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01 June 2018, Volume 35 Issue 6
    

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    SPECIAL CONTRIBUTION
  • NING Lei
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 1-5,18. https://doi.org/10.11988/ckyyb.20180298
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A clear perception on the current and historic flood control situation in the midstream and downstream of the Yangtze River is of crucial significance for future regulation and protection. The construction of water conservancy projects is a dominant measure of improving the flood control situation; in the meantime, the adaption of river-lake relation to natural evolution also affects the flood control situation. In view of this, the changes in river-lake relation in different periods since the 1960s are analyzed, and their influences on flood control situation are simulated.Furthermore, the favorable effect of water conservancy projects, in particular, the Three Gorges Project and its upstream control reservoirs, on flood control situation is examined; hence the variation process of flood control situation in the midstream and downstream of the Yangtze River is obtained. In addition, measures to improve flood control capacity, inclusive of upgrading project system, and enhancing joint scheduling ability, are discussed.
  • RIVER LAKE SEDIMENTATION AND REGULATION
  • TANG Jie, LIN Mu-song, YAN Xia, JIN Zhong-wu, LIU Tong-huan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 6-11. https://doi.org/10.11988/ckyyb.20170161
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    The deceleration flow, called backwater in engineering, is a pattern of non-uniform flow. Research of bed sediment’s incipient motion under deceleration flow condition is of great application value in water conservancy project.In line with generalized flume experiment and field measured natural flow data, four classic formulae for incipient flow velocity are verified and compared. Results suggest that all the four classic formulae are suitable for deceleration flow condition in flume experiment, yet difference still exists in the selection of particle size. Representative particle size d95 is of good accuracy. Moreover, the incipient motion of sediment under deceleration flow meets the Shields curve in general. According to verification of power incipient motion formula, the dimensionless incipient power is 0.0191, which can be used as the criterion of bed sediment initiation.
  • WATER RESOURCES AND ENVIRONMENT
  • SU Min-jie, BAI Xu-jia
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 12-18. https://doi.org/10.11988/ckyyb.20161295
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    Regional water resources carrying capacity in Yunnan Province is assessed by integrating maximum entropy with projection pursuit (MEPP) premised on an index system and rating standard involving water resources, economy and society, as well as ecological system. Data in the recent decade from 2006 to 2015 is taken as a case study. A MEPP model is established with its target functions constructed by random samples between the thresholds of the target classification criteria and its optimal projection direction optimized by shuffled frog leaping algorithm (SFLA). Moreover, models of biogeographic optimization (BBO)-MEPP, Harmony Search (HS)-MEPP and Particle Swarm Optimization (PSO)-MEPP are built as well for comparison. Results demonstrate that the SFLA is of better ability of searching optimal values globally, with its optimum value, most inferior value, mean value and standard deviation superior to those of BBO, HS and PSO. According to the results of SFLA-MEPP model, the water resources carrying capacity in Yunnan Province from 2006 to 2007 and from 2011 to 2012 are overall loadable, and in the other years are rated as loadable. The carrying capacity of water resources in Yunnan Province had been enhancing with time in 2006-2015, yet the trend was insignificant. The results of SFLA-MEPP model are identical with those of BBO-MEPP model with different ranking orders; but are different with those of HS-MEPP model and PSO-MEPP model.
  • XU Yu-cheng, ZHU Shou-xian, ZHANG Wen-jing, ZHOU Lin
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 19-23. https://doi.org/10.11988/ckyyb.20170533
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    In hydrological studies of river and estuary, high/medium/low flow year is generally classified according to annual average runoff. In response to the need of runoff classification in dry season, especially during saltwater intrusion in the Yangtze River Estuary, we examined the differences in classification results of high/medium/low flow year according to annual average runoff, flood-season average runoff, dry-season average runoff, and monthly average runoff in dry season. The classification results according to flood-season average runoff and annual average runoff coincide to a degree reaching 74%, while the results according to dry-season average runoff and annual average runoff coincide with only 38%, and the mean coincidence degree between monthly average runoff in dry season and annual average is 33%. The results suggest that multiple runoff indicators are indispensible for the classification of high/medium/low flow year in various researches on the Yangtze River Estuary.
