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Understanding groundwater table using a statistical model

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water Science and Engineering 2018年第1期11卷 1-7页

作者： Shao-feng Yan Shuang-en Yu Yu-bai Wu De-feng Pan Jia-gen Dong Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-water Environment in Southern China Ministry of EducationHohai UniversityNanjing 210098China Hubei Provincial water Resources and Hydropower Planning Survey and Design institute Wuhan 430064China jiangsu water conservancy research institute Nanjing 210017China jiangsu coastal water conservancy research institute Dongtui 224200China jiangsu Province Hydrology and water Resources Investigation Bureau Nanjing 210008China

In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict the groundwater table with easily measurable climate data in a coastal plain in eastern China. To achieve these objectives, groundwater table data from twelve wells in a farmland covering an area of 50 m ~ 150 m were measured over a 12-month period in 2013 in Dongtai City, jiangsu Province. Trend analysis and correlation analysis were conducted to study the patterns of changes in the groundwater table. In addition, a linear regression model was established and regression analysis was conducted to understand the relationships between precipitation, evaporation, river stage, tide level, and groundwater table. The results are as follows：（1） The groundwater table was strongly affected by climate factors （e.g., precipitation and evaporation）, and river stage was also a significant factor affecting the groundwater table in the study area （p 〈 0.01, where p is the probability value）. （2） The groundwater table was especially sensitive to precipitation. The significance of the factors of the groundwater table were ranked in the following descending order： precipitation, evaporation, and river stage. （3） A triple linear regression model of the groundwater table, precipitation, evaporation, and river stage was established. The linear relationship between the groundwater table and the main factors was satisfied by the actual values versus the simulated values of the groundwater table （R^2 = 0.841, where R^2 is the coefficient of determination）.

关键词： Groundwater table Precipitation Evaporation Climate factors Regression statistics coastal plain

A Siltation Simulation and Desiltation Measurement Study Downstream of the Suzhou Creek Sluice, China

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China Ocean Engineering 2013年第6期27卷 781-793页

作者：季永兴杨绯张汉云卢永金 College of water conservancy and Hydropower Engineering Hohai University Shanghai water Engineering Design and research institute

The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.

关键词： tidal estuary underwater plain gate siltation sluice Suzhou Creek

Experimental investigation of submerged impinging jets in a plunge pool downstream of large dams

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Science China(Technological Sciences) 1998年第4期41卷 357-365页

作者：刘沛清高季章李永梅 China institute of water conservancy and Hydroelectric Power research Beijing China

Submerged impinging jets in a plunge pool downstream of large dams are experimentally investigated in details. By use of the hot\|film anemometer, the velocity field in the plunge pool produced by middle orifices of 1∶400 scale Xiluodu spillway model is measured. The diffusive characteristics and energy dissipation mechanism of the submerged impinging jet in the plunge pool are analyzed.

关键词： impinging jet plunge pool energy dissipation.

Coupled hydro-mechanical analysis of slope under rainfall using modified elasto-plastic model for unsaturated soils

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Journal of Central South University 2015年第5期22卷 1892-1900页

作者：王柳江刘斯宏傅中志李卓 College of water conservancy and Hydropower Engineering Hohai University Nanjing Hydraulic research institute

Two modifications for the basic Barcelona model(BBM) are present. One is the replacement of the net stress by the average skeleton stress in unsaturated soil modeling, and the other is the adoption of an expression for the load-collapse(LC) yield surface that can match flexibly the normal compression lines at different suctions. The predictions of the modified BBM for the controlled-suction triaxial test on the unsaturated compacted clay are presented and compared with the experimental results. A good agreement between the predicted and experimental results demonstrates the reasonability of the modified BBM. On this basis, the coupled processes of groundwater flow and soil deformation in a homogeneous soil slope under a long heavy rainfall are simulated with the proposed elasto-plastic model. The numerical results reveal that the failure of a slope under rainfall infiltration is due to both the reduction of soil suction and the significant rise in groundwater table. The evolution of the displacements is greatly related to the change of suction. The maximum collapse deformation happens near the surface of slope where infiltrated rainwater can quickly reach. The results may provide a helpful reference for hazard assessment and control of rainfall-induced landslides.

关键词： unsaturated soils modified basic Barcelona model(BBM) numerical analysis rainfall infiltration model slope

Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 327-335页

作者： Zhang Jingkui Zhang Liaojun Anhui and Huaihe River institute of Hydraulic research College of water conservancy and Hydropower Engineering Hohai University

Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code(3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, infl uence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far fi eld energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice.

关键词： high arch dam complex foundation 3DEC disaster mechanism dam-break process simulation seismic safety evaluation

EXPERIMENTAL STUDY OF MOTION OF LAMINATED LOAD

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Science in China,Ser.A 1985年第1期28卷 102-112页

作者：王兆印钱宁 institute of water conservancy and Hydroelectric Power research Beijing Qinghua University

Whnen the sediment eonoentration surpasses a certain limit, turbulence disappears and flow becomes a laminar one. The sediment moves in layers and is ealled the laminated load in this article. By using light weight plastic particle as the sedimentary material, the velocity distribution, frictional loss and dispersive foree of such a flow in pipe are studied in detail.

