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20 October 2015, Volume 32 Issue 10
    

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    WATER RESOURCES AND ENVIRONMENT
  • ZHANG Yi-qing ,LIU Xiao-yan
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 1-5. https://doi.org/10.11988/ckyyb.20141035
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    There are abundant coal, petroleum and natural gas resources in China’s golden delta of energy. The exploitation of energy resources together with the related industries drives and supports the regional socio-economic development. But the region is located in the northwest of China, facing with severe water supply shortage. With Ningxia autonomous region as an example, the status of water resources is analyzed in this paper. Furthermore, on the premises of the balance constraint of regional water, the lowest per capita living water security constraint, the lowest per capita food security constraint and the regional eco-environmental water constraint, the method of optimizing the allocation of water resources among industries is given through calculations of potential water-saving quantity in the condition of marginal output equilibrium. Finally, policies of reducing the gap of water utilizing efficiency among industries are put forward.
  • HE Zi-Li,GUO Zhan-juan,YANG Jian-guo
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 6-10. https://doi.org/10.11988/ckyyb.20140181
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    In view of its excellent prediction performance of support vector machine regression (SVR) model for nonlinear system, a model of residual chlorine prediction was put forward to predict changes in water supply system based on SVR. Moreover, two-order oscillating particle swarm optimization algorithm (SOPSO) was employed to optimize the SVR model parameters in order to enhance the model precision in small sample situations and improve the generalization ability of the model. This optimized model was applied to predict the residual chlorine in a water supply system, and the results showed that: in the case of limited samples, the average prediction error of the optimized SVR model is 3.86%, which is better than that of BP and ARX prediction models, and also has strong stability. This model could solve the problems of low fitting accuracy and poor efficacy of prediction which often appear by traditional models. It provides a new approach for the model construction and algorithm selection in residual chlorine prediction for water supply system.
  • WATERSOIL CONSERVATION AND ECOCONSTRUCTION
  • PENG Jun ,LI Xiang-yu ,YAN Rui-xin ,MA Xiao-li
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 11-16. https://doi.org/10.11988/ckyyb.20150126
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    Loess collapse has become a technological problem in the infrastructure in Northern Shaanxi area severely threatening the safety of traffic and buildings. But systematic and summative studies on the failure modes and prevention measures are rarely seen. In this paper according to the peculiar development characteristics of loess slope in Northern Shaanxi, typical loess collapses in this region are comprehensively analysed, and the failure modes are summarized. In terms of failure pattern, the loess collapses are divided into spalling, caving, step-falling, toppling, sliding, and roof-falling. And in terms of collapse mechanism, the loess collapses are driven by stress, joint development, human and precipitation disturbance, as well as the combined action of multiple factors. In addition, commonly adopted countermeasures are summarized and effective measures corresponding to different failure modes are proposed.
  • ENGINEERING SAFETY AND DISASTER PREVENTION
  • WANG Jin-hai ,CAI Zhi-jie ,SU Wen-jun ,WU Rui ,YU Zhong-hong
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 17-22. https://doi.org/10.11988/ckyyb.20140486
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    To provide basis for the stability assessment and protection work design of Pilu Cave,high density electrical technique was applied to the geophysical prospecting of rock fracture and landslide disaster in the grotto.The effects of fracture development,engineering and hydrologic and geologic conditions on the deformation of grotto and ground surface were explored.Results indicated that rock fractures in the Liubenzhen Sculptures Grotto and Thousand Buddha Cave are well developed,and will develop further under the action of surface water erosion and plant’s root growth, posing severe adverse impact on the stability of the cave. Connected groundwater and vertically-developed water-bearing fracture zone are main factors affecting the stability of landslide, and the water-bearing fracture zone together with the weak contact zone of different rocks forms the attachment surface of the landslide’s back edge, which is unfavorable for the slope stability.
