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01 December 2017, Volume 34 Issue 12
    

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    RIVER-LAKE SEDIMENTATION AND REGULATION
  • HE Fang-zhou, ZHU Yong-hui, GUO Xiao-hu, CHEN Dong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 1-6. https://doi.org/10.11988/ckyyb.20160909
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    Recovery of suspended sediment concentration along the river downstream of reservoir is a core subject in river dynamics research. The research in this area helps to push the advances of river dynamics and solve problems in engineering application. In this article, the research achievements of vertical distribution of sediment concentration under equilibrium and non-equilibrium transport conditions are summarized. The observed data of suspended sediment concentration recovery along natural channels and the research results of recovery saturation coefficient are also concluded. Research on vertical distribution of sediment concentration under non-equilibrium state is still defective. The methods of observed data acquisition and data analysis also need to be improved. Finally, scientific and systematic flume experiments with accurate measuring instruments should be conducted in further studies.
  • LONG Rui, Tomoaki Nakamura, Yonghwan Cho, Norimi Mizutani, Tsuyoshi Kanazawa
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 7-11. https://doi.org/10.11988/ckyyb.20170785
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    It is essential to effectively reduce the generation of turbidity and pollution in dredging works. In this paper, the flow field during the drop of a sealed grab bucket was simulated with a three-dimensional coupled fluid-structure-sediment-seabed interaction model (FS3M), and the impact of different drop modes on turbidity was discussed in order to propose the optimal drop operation for reducing the turbidity effectively. Numerical results showed that a decrease in the drop speed of the bucket could effectively reduce flow velocity at the bottom, suggesting a reduction in the generation of turbidity from the bottom. In particular, reducing the drop speed of grab bucket to one-third at 3 meters from the bottom is found to be the most effective.
  • WATER RESOURCES AND ENVIRONMENT
  • LI Jun
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 12-16. https://doi.org/10.11988/ckyyb.20160841
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    In traditional fuzzy set analysis of flood season staging, the identification of interval and threshold of flood season is strong subjectivity, and in the meantime, only single factor is considered. In view of these problems, an improved fuzzy set analysis method is proposed. Index weights are calculated by using the variation coefficient method, and then all the indexes in every ten days are combined to obtain a comprehensive index to replace the original single indicator. Subsequently, the membership degree is calculated by fuzzy set analysis method, and flood season and non-flood season are divided. Finally, flood season staging is completed by searching the change point through the mean shift point method. The staging result of the improved fuzzy set analysis is generally consistent with those of mathematical statistics method and traditional fuzzy set analysis method. The improved fuzzy set analysis method proposed in this paper is proved to be of high applicability.
  • CHANG Jian-jun, CHEN Wei, AI Chan
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 17-21. https://doi.org/10.11988/ckyyb.20160729
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    The driving factors of industrial water consumption in Wuhan city circle is discussed in this article. The driving factors of industrial water consumption are divided into industrial water consumption per unit, industrial structure, economic scale and population size based on Logarithmic Mean Divisia Index. From the overall point of view, economic growth and population expansion promote the increase of industrial water consumption, and the main factor is economic growth; decrease of industrial water consumption per unit and the adjustment of industrial structure have inhibitory effect on industrial water consumption. The effects of driving factors on industrial water consumption in Wuhan city,Huangshi city,Xiaogan city and Qianjiang city are substantially consistent with the overall effect;in Ezhou city,only the decrease of industrial water consumption per unit shows inhibitory effect;in Huanggang city,Qianjiang city,Xiantao city and Tianmen city,only economy growth shows promoting effect on industrial water consumption. The results provide reference for the planning of industry water consumption and water-saving policy in Wuhan city circle.
