01 December 2014, Volume 31 Issue 12

    

• Select all
  |

RIVERLAKE SEDIMENTATION AND REGULATION
• Select
  Concentration and Temperature Field: Three-dimensional
  Numerical Simulation and Its Application

  CUI Zhan-feng, ZHANG Xi-bing

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 1-6. https://doi.org/10.3969/j.issn.1001-5485.2014.12.001

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Research on warm water and pollutant diffusion is of great significance to the health of river ecosystem. The convection and diffusion of warm water and pollutants in the adjacent of drainage outlet are strongly three-dimensional. In this research, a mathematical model of temperature and concentration field is developed based on 3-D turbulent flow hydrodynamic model. In the modeling, porosity is used to deal with irregular boundary, and VOF method is used to simulate free surface. In addition, the turbulent model and the Wall Function are used in the modeling. This model is applied to simulate water level, flow field, turbulent kinetic energy and its dissipation rate, and diffusion regularity of temperature and concentration field around the drainage outlet. This model could well simulate the stratification of concentration and temperature in vertical direction.
• Select
  Analysis of Water-sediment Relationship at Lutaizi Hydrological
  Station on Mainstream Huaihe River

  ZHOU He, YU Bang-yi, NI Jin

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 7-10. https://doi.org/10.3969/j.issn.1001-5485.2014.12.002

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Study on the relationship between flow and sediment is an important content of basic research in the regulation of rivers. Lutaizi hydrological station is a major control station in the upper reaches of Huaihe River. Water-sediment relationship at this station is important in revealing the fluvial process and river regulation in middle Huaihe River. On the basis of Ruijin Zhang’s formula of sediment carrying capacity and the Manning equation, we derived the formula of sediment carrying capacity for Lutaizi station in different conditions (sediment equilibrium, erosion, deposition) by analysing the hydraulic gradient-flow relationship, hydrogeometric relationship, and channel roughness. Furthermore, we took the measured sediment load in 1990-2007 to verify this formula, and the result suggest that this formula could reflect the relation of flow and sediment of Lutaizi Station.
• Select
  Multivariate Analysis on Low Flow Frequency at Duchang Station
  in Poyang Lake Using Copula Function

  HONG Xing-jun, GUO Sheng-lian, LI Tian-yuan

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 11-16. https://doi.org/10.3969/j.issn.1001-5485.2014.12.003

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Analysis on low flow features is of practical significance in the management of lake water resources in dry season. According to the theory of runs which is widely used in drought analysis, low flow duration, averaged low flow intensity and maximum low flow intensity were determined as the characteristic variables from the data of averaged daily lake level at Duchang hydrologic station from 1958 to 2007. Weibull, Logistic, and Generalized Extreme Value distributions were used to simulate low flow duration, averaged low flow intensity, and maximum low flow intensity, respectively. Several asymmetric Archimedean copulas were applied to construct three-dimensional joint distributions and the Clayton copula was selected as the best one. The joint probabilities and return periods of low flow variables were calculated and analyzed. It was concluded that the three-dimensional joint distribution could reveal the probability characteristics of low flow more comprehensively in the Poyang Lake.
WATER RESOURCES AND ENVIRONMENT
• Select
  Analysis of Water Intake Quantity and Quota of Thermal Power
  Industry in Yangtze River Basin

  SANG Lian-hai, ZENG Xiang, ZHANG Jin, FENG Zhao-yang

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 17-20. https://doi.org/10.3969/j.issn.1001-5485.2014.12.004

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  With the rapid economic development of the Yangtze River Basin, the quantity of industrial water consumption showed a increasing growth trend. Thermal power industry is one of the national economy’s major water consumers, and the water consumption growth rate is higher than the average level of all industries. In this paper the current situation and features of water consumption of thermal power industry in Yangtze River water basin are analyzed. Also the adaptability of water quota released by the local government is researched by using statistical analogy based on the analysis results of water quota of new thermal power projects in recent 5 years in the research basin. With reference to the advanced water use index abroad, the advancement of water quota in thermal power industry in Yangtze River basin is analyzed. Results suggest that the water consumption of new large thermal power projects in the Yangtze River Basin has reached the advanced level in foreign countries. But the gap between power plants is still large, and there’s still a large space for water saving in the entire power industry.
• Select
  Climate Change in the Upstream of Manas River Basin
  in the Past 5 Decades