  • WAN Chen ,LI Jian-feng ,ZHAO Yong ,ZHANG Jin-long
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 23-27,32. https://doi.org/10.11988/ckyyb.20140310
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    A dam settlement prediction model integrating BP neural network model and Markov chain prediction was built in this paper. Through emulating the training samples, rolling prediction for the settlement displacement time series was performed by the metabolism-improved BP neural network algorithm. Furthermore, Markov chain was used to correct its random disturbance and the prediction results were improved. This model was applied to the settlement displacement timing prediction of Changzhou dam lock control building. The result shows that the model has high prediction accuracy and good reliability. It improves the long-term prediction ability, and provides an effective method for dam settlement prediction.
  • HUANG Li, LUO Wen-qiang, LI Fei-ao, LIU Xiao-shan
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 28-32. https://doi.org/10.11988/ckyyb.20140350
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    Rainfall and reservoir water level variation are major external factors inducing landslide. Hysteresis and periodicity of rainfall and reservoir water level variation are important influence factors of landslide displacement. In this paper, a multivariate time series model with rainfall and reservoir water level variation as impact factors of displacement prediction was established. The effect of hysteresis and periodicity of rainfall and reservoir water level variation on the cumulative displacement of landslide was considered. Baishuihe landslide in Three Gorges Reservoir area was taken as a case study. Firstly, gray model was employed to extract the trend term displacement; and then the lagged variations of rainfall and reservoir water level were used to predict the displacement of the periodic term; finally, the predicted value of accumulative displacement is obtained by superposing the displacements of the trend term and the periodic term. Results prove that the dynamic effects of inducing factors on the cumulative displacement of landslide could be well reflected by this model. It has high prediction accuracy, with the average absolute error 1.97%.
  • HYDRAULICS
  • ZHU Hai-feng ,LIU Liu ,LU Bo ,LUO Jia ,WANG Yu ,QIAO Ye ,LIU De-fu ,SHI Xiao-tao
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 33-37. https://doi.org/10.11988/ckyyb.20140359
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    To conserve downstream migratory fish, a variety of fish passage facilities have been built in view of the specific operating characteristics and the needs of fish conservation when building dams and weirs. In this paper we first briefly introduce measures frequently adopted to help downstream migratory fish pass a dam through spillway, turbine, fishway, fish transportation system and ship lock, etc. In subsequence we introduce in details the new technologies in foreign countries developing passage facilities for downstream migratory fish such as surface collector, full-depth fish gathering technology, bypass, fish trap-transportation system, fish-friendly turbine and auxiliary technologies. Finally we propose that we should learn the experiences from developed countries to meet the great needs of downstream migratory fish to passage dams in China, particularly fish gathering and fish guiding technologies. Meanwhile, China will need to develop fundamental research and make breakthroughs in the area of fish passage.
  • YANG Ji-jian ,LIU Han-sheng ,ZHANG Wei-fa ,DAI Shu-bing
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 38-42. https://doi.org/10.11988/ckyyb.20140295
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    To explore the hydraulic characteristics of stepped spillway at high altitude, we conducted model test on the stepped spillway of a dam with slope θ=32°and dam crest at elevation 2586.0 m. By changing the incoming flow rate, we compared the hydraulic characteristics (time-averaged pressure in vertical and horizontal planes, water surface profile, flow velocity, and fluctuation pressure) in different conditions. Results prove that in all the three conditions, the stepped spillway has high energy dissipation efficiency and no cavitation. Pressure on step vertical plane and horizontal plane distributes in a bouncing manner along the spillway, and the height of water surface and the flow velocity will keep stable after reaching a certain value.
