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    15 June 2019, Issue 6
      
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  • MIN Xin-yi,YANG Chuan-guo,CHENG Yu-chun,LI Ying
    China Rural Water and Hydropower. 2019, (6):  1-5. 
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    The progress and extensive application of satellite technology provide the possibility to improve the accuracy and timeliness of rainfall monitoring. In this paper, using the HEC-HMS model, the TRMM RT satellite rainfall data is applied to flood simulation prediction. The results show that the real-time rainfall data of TRMM RT has the advantages of good temporal and spatial continuity, and the precipitation in general has a certain monitoring accuracy, but at present direct use of it to carry out flood simulation cannot meet the prediction accuracy requirements. In this paper, the rainfall classification correction method is used to effectively reduce the real-time satellite rainfall monitoring error and significantly improve the flood simulation accuracy. In the future, it is necessary to further improve the real-time monitoring ability of satellite rainfall, make full use of multi-source rainfall data such as site and satellite remote sensing to improve the accuracy of flood simulation prediction.
  • XIE Zhi-gang,SHI Peng,JI Xiao-min,ZHAO Lan-lan,QU Si-min,CUI Yan-ping
    China Rural Water and Hydropower. 2019, (6):  6-9. 
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    The calculation of flow velocity at each point in the basin has an important influence on the basin confluence. A calculation method of Manning formula considering rainfall intensity is proposed to construct the spatial velocity field so as to make the calculation of confluence more accurate. The calculation method considering the topography, hydraulic conditions and the influence of rainfall intensity on velocity, the comparative calculation method of Yu Manning formula, the calculation condition is more practical. Based on the spatial velocity field constructed by velocity calculation, the time probability density distribution function of watershed confluence, i.e. the geomorphological instantaneous unit line, is deduced and applied to the Dingan River Basin in Wanquan River System.The results show that the flood process line calculated by the Manning formula considering the rainfall intensity is better than that calculated by the Manning formula.
  • CHEN Ze-feng,WANG Wei-guang,LI Chang-ni,DING Yi-min,FU Jian-yu
    China Rural Water and Hydropower. 2019, (6):  10-15. 
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    Estimating continental water availability accurately is of great importance for water resources planning and management, maintaining ecological integrity and socio-economic development. This paper projected the future hydrometeorological variables and the uncertainty of water availability ratio in the four typical catchments based on the probability Budyko equation and the downscaling CMIP5 model. The result showed that the potential evapotranspiration in the four typical catchments (Heihe River Basin, Luanhe Mountain, Hanjiang River Basin above the Danjiangkou and Ganjiang River Basin above the Dongbei) had a significant increasing trend, while the increasing trend of precipitation was not obvious. The value of the water availability ratio increased with the increasing of the humidity. The uncertainty of the water availability ratio from high to low is the Luanhe Mountain, Ganjiang River Basin above the Dongbei, Hanjiang River Basin above the Danjiangkou and Heihe River Basin. The different emission scenarios have little effect on the distribution and uncertainty of the water availability ratio in the four typical catchments. After adding the same underlying surface factor (Normalized Difference Vegetation Index), the projection of the water availability ratio in arid area (Heihe River Basin) was more accurate than that in humid area (Ganjiang River Basin above the Dongbei).
  • LIU Hui-yuan,XIA Jun,ZOU Lei,HONG Si
    China Rural Water and Hydropower. 2019, (6):  16-22. 
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    In recent years, flood disasters have occurred frequently, and flood forecasting is an important non-engineering means to effectively prevent and resist mountain torrent disasters, and provide vital decision-making basis for watershed flood warning. Real-time correction method can effectively improve the accuracy of flood forecasting. In this paper, three typical small and medium-sized watersheds in Hubei Province (Gaojiayan, Xiheyi, Yuyangguan) are used as research areas. Based on the Time Variant Gain Model, the model prediction results are corrected in real time by recursive least square method with variable forgetting factor. The results show that the average Nash efficiency coefficient of flood forecasting in three watersheds is 0.78 before uncorrected. After real-time correction, the Nash efficiency coefficients of the three basins are all above 0.90, and the peak time forecast qualification rates and the peak flow forecast qualification rates are all up to Grade B or above. The forecast accuracy have been significantly improved.
  • JIN Hao-yu,JU Qin,XIE Ji-yao
    China Rural Water and Hydropower. 2019, (6):  23-28. 