  JI Lei, HE Xin-lin, LIU Bing,TANG Kai,ZHANG Shao-bo

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 21-27. https://doi.org/10.3969/j.issn.1001-5485.2014.12.005

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  According to observed data of temperature, precipitation series (1959-2008) and evaporation series (1984-2000) at Kensiwate hydrological gauging station in the upstream of Manas River Basin. We analysed the climate change in this region by using linear regression, Pearson correlation coefficient, moving average for five years, Mann-Kendall nonparametric statistical test and Morlet wavelet analysis method. Results showed that 1) the climate of upstream Manas River Basin was mostly warm and wet in the past 5 decades. The annual average temperature increased remarkably with obvious seasonal difference within the year (temperature increased in summer and autumn). Precipitation was increasing as a whole but was not significant, and distributed unevenly within the year (precipitation concentrated in spring and summer); 2) The annual evaporation fluctuated around 1651.2 mm in the recent two decades, displaying a trend of slight increase; 3) Temperature and precipitation increased abruptly from low level to high level during the 1990s, and there was an obvious inter-annual cycle change.
• Select
  Interpretation on Technical Standards for Comprehensive Control of Water
  and Soil Erosion in the Red Soil Hilly Region in Southern China

  ZHANG Ping-cang, CHENG Dong-bing

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 28-34. https://doi.org/10.3969/j.issn.1001-5485.2014.12.006

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Red soil hilly region in southern China is one of the regions with the most severe water and soil loss in China. Because of complex and unique natural conditions, the soil erosion characteristics and control measures in this region are very different from those in other regions. Among national standards for soil and water conservation techniques, there is no special technical standard for red soil hilly region in southern China. The promulgation and implementation of the Technical Standards for Comprehensive Control of Water and Soil Erosion in Red Soil Hilly Region in Southern China is of great practical significance. As a regulative document to guide the comprehensive control of water and soil erosion in this region, this standard is comprehensive, clear, scientific, practical, and is strongly operable. In order to help users to understand the standard, and to promote its implementation, this paper presents a detailed interpretation in terms of region definition, classification and gradation of soil erosion, regionalization of controlling work, countermeasures of water and soil erosion, measures configuration for different objects.
• Select
  New Concept of Water Loss in Technical Terms of Soil
  and Water Conservation

  ZHANG Hong

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 35-38. https://doi.org/10.3969/j.issn.1001-5485.2014.12.007

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Water loss is the basic form of soil and water loss. Technical terms in national standards is the theoretical foundation of researches in this regard. In view of the current water loss theory, the concept of water loss in national standard technical terms needs to be revised. The connotation of water loss is expounded from three respects runoff, evaporation and infiltration. The basic content of water loss prediction, control measures and monitoring are presented. This research could be a reference to improve regulation standards and prevent soil and water loss.
AGRICULTURAL WATER CONSERVANCY
• Select
  Effect of Controlled Drainage on Soil Moisture in Field

  YUAN Nian-nian, HUANG Jie-sheng, XIE Hua, LI Ya-long

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 39-42. https://doi.org/10.3969/j.issn.1001-5485.2014.12.008

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  In order to study the effect of controlled drainage on soil moisture, we carried out experiments of controlled drainage and free drainage for comparison in the land for growing field crops at Drainage and Irrigation Station in Jingzhou, Hubei province, 2010. We observed the soil water content in the whole cotton growth period and analysed the coefficient of soil water content variation. Results showed that controlled drainage had an obvious effect on soil water content in the whole growth period by retaining moisture and reducing the fluctuation of soil water content especially after rainfall, but the relation between soil water content and controlled water table was not definite.
ENGINEERING SAFETY AND DISASTER PREVENTION
• Select
  Prediction of Landslide Displacement Based on Reservoir
  Computing and Fractal Interpolation