  • LIU Jing, TANG De-shan, HAO Jian-hao
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 24-29. https://doi.org/10.11988/ckyyb.20161367
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    An index system for the risk assessment of water environment quality of Taihu Lake drainage basin is put forward. According to the measured data of seven sections during 2011-2015, we calculate the attribute importance of each index and select four important indexes together with the eutrophication indicator. Furthermore, in the light of measured water quality data and criterion for water quality classification, we obtain the results of water environment quality risk assessment for Taihu Lake drainage basin by combining Shannon entropy and cloud model under the principle of maximum degree of membership. Results reveal that the water environment quality of the Taihu Lake drainage basin is at medium risk level. Corresponding countermeasures need be taken to reduce the risk of water pollution.The research results offer scientific basis for improving the water quality in the Taihu lake drainage basin.
  • LI Rong-bo,JI Chang-ming,SUN Ping,LIU Dan,ZHANG Pu,LI Ji-qing
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 30-35. https://doi.org/10.11988/ckyyb.20161307
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    In view of the premature convergence in shuffled frog leaping algorithm (SFLA), an improved shuffled frog leaping algorithm (AISFLA) is proposed by coupling the local refine search strategy (LRSS) with the global incentive regulation strategy (GIRS). LRSS improves the local search ability by using chaos technology to conduct more refined search around the optimal individual of each group, while GIRS keeps an efficient global search performance by disturbing the optimum individual to improve the frogs’ population diversity and further motivate frogs jumping out of stable state. AISFLA is applied to the optimal operation of Lixianjiang cascade reservoirs as a demonstration. The modeling result proves that AISFLA is of high optimization quality and fast convergence by effectively handling the premature convergence of SFLA, hence can be a new approach to the solution of optimal operation of cascade reservoirs.
  • FLOOD PREVENTION AND DISASTER REDUCTION
  • LI Da-ming, CHEN Shuo, GU Li-jun, GAO Zheng-lian, GAO Jin-yan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 36-41,66. https://doi.org/10.11988/ckyyb.20161356
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    In this article, a mathematical model of flood routing is established by finite volume method based on two-dimensional unsteady flow equations. An improved water balance model is applied to the flood routing calculation to solve the problem of false flow in the unit of mountainous area. According to the boundary condition deter-mined by the flood process of Taolinkou reservoir, the submerged area, submerged depth and flow fields in the downstream mountainous area are calculated in consideration of the influence of mountainous terrain on flood routing. Furthermore, the values of flood marks on the riverbank were adopted for model validation, and the simulation results are overall consistent with historical observed data. On the basis of flood routing simulation, the economic and life losses caused by flood disaster are estimated. The research result provides necessary ideas and methods for impact assessment of regional flood control.
  • QIN Yi, CHEN Xing-xing, ZENG Shan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 42-46. https://doi.org/10.11988/ckyyb.20161341
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    Confusion arises in practical application due to multiple definitions of rainfall threshold for flash flood warning. In view of this, we analyzed and summarized the existing definitions, and redefined the rainfall threshold for early warning into two types planned rainfall threshold and emergency rainfall threshold. In line with the mechanism of flow yield and confluence, we proposed a simple and feasible method of calculating the emergency rainfall threshold for ungauged areas. Comparison of calculation result between the two types indicates that the variations of planned rainfall threshold and emergency rainfall threshold are featured with different rules. In forming prevention and control measures for flash flood, we should make clear the objectives (for early warning or for engineering design) in determining the indicator type to realize a reasonable prevention and control.