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    The Niyang River basin is located in the southeast of the Qinghai-Tibet Plateau. Due to the high altitude the warm and humid airflow from the Indian Ocean is affected by the decrease in temperature when it rises along the river valley, the precipitation is mainly consist of rainfall and snowfall.Through the observation of MODIS remote sensing data, the watershed is covered by snow cover all year round, the correlation between snow cover and runoff is obvious, the mechanism of snowmelt runoff is obvious. HBV model has snowmelt module, which is suitable for the use of hydrological mechanism in the region of snowmelt runoff. Through the application of HBV model in Niyang River basin, it is found that the overall average efficiency coefficient Reff is 0.75 in the calibration period and the overall average efficiency coefficient Reff is 0.81 in the verification period. This indicates that the HBV model has high applicability in the Qinghai-Tibet plateau area represented by the Niyang River Basin and lays the foundation for the study of the hydrological mechanism and water resources utilization in the plateau mountainous areas.
  • JIANG Heng,QIAN Zhan,ZHANG Shuang-hu,HUANG Bing,LI Xi-chun
    China Rural Water and Hydropower. 2019, (6):  29-34. 
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    In recent years,the seasonal drought problem in Dongting Lake has become increasingly prominent. In order to alleviate the drought in Dongting Lake,the Hunan Provincial Government and the Hubei Provincial Government have proposed the construction of the Chenglingji Integrated Hub Project. In this paper,the“Water and Power Model of the One River and Two Lakes in the Middle and Lower Reaches of the Yangtze River”of the China Institute of Water Resources and Hydropower Research is used to simulate and calculate the water level rise and change in the Dongting Lake area under different dispatching schemes. The results show that the water level of the Chenglingji water level is 1m and the water level of the antler station is high. The height is about 0.93 m and the water level at Yingtian Station is about 0.90 m. The water level of Chenglingji is raised from 25.5 to 26 m,26 is raised to 26.5,26.5 m is raised to 27 m,and 27 m is raised to 27.5 m. The corresponding water level of Yangliutan Station has increased by 0.17,0.22,0.3 and 0.4 m respectively. The water level of Xiaohezui Station has raised by 0.06,0.09,0.12 and 0.20 m respectively. The hub project can solve the problem of water shortage in Dongting Lake in the dry season. However,the water level rise may have a certain degree of impact on lake water quality and ecosystem evolution.
  • GUO Lei,SHU Quan-ying,LIU Pan,XIONG Meng-si,ZHU Jian-you
    China Rural Water and Hydropower. 2019, (6):  35-38. 
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    Flood warning and forecasting has become a key issue in water science research,with the concept of flood control shifting from“flood control”to“flood management”. With the case study in Aojiang River Basin,a coupled hydrological-hydrodynamic model for risk analysis is established in this paper,following the construction of a risk map management platform and the dynamic three-dimensional display of the flood evolution process. The results indicate that the risk map management platform can provide a strong technical support for the early warning and forecast of watershed risk.
  • PAN Zhi-jun,TAN Zhen,DU Zheng,WANG Sheng-kai
    China Rural Water and Hydropower. 2019, (6):  39-43. 
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    In recent years, the construction of river chief information system has been in full swing, Its large user base and massive geographic data require GP services to provide powerful web space analysis capabilities. On the basis of summarizing the previous studies, the paper puts forward the general idea of the GP service of river chief system, and introduces the key technologies of the GP service in detail, finally, through the construction, release and invocation of GP service to realize the application. Research shows that GP services can provide powerful spatial analysis services for the application of river chief information system, and realize the automatic association between massive location data and river sections.
  • GU Feng,DING Jian-li,WANG Jing-zhe,GE Xiang-yu
    China Rural Water and Hydropower. 2019, (6):  44-50. 
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    In this study, the Wetlands in Werigan-Kuqia River Delta Oasis (WKRDO), as a typical wetland on the banks of the Tarim River, is considered as study area. The method of Random Forests, which has obvious advantages in feature selection and classification, was chosen in order to extract wetland information from the study area. First of all, four different characteristic variables, including spectral features, vegetation indices, water indices, salinity indices and texture features, were generated based on Landsat8 OLI data with rich multi-temporal and spectral information, and then six different classification schemes were constructed based on the above characteristic information. At last, the random forest classifier was used to extract the wetland information of the WKRDO, and to verify the extraction accuracy of different results. The purpose is to select the best plan to improve the effect of wetland information extraction. The results show that :(1) The effective use of multiple feature variables is the key to improving information wetland of extraction. For the contribution of different characteristics to the wetland information extraction, spectral features > vegetation indices and water indices > texture feature > salinity indices;(2) the preferred features based on the Random Forest algorithm are significant to extraction accuracy, with the overall accuracy is up to 90.09 %, and the Kappa coefficient is 0.8825. The extracted types reflect the differences in soil properties. It shows that the random forest algorithm can effectively process the feature selection. While the feature variable data mining, the accuracy of the wetland information extraction can be guaranteed and the operation efficiency can be improved. The result has important practical significance for formulating scientific water and fertilizer management measures and evaluating drought situation in the local oasis.
