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01 November 2017, Volume 34 Issue 11
    

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    WATER RESOURCES AND ENVIRONMENT
  • HAN Hui-qing, SU Zhi-hua, ZHANG Jiao-yan, CAI Guang-peng, ZHANG Chao-qiong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 1-5. https://doi.org/10.11988/ckyyb.20160773
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    In this article,the spatial and temporal variation laws of heavy precipitation days in Guizhou Province in the past 54 years were analyzed based on daily precipitation data obtained from 19 meteorological stations from 1960 to 2013 by means of climate change trend analysis and Kriging interpolation. Results revealed a decline trend of heavy precipitation days in the past 54 years in Guizhou Province, with a sharp decline trend in the central and west parts whereas a slight increase or slight decline in the eastern, southern and northern parts. Heavy precipitation days in areas of different slope gradients were similar. With the increase of elevation, heavy precipitation days showed a decrease trend. Heavy precipitation days in Beipan River, Duliu River, Hongshui River and Nanpan River were greater than those in Chishui River, Niulan River, Wujiang River and Yuanjiang River. Heavy precipitation days showed an increase trend in Duliu River and Nanpan River, while a decline trend could be found in other watersheds. The study also showed significant differences in heavy precipitation days among elevation, slope gradient and watershed in flood season and non-flood season. The results offer reference for meteorological disaster prevention and control in Guizhou province.
  • YU Ze-xing,HU Guo-hua,CHEN Xiao,GU Qing-fu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 6-11. https://doi.org/10.11988/ckyyb.20160735
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    Quantitative evaluation of the effects of precipitation variation and human activities on runoff in Liuyang River watershed is conducive to a more rational utilization of water resource. In this paper we analyzed the evolution law of and the relationship between runoff and precipitation in 1969—2013 in Liuyang River basin by means of linear fitting, moving average and accumulative anomaly. We also estimated the contribution rates of precipitation variation and human activities to runoff variation in different periods quantitatively by comparing cumulative slope variance ratio. Results indicated that precipitation displayed an increasing trend in a rate of 3 mm/(10 a), while runoff represented a decreasing trend in a rate of 2.7 (m3·s-1)/(10 a). Precipitation and runoff both witnessed an abrupt change in 1989 and 1999 in a trend of “decrease-increase-decrease”. Compared with the baseline period from 1969 to 1988, the contribution rates of precipitation variation to runoff variation in 1989—1998 and 1999—2013 were 56.8% and 7.62%, while the contribution rates of human activities in 1989—1998 and 1999—2013 were 43.2% and 92.38%, indicating that human activity has become the main factor which affects the runoff variation in Liuyang River watershed.
  • SHENG Feng, ZHANG Li-yong, WU Dan
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 12-17. https://doi.org/10.11988/ckyyb.20160770
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    Preferential flow is a common flow pattern of infiltrated rain and irrigated water in unsaturated soils, and characterizing preferential flow is always a hot topic of soil hydrology researches. In this research, the wavelet packet entropy, including the Shannon entropy and logarithmic energy entropy, was used to characterizing the preferential flow heterogeneity under different infiltration conditions. The research results were compared with those characterized by matrix entropy and fractal characteristic parameter to show the feasibility of applying wavelet packet analysis to preferential soil water flow. The results show that: 1) the wavelet packet entropy is capable of characterizing the heterogeneity of preferential flow patterns; 2) the heterogeneity of preferential flow increases firstly and then decreases as the infiltration amount increases; 3) the heterogeneity of preferential flow increases steadily as the experimental scale increases within this research.
  • ZHANG Xiang-yu,DONG Zeng-chuan,SONG Rui-ming,HAN Rui,XU Bo-liu,LUO Yun
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 18-22. https://doi.org/10.11988/ckyyb.20160775
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    Due to problems in the water resources allocation of Yellow River basin, the method of water consumption in proportional increase or decrease with the increasing or decreasing of river discharge may have negative effects on rational water utilization. Traditional scheduling methods could not coordinate the harmonious development between resources and society. In view of this, a multi-objective optimization model for water resource allocation was established in consideration of the impartiality and rationality of regional water use based on the actual situation of the Yellow River. Furthermore, the model was solved by applying improved genetic algorithm. Research results show that through the improved genetic algorithm, water resources of the mainstream Yellow River can be rationally and scientifically allocated to different segments. The rate of water scarcity in the whole study area is below 10% and the water allocation results meet the requirements of ecological flow of river cross-section, which also conform to the ecological and social requirements of development and utilization of water resources. The comprehensive benefits of water resources developed to the greatest extent.