  • LIU Dan ,SUN Xi-huan ,SHI Ji-zhong ,Li Yong-ye
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 43-46. https://doi.org/10.11988/ckyyb.20140347
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    In order to solve the lack of energy dissipator and the low flood control capacity of spillway, rubber dam was constructed to improve the potential efficiency of spillway. To explore the effects of building rubber dam in the control segment on the hydraulic characteristics of spillway, factors such as the flood discharge capacity of spillway, the characteristics of flow and the effect of export energy dissipation were analyzed in association with engineering example. Research results show that: the discharge capacity of spillway decreases when being constructed with rubber dam, but safety operation of spillway can be guaranteed because the capacity still meets the damand of engineering design; the rubber dam has a little influence on flow velocity of spillway , and flow velocity variation of front of the dam is bigger than that of back of the dam; under the condition of rubber dam collapse or water filling, variation trend of water surface profile is similar, and sudden changing points are located near rubber dam or the position where gradient changes; moreover, the effect of rubber dam on energy dissipation and scouring prevention is slight, so it is feasible to construct a rubber dam in the control segment of spillway. The results can also be taken as reference for similar engineering design and disaster relief and strengthening of small and medium-sized reservoirs.
  • DAI Shu-bing ,LIU Han-sheng ,JIAN Yue ,YANG Ji-jian ,BIAN Xiao-wei
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 47-52. https://doi.org/10.11988/ckyyb.20140199
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    A set of theoretic hydraulic calculation method for X-shape flaring gate is presented for the first time to provide theoretical support for engineering design and scientific research. The water of X-shape flaring gate is divided into two parts: the water in the notch and the water above the notch. Through momentum equation, the hydraulic jump equation is derived and is converted mathematically in equivalence and simplified to get the conjugate depth ratio η, and then the depth after the jump is obtained. As an illustration, the measured data of Suofengying project and Shatuo project are taken to calculate corresponding parameters, which are subsequently put into the simplified water jump equation to calculate the conjugate depth ratio η. Finally, the maximum relative error between the calculated water depth after the jump and the test value is only -5.11%, indicating that the equation is convenient and is derived correctly and reliably.
  • DONG Yu,LIU Han-sheng, CAO Chang-chong
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 53-56. https://doi.org/10.11988/ckyyb.20140360
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    TVD method is especially suitable for the numerical simulation of discontinuous wave of hyperbolic partial differential equations. In this paper, four typical TVD schemes were presented for the numerical simulation of water hammer equations. Through comparison among example calculation, numerical results and theoretical solutions, the differences in numerical performances in aspects of the dissipative and compressible features of different types of TVD schemes were revealed, and TVD schemes were proved to be superior to conventional difference methods. Calculation results in the presence of varying Courant numbers showed that modified Harten’s TVD scheme, TVDMC scheme and full discrete TVD scheme have poor stability in the presence of a wide range of Courant numbers; whereas optimized Sweby’s TVD scheme for water hammer simulation has good stability and high precision.
  • ROCK-SOIL ENGINEERING
  • DAI Qing-li
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 57-64. https://doi.org/10.11988/ckyyb.20150165
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    In this paper, a numerical analysis procedure which integrates the first-order reliability method (FORM) and the modified Latin hypercube sampling technique (LHIS) is adopted in the probabilistic stability analysis to explore the inherent variability of parameters of a highly weathered rock slope in practical engineering. Effects of spatial variability of parameters on the slope stability are taken into consideration. The LHIS technique is employed to calculate the probability distribution of safety factor, and meanwhile the FORM is used to determine the critical failure surface and conduct preliminary sensitivity analysis, then the influence of model input parameters on slope stability is obtained. Moreover, Spencer’s limit equilibrium method is employed to calculate the value of Fs of the instability failure surface and to evaluate the function G(X) and then to calculate the reliability index. Results reveal that the characteristics of highly weathered rock slope can be more truly reflected by considering the spatial variability of parameters rather than traditional single parameters; the number of simulation is apparently reduced and the efficiency is improved by using LHIS rather than using traditional sampling method; the reliability theory and probabilistic stability analysis method are more suitable to analyze the effect of parameter’s spatial variability on the safety of highly weathered slope than traditional limit balance method.
