Flood Response Caused by Underlying Surface Change in Baipenzhu Reservoir Basin
CHEN Yu 1, HUANG Feng-hua 2, KONG Ci-fen 3 ª¤
(1.Department of Water Resources and Environment, Sun Yat-sen University, Guangzhou 510275, China; 2.Guangdong Research Institute of Water Resources and Hydropower, Guangzhou 510610, China; 3.College of Geography and Tourism, Chongqing Normal University, Chongqing 400047, China)
Abstract: In association with GIS technology, grid-distributed hydrological model is used to study the flood response caused by underlying surface change in the sub-basin of Baipenzhu reservoir in Dongjiang River basin. In light of the status quo of land use in this basin, 9 underlying surface scenarios are built by scenario analysis, and three typical floods respectively of large, medium, and small scale are chosen to quantitatively analyze the flood response caused by underlying surface change. It is found that forestry and its spatial distribution can effectively retain rainfall, reduce flood peak, and postpone flood peak lag time. In this sense, the protection of forestry, in particular, forestry along the river channel and in the upper reaches of the basin, is significant for the flood control and disaster mitigation in the basin. Moreover, since urbanization will increase runoff yield and speed up confluence, which is detrimental to flood control, hydropower projects are of great help by controlling floods in tributaries of the basin. Response of big floods caused by underlying surface change is greater than that of small floods.
Key words : Baipenzhu reservoir basin; distributed hydrological model; underlying surface change; scenario analysis; flood response
The Formation Mechanism of Tianxingzhou Central Island in the Lower Reach of Yangtze River
JI Rong-yao, LU Yong-jun, ZUO Li-qin ª¤
(State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering Science, Nanjing Hydraulic Research Institute, Nanjing210029, China)
Abstract: Developed in the early 1950s in the Taixing reach of the Yangtze River, Tianxingzhou central island experienced the rapid development stage from 1950s to 1970s, the scouring and silting adjustment stage from early 1980s to late 1990s, and the stable stage since late 1990s. The formation mechanism and the evolution of this central island is studied to provide reference for the harnessing of the river course and the development of the shore line. This study shows that large slow flow area was formed because of the riverbed broadening in the Taixing reach and the ski jump effect of the bank node, thereby resulting in sediment deposition and underwater shoal, which laid foundation for the formation of Tianxingzhou central island. Whereas the large scale collapse of the river bank in the upper Sima bend from the early 1950s to late 1970s provided sufficient sediment for the rapid development of Tianxingzhou central island.
Key words: central bar; formation mechanism; evolution; bank collapse; Tianxingzhou central island
Fractal Measurement of River Bed Erosion and Deposition
ZHOU Yin-jun 1,2, CHEN Li 2, SUN Yu-fei 2, CHENG Wei 2ª¤
(1.Yangtze River Scientific Research Institute, Wuhan 430010, China; 2.State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China)
Abstract: Fractal theory is associated with river dynamics to study the method of quantifying riverbed surface form and its physical significance. Typical bifurcate reaches with severe riverbed erosion and deposition in downstream Three Gorges Dam are taken as the example to analyze the BSD (bed surface fractal dimension) variation and its relation with the erosion-deposition adjustment of the corresponding surface, longitudinal section, and cross-section of each reach. BSD can be used to reflect the nonlinear feature of the bed form variation across time and space, which is different for different reaches on the one hand, and changes along with the riverbed erosion-deposition adjustment on the other. It can also be used to describe the extent of the bed form adjustment as BSD value is positively correlated with the complexity of typical cross-section bed form. As a method of quantifying riverbed surface adjustment, BSD will be valuable for the quantitative analysis of river regime, the discrimination of river pattern, and the prediction of bed resistance tendency.
Key words: river dynamics; bed surface fractal dimension; riverbed form; measurement
Empirical Study on Water Footprint of Water Resources Management in Hebei Province
CAO Yong-qiang 1,2 , MA Jing 1
(1.School of Urban Planning and Environmental Science, Liaoning Normal University, Dalian 116029, China; 2.State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China)
Abstract: Water footprint, which is developed from the concept of virtual water, indicates the water quantity in products and services consumed by the inhabitants in a certain area. Virtual water and water footprint are the new focus in the current research of water science and are recognized as important strategies in the solution of the security of food and water resources. Virtual water and water footprint are effective means of measuring the actual hold of water resources by human beings. This paper introduces the concepts of virtual water and water footprint as well as related theory and the computation method. Based on available information and actual data, the amount of virtual water and the total amount of water footprint consumed by residents in Hebei province from 2000 to 2007 are calculated as an example. The results reveal that the per capita amount of water footprint during these 8 years, which is still low though, increased steadily year on year with the consumed virtual water accounting for the largest proportion. The calculation and analysis of the virtual water quantity and the application of water footprint provide theoretical support for Hebei province to manage the water resources sustainably.