  • LAI Guang-dong, ZHOU Wei-bo, YAO Bing-guang
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 22-27. https://doi.org/10.11988/ckyyb.20161274
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    A suitability evaluation system for shallow confined water source heat pump in Xi’an is constructed in consideration of thirteen factors including water abundance, reinjection efficiency, hydraulic conductivity, and aquifer thickness. The weight of each factor is determined by using analytic hierarchy process method and Gini coefficient method. In addition, GIS technology is employed to build up a two-level evaluation model for spatial analysis, and the suitability of the study area is divided into four levels. Results reveal that the area of favorable region for constructing water source heat pump system in the study area is 1144.32 km2,the area of suitable region is 1393.57 km2, the area of moderately suitable region is 762.48 km2, and the area of unsuitable region is 6807.63 km2. The total area of suitable region is 3300.36 km2, accounting for 76.98% of the human activity area, indicating that shallow confined water source heat pump has a good prospect in Xi’an city.
  • QIU Yun-xiang, ZHANG Xiao-xiao, LIU Guo-dong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 28-32. https://doi.org/10.11988/ckyyb.20160837
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    To better describe the spatial distribution of rainfall, we applied BP neural network optimized by particle swarm optimization to the daily, monthly and yearly rainfall spatial interpolation of the Three Gorges reservoir area, and compared the performance with those of simple BP and Kriging interpolation. We found that in daily and yearly time-scale, PSO-BP neural network performs better than BP and Kriging; while in terms of monthly time-cale, PSO-BP result is close to BP and better than Kriging. We conclude that BP neural network optimized by particle swarm optimization could better reveal the law of spatial distribution of rainfall and has the ability of spatial interpolation in different timescales, and therefore is an excellent method for rainfall spatial interpolation.
  • ENGINEERING SAFETY AND DISASTER PREVENTION
  • ZHANG Hao-yu, ZHOU Ke-qin, SONG Ya-teng, LI Li-li
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 33-37. https://doi.org/10.11988/ckyyb.20160869
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    Dam deformation monitoring is an important task to refrain from hazardous situation for dam and population. The use of Ground Based Synthetic Aperture Radar (GB-SAR) provides great potential for dam deformation monitoring due to its strong capability of large area and high accuracy. In this paper, a Fast-GBSAR based on the Frequency Modulated Continuous Wave (FMCW) technology is presented to monitor the dam deformation when the dam discharges water. The data acquisition speed of the Fast-GBSAR could achieve 7 second per set, compared with 5 minute per set acquisition speed of the IBIS system. Besides, the SAR image is also combined with the DEM model to evaluate the overall deformation of the dam. Analytical results show that dam monitoring based on Fast-GBSAR can be nearly in real time.

  • LI Hua-jin, XU Qiang, HE Yu-sen
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 38-43. https://doi.org/10.11988/ckyyb.20160889
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    Hazard mapping is a prevailing part of spatial analysis of landslides. Previous researches use runout distances to map the hazard ranges. In this paper, we present an improved methodology by using the dataset that contains all runout distances of landslide locations in Heifangtai area. According to the runout distances, the landslide locations are categorized into six groups. For each group, the kernel density estimation and Value-at-Risk (VaR) measurement are conducted for statistical modeling. Statistical results indicate a kernel density with MISE=68.7238 fit the probability distributions of runout distances best. Furthermore, for each group, hazards are mapped according to the runout distances at different levels of risks (DR). According to the experimental results, a preventive construction measure is proposed in the location computed as DR for Groups I, II, III and VI. Meanwhile, the correlation between moisture content and runout distance in Group IV and V is derived by further numerical analysis.

  • HYDRAULICS
  • HUANG Guo-bing, DU Lan, WANG Cai-huan, NIE Yan-hua
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 44-47. https://doi.org/10.11988/ckyyb.20160864
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    Rare research has been reported on the water-wing in slit-type bucket caused by contracted sidewall which poses a threat on bank slope stability. In this article, a physical model is setup to investigate into the relation between the type of bucket (contraction ratio β and bucket angle θ) and the characteristic of water-wing for revealing the motion law of water-wing in slit-type bucket and the distribution characteristic of rainfall intensity formed by the water-wing near downstream. Results show that along with the decreasing of contraction ratio, the water-wing is ejected higher, and at the same time, the scope of rainfall is larger and its location is closer to the outlet; whereas along with the decreasing of bucket angle, the water-wing trajectory doesn’t change obviously, but the lateral diffusion aggravates, resulting in the increase of rainfall range. On this basis, a concept of secondary water-wing lateral diffusion coefficient is proposed to predict the shape and scope of rainfall caused by secondary water-wing in different slit-type buckets. The research results could enrich the research contents of slit-type bucket, expand research range, and provide more theory foundation for design.