  • HUANG Zhi-peng ,TANG Hui-ming ,DONG Zhi-hong ,YIN Jian-min ,GUO Xi-feng
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 65-69,73. https://doi.org/10.11988/ckyyb.20140720
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    Due to developed faults and structural planes and huge excavation height, the deformation and failure mechanisms of the high slope at Dabenliugou quarry of Jinping-ⅠHydropower Station are complicated. On the basis of engineering geological analysis, we analysed the deformation features and failure mechanism of the slope, and assessed the slope’s stability through numerical calculations. Results showed that: 1) unloading rebound is the major form of slope deformation, and vertical deformation is greater than horizontal deformation, the sliding deformations of interlayer staggered surface and steep dip fault are large, and shallow interlayer staggered surface is mostly in shear limit state and discontinuous opening state; 2) partial plastic zone (largely in tensile failure and a bit shear failure) mainly distributes in thin sandy slate, interlayer shear zone and the slope’s shallow surface; 3) the failure mechanism of high slope of Dabenliugou quarry is buckling failure; 4) the safety factor of slope after excavation meets standard requirements.
  • YANG Chen-guang ,ZHONG Quan ,LENG Zhen-dong ,YAN Peng ,LU Wen-bo
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 70-73. https://doi.org/10.11988/ckyyb.20140301
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    Good gradation is required for the filling material of concrete face rock-fill dam in order to ensure good compaction and drainage. Taking the rock-fill material quarrying at Houziyan hydropower station on Dadu river as a research background, we summarize 6 groups of field blasting test in Selonggou quarry, and analyze the main factors affecting the rock-fill material gradation based on different blasting designs and screening results. Research results show that the gradation is affected by spacing between blasting holes, length of stem blocking, and unit consumption of detonator. Before large-scale stone quarrying, blasting tests should be conducted for each impact factor in order to determine the optimal blasting parameters. Through the field blasting tests, blasting scheme and parameters that can be used to get eligible rock-fill material are obtained, and the achievements in this research can be guidance and reference for similar projects.
  • LIU Xiao-hong ,ZHU Jie-bing , ZENG Ping ,WANG Bin
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 74-77,84. https://doi.org/10.11988/ckyyb.20150141
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    As the hydro-fluctuation belt of 30 meters high in the Three Gorges Reservoir area becomes fragile and sensitive, the bank slope’s rock mass quality and its deterioration rules are increasingly becoming a research focus. In this paper, a typical siltstone rock slope in Badong segment of the Three Gorges Reservoir area was selected as a research object. Uniaxial compression test and slake durability test on siltstone samples were carried out by means of drilling in-site, in-door machining and wetting and drying cycles. The test results suggest that siltstones in the research area belong to hard rock, and its uniaxial compressive strength reduces along with the increase of cyclic number. However after 20 cycles of wetting and drying, the strength of siltstone weakens and displays the characteristics of soft rock. Moreover, the siltstone has high slake durability, and the slake durability index (Id) is in logarithm function relationship with the wet-dry cycle number (N), which means that Id reduces with the increase of N, and the decrease of Id gradually slows down along with N increasing. Meanwhile, in the presence of the same cyclic number, the higher elevation siltstone samples come from, the lower Id value they have. These research results could be reference for obtaining the deterioration rules of rock mass and rock slope stability analysis in the hydro-fluctuation belt of Three Gorges Reservoir area.