  • PAN Luo,HUANG Xiao-rong,WEI Xiao-yue,ZHANG Lang
    China Rural Water and Hydropower. 2019, (6):  51-55. 
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    This paper introduces the commonly used methods of evaluating river water quality in China and drinking water quality in foreign countries,including China ' s single - factor water quality evaluation method,Nemerow index method,and Canadian water quality index ( CCME WQI) method. Tuojiang River in Jintang,Sichuan Province is selected as the study case. The results show that for evaluating methods,the single-factor evaluation method and Nemerow index method are affected by extreme indicators,and the CCME WQI method considers the combination of“scope,frequency amplitude”,which can smooth the effect of extreme indicators. Besides,the CCME WQI method can use water quality index values to classify water bodies,which is a comprehensive water quality evaluation method. In terms of evaluation indicators,the choice of indicators would influence the evaluation results,and establishing a sound evaluation index system is necessary. Based on the evaluation index system,we can choose different sub -indicator systems for different needs,and different sub - indexes or grades are obtained to evaluate water quality.
  • ZHANG Meng,ZHAO Liang-fang,QUAN Xing
    China Rural Water and Hydropower. 2019, (6):  56-59. 
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    Regarding the low utilization rate of monitoring data from urban waterlogging monitoring system,a method based on PSO-ESN for prediction of water level at waterlogging sites is proposed.The historical rainfall and water level data are selected as input vector and the current water level is selected as output vector,the prediction model is established by dynamically approximating the mapping relationship between input and output vectors by echo state network,the future water level is predicted by iterative multi-step prediction method.Particle swarm optimization algorithm is used to relieve the subjective choice of key parameters of the model and the time series embedded dimension.The applicability of the model in the prediction of water level at waterlogging sites is showed by the example.Compared with traditional Elman neural network and BP neural network, the prediction accuracy of the model is respectively increased by 52.9 percent and 82.4 percent.The method can effectively use the monitoring data and provide a scientific foundation for the waterlogging warning and optimized scheduling of drainage system.
  • LI Si-yi,ZHANG Jian-feng,LI Tao,JI Bao-xin
    China Rural Water and Hydropower. 2019, (6):  60-65. 
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    In order to exploit the characteristics of rain flood runoff and the pattern of the influence on runoff depending on various low impact development ( LID) methods,this paper analyzes the high rainfall precipitation urban areas of Xi ' an. There are four types of LID combinations below based on the rainfall peak under the SWMM simulation conditions and the changes of runoff. Experimental results have proved that the elimination of rainfall works significantly better on 15% permeable surface and 75% green roofs. In addition,when the rainfall return period P= 1,the flood volume drops by 36%,and when the return period P= 10,the flood volume decreases to 24.3%. As much,LID plays an important role in decreasing the frequency of urban water logging. However,with the increase in design return period,the impact of LID is significantly reduced.
  • LI Ping-ping
    China Rural Water and Hydropower. 2019, (6):  74-77. 
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    The investigation has not found the underground water level dynamic monitoring data for many years,under the condition of ground subsidence phenomenon according to the thickness of the aquifer,water level decline and lithologic information,groundwater hydro -geological conditions match method is used to delimit the Gansu Provincial area land subsidence control. For land subsidence control area has carried on the classification of groundwater area,classification has 3 levels,and the area of the ground subsidence controlled area is named.The method of land subsidence control area is proposed for the first time without ground settlement monitoring data.
  • HU Fu-chang,AO Tian-qi,HU Zheng,LIU Ling-xue,LI Meng-rui
    China Rural Water and Hydropower. 2019, (6):  78-82. 
