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01 April 2018, Volume 35 Issue 4
    

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    SPECIAL CONTRIBUTION
  • MU Hong-qiang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 1-5. https://doi.org/10.11988/ckyyb.20180020
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    After decades of development, far-reaching progresses have been made in such aspects as water environment monitoring technology, basin water resources protection planning, environmental impact assessment for large- scale water project, and technical standard system in the scientific researches of water resources protection in the Yangtze River Basin. Supervision system, monitoring and control system, science and technology support system, as well as engineering system have been established for water resources protection. Despite the overall improvement of water environment in the Yangtze River Basin, local pollution is still outstanding, water security is insufficient,scientific support is inadequate,capacity construction lags,and regulatory means are weak,all far from the nation’s requirement for eco-civilization and environmental pollution as well as people’s demand for a better life. In view of this, we propose that scientific researches should be conducted based on the principle of great protection following the strategy of systematic protection and exploitation, and focusing on policies and safeguards, water-ecological civilization construction, control of total pollution into rivers, technical standard system, engineering system, as well as the introduction and application of new technologies.
  • RIVER-LAKE SEDIMENTATION AND REGULATION
  • WU Zhang-song, ZHANG Gen-guang, KOU Tan, WANG Xin-lei, ZHAO Jian-yong
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 6-12. https://doi.org/10.11988/ckyyb.20161010
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    The local scour process in the downstream of Dangka hydropower station is simulated based on Fluent dynamic mesh to predict the development and topography of local scour in the downstream of dam and sluice. The VOF water-air interface tracking method is used to deal with the complex free surface in the local scour. With transient shear stress on river bed as a crucial hydrodynamic condition for sediment’s incipient motion and transport, the volumetric transport rates per unit width of sediment on river bed in different directions are calculated, based on which the transient change of river bed elevation is obtained. Moreover, an improved formula of critical shear stressfor sediment’s incipient motion is employed to refrain from abnormal numerical values of sediment transport rate caused by bed slope gradient approaching sediment’s angle of repose. Finally, the 3-D evolutionary process of local scour is acquired by adopting the spring-based method and remeshing method. The accuracy and reliability of the mathematical model are verified by comparing the simulated depth and topography of local scour with model test values.
  • LI Lin-lin,ZHANG Gen-guang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 13-17. https://doi.org/10.11988/ckyyb.20161119
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    In line with probability and mechanics theory, a unified formula for the incipient velocity of sediment on slopes (including near bed velocity and average velocity along vertical direction) is deducted by introducing incipient probability and additional mass force in incipient sliding model. The influence of adhesive force and additional downward force among fine sediment particles are taken into consideration. Tested results reveal that calculated data from the formula are well consistent with observed data. The formula is of simple form and good calculation accuracy, hence can be used for the calculation of critical incipient velocity of adhesive and non-adhesive sediment particles on slopes with different dip angles.
  • WATER RESOURCES AND ENVIRONMENT
  • TANG Chao-chun, WU Qing-qing, DUAN Xian-yue, YE Xin, CHEN Hui-min
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 18-23. https://doi.org/10.11988/ckyyb.20161181
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    Eutrophication is a major environmental pollution facing all countries in the world. Efficient removal of phosphorus could control water eutrophication as phosphorus is a most critical factor of eutrophication. In this paper, the advantage of phosphorus removal by adsorption is reviewed. The efficiency and mechanism of clay mineral materials, metal oxides and metal mineral materials, biomass materials and active carbon in adsorbing phosphate are summarized; and the actual adsorption efficiencies of montmorillonite, vermiculite, dolomite, and attapulgite in clay mineral materials, as well as metal oxides, hydrotalcite, iron ore, and slag in metal oxides and metal minerals are analyzed in details. In addition, some defects which need improvement in the adsorption of phosphorus are pointed out, and the modification of adsorbent is regarded as the research direction in the future.