  • GAO Yu-qin, WANG Huai-zhi, LU Xiao-hua, WANG Dong-dong, YUAN Yu
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 47-52,66. https://doi.org/10.11988/ckyyb.20171082
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    An HEC-HMS (Hydrologic Engineering Center’s Hydrologic Modeling System) is built to research the rainstorm flood response mechanism of Qinhuai river drainage basin in the background of rapid urbanization. Three land use scenarios are set in the model natural development scenario, woodland restrictive policy scenario, and paddy field restrictive policy scenario in the year 2028 predicted by CA-Markov model. The HEC-HMS model is calibrated and validated to be applicable for flood simulation and flood response research under different land use scenarios. Results implies that the smaller the flood scale, the stronger the flood response. With the development of urbanization, the impact of land use on rainstorm flood aggrandizes the future flood peak and flood volume increase the most sharply under natural development scenario, followed by those under paddy field policy scenario and woodland policy scenario. The research findings provide a new idea for the analysis of storm flood response of land use cover change in the Qinhuai River basin, and also have some guiding significance for flood control planning and construction of the basin.
  • AGRICULTURAL WATER CONSERVANCY
  • TANG Ding-ding, QIAO Wei, LI Ya-long, YAO Fu-qi
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 53-59. https://doi.org/10.11988/ckyyb.20170335
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    In this study, three types of Ti-based single/composite oxide nanotube arrays are prepared by anodic oxidation of Ti and typical Ti alloys (Ti-0.2Pd and Ti-6Al-4V). The different fabrication processes and properties of these oxide nanotube arrays are analyzed using SEM, EIS, XRD, EDS, ICP, XPS and UV-Vis DRS. Their photocatalytic activities are determined by degradation of p-nitrophenol in aqueous solution under UV light irradiation. Al and V inside the Ti-6Al-4V alloy-derived nanotube arrays are detected by EDS or XPS. Pd inside the Ti-0.2Pd alloy-derived nanotube arrays cannot be detected by EDS or XPS, but is quantitatively determined by ICP analysis. Incorporation of Al and V significantly deteriorates the photoreactivity of the resultant nanotube arrays, while incorporation of Pd remarkably improves the photocatalytic activity of the resultant titania nanotube arrays powder. The presence of Pd element not only enhances the light absorption, but also facilitates the sulfur poison resistance and the separation of photogenerated charge carriers. Excessive dosage of Al and V element results in structure defect as recombination center and limits the separation of photogenerated charge carriers. This study suggests that anodization of Ti-0.2Pd alloy, rather than pure Ti metal, allows to produce high-performance photocatalysts for environmental and energy applications.
  • HYDRAULICS
  • ZHONG Liang,WANG Zhen-zhi,WANG Shu,ZHOU Xin-jing
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 60-66. https://doi.org/10.11988/ckyyb.20161305
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    Spur dike with compound section is a common structure used in waterway regulation. In this paper, the law of velocity distribution around non-submerged spur dike with compound section is researched via flume experiment, and the results manifest that I) In surface layer, large resultant velocity appears outside the downstream of the first-stage spur dike head; the length (b2) of the second-stage spur has noticeable impact on the value and morphological distribution of the zone of large resultant velocity whereas Froude number (Fr) only affects the value of velocity; transverse surface velocity distributes in an approximated fan shape, with the maximum value up to 0.45 times of test velocity. (II) In cross-sectional scale, large longitudinal velocity is located in the adjacent of the head of the first-stage spur dike, and intense transverse velocity zone is in the front of the second-stage spur dike, both distributing in a band shape; with the increase of b2, the band width declines, and the distribution is more concentrated. (III) In longitudinal profile, the maximum longitudinal velocity is found in the downstream of the spur dike near water surface, and its position moves up along with the increase of b2; while the transverse velocity increases first and then decreases, with its maximum value arising close to the bottom; intense high transverse velocity zone stretches in a maple leaf shape.The research results provide reference for waterway regulation and spur dike protection.
