01 January 2015, Volume 32 Issue 1

    

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RIVER-LAKE SEDIMENTATION AND REGULATION
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  Impact of Reservoir Scheduling Mode on Sedimentation

  YE Hui-hui, GAO Xue-ping, YUN Zhen-xing, ZHAO Zi-yue

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 1-5. https://doi.org/10.3969/j.issn.1001-5485.2015.01.001

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  We established physical model of sedimentation in 55km range in the reservoir area to study the sediment characteristics including sedimentation evolution and sedimentation amount. Two different scheduling modes of a reservoir was taken as case study. Research suggests that the control water level in flood period is very pivotal to the vertical distribution of reservoir sedimentation and the sedimentation at the reservoir tail. In the first 50 years of operation, the difference of sedimentation between the two scheduling modes is quite large: for the second mode, low water level in flood season is more conducive to sediment sluicing and deposition reduction. After 50 years of operation, the sedimentation in the two scheduling modes tends to be similar.
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  Approaches of Ising and Renormalization Group to Study the Incipient Motion of Sediment

  WANG Fu-quan

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 6-10. https://doi.org/10.3969/j.issn.1001-5485.2015.01.002

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  In the aim of exploring the physical mechanisms and critical probability of sediment’s incipient motion, the incipient motion is regarded as a critical phenomenon and is compared with continuous phase transition. Two-dimensional Ising model and renormalization group model as well as algorithm of sediment are established based on the principle and method of critical phenomena, continuous phase transition and renormalization group. By comprehensive analysis, a critical probability of sediment’s incipient motion is obtained (the threshold is about 0.42) which is approximate with the results of experiments and observations. In association with sediment movement mechanics and fractal dynamics, the physical mechanism of bed surface starting is discussed. The results show that the integral incipient motion of bed surface have similar physical mechanism with fractal growth DLA group. It gives a physical interpretation to the integral incipient motion of bed surface with a threshold less than 0.5.
WATER RESOURCES AND ENVIRONMENT
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  Analysis of Hydrology Response of Groundwater UsingMIKE SHE Model

  LU Xiao-hui, LI Qi-long

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 11-15. https://doi.org/10.3969/j.issn.1001-5485.2015.01.003

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  In order to study the time-lag of groundwater recharge peaks due to rainfall infiltration, the distributed hydrological model of Skjern watershed in Denmark was established through MIKE SHE software and ArcGIS technology, and was calibrated by observed data. Through the comparison between observed data and simulated data, the influence of climate and groundwater depth on the hydrological response was also analysed. The measured data matched well with the predicted values. Results suggest that since Denmark has temperate marine climate, the groundwater recharge of Skjern catchment mainly concentrates from September to November, and January to March. When groundwater level is 1m, the peak time-lag of rainfall infiltration is short (1-2d); as the depth of groundwater increases to 2-5m, the peak time-lag of rainfall infiltration is 4-5d; whereas when the groundwater depth is more than 10m, the peak time-lag is long. This model has satisfactory result and application potential in simulating Skjern catchment.
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  Total Amount Allocation of Water Pollutant Based on Modelof Maximum Weighted Information Entropy

  LIU Jie

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 16-20. https://doi.org/10.3969/j.issn.1001-5485.2015.01.004

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  Information entropy is applied to establish a fair and efficient allocation system of total water pollutant between areas. With COD (Chemical Oxygen Demand) in Hanzhong city which is the birthplace of Hanjiang river as an example, we select some indexes that are closely related with the emission of COD and quantified them in consideration of the natural and economic differences between areas. Then the index weights are decided by entropy evaluation method. The goal programming model is thus established for the maximal sum of weighted information entropy. Finally, the intelligent Harmony Search Algorithm is used to solve this problem to obtain fairer cuts. The results show that this method could quantify various fair standards and get optimized and feasible allocation schemes.
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  A 2-D Model Coupling Hydrodynamics and Water Quality for the Water Connection and Diversion of Shallow Lake Group

  LI Yu-hong, HE Shi-lei

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 21-27. https://doi.org/10.3969/j.issn.1001-5485.2015.01.005