  • JIA Lei, GUO Xin-yu
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 24-30. https://doi.org/10.11988/ckyyb.20170099
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    Large water diversion project has changed the natural flow regime in rivers, and has brought about out standing conflict between domestic water demand and eco-environmental water demand. With water demand and environmental flow components as sub-goals of optimization, the optimal combination of water diversion ratio and reservoir water storage is searched by using genetic algorithm with 39 decision variables, including 3 water diversion ratios and 36 reservoir storage levels. The trans-basin joint operation of Dahuofang water diversion project and Dahuofang reservoir is taken as a typical case study. Results conclude that the average annual water diversion amount is 172.42 million m3, which is 6.38 million m3 smaller than the original plan, obviously alleviating the conflict between the domestic and ecological water demand in the Hunjiang river basin and the ecological water demand in Dahuofang reservoir. Moreover, according to the weights of holistic domestic water shortage and environmental flow component, many combinations of sub-goals with different weights are designed to reflect the correlation between water shortage and environmental flow component. Decision-makers of reservoir operation could obtain the water diversion ratio and reservoir water storage which meets the water demand by adjusting the weights. The research results would offer reference for the decision-making of large hydro-projects.
  • WATER RESOURCES AND ENVIRONMENT
  • TANG De-yi, WENG Hao-xuan, SHI Yan-nan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 31-36. https://doi.org/10.11988/ckyyb.20170771
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    The efficiency of mud flocculation settling is an important factor affecting the dredging progress in lakes or reservoirs. To explore the effect of different flocculants (organic and inorganic) on the settling efficiency of dredged mud, we compared the flocculation settling efficiency and supernate quality of dredged mud treated by organic flocculant (PAM) and five inorganic flocculants(PAC,FeCl3,Na2CO3,Na2SiO3·9H2O, and KAl(SO4)2·12H2O), respectively. Furthermore we conducted optimization test on the combination of flocculants to achieve an optimum settling efficiency and supernate water quality. Through the indoor tests we conclude that PAM could effectively promote the flocculation settling of dredged mud soil particles, but the efficiency of reducing turbidity is low; CO32- could also improve the efficiency of flocculation settling by gathering fine particles into large particles; Fe3+ and Al3+could reduce the turbidity of supernate, but has limited effect in enhancing flocculation settling. The optimum combination of flocculants is 10 ml PAM+2gPAC+2gNa2CO3 in every 1 000 ml dredged mud, which could both accelerate the settling of dredged mud and reduce the turbidity of supernate effectively.
  • LIU Jin-gao, XU Ya-qian, MA Jun, LIU De-fu, YANG Zheng-jian
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 37-42. https://doi.org/10.11988/ckyyb.20161150
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    After the impoundment of the Three Gorges Reservoir, the hydrodynamics of branch bay together with the distribution of water temperature in vertical direction has changed. To investigate into the distribution of water temperature in the presence of different types of density current, we monitored the water temperature in-situ in different sections of the Xiangxi Bay, and established a hydrodynamic model (CE-QUAL-W2). We conclude that the main hydrodynamic conditions and water temperature distribution in normal periods of reservoir operation vary correspondingly: in discharge period, backward density current at surface layer is the major hydrodynamic pattern with conventional water temperature distribution; in flood season at low water level, backward density current at middle layer is the major hydrodynamic pattern, with water temperature distributes in double mixing-thermocline type; while in storage period, backward density current at bottom layer is the dominant hydrodynamic pattern, with the water temperature distributes in a half-U shape. The research results offer theoretical and technical support for revealing the water temperature distribution and nutrients transport as well as forecasting water bloom in the Xiangxi Bay.
  • WATER-SOIL CONSERVATION AND ECOCONSTRUCTION
  • SHEN Sheng-yu, ZHAO Yuan-ling, CHENG Dong-bing, ZHANG Ping-cang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 43-47. https://doi.org/10.11988/ckyyb.20170876
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    Slope collapse and erosion is severe in South China.As a key part of prevention work,slope collapse investigation requires long-term periodical repetition; hence the manpower, material and time costs of traditional in-vestigation method are very high, which limits the extensive implementation of investigation. In this article, an
    efficient method of investigating slope collapse based on unmanned aerial vehicle (UAV) remote sensing is proposed based on a summary of traditional investigation methods. Through reconstructing the geomorphology of the slope collapse areas with UAV aerial images, Digital Orthophoto Map (DOM), Digital Surface Model (DSM), and three-dimensional model can be generated, transferring the cumbersome field investigation work into indoor model measurement and manual interpretation. The feasibility and efficiency of the proposed method are demonstrated by three experiments. And the advantages of the present method are discussed in terms of information quantity, accuracy, efficiency, and cost.