  • ZHANG Lin, ZHOU Jian-yin, WANG Jia-sheng, LI Li-gang, YANG Qi-hong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 23-26. https://doi.org/10.11988/ckyyb.20160822
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    According to design hydrological conditions and water quality targets, the water environment capacity of control sections of Guanlan River in Shenzhen was calculated with COD as the calculation index, and the monthly environment capacity was allocated. Furthermore, based on pollution source investigation and the handling ability of ewage treatment plants, the total amount of pollutants discharged into the river was obtained and was compared with the environment capacity. Results show that the environmental capacity is very small compared with the amount of pollution into the river, which far exceeded the maximum carrying capacity of river. Especially in dry season in December, the total amount of pollutants into the river is 62.2 times the water environmental capacity. On this basis, a comprehensive plan of water pollution control is put forward: pollution discharge reduction, pollution dredging, clean water recharge, and ecological restoration.
  • LEI Meng-ting
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 27-32. https://doi.org/10.11988/ckyyb.20160690
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    In the aim of testifying the efficiency and feasibility of shuffled frog leaping algorithm(SFLA)- projection pursuit (PP) model in assessing utilization efficiency of regional water resources, an evaluation system consisting 15 indexes in terms of comprehensive aspect, industry, agriculture, living and ecological environment was established. Furthermore, SFLA algorithm was used to optimize the best projection direction of PP model. In consequence, a SFLA-PP model for evaluating utilization efficiency was proposed and compared with PP model optimized by invasive weed optimization (IWO) algorithm, particle swarm optimization (PSO) algorithm and cuckoo search (CS) PP algorithm, respectively. Then an evaluation standard of four levels (high, medium-high, medium and low) was constructed on the basis of the mean value and standard deviation σ of the model projection series. Eight counties of Wenshan autonomous prefecture were chosen for case analysis. Results showed that the fitness value of PP model optimized with SFLA algorithm was 715.800 2, superior to that with IWO, PSO and CS algorithm, with better precision and ability of seeking optimum extreme value. According to SFLA-PP model, the utilization efficiency of Wenshan City and Yanshan County was evaluated as high level, and that of Malipo County was evaluated as low level, and the remaining five counties as medium level. The utilization efficiency of water resources in the study area was at high level in general. Case evaluation and sorted results of SFLA-PP model were the same with those of IWO-PP model, but different from PSO-PP and CS-PP model. Finally, examples demonstrated that the solving accuracy of the four intelligent algorithms was crucial for the evaluation results.
  • WATER-SOIL CONSERVATION AND ECO-CONSTRUCTION
  • CHEN Xiao-lin,XU Wei-ming,XIAO Gui-rong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 33-38. https://doi.org/10.11988/ckyyb.20160780
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    Selecting indicators and determining their weights are worthy of discussion in the suitability assessment of soil and water conservation measures. In this article, a fuzzy weight-of-evidence model which is both knowledge and data driven was introduced to avoid the subjective arbitrariness in selecting indicators and determining their weights. The enclosing measures of Changting County were taken as case study. By screening out seven factors in natural suitability and social suitability, the posterior probability was calculated by comprehensively considering parameters of all factor layers, and then the maps of suitability classification were obtained. Compared with the distribution of enclosing measures from 2014 to 2015, the results show that 38.5% of the measures are highly suitable, 43.5% moderately suitable, 82% above moderately suitable, and 9.2% averagely suitable, which is highly consistent with the actual situation. The results prove that the fuzzy weight-of-evidence model could evaluate the suitability of soil and water conservation measures objectively and accurately. The results also provide reference and theoretical basis for governments in implementing soil and water conservation measures.
  • FLOOD PREVENTION AND DISASTER REDUCTION
  • LIU Lian,HU An-na,SONG Ling,LUO Shu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 39-43. https://doi.org/10.11988/ckyyb.20160740
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    Time variation of water-retaining risk and uncertainty of filling progress aggravate the difficulties in making decision for high rock-fill dam construction in flood period. Accordingly, the water retaining risk of high rock-fill dam was calculated by stochastic simulation, and then was classified into three risk states which could indicate the decision actions. With the objective of minimizing the cost of the entire construction process in flood season, the critical factors such as incoming flood flow, filling schedule and cost of decisions were taken into account to build a decision-making model based on Markov Processes. By using this model, the flood prevention strategies, cost functions and transfer probability for each risk degree were analyzed. After testing the Markov property, the optimal strategy for each state at current time and a sequential risk decision path in this process can be predicted by strategy iteration method. A study case shows that the adjustment results by the proposed model consists well with the actual construction plan change for water retaining elevation. The results offer reference for timely and accurate flood prevention scheme in construction period.