  • HUANG Ren-yong, WANG Min, ZHANG Xi-bing, ZHOU Man, LIU Liang, REN Shi
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 67-69,80. https://doi.org/10.11988/ckyyb.20170063
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    The Three Gorges Reservoir (TGR) is endowed with many tributaries and large local inflow. The correct calculation of local inflow process is an important issue in the hydrodynamics calculation for the TGR as the amount and process of inflow directly concerns the calculation precision of reservoir regulation and storage. In this article, the daily inflow process in the TGR area is back-calculated on the premise of water balance by a 1-D mathematical unsteady flow model proposed by the author previously. The local inflow process is added to the calculated reach by being distributed to each tributary in correspondence to the proportions of catchment area. The effect of adding local inflow to each reach is analyzed. Results demonstrate that the calculation results of the discharge process of the Three Gorges Reservoir are in good agreement with the measured results after the proposed method is adopted.
  • ROCK SOIL ENGINEERING
  • WANG Rui-hong, LI Wan-wen, LIU Jie, JIANG Yu-zhou, HUANG Fei
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 70-74,80. https://doi.org/10.11988/ckyyb.20170066
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    Since jointed rock mass exists extensively in practical engineering, in-depth research on the effect of joint’s dip angle on rock strength and physical characteristics is of great significance to the stability of jointed rock mass projects. The influence of joints on sandstone’s strength and physical properties is investigated through triaxial loading test and acoustic test on intact rock specimen and jointed rock specimens with different joint angles under varying confining pressure. Results are concluded as follows (1) With the change of dip angle, the decay rate of longitudinal wave velocity of rock varies, reaching the maximum when dip angle is 60°. (2) The elastic modulus of intact rock is the largest, followed by those of jointed rock specimens with 90° dip angle, 30° dip angle, and 60° dip angle. (3) Given the same dip angle, the peak strength of rock increases with the increase of confining pressure; while under the same confining pressure, the peak strength of rock specimens displays obvious anisotropy with the change of dip angle. (4) The cohesion of jointed rock specimens changes in a U-shape curve with varying dip angle, and reaches the minimum when dip angle is 60°; the internal friction angle increases with the increase of dip angle. In conclusion, joints have remarkable influence on the strength, deformation, and physical properties of sandstone. In particular, the influence reaches the maximum when joint’s dip angle is 60°.
  • WU Xiao-peng, ZHAO Yong-hu, XU An-hua, MI Wei-jun, ZHAO Shou-quan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 75-80. https://doi.org/10.11988/ckyyb.20170160
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    The collapsibility of loess can be evaluated rapidly through physical and mechanical indexes. On the basis of field immersion tests and corresponding indoor tests, we analyze the relationship of loess collapsibility against depth, water content, dry density, void ratio, plasticity index, and compressibility coefficient using mathematical statistics, theoretical analysis, and data mining. The thick Q3 loess along the Zhengzhou-Xi’an Highway is taken as research background. The research conclusions are as follows the coefficient of loess collapsibility is well correlated with physical and mechanical indexes, among which depth, moisture content, and dry density are linearly negatively correlated with collapsibility; void ratio is linearly positively correlated with collapsibility. The limit moisture content for loess collapse is 20%, limit dry density, 1.4 g/cm3, and limit void ratio, 0.9. In comparison, the collapsibility coefficient is mostly influenced by void ratio, followed by dry density, moisture content, plasticity index and coefficient of compressibility. In addition, we put forward an empirical formula of evaluating loess collapsibility by using multiple physical indexes based on data mining.
  • BIAN Jia-min
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 81-85,91. https://doi.org/10.11988/ckyyb.20160801
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    Direct shear test was conducted on weak expansive soil specimens of two different dry densities under dry-wet cycles. The test soils were collected from the bank slope of Xuhe River in Nanjing. The shear stress, cohesion and internal friction angle of soil after dry-wet cycles were analyzed, and the variation rules of direct shear strength were investigated. Test results indicated that cracks of expansive soil expanded and widened irreversibility with the increase of dry-wet cycles; cohesion of soil of different densities decreased with the increasing of dry-wet cycles, and tended to be uniform; internal friction angle showed no obvious change. Moreover, overburden pressure during the direct shear had an apparent influence on shear stress decay. Larger overburden pressure resulted in smaller decay. In conclusion, shear strength parameters under low stress is recommended for stability analysis of expansive soil slope.