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  The method of treating water pollution by reestablishing hydraulic connection between lakes and diverting water from a nearby river to the lake group which is seriously polluted is getting wider attention in shallow lake areas. To investigate the variation of hydrodynamics and water quality after lake connection and diversion, we built a 2-D model coupling hydrodynamics and water quality. The Project of East Lake Network in Wuhan was taken as research background. In this model, unstructured grid was adopted to fit the complex boundary, and lake topography and climate conditions were adequately reflected. In addition, the input, transport and transformation of nutrients and pollutants as well as the growing conditions of some algae such as cyanobacteria were taken into account. Moreover, field measurement data in June 2006 and June 2007 were used for the calibration and validation of the model parameters. Then the variation of indexes including BOD₅, TP, TN and Chl-a in three diversion conditions and three connection conditions after 30 days of stable operation were simulated based on the measured data in June 2012.Results suggest that wind force is still the major factor which induces the change of lake flow field for larger lakes in a water diversion project; in the presence of the same diversion flow, different diversion conditions has different effects on the water quality improvement. Dividing dikes in shallow lake group bring difficulties to the control of lake pollution, whereas setting up artificial island at suitable position of the shallow lake has no great impact on the water quality variation.
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  Preliminary Model Test of Vortex Basin for Oncomelania Control

  WANG Jia-sheng, MIN Feng-yang, WEI Guo-yuan, LI Ling-yun, WANG Jun-zhou

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 28-32. https://doi.org/10.3969/j.issn.1001-5485.2015.01.006

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  As some traditional water conservancy measures for schistosomiasis control (settling basin for oncomelania snail, and middle layer water intake projects) are restricted by a variety of conditions, it is imperative to conduct research on new measures of schistosomiasis control. In this research, vortex basin for oncomelania was developed based on the principles of desilting funnel, and model experiment was carried out to research the flow characteristics and trap efficiency of oncomelania by the vortex basin. Results show that as flow rate increases, the flow velocity and turbulence intensity increases. The tangential velocity decreases by moving from the center of the model towards sidewall along radial direction and by moving from the bottom of model to water surface along vertical direction. Large vertical velocity is found near the edge of deflector caused by the compress of deflector. Radial velocity at the inner edge is larger than that in outer regions. Vertical turbulence intensity in middle and upper part of flow is higher than that in low layer. Under different flow rates, a certain number of oncomelania snails are fed into the model and it is observed that the trap efficiency reaches 100%. It shows that vortex basin for oncomelania is an effective engineering measure.
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  Calculation Formulas for Particulate and Dissolved Phosphorus Concentrations

  LI Jian, JIN Zhong-wu, YANG Wen-jun

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 33-38. https://doi.org/10.3969/j.issn.1001-5485.2015.01.007

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  The adsorption-desorption between phosphorus and suspended sediment particles in rivers or lakes would influence the cycling process of water quality components. In this research, the calculation formulas for particulate phosphorus (PP) and dissolved phosphorus (DP) concentrations were deduced based on the classic Langmuir equation and the modified Langmuir equation, respectively. Furthermore, the experimental data and in-situ observed data of phosphorus and suspended sediment in Xiangxi River were used to verify the deduced formulas, and the calculated results were well consistent with the observed data. When suspended sediment concentration was low, the linear equation could work well, but when suspended sediment concentration was relatively high, the deduced formula needs be used, especially when adsorption and desorption coexisted, the formula deduced by modified Langmuir Equation needs be used. The research results could be applied for water quality and ecological modeling.
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  Key Points and Methods of Assessing the Environmental Impact of Water Project on Groundwater: A Case Study

  FENG Xue,ZHAO Xin,LI Qing-yun,HUANG Zhuo,LIN Li

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 39-42. https://doi.org/10.3969/j.issn.1001-5485.2015.01.008

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  The impacts of water projects on groundwater environment is analyzed in this paper. A hydropower station is taken as an example to discuss the technical points and methods of assessing the environmental impact, such as project classification, assessment grades and scope, groundwater survey and evaluation, prediction and evaluation of the impact. Furthermore, corresponding measures to control the impacts are proposed to provide technical basis to protecting groundwater and solving engineering problems caused by the construction and operation of the water projects.
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  Water Retention Characteristic of Five Forest Litters in Beimiao Reservoir in Baoshan City