Key words: water footprint; virtual water; water resources management; Hebei province
An Approach to Predict the Water Level of the Three Gorges Reservoir Using One Dimensional Hydrodynamic Model
LIU Zhi-wu 1, WANG Jing 1, XU Ji-jun 2 ª¤
(1.China Yangtze Power Co., Ltd., Yichang 443133, China; 2.Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract : As the Three Gorges Reservoir is a channel reservoir, the static reservoir cubage method is not suitable for the accurate calculation of the reservoir water level. In this paper, a hydrodynamic model is built based on one dimensional unsteady flow. The model can predict the processes of water level and flow in front of the reservoir by simulating the process of flood routing in the river channel. Moreover, this model is validated by computation result using the impoundment data from 25 September to 3 October in 2007 and the comparison with observed data. It is manifested that this model offers good accuracy and can be applied to reservoir operation.
Key words: one-dimensional hydrodynamic model; Three Gorges Reservoir; water level
Standard of the Bearable Vibration of Percussion Boring Cast-in-situ Pile Construction
LI Wei-shu1, KUANG Hua-feng2, HUANG Yong2 ª¤
(1.Yangtze River Scientific Research Institute, Chongqing 400014, China£» 2.Urban Development Investment Group Co. Ltd. of Fuling District of Chongqing City, Chongqing 408000, China)
Abstract: The vibration caused by percussion boring in urban area will affect the people in surrounding areas. Taking the acceptable vibration degree into consideration, a control standard acceptable for people and buildings is proposed based on domestic and international specifications and standards. Monitoring of the vibration in different aspects was made for the adjacent buildings, and the people nearby were investigated as well. The standard was proved to be reasonable in controlling the vibration so that the construction of the project can be carried out and the plan can be achieved.
Key words: mechanical percussion boring cast-in-situ pile construction; vibration of the percussion; building; people¡¯s feelings; particle vibration velocity; standard of bearable vibration
Study on the Hydraulic Characteristics of Stilling Basin with Step Down Floor by 2-D Numerical Simulation
WANG Zhi-juan, JIANG Bo-le, HUANG Guo-bing ª¤
(Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: The flow field of the surface spillway of an overflow dam and the tilling basin with step down floor at the end of the spillway was simulated by 2-D numerical simulation. The shape of the step down floor was modified from three aspects, namely changing the height of the step ª² down floor, adding a horizontal platform in front of the step down floor and changing the angle of the outlet. By comparing different plans, the rules of velocity variation near the stilling basin were obtained. The study can be regarded as a reference for engineering design and scientific experiments.
Key words: stilling basin; step down floor; 2-D numerical simulation; VOF model; velocity near the bottom
Numerical Simulation and Analysis on the Impact of Environmental Temperature and Humidity on Massive Concrete
LIU Zhi-yong ª¤
(School of Civil Engineering, Xuzhou Institute of Technology, Xuzhou 221008, China)
Abstract : The influence of environmental temperature and humidity change cannot be ignored in massive concrete structures. Much attention is paid to the analysis on temperature field, thermal stress field, humidity stress field, and especially its total stress field. In view of this, an ideal spherical mass concrete structure is selected, and the temperature field, temperature stress field and humidity stress field are numerically simulated successively through ANSYS on the premise of considering only the impact of environmental temperature and humidity. Furthermore, thermal stress field and the humidity stress field are overlaid to obtain the total stress field. Results of the simulation are analyzed and conclusion is put forward. Through the numerical simulation of stress field, the crack degradation of poured massive concrete can be predicted so as to formulate temperature control measures.
Key words: environmental temperature and humidity; massive concrete; temperature field; thermal stress field; humidity stress field; numerical simulation
Simulation of the Application of Sonic Reflection Method in Rockbolt Anchorage Quality Detection
QIN Qiang 1,2 , YIN Jian-min 1, WU Cong-qing 1, XIAO Guo-qiang 1
(1.Yangtze River Scientific Research Institute, Wuhan 430010, China£» ª¤ 2.Hunan Hydro-power Design Institute, Changsha 410076, China)
Abstract : Models of intact and defective anchor bolts of different lengths are tested to study the rules of acoustic wave propagation in the anchoring body when sonic reflection method is used to detect the anchorage quality. For the intact bolts, the response wave gets more regular with the increase of the bolt length; at the meantime, the amplitude of bottom reflected wave reduces gradually and the reflected wave decays more severely. For the defective anchor bolts, the wave at defective location is distorted with an irregular wave attenuating slowly or attenuating after intermittent increase. The testing curves of acceleration response signal at bolt head exhibit different waveform characteristics when the bolt length or defective location is different. The consolidation wave velocity of bolt anchoring system reduces slightly with the increase of bolt length, and increases slightly along with the increase of defect size both within the range of 4200 m /s to 4400m /s.