关键词： EXPERIMENTAL STUDY OF MOTION OF LAMINATED LOAD

EXPERIMENT STUDY OF TWO--PHASE TURBULENT FLOW WITH HYPERCONCENTRATION OF COARSE PARTICLES

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Science China Mathematics 1984年第12期27卷 1317-1322+1324-1327页

作者：王兆印钱宁 institute of water conservancy and Hydroelectric Power research Qinghua University Beijing

Through pipe-flow with rectangular cross-section, the velocity and sediment concentra-tion distribution of turbulent two-phase flow with hyperconcentration and consisting ofcoarse particles are studied. Within the main flow zone, logarithmic velocity distributionstill holds and von Karman constant is a function of the Richardson number and thesediment concentration. Close to the bed zone, the effect of lifting force on the velocitydistribution should be considered. The sediment concentration distribution in pipe-flow withhyperconcentration is distinctly different from that of sediment-laden flow in *** can be derived on the basis of the diffusion equation, which agrees well with the experi-mental results.

关键词： EXPERIMENT STUDY OF TWO PHASE TURBULENT FLOW WITH HYPERCONCENTRATION OF COARSE PARTICLES

Adaptive Extended Isogeometric Analysis for Steady-State Heat Transfer in Heterogeneous Media

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Computer Modeling in Engineering & Sciences 2021年第3期126卷 1315-1332页

作者： Weihua Fang Tiantang Yu Yin Yang Nanjing Automation institute of water conservancy and Hydrology Ministry of Water ResourcesNanjing210012China Department of Engineering Mechanics Hohai UniversityNanjing211100China Lake research institute Hydraulic Research Institute of Jiangsu ProvinceNanjing210017China

Steady-state heat transfer problems in heterogeneous solid are simulated by developing an adaptive extended isogeometric analysis(XIGA)method based on locally refined non-uniforms rational B-splines(LR NURBS).In the XIGA,the LR NURBS,which have a simple local refinement algorithm and good description ability for complex geometries,are employed to represent the geometry and discretize the field variables;and some special enrichment functions are introduced into the approximation of temperature field,thus the computational mesh is independent of the material interfaces,which are described with the level *** to the approximation of temperature field,a temperature gradient recovery technique for heterogeneous media is proposed,and based on the Zienkiewicz–Zhu recovery technique a posteriori error estimator is defined to automatically identify the locally refined *** convergence and performance properties of the developed method are verified by using three numerical *** numerical results show that(1)The convergence speed of the adaptive local refinement is faster than that of the uniform global refinement;(2)The convergence rate of the high-order basis functions is faster than that of the low-order basis functions;and(3)The existing inclusions change the local distributions of the temperature,and the extreme values of the temperature gradients take place around the inclusion interfaces.

关键词： Heterogeneous media steady-state heat transfer adaptive XIGA LR NURBS heat dissipation

Heavy mineral composition and texture of the recently formed fluvial delta sediment of Lake Nasser/Nubia,Egypt and Sudan

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International Journal of Sediment research 2022年第1期37卷 70-82页

作者： Omran E.Frihy Essam A.Deabes Abdelaleem A.budia Ahamed Adawi coastal research institute National Water Research Center Nuclear Materials Authority

Surficial sediment samples collected from the recently formed fluvial delta in Lake Nasser/Nubia (Egypt and Sudan) in conjunction with data on bottom current and depth soundings are examined to interpret hydraulic-sorting processes and transport/depositional ***～500 km long northeastwardtrending lake,lies within Egypt and Sudan,is created as a result of the construction of the Aswan High Dam in *** original grain-size distribution and heavy mineral compositions of these samples help to characterize the classical depositional features of the recently formed underwater delta-front and prodelta *** from the south,those delta-front deposits,which floor most of the narrow-shallow basin of Lake Nubia,are characterized by thick coarse-grained sandy deposits,rich in heavy minerals (averaged 12.8%).This delta-front is followed to the northeast by thin layers of prodelta mud,poor in heavy mineral contents (averaged 0.6%).These layers cover the entire broad basin of Lake *** northeasterly downslope fining-trend,along with a continuous decrease in heavy mineral composition,along the length of the lake,are attributable to processes of grain sorting,which take place due to contrasting densities and grain *** processes lead to the concentration of heavy mineral placer,mostly in the delta-front *** sorting mechanism,in turn,is controlled by the interplay of unidirectional-directed northeastward current,physiographic characteristics of the lake,including topographic configuration,geometry (cross-section),and floor topography (slope gradient).In terms of mineral exploration,the highest proportion of mineral grades in the delta-front sediments is likely to be considered as a viable source for economic placers that require more planning initiatives for industrial and commercial evaluation.

关键词： Heavy mineral Fluvial delta sediments Delta-front Aswan high dam Hydraulic-sorting processes