  • ENGINEERING SAFETY AND DISASTER PREVENTION
  • YUAN Dong,HU Sheng-gang,LI Yu-jie
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 44-47. https://doi.org/10.11988/ckyyb.20160746
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    With the reinforcement project of non-pressure diversion tunnel of a hydropower station in Guizhou as background, this research aims at the engineering diseases such as deformation and cracking of side wall of tunnel, detachment of rock blocks from tunnel vault and upheaving of tunnel floor caused by weak expansive mudstone. According to the geological characteristics of the study area, we analyzed the deformation of surrounding rock by means of tests and geological radar, and found that the swelling of rock triggered by long-term water immersion is the main cause of engineering diseases. Moreover, by simulating the stress and strain distribution of sidewall in 3-D model, we proposed a restoration scheme involving drainage and water insulation, supplemented by anchor reinforcement and partition demolition in severely deformed sidewall area. In addition, we put forward some requirements for construction techniques, such as the installation of check valve on sidewall and the demolition and reconstruction of sidewall. The restoration project has finally achieved good practical result.
  • HU Tian-yi, XU Pu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 48-53. https://doi.org/10.11988/ckyyb.20160657
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    Concrete arch dam, as a highly statically indeterminate structure, has strong adaptability and integrity. Traditional statistical models for concrete arch dam mainly focus on the deformation of a single point rather than the interaction among different points. In this article, the spatial autocorrelation of errors of different points at the same instance was mined by using spatial econometric method. Furthermore, the errors were modified by using the spatial regression model, and hence a spatial error model for concrete arch dam was established. As an example, the deformation sequences of 34 monitoring points in Xiaowan arch dam were studied and the results show that the error panel data are of strong positive correlation, and the spatial error model is superior to traditional statistical models.
  • HYDRAULICS
  • ZENG Tao,DONG Liang,LIU Shao-bei,ZHANG Chang-lian,WANG Yong,HE Yu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 54-60. https://doi.org/10.11988/ckyyb.20160718
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    The flow pattern of liquid phase in the first cell of anaerobic baffled reactor(ABR) was studied in association with laser particle image velocimetry(PIV) under the combined conditions of different inlet flow rates and suspension heights of inlet pipe of the ABR.Flow field data at key section in downward flow area and upward flow area of the reactor were obtained, and the curves of velocity of liquid phase and vorticity intensity vs. suspension height were acquired. Meanwhile, characteristics of relevant flow fields were obtained, including streamline pattern and vorticity field. Results revealed that reasonable suspension height of water inlet pipe was important for the first cell of ABR, for it could ensure good flow pattern, uniform distribution of ABR vortex area, effective prevention of local channel flow and dead zone at liquid phase and stable operation of ABR. According to the experimental results, we suggest the range of suspension height of inlet pipe between 230-530 mm when flow rate is in the range of0.018-0.270 m3/h , and 530 mm when flow rate is in the range of0.558-0.846 m3/h.
  • ROCK-SOIL ENGINEERING
  • YUAN Jun-ping, SHI Yu-zhou, DING Guo-quan, WANG Qiang-lin
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 61-65. https://doi.org/10.11988/ckyyb.20160795
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    The purpose of this research is to obtain the microscopic structural characteristics and the variation rules of macroscopic engineering properties of rock and soil materials. We discussed the issues of statistical error, pixel size, and statistical algorithms for pixel-particle-filling method by simulating pore structures in rock and soil samples using PFC2D (2-dimensional particle flow code). Results show that taking into account both statistical error and algorithmic efficiency, we recommend 1/20 of the radius of the smallest particle as the proper radius for pixel-particle-filling used for pore structure statistics. We also compared three pore volume statistical algorithms and found that round-off method is the optimal. Moreover, we proposed a method to obtain the curve of equivalent pore size distribution, based on which further research works are able to be conducted on the 3D pore structures model, the characteristics of the pore structures and the relationship among these characteristics and macro-mechanical behaviors and engineering properties of rock-soil.