  • XIE Ren-dong, ZHAO Cui-wei
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 48-53. https://doi.org/10.11988/ckyyb.20171227
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    According to the raster data of natural environment and socio-economy of Yinjiang County, a typical karst trough region in Guizhou Province, we established the spatial database of eco-environmental vulnerability indexes with grid size of 30 m × 30 m based on remote sensing (RS) and geography information system (GIS). The index system includes aspects of sensitivity, elasticity, and pressure. Moreover, the levels of ecological vulnerability are classified by using comprehensive index method and analytic hierarchy process (AHP). Results show that potentially and slightly vulnerable areas accounted for a large proportion of the study area, taking up 86.60% and 87.37% in 2010 and 2015 respectively; whereas heavily and extremely vulnerable areas accounted for a small proportion of the study area. Areas of high vulnerability mostly distributed in regions of large population density, low vegetation coverage, large topographic relief and high intensity of human activity. The research results would offer theoretical reference for the ecological restoration and reconstruction and the environmental protection of the study area, and the assessment model in the present research is applicable to the assessment of eco-environment vulnerability at provincial and municipal levels.
  • ENGINEERING SAFETY AND DISASTER PREVENTION
  • HU Ming-yu, XU Wang-min, HE Wen, PENG Jin-sheng
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 54-59. https://doi.org/10.11988/ckyyb.20161179
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    The dissoluble erosion of concrete affects the stability and safety of dams seriously. In this research, concrete’s dissoluble erosion of 35 dams in Jiangxi province was analyzed systematically by means of field survey, water and precipitate sampling and analyzing. Results show that the large and medium-sized dams in Jiangxi Province suffered from erosion of different levels, and the ambient water with low concentration of HCO32- is an important factor which leads to the corrosion of concrete. When dams are exposed to water of low HCO32- concentration, the composition, mix proportion, construction quality and curing time of concrete play critical roles in preventing the dam from dissoluble erosion. Though the dams have been reinforced in recent years, some of them are still suffering from severe dissoluble erosion. Therefore, in-depth and systematical researches are necessary on the dynamic migration of Ca2+, the microcosmic mechanism of dissolution and the way of inhibiting the erosion.
  • CHEN Yu, LI Tian-bin, ZENG Peng
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 60-66. https://doi.org/10.11988/ckyyb.20161186
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    Deposit slope, which widely distributes in southeast Tibet with complex climate condition and harsh geological condition, poses large potential risk due to multiple extreme factors. To investigate into the effect of complex environment on slope failure, a hazard evaluation method in consideration of coupled multiple triggering factors is proposed. The probability and return period of triggered events of different hazard levels are analyzed, and on this basis, the failure probability corresponding to different events is calculated by Monte Carlo simulation techniques. In the meantime, the stochastic characteristic of triggering factors and the uncertainty involved in the inducing process are considered. Furthermore, multiple factors are coupled with the law of total probability, thus the hazard degree and potential risk of deposit slope can be comprehensively assessed. Earthquake and rainfall, as two explicit scenarios, are incorporated into a real engineering case as an example. The results suggest that the hazard level of the case is moderate; and in general, when the combination of triggering factors gets more extreme, the comprehensive hazard level is smaller.
  • ZHANG Bi
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 67-71. https://doi.org/10.11988/ckyyb.20160857
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    Tunnel deformation is of obvious non-linear characteristics. In the present research, models based on the Kalman filter and a variety of optimization support vector machines are built for accurate prediction. The applicability of various models is discussed, and further combinatorial prediction is conducted. Meanwhile, V/S analysis is adopted to calculate the Hurst index of deformation series for deformation trend judgment. The judgment result iscompared with prediction result in the aim of obtaining the comprehensive deformation rules of tunnel. Results suggest that the least squares support vector machine has the optimum effect, and the deformation in the next four cycles would keep increasing. Moreover, the Hurst index of deformation series and deformation rate series is 0.845 and 0.602, respectively, both larger than 0.5, indicating that the deformation in late stage would experience a sustained growth, which is consistent with the prediction result.