  SHEN Ying-jia, ZENG Jian-jun

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 43-48. https://doi.org/10.3969/j.issn.1001-5485.2015.01.009

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  The water-holding capacities of five forest litters are analysed by using quadrat survey method and drying and soaking. These forest litters include Pinus yunnanensis, artificial Eucalyptus forest, mingled forest Ⅰ(Pinus yunnanensis + Eucalyptus), mingled forest Ⅱ(Pinus yunnanensis+Pinus armandi+Cunninghamia lanceolata+Cyclobalanopsis glauca),and Pinus armandi in the catchment area of Beimiao Reservoir in Baoshan City. Results show that the storage capacity of these five forest litters are small, with the maximum reaching 7.27 t/hm², and the minimum 4.51 t/hm²; the average water-holding capacity of forest litter’s undecomposed layer and half-decomposed layer increase with soaking time (respectively 5.22 mm and 5.83 mm in 8 h and 5.69 mm and 6.26 mm in 24 h); while the water absorption rate reduce with soaking time (respectively 0.65 mm/h and 0.73 mm/h in 8h, and 0.24 mm/h and 0.26 mm/h in 24 h). All of these values of half-decomposed layer are larger than those of undecomposed layer. The water holding performance of Eucalyptus and mingled forestⅡare better than that of the others.
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  Feasibility of Using Hot Spring Bathing Wastewater as the Water Supply for Water Source Heat Pump

  XING Hong-wei, XU Wu-dong, QIN Kun-rong

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 49-51. https://doi.org/10.3969/j.issn.1001-5485.2015.01.010

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  Groundwater is usually taken as the water source for water source heat pump. Compared with general groundwater, hot spring bathing wastewater has different temperature and in addition contains plenty of organic matters and microorganism. The quality of bathing wastewater from Chongqing South Hot Spring was detected and analyzed. Result shows that calcium and magnesium ions as well as sulfate ions exceed the standard design of Specification for the investigation and evaluation of shallow geothermal energy, and the turbidity, salinity, pH value, chlorine ion and silicon dioxide content meet the quality requirement of water supply. But it has high concentration of organic matter and biological contamination. If the wastewater is properly treated, it would be an ideal water supply for water source heat pump because of stable flow and relatively higher temperature.
WATER-SOIL CONSERVATION AND ECO-CONSTRUCTION
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  Analysis and Forecast of the Evolution Features of RockyDesertification Landscape by Markov Model

  ZHANG Yong-rong, ZHOU Zhong-fa, MA Shi-bin, YANG Qin

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 52-56. https://doi.org/10.3969/j.issn.1001-5485.2015.01.011

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  Karst rocky desertification is a process of land degradation and dynamic evolution resulted from the fragile ecosystem in Karst mountainous regions and the improper economic activities of human beings. Predicting its development trend would improve the control and defense against Karst rocky desertification. According to the Karst rocky desertification data interpreted from the remote sensing images obtained in 1990 and 2010, we analysed the features of Karst rocky desertification evolution and predicted its development trend by using Markov Model. Results showed that: 1) from 1990 to 2010, those invariable which accounted for 46.79% of the Karst region predominated the evolution of Karst rocky desertification in the study area; 2) by prediction, in 2030, light rocky desertification would predominate the study area, the area of non-desertification and potential desertification would decrease remarkably, and those of light and moderate would increase greatly; 3) under the present mode, the eco-environment of the study area would deteriorate in the forecast period. We should adjust the land use patterns and the governance mode appropriately and strengthen the ecological protection in the potential rocky desertification region in case that the ecological restoration falls into an infinite loop.
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  Spatial Heterogeneity of Nitrogen, Phosphorus and Potassiumof Soil in Forest Grassland

  XU Zhi,WANG Zhi-jun,FAN Wen-jing,YANG Guang

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 57-61. https://doi.org/10.3969/j.issn.1001-5485.2015.01.012