  • MA Gao-qiang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 86-91. https://doi.org/10.11988/ckyyb.20160787
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    In the aim of exploring the damage evolution of rock under load in the process of failure, the deformation and failure process of half-homogeneous sandstone are studied through triaxial compression test with acoustic emission monitor. The acoustic emission characters of sandstone in different stages of triaxial compaction under different confining pressures are analyzed. As confining pressure increases, acoustic emission activity weakens, which indicates that confining pressure could inhibit the emergence and development of internal crack and improve the strength of sample, and consequently delay the time of macroscopic damage. Furthermore, a new damage variable and damage evolution model is proposed based on AE events by assuming that the damage evolution equation obeys Weibull distribution and lognormal distribution, and a correction coefficient is introduced to modify the damage variable. The damage development of sandstone is mainly divided into four stages the stage of initial damage, the stage of steady development, the stage of accelerative development and the stage of damage after failure. By comparing the two acoustic emission damage models, we found that logarithmic normal distribution is more suitable for describing acoustic emission phenomenon of half-homogeneous sandstone.
  • LI Song, MA Yun, ZHANG De-le, LI Shou-zhi, LIU You-xiang, ZHANG Xiao-yu
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 92-97,106. https://doi.org/10.11988/ckyyb.20161287
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    An improved method for calculating the anti-overturning safety factor of supporting structure with double-row piles is presented. The method takes into consideration the influence of compressive resistance of first-row pile and uplift resistance of back-row pile coupled with groundwater buoyance. The calculation methods for anti-overtur-ning safety factor of double-row piles and gravity retaining structure in different specifications in China are compared. The compositions of overturning force and overturning resistance are also analyzed. The calculation results of engineering cases show that compared with the results calculated by specification formulas, the anti-overturning safety factor calculated by the present method could improve by 20%-55%. The influence factors of anti-overturning safety factor are analyzed by a self-developed software, and the results indicate that with the increase of built-in depth of supporting pile, the anti-overturning safety factor of double-row pile decreased firstly but then increased. The impacts of the torque generated by the coupling between compressive resistance of first-row pile and uplift resistance of back-row pile on the safety factor weakened. Moreover, with the increase of array pitch, the anti-overturning safety factor increased approximately linearly, and impacts of the torque generated by the coupling between compressive resistance of first-row pile and uplift resistance of back-row pile on the safety factor strengthened.
  • DING Sheng-hui,DING Shu-ping,ZHANG Ming-qiang
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 98-101,106. https://doi.org/10.11988/ckyyb.20180238
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    The land yard of Huashan wharf project of Wuhan Port is located in railway line area. To investigate into the influence of dynamic compaction on adjacent railway bridge, hence determining a reasonable compaction technique, we analyzed the relationship between tamping energy, tamping number, tamping distance and railway bridge vibration according to field compaction test.In field test,the vibration velocity of bridge floor converged to 3.5 cm/s when dynamic tamping energy was 4 500 kN·m after tamping number reached 5; the vibration velocity of bridge floor was smaller than 4.0 cm/s and vibration frequency less than 10 Hz when tamping energy amounted to 6 000 kN·m beyond 40 m, which meets the requirements of Standard for Allowable Vibration of Building Engineering. In addition, the equation of vibration velocity attenuation of buildings caused by clayey foundation compaction was deduced based on test results for reference for similar projects.
  • HUANG Hai-feng, JU Neng-pan, LAN Kang-wen, LI Meng, KONG Wei, GUO Lu-yao
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 102-106. https://doi.org/10.11988/ckyyb.20170042
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    On the premise of assuming that micro-unit strength obeys Weibull distribution, a statistical damage softening model for rock is established based on the continuum damage theories to reflect the strain softening of rock. The model contains two undetermined coefficients, one of which can be determined by the peaks of stress-strain curves, and another depends on the micro-unit strength parameters. By analyzing the influence of the micro-unit strength parameters on the model, the model parameters are determined through optimized back analysis. On this basis, reasonable strength criterion is selected according to the micro-unit strength parameters; hence the low precision of solving model parameters by traditional methods are overcome. Furthermore, the correctness and rationality of the proposed method are verified by conventional triaxial compressive test of red-bed mudstone on YSJ-01-00 rock triaxial creep testing machine.
