the income and livelihood level restoration of the resettlers.A regression analysis is conducted on the relationship between resettlers' income and Engel index that reflects their livelihood.

Key words: reservoir resettlement; livelihood restoration; quantitative analysis

Methods for estimating the ultimate bearing capacity of layered foundations

Abstract£ºThe Mayerhof and Hanna method for estimating the ultimate bearing capacity of layered foundations was improved. The suitability of the proposed method is verified by the observation data of loading tests in Tianjin Harbor.

Key words£ºultimate bearing capacity£»layered foundation£»Meyerhof and Hanna method

Phase transition of rheologic characteristics in non-viscous grain suspension and its percolation model

Abstract: It is supposed that there is a second order phase transition in the changing process of rheologic characteristic for varying volume concentration in non-viscous grain suspension.A directed cubic site-percolation model is introduced as the simplified physical picture of the forming mechanism of Bingham yield stress in suspension.Theoretically analytical concentration is 0.173,and it could be inlerpret as the theoretical lower limit of transition volume concentration.

Key words: non-viscous grain suspension; yield shear stress; phase transition; directed percolation

Numerical simulation and experimental study on water flow in Y-type tube

Abstract£ºA series of experiments and numerical simulation of water flow in the Y type tube with circular cross section have been carried on to meet the request of the design for fork tube in the Yixing Hydropower Plant. The SIMPLE method is applied in the calculations of Reynolds averaged flow equation and k ¦Å turbulence equation. By using DPIV system and pressure difference gauge, the detail measurement of water flow in the horizontal plane of fork tube is made. It is shown that the calculation result is in good agreement with the experimental data including the water head loss and flow pattern. It is also concluded that the flow losses of reverse flow in branches are larger than that of direct flow. Under the condition of the same velocity, the flow energy losse in single tube is larger than that in double tube. Energy losses of direct flow in single tube are larger than that of reverse flow.

Key words£ºY type tube; head loss; flow pattern; DPIV£»numerical simulation

The Green function of harmonic vertical load applied on the interior of the half space saturated soil

Abstract£ºBy using integral transform method, the problem of harmonic vertical force applied on the interior of the half space in saturated soil is solved. First, the Biot wave equation for frequency domain is solved using the Hankel transform method. Thus, the general solution is deduced. Utilizing the general solution and boundary conditions, the solution in transformed domain is obtained. The Green function in frequency domain can be obtained by using the corresponding inverse transform method.

Key words£ºBoit theory£»Green function£»Hankel transform

A integrated model for water heat CO2 flux and photosynthesis in SPAC system ¢ò.Verification

Abstract£ºThis paper presents the verification results of the integrated model proposed by the authors.The observation data of winter wheat with 1hour interval during growth period,April 1999,are adopted.The model output of evapotranspiration is compared with that estimated by the Bowen ratio method.The simulated soil moisture profile is compared with that measured by neutron probe,and the simulated CO2 flux from canopy is verified by the measured CO₂ concentration at different height.For soil moisture profile and the daily evapotransporation process,very good agreement between the simulated and measured result are obtained.The variation tendency of CO2 with time is also verified but fairly discrepancy is found.

Key words£ºCO₂ flux; photosynthesis; soil water; evapotranspiration; model

Types of failure in different soft clay slopes

Abstract: Two failures of soft clay slopes at different harbor engineering are calculated and compared.It is found that the type of failure,causes of failure as well as the land configurations after landslide are quite different.The calculation result of FEM shows that the stress and displacement fields of different slopes have its own specialties.It demonstrates that appropriate method for slope stability analysis is important.

Key words: soft clay; slope stability; FEM

Model test of axial flow pump with inducer

Abstract£ºThe effect of inducer installed in the entrance of the axial flow pump is tested in model stand. The result shows that with the installation of inducer the pressure distribution in the cross section of the inlet is uniformed, the vibration and cavitation are minimized and the hydraulic characteristics of the pump are improved as well.

Key words£ºaxial flow pump; cavitation; vibration; inducer; model test

Study on optimizing disposition technology of low pressure irrigation system for shallow well

Abstract£ºOn the basis of pumping test, irrigation test and theory analysis a method for calculating the irrigation soft pipe in low pressure irrigation system having reasonable yield of well, reasonable decent of water table, best pumping head and economical diameter is proposed. By this method the optimized irrigation system with highest benefit and lowest cost is derived.

Key words£ºshallow well; irrigation cost; optimizing disposition technology

Integrated management technology for flood control system of reservoirs

Abstract: The standardization of flood control system for reservoirs is of vital importance to improve the level of comprehensive management in China.The problems and difficulties occured to the implementation of standardization are discussed and the approach for solution is proposed.The approach includes:to select the typical systems for generality to form a comprehensive standard;to design the database libraries and table structures based on Client/Server platform;to create a list of model-method library and a series of control classes using the object-oriented technology.The software system established has been applied to 10 flood control systems of reservoir and tested more than 1 year.The application results show that the standardization implemented is successful.

Key words: flood control; standardization; integrated management

Study on the effects of wide river section and stabilized main channel on flood control of the Yellow River

Abstract: The effect of wide rever section on flood detention and the important role of stabilized main channel in river control are demonstrated according to the observation data. In view of the flood occurred in the downstream of the Yellow River possesses the characteristics of high peak but small volume,the great amount of detention capacity in wide river sections is in favor of cutting down the flood peak.Meanwhile,the sediment may deposit in floodplain area of these river sections and slow down the rising speed of riverbed.On this basis, the author suggests a principle of river training as ¡°combining the utilization of wide river sections with stabilizing the main channels¡±¡£It is the development of the traditional river training experiences ¡°to broaden the river and reinforcing the embankment¡±, which is effective in Yellow River in the history.

Key words: Yellow River; wide river section;stabilizing main channel;flood prevention;river training; floodplain

Abstract£ºUnder the long-term action of flood,the phreatic line rises and reaches the toe of the landslide slope.This results in an increase of pore pressure and a decrease in strength of unsaturated soil.Consequently,a slide or collapse of river embankmant occurs.In this paper,the process of infiltration in a prototype river embankment and its flow characteristics are observed and analyzed by FEM.