  • LAI Xia-lei,JIAN Wen-bin
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 66-71. https://doi.org/10.11988/ckyyb.20160754
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    In some projects there are restrictions in static loading tests and thus the characteristic load bearing capacity is unable to be determined. Through analyzing a project of cement-soil pile composite foundation, the ultimate bearing capacity of the piles and composite foundation is predicted with “gray model” under limited test conditions. Meanwhile, the ratio of the bearing capacity to the characteristic bearing capacity determined from relative deformation is defined as safety reserve index “K”, and 113 groups of static loading test are analyzed to obtain the K value of this region. The statistical result is confirmed by the project. It should be noticed that K is a regional and experiential value, and it can be used to predict the ultimate bearing capacity of cement-soil pile composite foundation based on the known bearing capacity determined by relative deformation.
  • WEI Xiang, YANG Chun-he, WANG Gui-bin,CHEN Shi-wan, HUO Liang
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 72-76. https://doi.org/10.11988/ckyyb.20160678
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    Structural homogeneity of rock mass is divided according to project features. In practice, we must choose influential elements of the project as the basis of dividing. In this article, a method integrating qualitative and quantitative approaches of dividing structural homogeneity of rock mass is put forward for researching the permeability of rock mass with boreholes for deep geological disposal of high-level radioactive waste. Research results revealed that fracture and alteration zone were not fully taken into account in the qualitative method based on mechanical causes of structural plane. On the other hand, in quantitative method such as Miller method, fracture width as a major factor affecting the permeability of rock mass was ignored. In conclusion, to combining qualitative and quantitative methods could achieve better results by taking into account more parameters of structural plane as well as more detailed dividing parts. The proposed method provides data support for subsequent network modeling and seepage calculation.
  • REN Guang-bo, XIAO Cheng-zhi, ZHOU Xia, HE Chen-xi
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 77-83. https://doi.org/10.11988/ckyyb.20160703
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    In this article, strength reduction method was employed to investigate the stability of slope reinforced in shallow surface. Moreover, the influences of reinforcement width, cohesion of reinforced soil, reinforcement depth (the depth of reinforcement area penetrating into foundation), and geometric parameters of slope on the stability and slip surface of slope were analyzed in the presence of soil foundation (the same material with slope soil) and rock foundation, respectively. Results showed that in the presence of soil foundation, the safety coefficient declined and then increased with the increasing of cohesion regardless of reinforcement width, and then remained stable once cohesion reached a critical value. With the increase of soil cohesion in the reinforced zone, the failure surface of slope moved from shallow surface to deep layer and then passed beyond the reinforced zone lastly. In this sense, increasing the depth of reinforced zone in the foundation could help enhance the stability. On the other hand, in the presence of rock foundation, the safety coefficient declined and then increased linearly in general with the increase of reinforced soil cohesion. With the same geometric parameters and soil material of slope, the safety coefficient was 0.5-1 times that of slope with soil foundation. As cohesion in reinforced zone increased, which means shear strength increased, the safety coefficient improved correspondingly.
  • PENG Shi-long, RONG Chuan-xin, CHENG Hua
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 84-88. https://doi.org/10.11988/ckyyb.20160731
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    Freezing pressure is an important basis for the design and calculation of the outer wall structure of shaft sinking by freezing method in deep alluvium. On the basis of uniaxial creep test of frozen soil, the generalized Kelvin rheological model and the elastic-viscoelastic correspondence principle were adopted to establish the viscoelastic equation of displacement field of frozen wall. Then, the mathematical expression of the freezing pressure acting on the outer shaft lining is deduced by considering the interaction among the frozen wall, the outer shaft lining and the peripheral unfrozen soil. Calculation results show that 1) the calculation value by theoretical formula and from mean measured value of the freezing pressure show a big difference(about 0.5 MPa) in the first ten days after the construction of outer shaft lining masonry; 2) the freezing pressure tends to be stable after 20 days, and the absolute value of the difference between the two is less than 0.2 MPa. In a word, the absolute deviation between the theoretical and calculated values of freezing pressure is less than 10%. The theoretical calculation formula of freezing pressure is quite practical and it could provide basis for the structural design of outer shaft lining of freezing well.