  • PEI Xue-ling, WANG Bo, DU Xing-zhong
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 72-75. https://doi.org/10.11988/ckyyb.20161192
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    Strong earthquake monitoring is an important content of dam monitoring. The response of dam subjected to strong motion influenced by geomorphology, site condition and structure of buildings is different. We made a series of preprocessing (eliminating wrong point, baseline correction, bandpass filter) and conventional processing (digital integration and spectrum calculating) for the monitoring record via using the Seismosignal software; and then analyzed the correlation between parameters (the peak of acceleration and Fourier amplitude) and the dam height. The results of analysis revealed that 1) the amplification of peak acceleration and peak Fourier amplitude increased with the increase of elevation, and the amplification at the dam crest was obvious, so did the altitude effect caused by strong-motion; 2) the peak dominant frequencies of the Fourier spectrum in three directions (transverse, longitudinal and vertical) mainly concentrated around 1.5-6.5 Hz, but filtered in other frequency bands.
  • AGRICULTURAL WATER CONSERVANCY
  • XIONG Yu-jiang, QIAO Wei, YAO Fu-qi, LUO Wen-bing, YUAN Nian-nian, FU Hao-long
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 76-80. https://doi.org/10.11988/ckyyb.20161176
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    Climate change has brought about alteration in rice water consumption, and thus affected the demand for irrigation water in paddy field. In this study, the changes in rice water consumption and irrigation water demand from 1955 to 2013 in Gaoyou irrigation area under water-saving irrigation (WSI) and flood irrigation (FI) were investigated by means of water balance calculation in the paddy field and Mann-Kendall analysis. Results indicated that air temperature presented significant increasing trends during the past six decades, and rainfall presented slight decreasing trends. Rice evapotranspiration and percolation under WSI and FI both presented gradual increasing trends, but rice water consumption decreased significantly under WSI; irrigation water demand in paddy field declined gradually under WSI while increased slightly under FI. Moreover, precipitation utilization efficiency has remarkably improved under WSI regimes. We conclude that the adverse effects of climate change on rice production can be effectively mitigated by using WSI technology, which would be an important measure of sustainable development for irrigation areas under changing environment.
  • ZHANG Li-xin, LIANG Wei, AI Wan-zheng
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 81-83. https://doi.org/10.11988/ckyyb.20170060
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    The distance between upper plug and lower plug affects the energy dissipation capacity of multi-stage plug discharge tunnel. In the present paper, the reasonable distance between the upper plug and the lower plug in multi-stage plug discharge tunnel is researched by numerical simulations. Result shows that when the contraction ratio is in the scope of 0.4-0.8, a reasonable distance between upper plug and lower plug equal to or more than 5.7D would guarantee the full display of plugs in different stages.
  • HYDRAULICS
  • LI LEI
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 84-87. https://doi.org/10.11988/ckyyb.20161216
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    The water surface profile of gradually broadened channel is simulated with HD (hydrodynamic) model in MIKE software, and the change rules of water surface profile and flow field of local head loss are obtained. The simulation results are compared with results calculated by empirical formula, and the conclusion reveals that the simulated water surface profile of gradually broadened channel agrees well with the calculation result; MIKE could better simulate the local head loss by reducing the difficulty and complexity of formula calculation, hence achieving a precise simulation.
  • TONG Jun, DING Jin-hua, SUN Hui
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 88-90. https://doi.org/10.11988/ckyyb.20161269
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    An outdoor aging test base for geosynthetics was established in Wuhan, central China to investigate the long-term aging performance of geosynthetics. Outdoor photo-oxygen aging tests for high density polyethylene (HDPE) geogrid have been carried out in the base. Test results show that in the initial nine months, the tensile strength of geogrid remains unchanged or even gets larger, while the corresponding strain at break decreases slightly, exhibiting hard and brittle trend due to secondary compensatory responses to the ultraviolet(UV) aging: UV provides the required chemical crosslinking energy, resulting in the polymer crosslinking reaction. Tensile strength of the geogrid increases by about 5% in the initial nine months, but decreases after the initial nine months. The long-term research results at the test base could provide first-hand data for researching the aging properties of HDPE geogrid.