  YAO Wei, LIAN Cheng

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 43-48. https://doi.org/10.3969/j.issn.1001-5485.2014.12.009

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Landslide disasters can be warned based on monitoring and prediction of displacements. In view of the complex internal mechanisms of landslides, data-driven model is an effective approach of simulating landslide evolvement when the precise models reflecting the mechanisms cannot be obtained. Considering the complex nonlinear dynamics of landslides, we built a recurrent dynamic neural network for landslide displacement based on reservoir computing. Furthermore, we further employed fractal interpolation to enhance the reservoir training process and expand the displacement data sets. The method was used to predict the developments of three different typical landslides, and the predictions are all very close to the actual measurements. It is a good solution for complex dynamic prediction with short-time sequence.
• Select
  Indexes of Monitoring Concrete Dam Displacement
  Based on Strength Reserve Method

  YU Jin-ping,DUAN Ya-hui,AI Li-shuang

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 49-53. https://doi.org/10.3969/j.issn.1001-5485.2014.12.010

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Safety monitoring index is important for monitoring dam safety. In the analysis of displacement deformation of concrete dam by FEM, we determined the first, second and third level monitoring indexes of the dam’s horizontal displacement by employing strength reserve method. The monitoring indexes determined by the method takes the various water level loads into consideration, therefore is more rational than monitoring indexes by conventional methods. This research provides an effective basis for the comprehensive evaluation and decision of the dam operation conditions.
• Select
  Engineering Influence of Debris Flows in the Reservoir Area of
  Zhongbo Hydropower Station in Tibet

  CHENG Ying-jian, SHI Yu-chuan, SHI Sheng-wei, WANG Jing-yong

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 54-58. https://doi.org/10.3969/j.issn.1001-5485.2014.12.011

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Zhongbo hydropower station is located in the lower reaches of the Yuqu River, Qamdo of Tibet. Investigation shows that 8 large debris flow gullies develop in the reservoir area. By analyzing the geological environment of debris flows, we assessed the risk degree of debris flows. We also analyzed the impacts of debris flows on the project in detail, such as river blocking, collision siltation and reservoir sedimentation. Results suggest that (1) none of the debris flows have confluence conditions for blocking rivers; (2) the total sediment of debris flows will reach 3,017,700 m³ in the later century, accounting for 1.125% of the total reservoir capacity; (3) we should focus on the Zhala gully near the dam because it has high risk of debris flow and directly threatens the construction safety in the hydro-junction area.The research results are of practical significance for hydraulic design and disaster prevention.
HYDRAULICS
• Select
  Hydraulic Characteristics and Operation Mode of
  Multipurpose Hydraulic Tunnel

  WANG Cai-huan, DU Lan, WANG Bing, GUO Xiao

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 59-64. https://doi.org/10.3969/j.issn.1001-5485.2014.12.012

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  In water conservancy and hydropower projects , hydraulic tunnel can be divided into diversion tunnel, spillway tunnel, emptying tunnel and water diversion tunnel for power generation, etc. Each of them has a certain flow condition, and it’s easy to control the hydraulic characteristics for a single-purpose tunnel. But when a tunnel has a variety of uses due to technical and economic conditions, the tunnel will be faced with significant hydraulic differences in various operation stages. In this paper, we researched the hydraulic characteristics of slope tunnel which integrates functions of diversion, flood discharge, emptying, and diversion for power generation in different operation stages by hydraulic model test of a water conservancy project. Results reveal that when the tunnel is used as spillway tunnel under normal operation, the flow pattern is normal at the tunnel inlet and in the tunnel, and the minimum pressure in the tunnel meets the requirements of specifications; when it’s used as diversion and emptying tunnel, vertical suction vortex is formed at inlet under certain flow conditions, and air bag whose shape changes and collapses constantly is formed in the tunnel. In long tunnel section and large flow range, mixed free-surface-pressure flow as well as free flow shockwave and deflected flow caused by the bifurcated pipe for power tunnel will also occur. Such flow patterns could induce harmful vibration of tunnel wall and cavitation. Furthermore, through experimental optimization and associated with reasonable dispatch of terminal working gate, the safe operation mode for multipurpose hydraulic tunnel is put forward.
ROCKSOIL ENGINEERING
• Select
  Finite Element Method for Predicting Synthetic Deformation
  Modulus and Poisson Ratio of Arch Dam Foundation