  • BAO Lei ,CHEN Chun-wu ,PAN Kun ,LUO Xiao-qin ,ZHANG Jin ,LEI Jin-sheng
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 78-84. https://doi.org/10.11988/ckyyb.20140314
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    A model of analyzing the mechanics of hydraulic tunnel with gently dipped layered jointed rock with long span and high sidewall was established using UDEC based on the non-continum theory. The wave velocity characters, displacement distribution, stress distribution and plastic zone distribution, as well as the stability of surrounding rock at different positions of the tunnel under seismic action were analyzed. The response of surrounding rock during earthquake action was acquired. Results revealed that under sine shear seismic wave in vertical direction, the dynamic characteristic of monitoring points in vertical direction were more apparent than that in horizontal direction; in the initial stage of seismic wave action, the displacement of sidewall was larger than that of the roof, and the displacement of bottom surrounding rock was largely affected by seismic action as time went by; after the seismic action, the stress of monitoring points all increased slightly; and plastic zone in the tunnel’s sidewall and the bottom surrounding rock enlarged obviously. The results provide references for further analysis on the deformation and failure mechanism of surrounding rock under seismic load.
  • WANG Zhong-hao,ZHOU Huo-ming,LI Wei-shu,LU Yang
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 85-89,106. https://doi.org/10.11988/ckyyb.20140298
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    In order to explore the ways of applying bacterial foraging optimization(BFO) algorithm to geotechnical engineering, we adopted BFO algorithm to invert objective function of rheological model based on data collected from rock mass rheological test of rigid bearing plate. The tunnel anchorage project on the north shore of the proposed Jijiang Yangtze River Bridge was taken as research background. Furthermore we compared the inversion surface displacement curve with the measured displacement curve and found that the curves were generally consistent, indicating that the compressive rheological properties of rock mass can be reflected by generalized Kelvin model and parameters inverted by BFO algorithm. It is effective to invert compressive rheological parameters using BFO algorithm. Meanwhile, it has high computation speed, high efficiency and precision, hence is an effective approach to invert compressive rheological parameters.
  • ZHOU Xian-qi,ZHAO Hua-li,CHEN Zi-li
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 90-95,106. https://doi.org/10.11988/ckyyb.20140307
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    In the design and construction of rock engineering, mechanical calculation is an important way to understand the properties of rock mass. In the rheological simulation of rockmass, mechanical parameters of constitutive model of rock mass become key factor to the accuracy of the calculation results. In this paper, on the basis of previous researches, sensitivity analysis of the mechanical parameters of viscoplastic rheological model is conducted. The parameter identification result under three confining pressures is regarded as the reference value, and each parameter of these reference values is increased by 20%, 40%, and decreased by 20%, 40% respectively. The other parameters remain unchanged. The strain value can be calculated by deduced rheological constitutive model and then the difference between calculated strain value and test strain value is obtained. According to the difference, the relative change of total error can be obtained and is used to measure the trend and degree of the deviation between calculated strain value and test strain value caused by parameter alteration. Among the 6 parameters in the sensitivity analysis, the sensitivity of E is the highest, the sensitivities of m and β are high in different regions, followed by γ,n, and g. Through the sensitivity analysis, the importance of mechanical parameters to the accuracy of calculation results are verified.
  • NI Zhen-qiang
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 96-100. https://doi.org/10.11988/ckyyb.20140339
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    Finite element software ANSYS was used to establish a numerical model to research the rock slope containing intermittent joints under earthquake. Numerical simulation results showed that: under earthquake action, the stability coefficient of rock slope with intermittent joints was influenced by the length density, rate of connectivity, spreading directions of structural planes; the displacement amplification effect and deformation accumulation effect of joint surface were obvious. In the early stage of earthquake action, the damage of rock bridges was very violent, and then the damage continued under earthquake. The deformation and failure of slope stabilized until after large amplitude band. Moreover, the internal stress of the rock bridges fluctuated remarkably under earthquake, and the tension action and shearing action together led to the final failure of the noncoalescence regions; the contact sliding distance and frictional stress between layers distributed very unevenly, and the dynamic response of joints at different positions were quite different.