  • HYDRAULIC STRUCTURE AND MATERIAL
  • LIU Yu, HUANG Yao-ying, TANG Teng-fei, XIAO Lei, GAO Jun
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 107-110. https://doi.org/10.11988/ckyyb.20170190
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    Concrete, a creep material between ideal solid and fluid, is related to loading age and load-bearing time. In this article, the fractional order calculus model is applied to the analysis of concrete’s creep. A fractional order creep model with five parameters is established based on the generalized Kelvin model with software components. Furthermore, according to measured creep values of three engineering cases, the five parameters of the established fractional order creep model are inverted and optimized by using the complex optimization algorithm. The expressions of concrete creep model in consideration of loading age are given. Engineering case study demonstrates that the calculated values of the fractional order model agree well with test values, close to those of eight-parameter model. Fractional order model could be a new approach in creep analysis of concrete.
  • ZHU Peng-fei, GONG Jing-wei, TANG Xin-jun
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 111-116. https://doi.org/10.11988/ckyyb.20170002
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    The present study aims to provide basis for the temperature and crack control of mass concrete by investigating the difference of hydration heat between low-heat Portland cement and mineral-mixed cementitious material. Firstly, the processes of hydration heat release in low-heat Portland cement and mineral-mixed cementitious material were determined via direct method. According to the calculated hydration heat release curve and hydration rate curve, the differences between the two in terms of hydration law were analyzed. Furthermore, the hydration processes were characterized by the integral equations of Krstulovic-Dabic model in three stages and the differences in the process of hydration were further studied. Research results show that in the early stage of hydration, the hydration heat of cementitious material with slag was lower than that of low-heat Portland cement, but was higher than that of low-heat Portland cement in the later stage; compared with those of low-heat Portland cement, the initial and final setting time was delayed and the accelerating period and the deceleration period was prolonged by adding a certain amount of mineral admixture. In addition, in nucleation and crystal growth period (NG), hydration resistance increased as the n value became larger, and the initial setting time was delayed; as the kNG value climbed, rate of hydration increased and the acceleration period shortened, so that the final setting time was in advance; while in the phase boundary reaction period (I) and diffusion period (D), the greater values of kI and kD, the faster hydration speed and the longer deceleration period would be.
  • INFORMATION TECHNOLOGY APPLICATION
  • JIANG Cheng-wei, LIU Jin-tao, LIN Lu, XU Shan-shan, JI Hai-juan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 117-121,134. https://doi.org/10.11988/ckyyb.20170480
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    The average river flow width of ten main river segments in Lhasa River drainage basin were obtained with the help of remote sensing data of Google Earth after gauging the river width of 451 reaches. On this premise, the correlation between river flow width and five topographic factors, inclusive of river’s longitudinal slope, river’s tortuosity, river’s concavity, upstream catchment area and catchment average slope, were plotted with four different functionslinear function, exponential function, logarithmic function, and power function. Results implied that, among the five factors, upstream catchment area is of the largest correlation with river flow width with the coefficient of certainty amounting to 0.81 when fitted by linear function; longitudinal slope of river also has a remarkable impact on river flow width, with the coefficient of certainty reaching 0.76 fitted by power function and exponential function. Researching the correlation between river flow width and topographic structure factors in Lhasa River drainage basin would be of crucial significance for us to understanding the river geomorphology in Qinghai-Tibet Plateau and improving our ability of estimating flow rate and total flow amount in ungauged basins.