  ZHANG Ping, LIU De-fu, ZHANG Bo, ZHANG Li-jun

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 65-68. https://doi.org/10.3969/j.issn.1001-5485.2014.12.013

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  A reasonable determination of deformation modulus and Poisson ratio of arch dam foundation rock is very necessary for arch-cantilever method in arch stress analysis. Dam foundation is composed of different lithology rock masses, which shows significant mechanical anisotropy, inhomogeneity and discontinuity. Any rock deformation parameter to replace the whole deformation parameters or a simple averaging of all deformation parameters is unreasonable. In the present paper we present a 3-D finite element method for predicting the synthetic deformation modulus and synthetic Poisson ratio of arch dam foundation based on the least squares method. By comparing with theoretical solution, we found this approach is feasible for predicting the synthetic deformation modulus and synthetic Poisson ratio of complex foundation composed of different lithology rock masses, faults and weak interlayers. As an application of this approach, the synthetic deformation modulus and synthetic Poisson ratio of Jinping arch dam foundation are calculated. Results demonstrate that the deformation modulus calculated by this method is reasonable on the premise of considering geological structures and foundation treatments.
• Select
  Numerical Analysis of Supporting Effects of the Reinforced Ribs
  of Sprayed Concrete

  LI Jin-shan, QIN Wei-xing, SHENG Song-tao, LI He

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 69-73. https://doi.org/10.3969/j.issn.1001-5485.2014.12.014

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The reinforced ribs of sprayed concrete(RRS) in the Norwegian Method of Tunneling has been proved to be an economical and efficient supporting structure for the weak surrounding rock engineering in China and abroad. The weak zone in the Finnfast subsea tunnel in Norway was taken as a case study to demonstrate the supporting effects of RRS on weak surrounding rock. In view of the Q system for the classification of surrounding rock quality, finite difference method was employed to compare the deformation, the stress distribution, and the yield volume of surrounding rock in the presence and in the absence of RRS. The results show that RRS has good supporting effects on weak surrounding rock.
• Select
  Effect of Connectivity Rate of Dominant Joints Extending Outward
  of the Slope on High Slope Stability

  LIU Chong-ping, HAO Wen-zhong, WANG Ji-liang, BAI Wei, QIN Zhen-hua, LI Zhi

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 74-77. https://doi.org/10.3969/j.issn.1001-5485.2014.12.015

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The connectivity rate of dominant joints which extend outward along high rock slope plays an important role in the slope’s overall stability, but research on the sensitivity of slope stability to connectivity rate is insufficient. In view of this, qualitative and quantitative methods were employed to research the high rock slope (180m) at the water inlet of Wudongde hydropower station at Jinsha River. On the basis of connectivity rate statistics and the weighted average parameters of the “bottom sliding surface” combined with rock bridge, the stability factor of slope was calculated by using rigid limit equilibrium method. The degrees of connectivity rate’s influence on slope stability were obtained. Moreover, in the statistics using bandwidth projection method, the selection of bandwidth also has big influence on the connectivity rate and the stability factors.
• Select
  Analysis of Anti-crack Design of Shallow Buried Pressurized Tunnel
  by Numerical Simulation

  LIU Yang

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 78-82. https://doi.org/10.3969/j.issn.1001-5485.2014.12.016