Key words: anchor bolt model; anchorage defect; sonic reflection method; quality detection
Computation and Evaluation Method of Dynamic Safety Factor for Unlocated Block under Earthquakes
XU Dong-dong ª¤
(Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: Considering the weight value of safety factors in different intervals, a new evaluation method for dynamic safety factor is proposed. Vector analysis method of the block theory is adopted for programming. The detailed research approach is resented as follows: first of all, the required information of structural planes and free face is input to form the unlocated block, and the finiteness and mobility of the block are determined subsequently according to finiteness theorem and mobility theorem. If the block is movable, find out the sliding mode (separating, single face sliding or double face sliding) of the block under the combined action of dead eight and seismic load as well as the safety factor under that sliding mode. Finally the time ª² history curve of dynamic safety factor is obtained by cycling all the earthquake times. This study can be regarded as an exploration in the evaluation index of dynamic safety factor.
Key words: block theory; unlocated block; dynamic safety factor; seismic load; FORTRAN
Application of Information Entropy Theory to the Failure Analysis of Accelerated Rheology of Rock Structure
HUANG Yao-ying 1,2 , ZHENG Hong 2, TIAN Bin 1
(1.College of Hydraulic & Environmental Engineering, China Three Gorges University, Yichang 443002, China; 2. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China)
Abstract : Information entropy theory is used to analyze viscoelastic and viscoplastic problems. Based on the comparison of information entropy corresponding to the element's elastic strain energy and total strain energy, it is found that the energy corresponding to irreversible rheological strain is dissipative. The information entropy calculated by element¡¯s elastic strain energy can exactly reflect the development of rock structure from disorder to order. Furthermore, information entropy is applied to the failure analysis of accelerated rheology of different rock structures. It is shown that the information entropy is well consistent with the node ' s displacement. Information entropy reduces gradually as energy dissipates, and then reaches the minimum value when the accelerated rheology of rock structure is destroyed.
Key words: information entropy; dissipation; accelerated rheology; destroy
Extensible Evaluation for Rock Mass Quality of Petroleum Storage Cavern Sealed by Groundwater
LI Hui, JI Hui-bin, YAN E-chuan, YANG Ju ª¤
(Faculty of Engineering, China University of Geosciences, Wuhan 430074, China)
Abstract : With extensionable evaluation model, the quality of rock mass of petroleum storage cavern sealed by groundwater is classified in this paper based on Extenics Matter- Element model. According to the influencing factors of rock mass quality classification, the classical field and segment field are determined. Meanwhile, by means of weight coefficients obtained by mean square deviation and the introduced correlation degree, an extensible evaluation model is made for the rock mass quality. This model is applied in the Huangdao cavern sealed by groundwater, and good prediction result has been obtained. By sampling analysis, it shows that even though the result differs somewhat from that of BQ method and RMR method, this model is more reasonable, and is capable of reflecting the grade of rock mass quality.
Key words: petroleum storage cavern sealed by groundwater; rock mass quality; extenics; weight coefficients
Review on the Classification of Engineering Rock Mass
YIN Hong-mei 1 , ZHANG Yi-hu 2 , ZHOU Huo-ming 2 , ZHONG Zuo-wu 2
(1.CCCC Second Harbor Consultants Co., Ltd., Wuhan 430000, China; ª¤ 2.Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of MWR, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: Rock mass classification is an important means for engineers to identify the properties of engineering rock mass. The development of the classification methods somewhat reflects the status quo of rock engineering. The commonly used classification methods were introduced so as to elaborate on the characteristics of classification method development as follows: 1. the core factor changed from the strength of rock block to the rock mass structure and the properties of structural plane; 2. apart from the properties of rock block itself, the surrounding conditions of the rock were also covered in nowadays classification methods; 3. instead of qualitative classification, the integration of qualitative classification and quantitative classification were used in the newly developed methods. It ' s also summarized that the classification methods exhibit the following developing trends: firstly, classification methods should be developed to meet the requirements of rock engineering in deep or complex conditions. Secondly, the output information should not only include rock stability states, but also parameters and treating methods. Thirdly, domestic classification systems are disordered and inefficient, and therefore needs to be unified and subdivided. Suggestions are also given to improve the classification systems.