  • ZHU Shi-hong, WANG Zhi-juan, LI Xian-fang, WANG Gai-hui
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 48-52. https://doi.org/10.11988/ckyyb.20161332
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    To improve the design of nature-like and technical fish passage, we propose a pool structure for a hydropower plant based on the target fish species requirements, and analyse the plane and 3-D flow pattern in pools by numerical simulation and physical model test. Result shows that by adding contraction section, side baffle block and strip bottom sills in nature-like and technical fish passage pools, the flow field in pools can be divided into different layers in longitudinal direction and different zones in horizontal direction to meet the requirements of different fish species with varying swimming performance. The proposed pool structure has advantages in velocity control and species selectivity compared with traditional nature-like and technical fish passage, and has practical application value.
  • ZUO Hai-feng
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 53-56. https://doi.org/10.11988/ckyyb.20160890
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    In order to improve the stability and computational efficiency of hydrodynamic simulation, a method of junction-point water stage prediction and correction(JPWSPC)is proposed to deal with the backwater effects at the junctions between general open-channel networks and hydraulic structures. On this basis, a one-dimensional hydrodynamic model is established to calculate the variations of water level process and hydraulic detention time under different water diversion demands. Results show that in the presence of diversion and storage of hydraulic structures, different diversion flow has no obvious effect on water areas and water landscapes; while hydraulic detention time is closely related to overflow discharge. Through optimizing and adjusting diversion flow and diversion ratio, the model provides a technical basis for ensuring efficient utilization of water and reducing economic costs.
  • ROCK-SOIL ENGINEERING
  • ZHANG Jia-fa, DING Pei-zhong, CHANG Jing-xiong, WANG Jin-long
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 57-62. https://doi.org/10.11988/ckyyb.20160939
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    Cushion layer is an important subarea of concrete faced rockfill dam (CFRD). Prior to the construction of CFRD for Shitouxia Hydropower Station in Qinghai, China, sandy gravel materials collected from riverbed were checked, and the results revealed that the weight percentage of fine grains in the samples screened under mesh size of 100 mm( directly screened cushion material) was likely inferior to the low limit required for cushion layer. Seepage destruction and filter tests were performed for the directly screened materials and transition zone materials. Seepage field in the dam and probable maximum hydraulic gradient values both in cushion and transition zones were forecasted by numerical simulation method. The applicability of tested samples were assessed on the basis of seepage characteristics for cushion zone materials in response to the functional requirements of water leakage and seepage destruction control. The directly screened materials were judged unsuitable for cushion layer. Moreover, a scheme was proposed to improve the filling material by adding fine grains screened under mesh size of 5 mm to the directly screened material. The improved materials were checked with seepage destruction and filter tests, and were demonstrated applicable for dam cushion layer. The dam has been built up and has performed well during reservoir impoundment even under earthquake. This example tells the necessity of research on filling material throughout the construction of any embankment dam. Proof tests and applicability assessment should be taken for the natural or produced materials as early as possible before the dam fill construction.
  • LIU Yuan-kun, SHI An-chi, HAN Xiao-yu, XU Jing
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 63-67. https://doi.org/10.11988/ckyyb.20160806
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    In order to address the difficulty and low success rate of conventional stress detection methods applied to jointed and fractured rock mass, we found that the method of strain relieving in the bottom of borehole is applicable and we employed this method to the columnar jointed rock mass of the dam foundation of a hydropower station. Through this method, we obtained the plane stress of the jointed rock mass and the three-dimensional stress state from three boreholes in different directions. The stress results transformed to the borehole coordinate system were close to the test results of single borehole stress, verifying the calculation results. In conclusion, the method of strain relieving in the bottom of borehole could be well applied to the stress measurement of fractured rock mass such as columnar joints.