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    In order to more accurately study the current status of non-point source pollution in Shehong County, the Improved Export Coefficient Model (IECM) by considering precipitation and terrain effects is used to calculate the non-point source pollution load of Shehong County in 2016 by ArcGIS software. The calculation results are: TN, TP The load is 2854.32t, 256.42t, TN, TP load spatial distribution pattern is consistent, with large spatial heterogeneity, local concentration, close to river waters. The contribution rates of land use types, rural living pollution, and livestock and poultry breeding in the TN load are 65.57%, 29.22%, and 5.21%, respectively. Land use types, rural living pollution, and livestock and poultry farming are the three sources of pollution. The contribution rate is 57.57%, 38.80%, and 3.63%. Comparing the simulated calculation results with the unimproved model calculation results and the monitored values, the improved model can improve the accuracy of the model simulation and improve the applicability of the model in hilly areas with uneven rainfall.
  • ZHANG Li-juan,ZHAO Xue-hua,ZHU Xue-ping
    China Rural Water and Hydropower. 2019, (6):  83-87. 
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    The comprehensive management of the soil erosion area has changed the water cycle at the same time. In order to study the effect of soil and water conservation measures on runoff yield in the watershed, based on the rainfall-runoff data of comparative observation small watershed in Wangjia channel, the rainfall is divided into five types: A, B, C, D and E. The NRCS-CN model is used to simulate the runoff, and the parameters of different rainfall types in the two watersheds are determined. The results indicate that after comprehensive management, the model parameters are generally reduced, the initial abstraction ratio of Yangdao channel ranged from 0.05 to 0.2, and the CN value ranged from 40.72 to 92. The suitable value of the initial abstraction ratio of the Chacai channel was 0.01, and the CN value concentrated in the range of 20 to 50. The decrease rate of B-type and E-type rainfall runoff depth is positively correlated with the decrease rate of C N value, negatively correlated with the decrease rate of initial loss rate. The decrease rate of A-type and D-type runoff depth which shows the opposite law, however, there is no such rule in C-type.
  • LI Zi-yang,MA Fu-heng,LI Han-man,WANG Kai
    China Rural Water and Hydropower. 2019, (6):  88-92. 
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    People's Victory Canal has a wide coverage and many node buildings. Its information management is faced with the difficulty of transmission and analysis of massive scattered data. Combined with modern information technology,this paper explores the construction of the irrigation district intelligent management platform. Firstly,the connotation and important characteristics of intelligent management in large irrigation districts are analyzed in the light of the internal demand of information construction in irrigation districts,including the comprehensive perception,extensive interconnection,deep integration and intelligent application of multi-source information. Then,some key technologies such as NB-IoT based signal wireless sensor nodes,cloud detection and cloud computing based on the Internet of things,and system diagnosis based on deep learning are proposed,focusing on the efficient transmission,sharing,deep mining and diagnosis of information. The topology structure of multi-source information transmission and the intelligent management platform framework of channel system are built,including information perception transmission,interconnection processing,fusion reproduction and ubiquitous service. The construction of the platform provides scientific and technological support for giving full play to the overall efficiency of the People's Victory Canal and further improving management.
  • NULL
    China Rural Water and Hydropower. 2019, (6):  93-99. 
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  • XU Rui,LUO Tian-wen
    China Rural Water and Hydropower. 2019, (6):  100-103. 
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    The three-dimensional laser scanner is used to produce 1: 500 topographic map in the mountainous area with multiple ground object. How to quickly get high precision of elevation and plane information from point cloud data has always been a major point and a hard nut to crack in the study of surveying and mapping filed,through the experiment and practice,using the theory of spatial clustering and statistical ideas. For the ground object-field ridges that appear most frequently in Guizhou mountainous areas,the automatic extraction and mapping are studied. The research results have been successfully applied to the Jiayan Water Conservancy Project and Huangjiawan Water Conservancy Project,thus improving the efficiency of three-dimensional point cloud data processing,which has a great popularization and application value.
  • HE Zhen-jia
    China Rural Water and Hydropower. 2019, (6):  104-110. 