  • ROCK-SOIL ENGINEERING
  • GONG Hui, ZHANG Xiao-jian, AI Chuan-jing, SHANG Si-liang, XU Yan-bing
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 91-96. https://doi.org/10.11988/ckyyb.20161171
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    In-situ shear test is an optimum means of obtaining targeted strength parameters of rock-soil aggregate for specific project as sampling and in-door test are demanding because of the complex composition and irregular structure of soil-rock mixture. Nonetheless, problems arise in conventional in-situ shear test due to large particles, posing unneglectable impact on test results. In view of this, we compared and analysed the problems in in-situ shear test and horizontal push-shear test, and concluded that horizontal push-shear test is more suitable for heterogeneous body such as soil-rock mixture. We also found that the internal friction angles obtained by the two methods are close, whereas cohesions differ greatly. Finally, we gave some suggestions on determining the parameter values for in-situ pull-shear test.
  • CHEN Zhen, WANG Guo-fu, LU Lin-hai, WANG Wei-ming, WANG Dan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 97-103. https://doi.org/10.11988/ckyyb.20161140
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    The stability of excavation pit in northwest Ji’nan, which locates in alluvial clayey-sand interbedded zone of downstream Yellow River, is greatly affected by soil strata. The pile insertion ratio (defined as the pile length above excavation bottom to the length below excavation bottom) is directly affected by soil strata quality. In this article, the stability of support piles with different insertion ratios are analyzed through theoretical calculation and numerical simulation. The excavation pit at the Shandong Provincial Cultural and Arts Center is taken as engineering background. Research results reveal that parameters of soil strata quality are in linear relations with insertion ratio. By introducing the earth pressure reduction coefficient into the calculation of embedded depth of pile, we found that the optimum insertion ratio is 0.55. According to measured insertion ratio 0.58, the numerical result is verified. The maximum lateral displacement of pile top is 0.05% of the pit depth (H), and maximum settlement 0.04%H, indicating that the excavation structure is stable enough with sufficient safety reserve. Therefore, the insertion ratio in the study case can be reduced to cut project cost and shorten construction period. The research results are of reference value for excavation pit construction in special alluvial areas of the Yellow River.
  • LIU Hai-tao, WU Meng-meng, XIONG You-liang, DONG Liang, YI Du-liang-zi
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 104-108. https://doi.org/10.11988/ckyyb.20161188
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    In elastic wave computerized tomography (CT) detection, PVC cases are always arranged in boreholes to protect the borehole wall as well as the transmitting and receiving transducers. Refracted wave would be generated when the elastic wave velocity in casing is larger than that in surrounding medium, hence reducing the accuracy of inversion result (dislocated or even false anomalies). In this article, we took a subway line investigation as a research case, and analyzed the complicated detection of high-velocity anomalies (boulders) in low-velocity medium (clay). According to two principles of identifying refracted wave, namely, first arrival travelling time being linear and take-off phase being positive, we could differentiate between refracted wave and direct wave, and pick up the correct direct wave for inversion. The proposed method is efficient and accurate in identifying the location and distribution of anomalies.
  • DU De-chi, WANG Wei-ming, LIU Peng, LÜ Xian-zhou, ZHANG Wei-she
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 109-116. https://doi.org/10.11988/ckyyb.20161260
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    Maximum vault settlement, plastic zone volume, maximum shear rock stress and maximum axial force of bolt etc., are determinant factors which reflect the stability of tunnel group with small clear distance. To investigate into the correlation degree among these factors, we obtained the values of these determinant indexes by using finite difference software together with modified Drucker-Prager model. Dunhua road station of Qingdao metro is taken as engineering background. In line with fuzzy grey relational theory, the order of determinant factors and the optimum scheme of construction sequence are analyzed. Results reveal that maximum axial force of bolt can be taken as the primary determinant factor of tunnel group stability; while maximum vault settlement and plastic zone volume could also reflect the tunnel group stability significantly; maximum shear rock stress has the smallest influence on tunnel group stability. In the present study, scheme 4 and scheme 5 are concluded as the optimum construction sequences, and both are verified by equivalent stress analysis.