  • WANG Peng, XING Cheng
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 122-127. https://doi.org/10.11988/ckyyb.20161314
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    In an attempt to improve the global accuracy and reliability of the transformation from 2D coordinates of GB-SAR images to local 3D coordinates, and to overcome the limitation of traditional similarity transformation parameter estimation method, we propose to employ 3D laser scanning data to assisting the transformation of GB-SAR image coordinates. Firstly we derive the formula for calculating the scaling factor of the similarity transformation parameter estimation method. Analysis results suggest that the similarity transformation method is only applicable to local areas far away from radar and small in range with no dramatic change of height relative to the radar center because the calculation precision is not uniform for targets with varying relative height. We propose to provide external elevation information by 3D laser scanning technology, and subsequently transform GB-SAR image coordinates to local 3D coordinates by matching of point clouds and pixels on projection plane according to the geometric projection principle of GB-SAR imaging. Finally, we verified the effectiveness of the method of transforming GB-SAR by deformation monitoring experiment on the high slope of Geheyan dam. The research result is conducive to the 3D interpretation and analysis of GB-SAR deformation monitoring.
  • INSTRUMENTATION DEVELOPMENT AND TESTING TECHNIQUES
  • TAO Zhi-gang, YANG Wei, LIU Wei-xin, JIANG Chao-chao, CHEN Yi-fan
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 128-134. https://doi.org/10.11988/ckyyb.20161243
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    Practice has proved that in using traditional pre-stressed cable for the monitoring and early warning of open-pit mine landslide, cables would fracture and result in failure of the whole monitoring system when sliding force is higher than the material strength of pre-stressed cables. In view of this, Prof. Manchao He developed a system of anchor cables with high constant resistance for monitoring large deformation. The system has been used in open-pit mine for landslide monitoring. In this paper, the effect of negative Poisson’s ratio of the cables is revealed in geometric and strain dimensions through indoor static tensile tests. The structure of the high constant-resistance cable is described, and the working mechanism of monitoring large deformation is analyzed by establishing a mechanics model of high constant resistance. Results manifest that the cable of high constant-resistance can be stretched to a maximum of 850 mm with a constant resistance of 500 kN. The cable has been applied to the safety monitoring of slope at Nanfen open-pit iron mine, and provided monitoring and early-warning for the landslide on 31st July, 2010.
  • CONSTRUCTION AND MANAGEMENT OF WATER CONSERVANCY PROJECTS
  • HUANG Jian-wen, ZHANG Yi-chi, YUAN Hua, HUANG Ming, GONG Shi-qi, JIANG Hai-long
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 135-140. https://doi.org/10.11988/ckyyb.20171250
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    Construction road is a crucial factor to ensuring the construction of high arch dam project; however, construction road is often damaged because of complex environment and uncertain factors. In an attempt to restoring the function and transport intensity of the damaged road as soon as possible, a network model for internal construction road of a high arch dam containing twenty-three nodes is established as case study based on complex network theory in line with the characteristic of high arch dam’s construction site. Leaderrank algorithm is employed for the mining and verification of important nodes of the road network. Node-failure mode verification results demonstrate that the node rank result accords with the actual project. The research could offer theoretical basis for road management and emergency maintenance of construction road for high arch dam.
  • THE TENTH NATIONAL SYMPOSIUM ON FUNDAMENTAL THEORIES OF SEDIMENT RESEARCH
  • WU Men-wu, YAN Li, YANG Liu-zhu, LU Chen, YANG Yu-gui
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 141-145,153. https://doi.org/10.11988/ckyyb.20171029
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    The formation of mouth sand bar outside Modaomen Estuary of the Pearl River is subject to the influences of stream flow, tidal current, offshore current and wave. Besides, morphological condition and sediment transport are also key factors affecting the evolution of mouth sand bar. According to measured topographic data in the last four decades, this study is devoted to analyze the evolution of the central and western parts of mouth sand bar and its tidal channels. The morphological evolution in the mouth sand bar area is also investigated. Results indicated that 1) promoted by big flood events, the tidal channels on both sides of mouth sand bar extended and broadened stepwisely; 2) the eastern channel presented a certain swing trend, which was affected by explicit seasonal characteristic and wave effect; 3) the inner and outer slopes of central mouth sand bar were eroded, while the crest was deposited and heightened, with the north-south diameter shortened; 4) the Jiaobei sand bar on the west side was crescent-shaped due to the wave effect, and was prone to be scoured with channel down cutting by flood. The research result provides reference for the planning and rectification of the estuary.