  • YANG Jun ,ZHU Chang-wei ,ZHANG Guo-dong
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 101-106. https://doi.org/10.11988/ckyyb.20140160
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    The unconfined compressive strength and road-use performance of lime-flyash stabilized weathered sand were researched through unconfined compressive strength test. Different dosages of lime and flyash were added into the weathered sand of the three gorges reservoir, and lime content, lime-flyash ratio, as well as age varied during the test. The aim of this research is to provide basis for the proportioning of lime-flyash stabilized weathered sand used as base or subbase. Furthermore, range analysis and multi-factor variance analysis were conducted to analyse the influence of lime dosage and lime-flyash ratio on the unconfined compressive strength. Results show that weathered sand stabilized by lime and flyash can be used as the subbase of highway and primary highway, or the base of secondary and under-secondary highway. At a certain dosage of lime and the same lime-flyash ratio, the unconfined compressive strength increases with the increase of age, but this increment speed differs greatly. Lime is the primary factor which affects the strength, and lime-flyash ratio is the secondary factors. Moreover, the optimal proportion of lime-flyash stabilized weathered sand was obtained.
  • SHAO Yong ,YAN Chang-hong ,MA Qing-hua
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 107-110,115. https://doi.org/10.11988/ckyyb.20140377
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    The point load strength, uniaxial compressive strength and rebound strength of representative rocks in Dayangshan tunnel project were tested, and the correlation among them was fitted by power function, exponential function and linear function. The results show that it’s better to use power function to fit the relationship between point load strength and uniaxial compressive strength, and exponential function to fit the relationship between rebound strength and uniaxial compressive strength, point load strength and rebound strength. In order to reduce the number of laboratory tests, we use these related formulas to predict the uniaxial compressive strength of rock. Moreover, uniaxial compressive strength has influence on the fitting accuracy, which should be considered in the prediction.
  • HYDRAULIC STRUCTURE AND MATERIAL
  • ZOU San-bing ,HU Wei-hua ,HUANG Shi-chao ,PENG Gang
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 111-115. https://doi.org/10.11988/ckyyb.20140392
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    Splitting tensile tests were conducted on concrete with different gradations (two gradations, three gradations, and four gradations) under different strain rates (10-5/s, 10-4/s, 10-3/s, 10-2/s). The splitting tensile strength and axial strain of concrete were analyzed, and the energy release characteristics and damage regularity of mass concrete in the whole process of splitting tensile damage were researched through collected real-time acoustic emission data. Results show that with the strain rate increasing, the splitting tensile strength of concrete displays a trend of increasing. Singularity in the variation of splitting tensile strength is larger when the gradation of concrete is higher. The process of splitting tensile failure does not have the characteristics of a typical three-stage: stage without cracks, stage with cracks, and stage of failure. The acoustic emission signal is weak in the early stage of loading, but rises sharply when the material reaches peak stress. Acoustic emission data can truly reflect the process of concrete splitting tensile failure.
  • LIU Lu-lu ,CHANG Fang-fang ,XIE Wei ,WANG Xue-kui
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 116-120. https://doi.org/10.11988/ckyyb.20140863
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    Previous researches on the stress-strain curve of plastic concrete are focused on the curve in the absence of preloading. In this paper, compressive strength and elastic modulus tests were conducted on cylinder and prismoid concrete specimens poured with different mix proportions. The characteristics of the stress-strain curve,the stress-strain curves in the presence of preloading and in the absence of preloading and under cyclic loading were respectively analyzed. Moreover, the stress-strain curves with preloading and no preloading were compared. Through analysis on the slope of the curves, micropores were proved to exist in the concrete, and how the number of cycles during preloading affecting the curves was obtained. The results show that the rise stage of stress-strain curves of plastic concrete is significantly different from that of normal concrete, and the slope of stress-strain curves of preloading stage firstly increases then decreases, whereas the slope of stress-strain curves always increases at none-preloading stage. At the same time, we can macroscopically understand the existence of inner micro pores in the specimens, and the number of preloading cycles has a little effect on stress-strain curves.The results show that the rise of stress-strain curves of plastic concrete is significantly different than those of normal, the slope of stress-strain curves of preloading firstly increases then decreases, and the slope of stress-strain curves of no preloading has been increased. At the same time, we can understand the macro of the specimens, and number of preloading has no effect on stress-strain curves. The results have reference significance to the scientific and engineering applications.The results can be referenced for the scientific research and engineering applications of plastic concrete.