  • ROCK-SOIL ENGINEERING
  • JIANG Yu-zhou,WANG Ben,WANG Rui-hong,LU Bo,LI Cong, ZHU Jie-bing
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 89-95. https://doi.org/10.11988/ckyyb.20170327
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    According to rock mechanical characteristics of creep deformation at different stages, the visco-elastic-plastic states from deformation to rupture are classified, and the corresponding creep mechanical properties at different states are given. Under the assumption that ductile shear failure occurs in triaxial compression test, the maximum principal strain discriminant for the critical state transformation is derived using Drucker-Prager strain criterion. Furthermore, a visco-elastic-plastic damage evolution model for describing the nonlinear acceleration creep behavior is constructed by introducing a statistical damage factor based on the theory of Perzyna in consideration of the hardening effect in subsequent yield. Moreover, triaxial creep test is conducted with sandstone specimens from the Three Gorges Reservoir area, and the creep deformation curves under different pressures are acquired. Test results show that the creep characteristics of rock specimens are obvious, and non-linear accelerated creep happened under the final stress level. The proposed model is used for the fitting of test creep curves, and the fitting results suggest that the model could accurately describe different stages of sandstone’s creep deformation.
  • WANG Yang, MA Shu-zhi, JIA Hong-biao, REN Chuan-jian
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 96-100. https://doi.org/10.11988/ckyyb.20160733
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    Rainfall and evaporation give rise to the change of moisture in unsaturated soil, hence resulting in the change of matrix suction. In view of this, we applied the water flow control equation to the calculation of Rankine’s earth pressure of unsaturated soil at steady state. Meanwhile, we overcome the shortcomings of Rankine’s earth pressure by deriving the formulas of active earth pressure and passive earth pressure under rainfall and evaporation conditions in consideration of the influence of intermediate earth pressure. Results showed that under the condition of rainfall, with the increase of parameter b and the decrease of rainfall intensity, the active earth pressure decreased gradually and the passive earth pressure increased gradually; while under the condition of evaporation, with a gradual increase of parameter b and evaporation intensity, the active earth pressure decreased gradually and the passive earth pressure increased gradually. Taking the influences of rainfall, evaporation and intermediate principal stress into account in calculating the earth pressure is more consistent with the actual situation, and could also give more play to unsaturated soil’s properties.
  • ZHANG Zhi-qiang, GUO Yuan-cheng, DU Hao-ming, JIN Jun-wei
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 101-106. https://doi.org/10.11988/ckyyb.20160784
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    An increasing number of deep foundation pit project in complex conditions has emerged with the comprehensive transformation of old urban area in the process of urbanization. Deep foundation pit projects with single sup-port could not easily meet the requirements of usage and economic benefit simultaneously, which, however, can be effectively addressed by composite support. In this research, a foundation pit project encountering existing power tunnel, air-raid shelter and old pile foundation in Zhengzhou city was taken as a case study of composite support form. Through analysis on geographical environment, engineering geological conditions, construction condition, and construction safety, a composite support plan integrating pile anchor and soil nailing structure is adopted. Monitoring results show that the composite support plan could well solve the problems posed by complex environment.
  • WANG Chong,WANG Qi-cai,ZHANG Rong-ling,MA Li-na, XUE Yan-jin,CUI Xiao-ning,LI Jin-qian,WANG Bing-zhong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 107-111. https://doi.org/10.11988/ckyyb.20160761
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    Mudstone with low content of clay minerals is determined not expansive by existing railway standards. However,it is still of weak expansion in water,and has potential damage to high-speed railway which is tolerable to a deformation of only 4 mm. In this article,we take the reshaped mudstone with low content of clay minerals in the foundation of a high speed railway as research object, and analyze the effects of initial water content, dry density and overburden load on the bulging limit condition by expansion test under overburden load. Results show that:1) expansion ratio of mudstone in bulging limit condition increases with the increase of dry density when initial water content and overburden load are stable;2)the greater the initial water content is, the smaller the expansion rate in bulging limit condition is when dry density and overburden load are stable;3) expansion rate and water content in bulging limit condition both decrease with the increasing of overburden load when the initial water content and dry density are stable. Furthermore, we obtained the fitting calculation formula of expansion rate in bulging limit condition of mudstone. Verification result shows that the difference between measured value and predicted value by the formula of expansion rate in bulging limit condition is small. The fitted formula could be used to predict expansion in practical engineering to provide guidance for engineering.