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  Statistical approaches were employed to research the small-scale spatial heterogeneity of hydrolytic nitrogen, available phosphorus, and rapidly available potassium in the soil of forest grassland. The relationship between the content of nitrogen, phosphorus, and potassium and the distribution of vegetation were obtained. Results revealed that 1) contents of hydrolytic nitrogen, available phosphorus and rapidly available potassium in soil surface were significantly higher than those in the bottom;2) contents of hydrolytic nitrogen, available phosphorus and rapidly available potassium at sampling points in each soil layer in the adjacent of trees were the highest, followed by those at points where the ground is dominated by herbaceous and points at roadside;3) contents of hydrolytic nitrogen, available phosphorus and rapidly available potassium were in highly-significant (P<0.01) or significant (P<0.05) negative correlation with soil thickness. Apart from potassium, the distribution of hydrolytic nitrogen and phosphorus had highly significant (P<0.01) or significant (P<0.05) difference under the influence of vegetation types. Vegetation and soil layer had significant (P<0.05) interaction effect on the distribution of soil hydrolytic nitrogen, phosphorus and potassium.
ENGINEERING SAFETY AND DISASTER PREVENTION
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  Numerical Study on Dynamic Testing of Anchorage Qualityof Rock Bolt (Cable) by Stress Wave Method

  DENG Dong-ping, LI Liang, ZHAO Lian-heng

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 62-69. https://doi.org/10.3969/j.issn.1001-5485.2015.01.013

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  Rock bolt (cable) is widely used in slope reinforcement. To ensure rock bolts (cables) work effectively, the stress wave method is generally adopted to detect anchorage quality. Length of rock bolt (cable) and position of defective segment are two main indicators of detection. In this research, dynamic model of stress wave of anchorage body is established in ANSYS/LS-DYNA. The percussion effect of hammers on rock bolt (cable) is presumed to be equivalent to the collision between hammer with a certain speed v₀ and rock bolt (cable), and stress wave signal is gathered on midpoint of rock bolt (cable) top section. Feasibility of the numerical model is verified by comparing with the results of theoretical studies in examples. Moreover, the effect of elastic modulus and excitation speed v₀ of hammer on stress wave signal is analyzed, and the accuracy of defective segment position detected by using stress wave method is studied. The applicability of two excitation modes (excitation on top and excitation on top and bottom simultaneously) in the detection is compared. Results reveal that: (1) Increasing the elastic modulus of hammer only affects the initial stress wave signal, but has little effect on stress wave signal reflected once back from the bottom of anchorage body; while the increase of excitation speed v₀ of hammer is conducive to both the signals and is linearly proportional to the latter. (2) It is reliable to use stress wave method to detect the defective segment position of anchorage body, and the detection accuracy is higher when defective segment is more complete. (3) The mode of excitation on top and bottom simultaneously shortens the time of stress wave signal reflecting the positions of section change and bottom of anchorage body, so it is conducive to engineering applications.
HYDRAULICS
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  Characteristics of Pressure on Baffle Plate at the End of Jet Outlet

  QIAO Dan,LI Long-guo,LI Nai-wen,LIU Chao

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 70-74. https://doi.org/10.3969/j.issn.1001-5485.2015.01.014

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  Flow from the orifice of high dam usually fall with full diffusion in horizontal direction, but in narrow valley it is limited by the width of river. By setting transverse shrinkage baffle plates at the end of the dam orifice, the flow jet becomes narrow and long spreading well in vertical and longitudinal directions, which gives full play to the longitudinal space of river for flood discharge and energy dissipation. However in this case, the pressure on the baffle plate surged due to jet impact, which is detrimental to the structure design of the baffle plate. In this paper, the impact pressure on the baffle plate was researched by changing the shape parameters of baffle plate (contraction ratio β, relative contract length δ and outlet angle γ) as well as water head at the entrance of orifice. Research results revealed that the maximum pressure on the baffle plate was at the beginning point (which is at the joint between suddenly-enlarged side-wall and baffle plate), while no negative pressure was found on the baffle plate which is beneficial to alleviating cavitation of the plate. The maximum impact pressure reduced with the increase of contraction ratio and relative contract length, while increased with the increase of outlet angle and water head at the entrance of orifice.
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  Numerical Study of High-lift Siphon Cavitations