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    The bubbled-root irrigation infiltration solution in experiments is conducted at the experimental base of the Northwest Agricultural and Forestry University in Mizhi County in northern Shaanxi Province. The characteristics of the wettability and the transport characteristics of the water and nitrogen are studied under different depths of the emitter. The results show that the cumulative infiltration and infiltration rates of infiltration of Bubbled - root irrigation infiltration solution all decrease with the depth of the emitter; the cumulative infiltration and infiltration time were in accordance with the Kostiakov power function model; horizontal direction and vertical The migration distance of vertical wetting front increase with the increase in infiltration time. With the deeper depth of the emitter,the migration distance of the anisotropic front shows a decreasing trend. The deeper the burial depth,the deeper the location of the peak soil moisture content,the lower the moisture content of the upper wetted body,which helps reduce surface evaporation losses. With the increase in burier depth,the deeper the peak of NH+ 4 -N content,the higher the peak value of NH+ 4 -N,the deeper the burial depth of the emitter,and the lower the NH+ 4 -N content at the same location,below the peak value. Under different buried depths of emitters,the distribution of NH+ 4 -N content in soil profiles is quite different. The deeper the burial depth,the deeper the peak value of NH+ 4 -N content after infiltration,but with the extension of time,the content of NH+ 4 -N in the soil surface increases faster.
  • QIU Yong,ZHANG Ke-ke,TANG Xiao-chen,WU Xian-fang,TAN Ming-gao
    China Rural Water and Hydropower. 2019, (6):  111-115. 
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    Radial force characteristics are an important indicator of pump stability. In order to study the influence of solid particle physical properties on the radial force of solid-liquid two-phase flow pump,the mixture multiphase flow model is used to perform three-dimensional unsteady simulation calculations on the internal flow of a two-blade pump,and the variation law of pump radial force characteristics under different working conditions and particle properties is analyzed. The results show that the peak value of the impeller radial force and its peak-to-peak value in the solid-liquid two-phase flow condition under each flow rate is more than those in the corresponding flow rate,and the radial force peak and its peak-to-peak maximum increase by 7.8% and 8.2%. Under the condition of two-phase flow,the overlap of the radial force distribution of the impeller in the first half cycle of one impeller rotation period is less. With the increase in particle density,volume fraction and particle size,the impeller radial force magnitude and direction fluctuations are more intense. The impeller radial force vector center has a tendency to move from the second quadrant to the fourth quadrant in the coordinate system.
  • ZHANG Song,QIAN Jun,GAO Hui,YANG Fan
    China Rural Water and Hydropower. 2019, (6):  121-124. 
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    The planar S-shaped shaft extension pumping system is an important device for the low-lift pumping station,and the existing planar S-shaped shaft secondary pump device is inefficient. By optimizing the traditional S-shaped elbow and flow conduits,the efficiency of the planar S-shaped shaft extension pumping system can be improved. To obtain the performance data of the pumping system,the pumping system model is tested on a high-precision hydro-mechanical test bench in the five different blade arrangement angles. The results show that,the highest efficiency of S-shaped shaft extension tubular pumping device is 78.35% at the blade angle +2°. At this moment,the flow rate of the pumping device is 244.21 L/ s,and the head is 2.003 m. Within the head range of 1.5 ~ 2.0 m,the efficiency of the pump device is above 73%.
  • ZHU Wen-feng,GAO Chao-dang,ZHUANG Ke-yun,LI Ze
    China Rural Water and Hydropower. 2019, (6):  125-130. 
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    Dam safety evaluation is a complex comprehensive evaluation problem with multi-factor, multi-level and compound uncertainty. Considering the fuzziness and randomness in the process of comprehensive evaluation of dam safety, the cloud model theory is introduced to determine the fuzzy membership degree, and the Dematel method is introduced to optimize the index weight according to the influence of AHP method, and the Wind Safety Evaluation Index system is constructed according to the characteristics of gravity dam. A comprehensive evaluation model of gravity dam safety based on Ahp-dematel and cloud model is proposed, which is applied to the practical engineering case analysis to verify the rationality and feasibility of the method. The example shows that the model has good applicability and provides a new method for comprehensive evaluation of dam safety.
  • WANG Jun,WU Ze-yu2,WANG Zhi-hao
    China Rural Water and Hydropower. 2019, (6):  134-137. 
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    In order to control the excessive vibration caused by the flow induced vibration of the steel tainter gate, a constrained damping layer is arranged on the gate arm to ensure the overall safety operation of the structure. Firstly, the modal strain energy method and the complex modal method are used to analyze the dynamic parameters of the constrained damping layer, and compared with the exact solution; next, the dynamic parameters of the steel gate are calculated by the complex mode method. Based on the space finite element theory, the position and the physical size of the constrained damping layer are reasonably determined by the modal strain energy distribution and the dynamic parameters. By using precise integration method, the flow induced load of steel gate is analyzed, and the results show that the constrained damping layer can effectively reduce the flow induced load response. In this paper, the results provide a reliable design basis for constrained damping layer in hydraulic structures.