  • ZHANG Liang-hua, XIE Liang-fu, LI Xing-ming
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 112-115. https://doi.org/10.11988/ckyyb.20160673
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    The spatio-temporal evolution of toppling deformation of an anti-dip bedded rock slope was researched in this article. On the basis of engineering geological survey data, the toppling deformation of bank slope was partitioned into many zones, and then the temporal variations of toppling deformation in different zones were analyzed based on surface displacement monitoring data. Furthermore, inverse distance weighting (IDW) interpolation method was employed to obtain the contours of toppling deformation. Results suggest that 1) the front part of the bank slope is dominated by horizontal deformation and the back part by vertical deformation; the global deformation of slope is controlled by the front part’s deformation; 2) the belt-like deformation area in the middle of bank slope determines the evolution of global deformation of bank slope, which correspondingly lags behind the deformation in central area. Moreover, the increase in the displacement of central belt-like deformation area would induce the increase in the total displacement of the rear. The belt-like area is considered as collarbone section of the toppling deformation.
  • HYDRAULIC STRUCTURE AND MATERIAL
  • WANG Xing-meng, LU Yi-yan, JIN Lu, LEI Dong-shan
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 116-120. https://doi.org/10.11988/ckyyb.20160256
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    In order to ensure the safe operation, we carried out quality inspection and analysis on the aqueduct structure of Wangchuan River diversion project. Parameters of the aqueduct inclusive of appearance defects, concrete strength, concrete carbonization depth, and corrosion of steel reinforcement were obtained through the quality inspection. On this basis, an ANSYS finite element model was established and the internal forces of control sections of the aqueduct were analyzed. By comparing the model results with the ultimate bearing capacity of aqueduct, we conclude that the bearing capacity of aqueduct body was insufficient, and the structure needs to be reinforced.
  • LIU Bo-wen, PENG Gang, MA Xiao-liang, XIE Jing-hui
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 121-125. https://doi.org/10.11988/ckyyb.20160674
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    In this research, dynamic cyclic loading and unloading tests at strain rate of 10-4s-1 under different unidirectional constant pressures are conducted on a large multi-functional static and dynamic force triaxial apparatus. Constant lateral pressures are 0%, 5%, 10% of the static uniaxial compressive strength. On this basis, the variation of hysteresis loop of stress-strain curve of concrete under cyclic loading and unloading with varying stress level is researched. The relation between dispersion hysteresis loop and energy dissipation is analyzed, and the damage estimation model is built. Furthermore, the damage characteristics of concrete are researched based on energy dissipation statistics. The following conclusions are obtained: 1) in initial unloading stage, the stress decreases rapidly and deformation recovers slowly, but the speed of recovery begins to accelerate with stress declining; 2) dissipative energy significantly increases with the increase of lateral stress under the same number of cycles, indicating that unit dissipated energy is apparently sensitive to lateral stress; 3) the damage estimation model of concrete is verified to perform well in fitting the relationship between damage and cumulative residue strain; 4) the development of damage decreases gradually with the increase of lateral pressure ratio, and in addition, the path of damage accumulation is greatly extended.
  • DU Chao, WU He-gao, SHI Chang-zheng, SU Kai
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 126-131. https://doi.org/10.11988/ckyyb.20160878
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    The deformation and stress condition of exposed steel penstock under non-uniform temperature due to sunshine during overhaul are analyzed through ANSYS which is based on a typical part of penstock in a hydropower station. Further simulations on the deformed penstock applied with internal water pressure are also carried out. Results indicate that when bearing internal water pressure, the deformed exposed penstock induced from the former non-uniform temperature shows obvious increasing lateral displacement to the cold side and bending in horizontal plane. The temperature effects are more obvious if the pressure is higher. A bigger gap between supports and lateral dampers brings about lower reaction around supports and constraint plates while weakens the restraint of dampers to penstock. In order to strengthen the restriction to penstock and relieve reaction, it is recommended to reduce the distance between pier foundations around bellows expansion joint because deformation and reaction here are enormous. Meanwhile, enlarging the lateral damper appropriately is necessary to avoid penstock sliding away from supports under the non-uniform temperature.