  • ROCK-SOIL ENGINEERING
  • CUI Hao-dong, ZHANG Wei, ZHANG Jia-fa, WU De-xu
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 68-72. https://doi.org/10.11988/ckyyb.20161358
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    Seepage field regulation is crucial for the stability of canal slope and liner plate along the middle route of the South-to-North Water Transfer Project, especially for stretches excavated in expensive soil area with high groundwater level. In this article, the seepage field of a typical section was simulated with 3-D finite element technology to investigate into the rationality and effectiveness of seepage regulation measures comprehensively. The distribution of seepage field was analyzed and the seepage control measures were compared. Results show that the uplift pressure on canal pavement would be reduced significantly by drainage cushion with drainage holes opening only when groundwater level is higher than the canal water level, by drainage cushion replaced by drainage board, and by drainage holes replaced with permeable joints of liner plate in addition. The differences in the three measures were compared, and their application conditions were discussed and corresponding suggestions were given.
  • JIANG Jie, CHEN Jun, XIAO Meng, WEI Yong-chao, MA Shao-kun
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 73-77. https://doi.org/10.11988/ckyyb.20160904
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    The bearing capacity of cast-in-place bored pile of large diameter in soft rock foundation in Nanning is difficult to determine due to softening and disintegration characteristics when soaked in water. Static load test was conducted to determine the bearing capacity of bored pile in the soft rock interbedding foundation of an elevated platform project in the railway station of Nanning Ciy. Both exponential function fitting method and numerical back analysis were used to accurately predict the load-settlement relation and ultimate bearing capacity of test pile which did not reach the ultimate state. Results show that the load-settlement curve of bored pile in soft rock interbedding foundation is an adjustment curve and the pile works as end bearing friction pile. As common design methods of pile foundation at present underestimates the bearing capacity of pile in this foundation, exponential function which is used to describe the load-settlement behaviour of test pile and numerical back analysis can be combined to estimate the ultimate bearing capacity of test pile.
  • WU Yong-jin, DONG Zhi-hong, ZHANG Cun-hui, ZHANG Lian
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 78-83. https://doi.org/10.11988/ckyyb.20170437
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    The problem of horizontal cracks in rock-bolted crane girders in underground powerhouse of a hydropower station was very prominent with a lot of penetrating cracks even in construction period, posing safety risks on the long-term stable operation. According to the design and construction condition, the bearing behaviors of the girders with different horizontal cracks distribution were studied by numerical approach and the deformation and forces of crane girder were analyzed. Results show that the horizontal cracks could reduce the local stiffness of girders and increase the deformation. Tensile stress concentrated near the crack tip, and the distribution of tensile stress widened, with some exceeding the allowable range. Nevertheless, the horizontal crack has little effect on the safety factor of the anti-sliding stability. Since the rock-bolted crane girders must be in long-term safety, reinforcement in the horizontal crack concentrated area is needed.
  • KOU Tian, HU Bin, HE Da-zhao, MAO Yuan-jing, YAO Wen-min
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 84-88. https://doi.org/10.11988/ckyyb.20160797
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    The aim of this research is to investigate the feasibility of non-proportional dynamic double strength reduction method in slope stability analysis. According to the 3-D progressive failure process and strength parameters of slope in ABAQUS software, the cohesion c and internal friction angle φ in Mohr-Coulomb strength criterion are converted into yield strength σ and internal friction angle β in Drucker-Prager strength criterion, and then the comprehensive stability coefficient of slope is determined through the shortest path to evaluate the slope stability. Results suggest that the non-proportional dynamic double strength reduction method based on Drucker-Prager criterion could reflect the progressive failure process and the roles of strength parameters; the slope stability coefficient obtained by Drucker-Prager criterion is highly close to that calculated by the M-C strength criterion, and the slope stability coefficient and displacement are both smaller than those of traditional strength reduction results with higher safety reserve.