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Anti-crack prestressed lining is mostly used in shallow-buried pressurized tunnels in China. However it is costly when widely used in long-distance water diversion tunnels. In view of this, we simulated the exosmosis of shallow-buried pressurized tunnel by using finite element method according to the coupling of seepage field and stress field of fractured rockmass. In the simulation we considered the impact of consolidated grouting, underground water level, and seepage field variation on the rockmass to reflect the changes of surrounding rock stress during the tunnel excavation, water filling and pressurization. We obtained that the increase and decrease of pore water pressure both could reduce the effective stress of rockmass. Thicker surrounding rock will bring about larger bearing capacity. Whether anti-crack design should be adopted in shallow-buried long-distance pressurized diversion tunnel is dependent on multiple factors. These factors include the frequency of high pressure water, leakage amount, consolidation grouting to improve the impermeability of surrounding rock, seepage pressure of rockmass, effective stress and rock mass structure, as well as drainage channel structure and control of rockmass leakage instability.
• Select
  High-pressure Water Jet to Assist Pile Driving for Offshore Platform

  ZHU Li-hong, CHEN Xin-yong, WANG Jing-yin, XING Yong-chao

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 83-87. https://doi.org/10.3969/j.issn.1001-5485.2014.12.017

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  In the pile foundation construction for offshore oil platform, pile drilling becomes difficult after hammer stops and even repelling of hammering occurs. To explore efficient approach of pile construction, we present a technical proposal of driving pile by high-pressure water jet, and design apparatus for model test. Forces generated by jets with six different nozzles acting on the soil plug are tested, and the stress distributions in the soil are numerically simulated. The maximum and minimum stresses in the soil plug under jet forces are obtained, and model test results are verified. Results showed that it is feasible to improve pile construction efficiency by employing high pressure water jet. Among the six different nozzles, nozzle with iso-variable velocity could generate the longest limited jet distance and in the meantime the largest force on the soil plug surface center. This research provides basis for the preparation of model machine.
HYDRAULIC STRUCTURE AND MATERIAL
• Select
  An Algorithm for Automatic Selection of Independent Cover Regions
  of Numerical Manifold Method

  LIN Shao-zhong, SU Hai-dong

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 88-91. https://doi.org/10.3969/j.issn.1001-5485.2014.12.018

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Numerical manifold method with partially overlapping covers is an analysis mode mainly concerning independent covers. To automatically select independent cover regions in a mathematical mesh with general element size, the elements of the mathematical mesh are partitioned into a number of independent sets by graph colouring. Based on this, the elements for defining independent covers (i.e. the covers of all nodes of an element are merged into single one) are selected according to the principle of as many regions with independent covers as possible, and the rest of elements is defined as the overlapping cover regions for keeping the continuity, and the nodes which do not belong to the independent cover elements are defined as general nodal covers. Examples reveal that the linear dependencies between the overlapping covers exist only in the nodal covers on the mathematical mesh boundary, and cover merging could reduce the nullity of stiffness matrix or even avoid the linear dependencies.
• Select
  Fast Control of Pipe Cooling in Middle-later Period for Concrete Dam

  HUANG Yao-ying,ZHOU Shao-wu,ZHENG Dong-jian,ZHOU Yi-hong

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 92-96. https://doi.org/10.3969/j.issn.1001-5485.2014.12.019

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Pipe cooling for concrete dam in middle-later period is complicated relating with multiple factors including water cooling temperature, water flow and duration. A fast control method for concrete dam in middle-later cooling period is presented based on the dynamic prediction model of concrete pouring surface temperature. In association with the current measured temperature, the curve of temperature decrease is predicted based on calculation formula of pipe cooling without heat resource. Then the optimal pipe cooling scheme is obtained by adopting optimization algorithm according to temperature cooling rate and target temperature in middle-later period. Case study shows that the prediction model based on calculation formula of pipe cooling without heat resource has small workload, and the fast control of concrete dam in middle-later cooling period is feasible.
• Select
  Temperature Control and Crack Prevention for the Lining Concrete
  of Diversion Tunnel of Xiluodu Project