  • WANG Bin-yan, YAN Dong-chun
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 146-153. https://doi.org/10.11988/ckyyb.20171063
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    Sediment source is an important information that connects particles from hill slopes and small watersheds to river channels. In order to reveal the basic law of sediment transport and deposition in the riparian zone of the Three Gorges Reservoir, we investigated the horizontal and vertical variation of particle size distribution and 137Cs activity among sediment samples collected in the study area, and analyzed the implication of such variations on sediment sources. Results showed that median particle size (D50) of sediments gradually became finer along the flow direction and stabilized in general in Zhongxian County and its lower reach; while the 137Cs activity of sediment samples rose along the flow direction but was not as stable as particle size in the downstream of Zhongxian County. Sediments collected around H=148 m had the largest particle size and the lowest 137Cs activity compared to samples from other altitudes. Except for this river-adjacent area, particle size grew larger with the increase of altitude when the soil could be eroded easily in the upper hill slope; on the contrary, particle size became smaller with the increase of altitude when the upper hill slope was used for forest, indicating slight soil erosion. Therefore, vertical variation of particle size was greatly influenced by the land use of the hill slope above the riparian zone. In contrast, vertical variation of 137Cs activity in three sampling transects were all falling at first and rising later with the increase of altitude despite the different land use of upper hill slope. On the basis of these variations, it could be judged that sediment deposited at the riparian zone in the fluctuant backwater area was sourced mostly from the Jinsha River and the Jialing River. In the permanent backwater area, coarse sediment with a grain diameter ≥62 μm in the riparian zone had distinct sources compared to fine sediment whose grain diameter was <62 μm. Coarse sediments from the Wujiang River deposited at the reach from Fuling to Renjia. In the reach from Renjia to the Three Gorges Dam, coarse deposited sediment sourced dominantly from soil erosion in the tributaries within the Three Gorges Reservoir basin. All potential sources including the Jinsha River, the Jialing River, the Wujiang River and soil erosion within the basin all showed significant contributions to the fine sediments in the permanent backwater area. In addition, wave erosion redistributed deposited sediments. Surface particles could be eroded into the water and deposit on the locations with lower altitudes.
  • RAN Xi, GU Pan, LIAN Lei-lei, ZUO Jian, QIU Rui-ming
    Journal of Changjiang River Scientific Research Institute. 2018, 35(6): 154-158. https://doi.org/10.11988/ckyyb.20171035
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    In an attempt to explore the influence of coal mining and karst water exploitation on Jinci spring, the discharges in spring area are simulated by multiple linear regression model and back propagation (BP) neural network model under two scenarios (in the absence of karst water exploitation and in the absence of coal mining drainage, respectively) for comparison. In line with the study area’s driving factors, the Jinci spring area is generalized as a multi-input system with dual output. Precipitation, karst water exploitation amount, and coal mining drainage amount in the current year and previous seven years are selected as input; the total discharge of Jinci spring, inclusive of outflow and side discharge, is taken as output. The relations between each input and output are established. Under the annual average conditions of 1956-1994, 1) the results of multiple linear regression model manifest that karst water exploitation had reduced the discharges of Jinci spring area by 0.42 m3/s, coal mining had cut the outflow by 0.23 m3/s, in total of 0.65 m3/s; 2) while the results of BP neural network model shows that karst water exploitation reduced the discharges by 0.30 m3/s,coal mining by 0.27 m3/s,and the total influence was 0.65 m3/s, which was nonlinear. Both stochastic models reflected severe impact of coal mining on Jinci spring area since coal mining and karst water exploitation exacerbated after the 1980s.