  • ZHAO Xuan, MA Shu-zhi, TANG Wei-min, FENG Cong-jie
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 89-93. https://doi.org/10.11988/ckyyb.20160872
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    Due to strict control for the displacement of retaining structure in excavation engineering, the theory of soil pressure in non-limit state should be considered in the calculation of soil pressure of limited soils. However, most previous studies were confined to the earth pressure of sandy limited soil under non-limit state, and the calculation methods are based on traditional Rankine’s earth pressure theory which is not applicable in semi-infinite boundary condition. In view of this, for cohesive limited soils which do not meet the semi-infinite boundary conditions, we divided the trapezoidal sliding wedge soil into blocks, and established the differential equation of earth pressure strength of cohesive limited soil at non-limit state according to the curves of mobilized angles of internal friction and external friction and mobilized cohesion vs. displacement angle, respectively. Furthermore, we derived the calculating formula for earth pressure of cohesive limited soils at non-limit state. Calculated values are larger than measured values in the range from soil surface to a certain depth of the pit; while beyond that depth, the calculated values conformed well with measured values but differed greatly from Rankine’s value. In general, the calculation method presented in this paper is reasonable and feasible.
  • CHEN Jun, ZHAO Peng, HE Wei-feng, WANG Qi
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 94-100. https://doi.org/10.11988/ckyyb.20160816
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    In the aim of researching the shear strength properties of red clay under the condition of alkali pollution, laboratory simulation test with varying lye concentration and curing time was conducted to analyze the interaction between lye and red clay. Results showed that the shear strength, cohesion, and internal friction angle of the alkali-polluted red clay were higher than those of undisturbed red clay when the alkali concentration was high to some extent. The time when shear strength, cohesion and internal friction angle reached maximum was affected by lye concentration. On the contrary, in the presence of low lye concentration, the shear strength of alkali-polluted red clay decreased until a minimum value; while cohesion increased and then decreased, and internal friction angle decreased and then increased. Shear strength behaviors of red clay in the presence of alkali pollution is the result of hydration, ion adsorption, cation exchange, dissolution and external forces.
  • LIU Xiao-yan, LIU Lu-lu, YAN Kun-fa
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 101-105. https://doi.org/10.11988/ckyyb.20160466
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    In the present research, uniaxial creep test was conducted under different axial compression levels at varying freezing temperature (-5℃,-10℃,-15℃) by WTD-100 artificial frozen soil apparatus to investigate the accelerating creep of frozen brown mudstone. The brown mudstone in a coal mine shaft in Shaanxi Province was taken as research object. Test results showed that the frozen brown mudstone experienced three stages of transient elasticity, deceleration and stability under low axial pressure, and four stages of instantaneous elasticity, deceleration, constant velocity, and acceleration under high axial compression level. The influence of axial compression on frozen brown mudstone is much greater than that of temperature. Moreover, by connecting nonlinear viscous dampers with strain start, an optimized Nishihara model with seven elements was established based on classical Nishihara model, and the model parameters are analyzed through nonlinear regression by the least square method. Analysis results showed that the fitting curves of the optimized Nishihara model are in good agreement with the experimental results. The optimized Nishihara model is more specifically suitable for describing the variation rule of nonlinear accelerating creep characteristics of frozen brown mudstone.
  • XIE Wo, LU Kun-lin, ZHU Da-yong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 106-110. https://doi.org/10.11988/ckyyb.20160781
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    In practical engineering, rock mass in the long and narrow deep foundation pit of subway station is usually excavated in partitions. To obtain the stability rules of deep foundation pit excavated in partitions, finite difference software was adopted for numerical simulation. The deep foundation pit of a subway station in Hefei was taken as a case study. Through comparison between model results and field measurement results, the variation rules of retaining structure’s lateral displacement and lateral support axial force and ground surface settlement during partition excavation were obtained. Results show that 1)field measurement results are in agreement with numerical simulation results, both within standard limits, indicating that the numerical model could well reflect the deformation characteristics of the foundation pit; 2) with the proceeding of excavation, the “belly” of retaining structure bulged apparently, with the maximum displacement point moving towards the middle of the foundation pit; 3) axial force of support developed rapidly in the early stage, and then tended to be stable; 4) the adjacent ground surface settlement was in a groove shape, and the range within 40 m was affected by foundation pit excavation. The results could be taken as reference for the design and construction of similar projects.