  • ZHANG Li,QU Zhu,JI Tong-xu
    China Rural Water and Hydropower. 2019, (6):  138-141. 
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    Under the condition of long-term fluctuation of reservoir water level, the soil and rock mass in the fluctuation zone is in the periodic saturation and drying process, which is harmful to the stability of the slope. This paper simulates the water level fluctuation environment of the soil and rock mass in the fluctuation zone with the process of dry-wet cycle, and the direct shear test is conducted with the soil of a landslide fluctuation zone, and the stability of the landslide with Geo-slope software is analyzed. The experimental results indicate that the cohesion force cand the friction angle φ are decreased exponentially with the increasing of dry-wet cycles n, with a fitting degree of more than 0.99;the weakening degree of the soil has a non-linear increasing trend with the increasing of the dry-wet cycle n. The soil strength is weakened by the infiltration and exudation of water in the dry-wet cycle process. The landslide regional is divided into three parts: natural conditions area, dry-wet cycle area and soaked saturation area, and the numerical simulation is performed based on the soil strength results of dry-wet cycles. The results show that the safety coefficient F of the landslide is decreased exponentially with the increasing dry-wet cycle n. The stability of the landslide changes from the basic stable state to the under steady state, until the landslide becomes unstable.
  • ZHU Bo,FENG Yi-jia,DING Lei,WANG Li
    China Rural Water and Hydropower. 2019, (6):  142-144. 
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    In order to control pipeline flow rate strictly,velocity flowmeter has been widely used in hydraulic engineering. To ensure the accuracy of the velocity type flowmeter,its calibration work must be performed regularly. To fully grasp the accuracy of measurement results,based on engineering calibration example and combined with the calculation formula of pipe flow in hydraulics,this paper analyzes the evaluation conditions and results of measurement uncertainty in on-line calibration of velocity flowmeter and introduces the measurement uncertainty analysis and calculation method,including the introduction of uncertainty components,standard uncertainty class A evaluation, class B evaluation and synthetic uncertainty evaluation. This paper provides a reference for similar flowmeter calibration analysis.
  • YUAN Xi-lai,LIU Dong,HU Xiao,LIU Dong
    China Rural Water and Hydropower. 2019, (6):  149-152. 
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    In the state monitoring and fault diagnosis of hydropower units,the shaft orbit is an important feature that reflects the operating state of the unit. In this paper,the method of combining the improved invariant moment algorithm with the PNN is proposed. The improved invariant moment algorithm is used to extract the shaft orbits of hydropower units under different operating conditions,and the corresponding characteristic moment vectors are obtained. A PNN is constructed for classification. The method is verified with the measured data of the power station. The results show that the feature extraction and classification method is simple and stable,and has a high degree of discrimination and good recognition rate for different shapes of the shaft orbit,which can provide an effective basis for fault diagnosis of hydropower units.
  • ZHU Min,QU Bo,SHEN Yong-cheng,LU Yue,ZHANG Xun,SHUI Xu-feng,WANG Shan
    China Rural Water and Hydropower. 2019, (6):  153-158. 
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    Aiming at a new type of hydraulic turbine with radial distribution of impellers for cooling towers, this paper designs a special volute suitable for the turbine, which, for the first time in structure, adopts the axial effluent transitioning from circular truncation to elliptical section, which not only can effectively save the interior space of the cooling tower, but also has considerable water diversion performance. In this paper, the design and optimization of the volute are based on the combination of theoretical analysis and CFD numerical simulation, and the pressure and velocity distribution of the volute sections are obtained according to the distribution diagram from CFD calculation. With the analysis of the velocity vectogram of volute outlet, the distribution characteristics of nominal circular circumference velocity, random point axial velocity and circumference velocity moment on ring surface of volute outlet are concluded. The results show that the hydraulic performance of the volute is consistent with the theoretical design and it has high practical value.
  • ZHANG Chang-wei,XU Cheng-mai,WANG Wei-yu,ZHENG Yang,CHENG Qi-juan
    China Rural Water and Hydropower. 2019, (6):  159-162. 
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    To accurately extract the effective fault features,an adaptive VMD method based on backtracking algorithm and parameter sensitivity analysis is proposed. Firstly,appropriate decomposition preset parameters are selected by parameter sensitivity analysis,and then the optimal parameters are calculated by backtracking algorithm. Finally,the adaptive VMD method is used to analyze the vibration signal.The results show that this method not only solves the problem that the parameters of VMD cannot be adapted,but also has good vibration signal feature extraction function.