  • DU Dong-ning, WANG Lai-gui, ZHANG Xiang-dong, GAO Long-fei, ZHANG Shu-kun
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 117-122. https://doi.org/10.11988/ckyyb.20161132
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    The seepage induced by moving water and sand in composite slope in surface mine threatens the slope safety and surrounding environment. In order to reveal the interaction mechanism among sand particles under the action of seepage,with characteristic structure unit of sand clusters as object, we analyzed the process of nonlinear movement and deformation and mechanical behavior of the strong chain among sand particles under actions of gravity, buoyancy, normal and shear contact force and seepage force in particle size scale. Furthermore, we proposed a new plastic-to-hinge element to improve the Будин model and established a mechanical model of sand creep with elastic-visco-plastic hinge. According to model test of moving water and sand and data from sand creep test, we gave constitutive equation and creep curve equation of the model and identified the parameters of the improved Будин model and verified its accuracy. Results show that the model could describe the contact, friction and rotation among sand particles during creep process with good accuracy; secondly, the model reveals the graded ladder-like failure phenomenon in the water-sand layer and shear attenuation and non-attenuation among sand particles, as well as the positive and negative accelerating shear creep process in the third stage.The present model offers a new mechanical approach for analyzing the interaction mechanism among discrete particles.
  • LÜJiao-jiao, FAN Wen, LÜYuan-qiang, LI Kai, DU Qian
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 123-128. https://doi.org/10.11988/ckyyb.20161267
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    Through field investigation and lab analysis, computation models of landslides with topographic hollows in Ziyang county of the Qinling-Daba Mountains were set up based on unsaturated soil mechanics theory. The stability and seepage with saturated and unsaturated properties under transient conditions were computed by limit equilibrium method in consideration of pore water pressure and unsaturated strength. Results show that topographic hollows induce slope failure through convergence of subsurface flow into small areas in the slope. Per unit depth of the maximum pore water pressure measured in an area close to the base of topographic hollows was found to be higher with bigger topographic hollows. Furthermore, a threshold relationship between the topographic hollow area and maximum pore water pressure in this study indicates that a topographic hollow of 1 000 m2 area could generate a maximum pore water pressure of 1.47 kPa.

  • HYDRAULIC STRUCTURE AND MATERIAL
  • HUANG Ya-mei, WANG Li-hua, CHEN Xi-rong
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 129-133. https://doi.org/10.11988/ckyyb.20170147
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    Aggregate shape greatly affects the workability and mechanical properties of concrete. Nevertheless, the irregular shape of aggregate particle defies full definition and measurements. In this article, the particle shape and particle size of crushed limestone coarse aggregate were studied with Digital Image Processing (DIP) method, and the results were compared with the values measured by caliper gauge. Results revealed that the length, width and length-diameter ratio measured by the two methods were almost equal; but the thickness, flatness ratio, sphericity and the grain shape factor obtained by the DIP method varied remarkably. The value of λ was corrected, and the correction factor was 1.82. The deviation of the corrected results was less than 2%.
  • FU Shu-yan, ZHAO Zhi-yong, YANG Shuo-wen, FANG Zhi-yuan, FANG Wei
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 134-136. https://doi.org/10.11988/ckyyb.20161219
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    In order to integrate various kinds of water resource information and guarantee the sharing and united management of information among regional administrations, we established a 3D visual safety management system for regional reservoir based on Building Information Modeling (BIM) and Geo-Information System (GIS). This system offers a technical support for the scientific decision-making for reservoir management by real-time comprehensive analysis, sharing of regional digital information among different levels, and 3D visualization of the reservoir’s BIM information. The improvement and promotion of this system would be of great significance for the scientific management of reservoir safety in China.