Key words: rock mass; quality; classification; status quo; improve
Partial Freezing Method Applied in the Restoration of Damaged Subway Tunnels
SUN Chuang 1 , ZHOU Xing-wang 2 , HAN Yu-fu 2
(1.Institute of Civil Engineering and Transportation, Liaoning Technical University, Fuxin Liaoning 123000, China; 2.Beijing Coal Mining Engineering Company Ltd., Beijing 100013, China)
Abstract : The construction of the pile foundation of Beijing-Shanghai high-speed railway damaged the tunnel lining of a segment of Shanghai subway with large amounts of sludge silted into the tunnel. This paper introduces the repairing of the damaged tunnel and analyzes the site monitoring data to provide reference for alike projects. Firstly, stepped plugging wall was used to plug the solum in the tunnel, and the internal of the damaged tunnel was grouted. The upper solum in the tunnel was treated by ground filling and grouting to reinforce the turbulent solum. Moreover, the restoration segment was reinforced by vertical freezing on the ground and horizontal freezing as well as excavation construction inside the tunnel. Freezing soil curtain with high strength and good sealing property was produced by partial freezing in the upper damaged tunnel and in its surrounding 3 meters area. Subsequently, mining method was employed in the excavation and the damaged lining was repaired by in-situ restoration. The restoration finally achieved great success.
Key words: freezing method; freezing soil curtain; tunnel; plugging wall
Emergency Treatment for Sudden Water Pollution in Central Urban Area of Nanyang City
CAO Bang-qing, JIA Hu ª¤
(School of Civil Engineering and Architecture, Nanyang Normal University, Nanyang 473061, China)
Abstract: Sudden water pollution in the central urban area of Nanyang City generally happens in a basin-wide area with great uncertainty and long-term impact. It is hard to tackle with and requires complex entities for the emergency response. To improve the ability of emergency response management for sudden water pollution and the ability of disaster prevention and mitigation in urban area, a WebGIS-based management system and information service system for water pollution in the city is established. Measures including promoting crisis awareness, establishing emergency management system, formulating emergency planning, organizing regular training and maneuver, publishing information timely, as well as pollution control and treatment in later period are also proposed.
Key words: sudden water pollution; emergency treatment; information service system; monitoring and early warning
Physical Modeling of Morphological Changes in Tiaoguan Bend Reach of Jingjiang River at the Initial Operation Stage of Three Gorges Project
TANG Feng, LI Fa-zheng,YAO Shi-ming, ZHU Yong-hui ª¤
(Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract : Both the process and the amount of the water and sediment load flowing into the Jingjiang river reach downstream of the Three Gorges Project (TGP) have changed significantly due to the regulation and storage of the reservoir. Conspicuous erosion in Jingjiang river channel has resulted in river regime changes in parts of the reach, and will consequently influence the embankments and bank protection works along both sides, the river regulation projects and the stability of riverbed, thereby further affecting the flood control, navigation, ecology, environment and the integrated service function of the river in these areas. In this study, movable bed model of the Changjiang River Flood Protection Physical Model was used to study the changes of erosion and sedimentation in this reach at the initial operation stage of TGP. The tendency of river regime changes were predicted as well. Research results will offer technical reference for the planning and design of river regulation and river regime control projects in this river course.
Key words: Changjiang River Flood Protection Physical Model; Three Gorges Project; Tiaoguan bend reach; changes of erosion and sedimentation
Variation of Split Flow and Sediment Diversion at the Three Outlets along Jingjiang River and Water and Sediment Transport at the Outlet of Dongting Lake
GUO Xiao-hu 1, YAO Shi-ming 1, YAN Li-ming 2
(1.Laboratory of River Regulation and Flood Control of MWR, Yangtze River Scientific Research Institute, Wuhan430010, China; 2.Jingjiang Bureau of Hydrology and Water Resources Survey, Jingzhou 434020, China)
Abstract: The variation of flow and sediment diversion at the three outlets along Jingjiang river and the change of water-sediment transport at the outlet of Dongting Lake are studied on the basis of field data before and after the impoundment of Three Gorges Reservoir. The above changes influence the flood control, navigation and water resources utilization of Dongting Lake, and affect the relationship between the Yangtze River and the Dongting Lake as well. Results indicate that ratios of split-flow and sediment diversion at the three outlets saw no obvious change since the impoundment of the reservoir; whereas the amount of sediment diversion reduced by a large margin. The days of zero-flow at five stations barely changed, with the critical flow in mainstream Yangtze River reduced slightly during zero-flow days at Mituosi station and Kangjiagang station, and changed little at the other three stations. The average annual sediment load had no big decrease at Qilishan station, while the sediment delivery ratio of Dongting Lake increased remarkably, larger than 100% in some specific years.
Key words: Three Gorges Reservoir; three outlets along Jingjiang River; split flow and sediment diversion; Dongting Lake; sediment delivery ratio