  XIONG Xiao-liang, ZHANG Shi-hua, ZHANG Wen-jun

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 75-78. https://doi.org/10.3969/j.issn.1001-5485.2015.01.015

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  Siphon technology has been widely used in engineering practice. It has great application value especially in draining slope’s groundwater and reducing debris flow’s hydrodynamic conditions. The drainage of groundwater in middle and deep part of slope requires the use of high-lift siphon. However, the cutoff of high-lift and self-balancing siphon causes siphon drainage failures in practical use. In this paper, we analyzed the mechanism of bubble generation in the siphon based on the cavitations theory, and employed the fluid numerical analysis software FLUENT to found that the gas-liquid two-phase flow in self-balancing siphon is from bubble flow to slug flow. After slug flow is formed in siphon, the siphon flow pressure drop will increase, resulting in the decrease of vacuum degree in the top of siphon, thus damaging the continuity of water flow and leading to interception of siphon, and finally, negatively affecting siphon’s next startup.
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  Effect of Pool Structure Variation on Hydraulic Characteristicsof Vertical-slot Fishway

  WANG Meng,SHI De-liang,CHEN Hui,ZUO Yan-xia

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 79-83. https://doi.org/10.3969/j.issn.1001-5485.2015.01.016

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  The energy dissipation of vertical-slot fishway is concentrated near the slot. Due to the shrinkage and constraint of the slot, vortex is generated, and the flow in the fishway is made faster and tangled. In order to improve the hydraulic characteristics of fishway pool room, the RSM(Reynold’s stress model) was applied to numerically simulate the same side of vertical-slot fishways of different structures. Results suggest that a cylindrical barrier in the pool at the slot exit could help attenuate the velocity gradients at the slot, and reduce the turbulent kinetic energy and Reynolds shear stress by 20%-30%. The hydraulic characteristic of this fishway is stable and it could meet the hydrodynamic requirements of more fishes passing through the dam.
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  Numerical Simulation on Hydraulic Characteristic ofHigh Head Ogee Spillway Tunnel

  XU Guo-bin, ZHANG Huan-jing, LIU Fang, HAN Wen-wen

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 84-87. https://doi.org/10.3969/j.issn.1001-5485.2015.01.017

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  The 3-D flow fields of high-head spillway tunnel with its inlet raised was numerically simulated using VOF method to track the free surface based on RNG k-ε turbulence model. The numerical model was verified by the results of large-scale model test. The computational result and experiment result agreed well. Two modification proposals for aeration facilities were presented. The result demonstrates that the modified aeration facilities could effectively avoid the cavitation damage in the downstream anti-arch section, and this turbulence flow model could well simulate the 3-D flow field.
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  Arrangement of Permeable Cut-off Wall at the Upstream ApproachChannel of Dayuandu Navigation-Hydropower Junction

  REN Qi-ming, LIU Xiao-ping, ZHAO Jiang, ZHOU Xiao-ling, HU Shi-long

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 88-91. https://doi.org/10.3969/j.issn.1001-5485.2015.01.018

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  To meet the requirements of shipping and economic development, a second shiplock is planned to be built at Dayuandu Navigation-Hydropower Junction, but the approach channel’s entrance area in the upstream of the existing first shiplock is in bend reach with complex flow conditions. To make sure that the flow condition at the second shiplock could meet standard requirements, we designed three cases of cut-off wall pattern, and analyzed the navigation condition, flood discharge capacity and improvement measures under maximum flow (Q=17 500 m³/s, once in 10 years) respectively in the presence of these three cut-off walls.　According to calculation results and comprehensive considerations, we recommend permeable cut-off wall at upstream entrance area of approach channel. The research result could be regarded as reference for similar engineering design.
ROCK-SOIL ENGINEERING
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  Environmental Monitoring and Analysis on the Compacting Effects of PHC Pipe Piles

  JIA Zhi-gang,ZHANG Rui-min,LI Ke,ZENG Hong-biao

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 92-96. https://doi.org/10.3969/j.issn.1001-5485.2015.01.019