  • HYDRAULICS STRUCTURE AND MATERIAL
  • CHEN Qin, GONG Ya-qi, QI Yong-feng, XIE Zhi-qiang
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 111-114. https://doi.org/10.11988/ckyyb.20170408
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    Gravity load case is generally the control condition of the reinforcement design of high arch dam. Because of the particularity and complexity of the construction process of high arch dam, there are several ways to apply gravity load, such as joint deadweight and whole deadweight. In this paper, the influence of gravity applying approach on corridor stress and reinforcement of high arch dam is studied through three-dimensional finite element analysis. Results show that in whole deadweight case, the stress and reinforcement area of the corridor structure are apparently small; while in joint deadweight case, the stress and reinforcement area of the corridor structure of are obviously larger than those of the deadweight results according to construction process. According to the actual construction process and the bearing capacity law of the structure, gravity load should be considered in the construction process in finite element calculation of arch dam to ensure structural safety and economic rationality. The research achievements could be taken as reference for the design of overflow outlet structure.
  • LIU Qi, XIA Zhen-yao, LIU Da-xiang, ZHANG Lun, YAO Xiao-yue, XU Wen-nian
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 115-121. https://doi.org/10.11988/ckyyb.20160800
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    The aim of this research is to study the influence of grain size distribution of shale ceramsite on the bulk density, compressive strength, void ratio and pH value in the internal voids of porous concrete for plant growing. First of all, we set up two groups of grain size distribution of shale ceramsite, and measured the basic physical properties such as stack density, apparent density, void ratio and bibulous rate for mixture proportion design. Furthermore, we added fly ash, compound fertilizer, FeSO4 and vinyl acetate emulsion into yellow brown loam to prepare modified soil, which was further mixed with humus and vermiculite powder in a proportion of 2∶2∶1 to obtain planting substrate flurry of a fluidity of 210-240 mm. Then we carried out planting tests with two planting structures: a. seeds in humus overhead the porous concrete; b. seeds in substrate among voids of the porous concrete. Test results showed that with the changes of grain size distribution and target void ratio, the bulk density of 12 groups of porous concrete varied between 600-800 kg/m3; compressive strength of the porous concrete at the age of 28-day was above 5 MPa; and the pH value of internal voids between 11 to 12. Under necessary maintenance and management conditions, plants could completely grow well in the porous concrete, indicating that the mixture proportion of planting substrate is good.
  • LI Yu-jie , ZHAO Shi-ying, LUO Rong
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 122-125. https://doi.org/10.11988/ckyyb.20160802
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    Wall and column structures above the generator layer are primary concerns for studying structural vibration issues of ground powerhouses in hydropower plants. In this article, the influences on free vibration characteristics of a powerhouse when the wall and column structures are connected by steel frames with large stiffness are studied. Furthermore, the influences of sealing structures on stress distribution of powerhouse structures are also studied with design schemes in ANSYS models. The calculation results show that connecting the wall and column structures with steel frames is favorable for the overall vibration characteristics of powerhouse. But the improvement is not remarkable. On the other hand, the position of sealing structures significantly affects the stress distribution, especially stress distribution of volute concrete, of powerhouse structures under designed working loads. These findings provide useful references for the structural design and sealing structure optimization of powerhouses in hydropower plants.
  • INFORMATION TECHNOLOGY APPLICATION
  • LIU Pei, YANG Jun, SONG Pu-bin
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 126-129. https://doi.org/10.11988/ckyyb.20170773
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    Widely applied in OA (Office Automation) systems, workflow technology is faced with challenges of diversity and volatility. In view of this, we found that the diverse and volatile work flows are mainly caused by the coordination among departments and individuals instead of single procedure change. On this basis, we present a scalable workflow system based on procedure profiling. First, the functionalities of OA system are split and mapped to different atomic units according to the functions of different departments. Second, to satisfy the requirements of inter-departmental collaboration and continuous updates for workflows, a workflow is combined with atomic steps within the jurisdiction of each department. The system retains usability and scalability characteristics.