  LI Sheng-qing, AO Xin, LI Feng

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 97-100. https://doi.org/10.3969/j.issn.1001-5485.2014.12.020

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  In the early construction period of lining concrete for the diversion tunnel of Xiluodu Hydropower Station, some cracks were found in the lining concrete. In view of this, ANSYS was employed to simulate the temperature and thermal stress of lining concrete based on the principle of elastic creep thermal stress calculation. According to the calculation result, the main causes of cracks were analyzed as follows large hydration heat and quick temperature decrease, improper surface curing measure, low temperature in the tunnel in winter, and strong restrain of surrounding rock. Moreover, measures of temperature control and crack prevention were proposed as follows to adjust concrete’s design age and optimize concrete mix ratio; to immediately spray water for concrete curing; to properly determine concrete grouting blocks; to seal the hole for thermal insulation in winter, etc. These measures were applied in the later stage of concrete construction and has effectively prevented further cracks.
• Select
  Analysis on Global Stability Condition of Concrete Dams in
  Consideration of Limit Overturning Failure

  HU Jiang, MA Fu-heng, LI Zi-yang, SU Huai-zhi

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 101-106. https://doi.org/10.3969/j.issn.1001-5485.2014.12.021

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Identification and determination of main failure modes are important in dam safety analysis. In traditional analysis, serviceability limit states (e.g., overstressing) are considered together with ultimate limit states. Overstressing may be the cause and initiating factor leading to global failure and must be analyzed. However, overstressing in itself is, generally, not a global limit failure mode. In this paper, this bearing capacity failure mode is included in the limit overturning failure mode. With gravity dam as an example, the limit state function for overturning is derived with the help of moment balance relationship; and methods of determining and estimating the parameters in the function are also discussed. On this basis, a general system failure model for gravity dams in consideration of main ultimate limit states is proposed. An in-service gravity dam is investigated, and the results show that, for gravity dams on intact weak rock foundation, the limit state for overturning caused by overstressing must be taken into account due to inadequate rock crushing resistance.
INFORMATION TECHNOLOGY APPLICATION
• Select
  A Scalable Structure for the Storage of High-resolution Remote
  Sensing Images in Cloud Computing Environment

  SHEN Sheng-yu,LIU Zhe,ZHANG Ping-cang,ZHANG Tong,WU Hua-yi,CHEN Xiao-ping

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 107-112. https://doi.org/10.3969/j.issn.1001-5485.2014.12.022

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Traditional methods of processing remote sensing images could not effectively handle the mass daily production, mass pixel of single image, as well as the mass type and amount of objects. To solve the problem of image storage, we propose a structure for the storage of high-resolution remote sensing images in cloud computing environment, and expound the construction method based on MapReduce framework. We conducted experiments on large files of small image set in a Hadoop cluster and compared the image reading efficiency with that of traditional methods. The results proved that this storage structure has high scalability. Experiments also demonstrate this construction method has efficient reading/writing and processing ability.
• Select
  Automatic Generation of Contours Based on Feature
  Constraints from LiDAR Point Clouds

  YAO Chun-jin, HU Wei

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 113-116. https://doi.org/10.3969/j.issn.1001-5485.2014.12.023

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  As a new remote sensing technology, LiDAR (Light Detection and Ranging) is getting wide attentions from users and researchers for its outstanding features. LiDAR is less affected by weather and shadow and has a certain degree of penetration to the gap between surface features. It gets high-precision 3D point cloud data of the land surface and provides a new method for contour extraction. Since contours can’t pass through the buildings and the water areas, the traditional methods need a lot of manual works to edit the contours in these areas, which costs much time. Therefore a method which could generate contours automatically based on the feature constraints from LiDAR point clouds is proposed in this paper. This method mainly includes the following aspects (1) DEM generation which provides basic data for the generation of contours; (2) Feature extraction based on LiDAR point data, mainly including buildings and waters, etc. (3) Automatic generation of TIN based on feature extraction, and on this basis, extraction of fine contours by tension spline function. Compared with the traditional technology of photogrammetry and stereopair, the method in this paper is more reliable, efficient and precise.
INSTRUMENTATION DEVELOPMENT AND TESTING TECHNIQUES
• Select
  Research Progress of the Processing of Pump
  Turbine Characteristic Curve