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  In order to investigate the compacting effects caused by the penetration of pre-stressed high-strength concrete (PHC) pipe pile group on surrounding engineering environment, we carried out on-site monitoring on the excess pore water pressure and deep soil displacement in Zhumadian. Results show that the excess pore water pressure approximately linearly reduces as the distance to the pile group boundary increases, and the radius of excess pore water pressure’s influence increases with depth, the maximum radius of influence is about 29 times the diameter of the pile. The surface soil displacement is large, and the displacement decreases with the depth to almost zero until the pile end. The horizontal displacement is significantly affected by the relief grooves, and the effective impact depth is approximately two times its depth.
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  Limit Curve Method to Assess the Stability of Layered Soil Slope

  FANG Hong-wei, ZHAO Li-jun

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 97-101. https://doi.org/10.3969/j.issn.1001-5485.2015.01.020

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  The independent application of slip line field theory in slope stability analysis has not been reported yet. On the basis of slip line field theory, we propose a limit curve method of assessing the stability of layered soil slope according to the slope deformation situation. This method is the inverse process for the ultimate load of heavy slope and the dual process of strength reduction method. Considering the intersection of slope surface curve under limit state and the original slope surface as failure criterion, we define two assessment indicators: Degree of Safety (DOS) and Degree of Failure (DOF). Then we extend the characteristic line equation of homogeneous soil to the layered soil condition, with the original equation as its special case, and soil interface as the special surface of discontinuity. On this basis, we obtained the condition and formula of slip line refraction in soil interface. Compared with traditional methods, this method needs not assume and search critical slip surface. Seven calculation examples verified the correctness of the deformation failure criterion. The stability evaluations of DOS/DOF with different theoretical methods are consistent, indicating this method is applicable to analyse the stability of layered soil slope.
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  Hydraulic Conductivity Functions for Unsaturated SoilsBased on Statistical Models

  WANG Xiao-feng, SHI Hong-lian, TANG Zhi-zheng, NIU Chao-ying

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 102-105. https://doi.org/10.3969/j.issn.1001-5485.2015.01.021

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  By comparing and analyzing two methods (Kunze’s method and Fredlund’s method) based on statistical models to predicting the hydraulic conductivity of unsaturated soils, we found that they are exactly the same in essence just with different limits of integration and integration variable forms. Moreover, by analyzing the selection of parameters in their simplified calculation we obtain that it is more reasonable to determine the value of m within 15-50. Theoretically the prediction result will be larger if ln(1000000) (residual water content is assumed to be 0) is taken as the integration upper limit and logarithm of air-entry value as the integration lower limit in Fredlund method.
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  Research and Development of Geotechnical Drum Centrifugeand Its Application to Submarine Landslides

  LI Jia-gang, WANG Zhong-tao, XU Bo, LUAN Mao-tian

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 106-111. https://doi.org/10.3969/j.issn.1001-5485.2015.01.022

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  The first geotechnical drum centrifuge GT450/1.4 in China was introduced by Dalian University of Technology in 2009 with the aim of building an integrated testing platform to face the rapid development of marine soil mechanics. The details of mechanical system, control system, data acquisition system and other corollary equipment including PIV system, vacuum mixer for clay, large-scale consolidation apparatus and soil placement device, are presented through a comparison with the corresponding products in the world. Furthermore, submarine landslide is simulated by centrifugal tests with remoulded soil obtained in-situ. The results of centrifugal test show that drum centrifuge GT450/1.4 is of high performance and comprehensive capacity, and is better than other similar products in terms of mechanical system scale, data acquisition accuracy, automation of control system and load mode of actuator. Meanwhile, drum centrifuge GT450/1.4 is easy to be developed to be a modular geotechnical drum-beam centrifuge. Geotechnical drum centrifuge has advantages in the research of ocean engineering structures such as submarine landslide.
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  Method of Driving Force Loading in Model Testof Landslide Caused by Thrust Load

  XIA Hao,YONG Rui,MA Jun-wei

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 112-116. https://doi.org/10.3969/j.issn.1001-5485.2015.01.023