  • INFORMATION TECHNOLOGY APPLICATION
  • KUANG Run-yuan, XIE Jia, ZHANG Meng, LI Wen-hong, ZHANG Gang-hua
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 132-137. https://doi.org/10.11988/ckyyb.20160728
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    Particle size of suspended sediment, as an important parameter reflecting water quality, has an influence on the spectral reflectance of water. Study of the relationship between particle size and reflectance is of great significance to water environment monitoring in inland lakes. In this paper, the suspended sediment particle size of the Poyang Lake was retrieved using different mathematical models based on correlation analysis according to measured spectral reflectance data. Results show that: 1) volume percentage median diameter is suitable for the retrieval model for turbid area; while quantity percentage median diameter is suitable for clear water; 2) in turbid area, single band Ⅳ is the sensitive wave band; whereas in clear water, single band Ⅱ and single band Ⅲ are sensitive wave bands. In addition, the reflectance ratio of band Ⅱ to band Ⅲ is the sensitive wave band in the whole study area; 3) in the retrieval model of single band reflectance, power function is suitable for the retrieval of suspended sediment particle size in the Poyang lake; while in the model of band reflectance ratio, polynomial model is the most suitable.
  • ZHENG Ru-bin,WANG Hao-wei, XU Tong, ZHU Li-chen
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 138-143. https://doi.org/10.11988/ckyyb.20161262
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    Environmental Internet of Things (EIoT) has been widely applied to environmental monitoring. The existing research of environmental monitoring based on EIoT mostly aim at specific location and specific problem without considering the management of many separate EIoT systems. With the growing number of EIoT system, how to manage these systems centrally and effectively becomes concerned focus. The problem faced by step-by-step deployment of EIoT systems is the ubiquitous heterogeneity in the sensing layer, transmission layer and application layer of EIoT. Through analyzing the characteristic of environmental monitoring and EIoT system, the meta data that can be used for EIoT system management is extracted. A unified management framework of EIoT system is proposed to manage the heterogeneous EIoT system effectively. The heterogeneity problem can be solved by detecting the abnormal data in application layer and blocking the differences in sensing layer and transmission layer among various EIoT systems.
  • INSTRUMENTATION DEVELOPMENT AND TESTING TECHNIQUES
  • HU Xiang-yang, XU Ming, ZHANG Wen-er, MA Zhi-min
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 144-147. https://doi.org/10.11988/ckyyb.20160669
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    In response to the demand of rapid measurement of water surface boundary in river model test, an instrument based on the laser scanning principle is developed. The instrument adopts high-resolution line matrix CCD and laser triangulation principle to detect and identify the water surface rapidly. It has been successfully applied to the synchronization acquisition of a wide range of flow velocity in physical river model. The instrument has advantages of high speed, high precision, and non-contact measuring, hence could be a feasible alternative for rapid measurement of water surface boundary in physical river model.
  • THE NINTH NATIONAL FORUM ON RIVER LAKE REGULATION AND WATER ECOLOGY CIVILIZATION DEVELOPMENT
  • LIU Chuan-shun, LU Xiao-yi, WANG Shu-fa, CHEN Xi-meng, HUA Cheng-pu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 148-152. https://doi.org/10.11988/ckyyb.20170725
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    Lakeshore slumping and recession resulting from wave erosion usually causes heavy loss of waterfront property and land resources. Ecological revetment has become the new trend of lakeshore erosion control. In this paper, vetiver is adopted to protect lakeshore against wave attack because of its well-developed root system, phytomechanical properties and adaptability to adverse environment. With the shore-protection works of Donggang Lake as a case study, the patterns and techniques of planting vetiver are introduced. Furthermore, the erosion rates of bare soil lakeshore and vetiver lakeshore were computed and compared using lateral erosion model. Results show that vetiver planting on lakeshore could reduce the shore erosion rate by over 90%. Compared with rigid revetment, ecological revetment is more economic and more environmentally friendly.
  • LIAO Wei-ling, HUANG Jian-sheng, DING Jian-gang, LIU Min, CHEN Ting-ting, TONG Qi-bang, YAO Yuan, LU Sheng-hong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(11): 153-158. https://doi.org/10.11988/ckyyb.20170730
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    As an extreme phenomenon of water pollution, malodorous black water body causes ecological damage, and seriously affects residents’ life and physical and mental health as well as the sound development of city. In this paper, the causes and pollution status of malodorous black water bodies in China were analyzed. The remediation technologies were classified into physical technology, chemical technology and biotechnology, and the principles, advantages, disadvantages and applicability of these remediation technologies were introduced. Through the analysis of practical projects in China and abroad, the experiences of success and failure were summed up. It is necessary to transform the traditional concept of remediation into a feasible remediation route. Only if we select proper combinations of technologies according to the actual situation and local conditions can we maintain a long-term remediation effect.