  PAN Xi-he,CHENG Yuan-chu,WANG Jie-fei

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 117-123. https://doi.org/10.3969/j.issn.1001-5485.2014.12.024

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Intersection, aggregation, intertangling and the extremely unstable S-shape area on both ends of the characteristic curve of pump turbine pose great difficulty for the accurate simulation of pump turbine’s transition process. In view of this, scholars both in China and abroad conducted in-depth researches on the mathematic transform and the fitting method for characteristic curve. In this paper we summarize the research achievements. According to the expression method we divide the research results into two-dimensional mathematical transformation and three-dimensional curved surface fitting. We also point out the breakthrough and insufficiency of the research results, and finally propose the direction and several suggestions for further research.
• Select
  Test of Vertical Flow-velocity Distribution Using ADCP on
  Ship-borne Floating Platform

  ZHANG Ying-hao,LAI Xi-jun

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 124-128. https://doi.org/10.3969/j.issn.1001-5485.2014.12.025

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  The velocity data of natural turbulence flow in rivers and lakes is significant to water environment and ecology research. We carried out research on the vertical velocity distribution test using ADCP (Acoustic Doppler Current Profiler) on ship-borne floating platform. According to field measurement data under different flow conditions, we analysed the reliability of ADCP data received on ship-borne floating platform, and compared the vertical velocity distribution data under pulse coherent measurement mode and pulse incoherent measurement mode. The result indicates that vertical velocity distribution measurement using ADCP on ship-borne floating platform is feasible. In shallow water, the pulse coherent mode is recommended because it can notably improve measurement accuracy and resolution.
• Select
  Numerical Research on the Performance of Differential Pressure
  Orifice-plate Flowmeter

  LI Zhi-hua, CHEN Shao-hua, CHEN Kun, ZHAO Ya-ping

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 129-134. https://doi.org/10.3969/j.issn.1001-5485.2014.12.026

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  Numerical research on the orifice-plate of a powerplant was carried out to analyse the discharge coefficient and pressure distribution at different sections. Results shows that the pressure measurement holes should be set at positions with the maximum pressure in the upstream and minimum pressure in the downstream. The downstream pressure measurement hole should be set at a distance 0.3D to 0.5D away from the plate center; while the upstream pressure measurement hole should be set at a distance 0.5D to 1.5D away from the plate center. Since the distance between the pressure measurement holes could seriously affect the measurement accuracy of flow rate, the installation of the orifice-plate flowmeter must be in strict accordance with the size of pressure hole, and the discharge coefficient should be corrected according to the actual position of measurement holes. There were obvious reflux at the downstream of the typical section, and the reflux flow rate accounted for 15% of the total flow rate. This research could provide reference for the pressure measurement, installation, test and adjustment of orifice-plate flowmeter.
CONSTRUCTION AND MANAGEMENT OF WATER CONSERVANCY PROJECTS
• Select
  Integration of Large Diameter Drilling and
  High Pressure Jet Grouting:A Case of Application

  WANG Gang, ZHANG Song

  Journal of Changjiang River Scientific Research Institute. 2014, 31(12): 135-138. https://doi.org/10.3969/j.issn.1001-5485.2014.12.027

  Abstract ( ) Download PDF ( )   Knowledge map   Save

  High pressure rotary jet grouting and large diameter drilling are integrated to treat the seepage of levees at Liaofang hydropower station in Jiangxi Province. Typical segments are selected for the jet grouting test. The grouting result is inspected and analysed to obtain technical parameters of the jet grouting. Through in-site test and water storage operation, this technique is verified to have good effect and sound quality in sandy gravel stratum. It could be a reference for the application of high pressure jet grouting in other seepage prevention projects.