  • INFORMATION TECHNOLOGY APPLICATION
  • WANG Xin-yun, TIAN Jian, GUO Yi-ge, HE Jie
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 121-125,133. https://doi.org/10.11988/ckyyb.20140194
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    In order to increase the accuracy of the land use and land cover (LULC) classification via multisource remote sensing data, we explored an effective algorithm by fusion of HJ1B images from optical sensors and ALOS/PALSAR data from radar remote sensing. In the process of fusion, the discrete wavelet transform (DWT) was utilized. The landcover classification mapping was performed by using the classification and regression tree (CART) approach. The classification result by CRT approach was compared with that by support vector machine (SVM) approach. The results show that: 1) through fusing HJ1B optical images with ALOS/PALSAR radar data, we obtain an overall Kappa coefficient (0.826 9) and total accuracy(85.60 %) by CRT approach, while by SVM approach the value is 0.816 7 and 84.82 %, respectively; 2) in terms of classification accuracy, CRT approach is superior to SVM approach; 3) by means of fusing optical images with radar data , we can effectively carry out object recognition and improve classification accuracy through applying CART approach.
  • SONG Li-song ,CHENG Hai-yang ,ZHANG Yi-jian
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 126-129. https://doi.org/10.11988/ckyyb.20140370
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    Tideland resource is an important natural resource and also environmental resource and economic resource. To grasp accurately the present situation and dynamic changes of tideland resource, a three-dimensional management information system for tideland resource was developed based on the platforms of SuperMap and Skyline. The system has functions of managing tide resources reclamation and reclamation projects, analyzing spatio-temporal changes of resource and tideland evolution. Application shows this system could provide information support for the sustainable utilization and decision support for the planning and exploitation of tideland resources.
  • INSTRUMENTATION DEVELOPMENT AND TESTING TECHNIQUES
  • ZOU Shuang-chao ,YE Min-lv ,HUA Xiang-hong
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 130-133. https://doi.org/10.11988/ckyyb.20140174
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    Traditional model for assessing the single point cloud data’s quality is incomprehensive because only distance values, angle values and instrument’s measuring accuracy are taken into consideration. But the appearance of irregular object will affect the incident beam’s reflected path and strength, and thus affect the quality of the point cloud data. According to the appearance’s effect on the point cloud data’s quality, we propose a point accuracy assessment model in consideration of incident angle to quantitatively assess the point cloud data’s quality, and verify the model’s feasibility through experiment.
  • XU Wei,ZHANG Qian,ZHOU Wu
    Journal of Changjiang River Scientific Research Institute. 2015, 32(10): 134-138. https://doi.org/10.11988/ckyyb.20140317
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    In order to solve the real-time and non-contact problems in collecting dam safety monitoring information during the construction of water conservancy project, a micro-power measurement system of vibrating wire sensor based on wireless network is developed. The system consists of two parts: the front collector and the handset. By applying the same pressure on test table, we compare the frequencies measured by this system and BGK-408 Reader. Results show that the absolute error of measured mean frequencies between the two measurement systems is less than 0.25 Hz,which proves that the collection accuracy of this developed system meets design requirements and practical engineering needs. The system has functions of remote collection (more than 80m), transmission, storage and analysis of monitoring data for dam safety. It can instantly track the dynamic changes of monitoring data for dam safety, and well meets the real-time demands for the monitoring data, which cannot be satisfied by traditional wire measurement systems and other wireless measurement system during construction. The system is of high measurement accuracy, low power consumption, stable performance, convenient application, flexible installation, low labor intensity for its users, low construction and maintenance cost and strong in-spot adaptive ability.