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  The method of loading in landslide physical model test is often related with the prototype. In this research we applied driving force at the back of the slope model to simulate the deformation failure of landslide caused by thrust load. To verify the feasibility of this method, we took simplified rigid slip mass for example and analysed the driving force loading and the inclined loading which are commonly used in model test for comparison. Results show that the back force loading could also change the anti-sliding safety factor of rigid slip mass continuously. Furthermore, we conducted numerical simulation and physical model test to research the stress field and strain field of the slope model subjected to back force already. Results reveal that as the force applied at the back of the slope model increases, the shear failure of slope expands gradually from the back of the slope model to the front until the shear plane penetrates through the slope and the slope begins to slip. This failure process is consistent with the failure process of landslide caused by thrust load. The method of loading driving force is verified to be feasible in the simulation of landslide caused by thrust load.
HYDRAULICS STRUCTURE AND MATERIAL
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  Regression Model of Bolt Anchoring Strength in Concrete Based on SVM

  LEI Jin-sheng, CHEN Jian-fei, WANG Qian-feng, PENG Gang, ZENG You-wei

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 117-120. https://doi.org/10.3969/j.issn.1001-5485.2015.01.024

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  As one of the main factors of evaluating the anchoring quality, bolt anchoring strength in the concrete is affected by many factors which have complex interrelationships with each other. Concrete age, bolt diameter and anchorage length are used as the input column vector to build sample set, and radial basis kernel function is adopted for an prediction model of bolt anchoring strength in concrete based on support vector machine for regression. There are 30 groups of experimental data of anchoring strength. Two-thirds of those groups are selected as training samples, and the others are selected as predicted samples to forecast anchorage strength. Then the predicted results are compared with the test result and BP network result. Comparison suggest that this model has high prediction accuracy and good generalization ability, and the prediction results are credible. It is reasonable and effective to apply SVM to predict the anchorage strength in concrete.
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  Reinforcement Technique by Using BZK-G High StrengthGrouting Material to Resist Abrasion

  MA Jun

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 121-124. https://doi.org/10.3969/j.issn.1001-5485.2015.01.025

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  To solve the problem of culvert’s bottom plate abrasion in Toutun river reservoir, reinforcement with an average thickness of 10cm was applied at places where the washout area reached 7.5m² on the bottom plate. According to the features of water and sediment in the culvert and the previous measures and experiences, GHJ planting-bar anchorage glue of high strength was used for the anchorage of rebars of 16mm diameter. Through the bonded anchorage, single-layer reinforcement mesh with vertical and horizontal spacing (20cm× 20cm) between rebars of 12mm diameter was integrated with the basal layer as a whole, and then BZK-G grouting material was used for the grouting reinforcement. Two years of practice proved that this technique has good effect on the anti-abrasion of culvert bottom.
INFORMATION TECHNOLOGY APPLICATION
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  Research Advance of Broadband Vegetation Index UsingRemotely Sensed Images

  LI Zhe, HU Die, ZHAO Deng-zhong, XIANG Da-xiang

  Journal of Changjiang River Scientific Research Institute. 2015, 32(1): 125-130. https://doi.org/10.3969/j.issn.1001-5485.2015.01.026

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  Broadband vegetation index, which embodies the growth of green vegetation and surface biomass, plays an important role in quantitative management and prediction of surface resource and environment. According to the remotely-sensed spectral features of green vegetation, we summarize some typical vegetation indices and divide them into three categories: simple band combination approach, soil adjusted approach and atmospheric adjusted approach. Simple band combination approach includes ratio vegetation index, differential vegetation index, and normalized differential vegetation index, but the physical principle of them is still unclear. Soil adjustment approach includes perpendicular vegetation index, soil-adjusted vegetation index, and global environment monitoring index, which enhance vegetation information and reduce the interruption of soil background through the introduction of soil-adjusted parameter. Atmospheric adjusted approach includes atmospheric-resistant vegetation index, and enhanced vegetation index, which enhance atmospheric information and reduce the impact of atmospheric aerosol through the introduction of atmosphere adjusted parameter. Finally, the development trends and future prospects are also discussed.