  • INSTRUMENTATION DEVELOPMENT AND TESTING TECHNIQUES
  • YAN Cheng-ming, CHEN Hong, WU Yan-jun, ZHANG Jun
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 130-132. https://doi.org/10.11988/ckyyb.20160960
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    Real-time topographic data are useful for river bed evolution analysis and engineering assessment. In this article, a real-time online monitoring system for riverbed terrain is developed based on ultrasonic technology, 4G
    wireless transmission and network database. An ultrasonic sound speed calibration device is presented to eliminate the influence of temperature and salinity on measurement results. The sound speed is obtained by inversion and is calibrated in real time according to the time intervals of ultrasonic transmission and reflection signal acquired by timer. The system is applied to the terrain monitoring in the downstream of Yaojiang Gate. In monitoring period, the river bed silted by 0.041 m, while the GPS-RTK observation result is 0.050 m, consistent with each other in general. Practice has shown that the presented system is reliable and feasible in real-time monitoring of river terrain.

  • NUMERICAL MANIFOLG METHOD BASED ON INDEPENDENT COVERS
  • SU Hai-dong, CHEN Ji-zhan, XIE Zhi-qiang, QI Yong-feng
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 133-139. https://doi.org/10.11988/ckyyb.20160710
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    Using Numerical Manifold Method (NMM) based on independent covers proposed in previous study, we attempted a new way of integrating Computer Aided Design (CAD) and Computer Aided Engineering (CAE). Taking 2D static analysis of linear-elastic structures for example, we accomplished the seamless link from CAD to CAE and the total automatic CAE analysis. On the basis of previous study of NMM based on CAD geometry, we put forward algorithms for cutting NURBS (Non-uniform Rational B-spines, regarded as the general graphic standard in CAD) curves with straight lines, hence preserving the shape of geometric model in procedures of CAE modeling and mesh refinement. Meanwhile, data of structural shape, loads and constraints defined in CAD are directly transferred to CAE by means of DXF graphic format of AutoCAD. Furthermore, by using adaptive analysis based on rectangular independent covers, we conducted automatic static analysis of structures and automatic finite elementmeshes for post-processing graphic output of computational results. In association with the above studies, we took a 2D static structure as example to illustrate the entire procedures, including CAD modeling and output, automatic pre-processing, automatic analysis and automatic post-processing in CAE, in which all procedures were automatically accomplished by computer, except for manual operation of CAD model. Finally, we obtained calculated results with given precision.
  • SU Hai-dong, XIE Zhi-qiang
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 140-146. https://doi.org/10.11988/ckyyb.20161345
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    At present, some new numerical methods such as Numerical Manifold Method (NMM) and Meshless Method are facing with the difficulty of strictly applying essential boundary conditions. Through a case study of a cantilever beam, the application of essential boundary conditions is systematically analyzed in NMM based on independent covers previously proposed by the authors. On the basis of polynomial cover functions, two methods are presented: one is the improved method of boundary cover functions; and the other is the method of setting independent cover functions. The boundary conditions are strictly satisfied, and the approximate functions near the boundaries are guaranteed to approach the real solutions. The proposed methods are refrained from the influence of penalty number in common penalty method on computational results and linear equation conditions. Moreover, the implementation is very simple, for it just needs some degrees of freedom not involved in the computation.The proposed approach of applying boundary conditions by setting cover functions has a reference value for other new methods.
  • SU Hai-dong, YUAN Xiao-chen, GONG Ya-qi
    Journal of Changjiang River Scientific Research Institute. 2017, 34(12): 147-154. https://doi.org/10.11988/ckyyb.20170128
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    In previous research of adaptive analysis using Numerical Manifold Method based on independent covers, the internal error in an independent cover cannot be effectively controlled. In view of this, a submodel method for error analysis of independent covers is presented, in which, by means of increasing the cover function order in an individual independent cover, a new error estimator for point-by-point error is obtained by calculating the differences of the results between high-order and low-order cover functions. The procedures of the submodel method are introduced in detail, and a case study of a gravity dam shows that the method could effectively control the internal error of independent covers, laying foundation for point-by-point error control in the future. Finally some preliminary theoretical analysis and discussions are given for the convergence principle and the error-control method of Numerical Manifold Method based on independent covers.