  • WATER CONSERVANCY ECONOMY
  • GAO Jin-jin, ZHENG Yuan, LI Jian-ming
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 137-142. https://doi.org/10.11988/ckyyb.20161372
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    In view of the functional characteristic of pumped storage power plant, the concept of “auxiliary service benefit” is put forward, and the economic benefit index system of pumped storage power plants composed of financial evaluation, national economic evaluation and auxiliary service benefit is established. Firstly, the improved order relation analysis method is employed to determine the weight value of each index, and the point assignment is extended to interval assignment, hence improving the overall evaluation result. Subsequently, the quantitative indexes are processed dimensionless by non-linear method, and the qualitative indexes are quantified by the triangular fuzzy number method. Finally, the comprehensive values of the evaluation indexes are obtained via linear weighting. The applicability of the present method and the logic of the evaluation are verified through a practical case.
  • NUMERICAL MANIFOLD METHOD BASED ON INDEPENDENT COVERS
  • SU Hai-dong, XIE Zhi-qiang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 143-150. https://doi.org/10.11988/ckyyb.20161045
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    Using Numerical Manifold Method (NMM) based on independent covers proposed in previous studies, a numerical method for beam analysis based on independent covers is presented. The solution process is almost the same with solid analysis: complete polynomials can be used as cover functions to analyze beams as solids; or, with some polynomial terms not involved in the computation, the fundamental beam assumptions, such as the assumption for Timoshenko beam, or the assumption for Euler-Bernoulli beam, are implemented. The approximate field functions with only C0 continuity are needed. In the meantime, the “shear locking” problem for Timoshenko beam is avoided when dealing with long beams with small cross-sections. Even for totally solid analysis, the numerical ill-conditioning problem due to very small ratio of height to length does not exist in general situations. With two-dimensional beams with rectangular cross-sections as a case study, the formulae of independent covers in the local coordinate system are given to reflect the features of beams, together with the integration approach of “firstly along the cross-section, and then along the axial direction”. Some numerical examples demonstrate the validity of the method. The idea of the paper can be directly expanded to solve three-dimensional problems, and to provide a new approach for analysis of beams, plates and shells.
  • SU Hai-dong, ZHOU Chao, XIE Zhi-qiang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 151-157. https://doi.org/10.11988/ckyyb.20170321
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    On the basis of straight beam analysis using Numerical Manifold Method (NMM) based on independentcovers proposed in previous study, a novel method for curved beam analysis is presented. In the mode of solid analysis, the fundamental assumptions of beams are simulated by only eliminating some terms of polynomial cover functions. And therefore the relative complexity of the derivation procedures for the governing equation and the corresponding numerical calculation formula of curved beam is avoided. By means of the local coordinate system varying with the middle plane of the beam described by parametric equations, and in subsequence by calculating the derivatives of the local coordinates and the direction cosines with respect to the global coordinates, curved beam analysis based on exact geometric description can be realized. Two examples are given to verify the feasibility of the method: one is a circular curved beam with constant curvature, and the other is an ellipse curved beam with variable curvature. The proposed method provides a new way for the analysis of curved beams and further study of curved shells. It is also a new approach for geometric shape preserving in addition to Isogeometric Analysis (IGA) method.
  • SU Hai-dong, ZHOU Chao, XIE Zhi-qiang, CHEN Qin
    Journal of Changjiang River Scientific Research Institute. 2018, 35(4): 158-166. https://doi.org/10.11988/ckyyb.20171002
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    On the basis of the new methods for straight and curved beam analysis proposed in previous study, a Numerical Manifold Method for curved shell analysis based on independent covers is presented. In the mode of solid analysis, the Reissner-Mindlin assumption for 3D plate and curved shells is strictly simulated just by eliminating some terms of polynomial cover functions. And therefore the complexity of the derivation for the governing equation of curved shells and the corresponding numerical calculation formula is avoided. By means of the local coordinate system varying with the middle layer of the shell described by parametric equations, and also by calculating the derivatives of the local coordinates and the direction cosines with respect to the global coordinates, curved shell analysis based on exact geometric description can be realized. The detailed procedures including the integrating method and geometric formula are given. Examples of a spherical shell and a plate are used to verify the convergence of the method. In the end, the characteristics and advantages of the new method for beam, plate and shell analysis are summarized, including the complete solution for locking problem, via previous studies of 2D straight and curved beams as well as the study of 3D plates and curved shells in this paper.