Channel Evolution and Regulation of Zhenjiang-Yangzhou Reach of the Lower Yangtze River
LIU Xiao-bin1,2, LIN Mu-song2, LI Zhen-qing2
(1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; 2.Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: The Zhenjiang-Yangzhou reach (hereafter referred to as Z-Y reach) is one of the river sections with the most severe changes in lower Yangtze River. The evolution of this reach is complicated and the river regulation involves great difficulty. Changes of the river in the past century are described as follows: the head of Shiye sandbar collapsed continually and the left branch developed slowly with the mainstream moving towards the right after the confluence. The concave bank of Liuyu bend, which developed towards the downstream afterwards, collapsed constantly since the concave bank and convex bank exchanged. The multi-braided channel at Hechang island developed into a goose-head shaped double-braided channel, and afterwards the main channel exchanged with the branch channel while the left branch developed steadily. The effects of regulation works in this reach is analyzed, and regulation ideas are proposed for the existing problems.
Key words: Zhenjiang-Yangzhou reach of the Yangtze River; channel evolution; river regulation; regulation countermeasures
Experimental Study on Local Scour Around Annulus Pile-Group Foundation with Cushion Caps
ZHANG Lei, SHE Xiao-jian
(River Harbor Engineering Department, Nanjing Hydraulic Research Institute, Nanjing210029, China)
Abstract: Scour tests on annulus pile-group foundation with cushion caps is of great significance since the stability of the foundation essentially guarantees the structural safety. Limited by test site and model sand selection, the model test requires an extension method for series model to study the local scour at the foundation. The flow regime indicates that wake vortex and lateral flow are main influencing factors of scouring. Tests show that local scour generally happens at both sides of the foundation structure and the backside of water. The scour depth reaches its maximum of 6.01m in extreme high mean sea level (MSL) and decreases as the sea level falls.
Key words: annulus pile group; local scour; series model; experiment; maximum scour depth
Study on the Changes of Historical Flood and Drought Series in Haihe River Basin
LU Lu, LIU Jia-hong, QIN Da-yong, WANG Hao, YU Ying-dong
(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing100038, China)
Abstract: The simulation analysis on floods and droughts and research on their influences are hot topics in the study on regularity of climate events. The calculation of flood and drought periods and the detection of sudden changes are important approaches in exploring the regularity. Based on the historical data of flood-drought grades in the past 540 years, the flood and drought periods and the sudden changes are calculated by means of power spectrum, wavelet analysis, index analysis and Mann-Kendall method. The results showed that the floods and droughts of Haihe river basin took predominance for 10, 23, 37, and 75 years in the history with a transformation from drought to flood in the 17th to the 18th century.
Key words: Haihe river basin; flood and drought series; periods; sudden changes; Mann-Kendall method
Combined Effect of Microwave and Activated Carbon on the Removal of Ammonia Nitrogen and COD in Coking Wastewater
LIN Li1, LU Xiao-hua2, LI Qing-yun1, WANG Zhen-hua1, CAO Xiao-huan1
(1.Yangtze River Scientific Research Institute, Wuhan 430010, China; 2.Environmental Science Research Institute, Huazhong University of Science and Technology, Wuhan430074, China)
Abstract: Industrial waste which exceeds the national emission standard for the discharge of pollutants was a major cause of receiving waters pollution. The application of microwave(MW) and activated carbon (GAC) in the treatment of ammonia nitrogen (NH3-N) and Chemical Oxygen Demand(COD) in coking wastewater was explored in this study. It was shown that when GAC dosage increased, the removal rate of COD raised while the removal of NH3-N reduced. Removal of ammonia and COD in wastewater increased with the rise of MW power and radiation time. The removal rate of NH3-N and COD reached 85.3% and 60.3% respectively when the continuous flow microwave system was used to treat the coking wastewater. This study provided an alternative process for the treatment of coking wastewater.
Key words: microwave; ammonia nitrogen; COD; water treatment
Experimental Study on Characteristics of Runoff and Erosional Sediment Yield on Purple Soil Slope
ZHONG Ren-lin1,2, ZHANG Ping-cang2
(1.Water and Soil Conservation Monitoring Center of Zhejiang Province, Hangzhou 310009, China; 2.Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: We study the characteristics of runoff and erosional sediment yield on purple soil slopes by artificial rainfall simulation experiments. The result reveals that the initial runoff yield duration of purple soil slope decreases as rainfall intensifies, and the initial runoff yield is remarkably affected by the slope gradient under small rainfall intensity. The total volume of runoff on purple soil slope tends to rise with the increase of slope gradient and rainfall intensity; whereas rainfall intensity has no obvious influence on the total runoff on a steep slope. The sediment yield on purple soil slope goes up as the slope gradient and rainfall increases, for instance, when the slope gradient is 10°, 15°, and 20°, the sediment yield is relatively large, ranging from 3 106.03 g to 8 117.09 g . In view of this, effective water and soil conservation measures should be implemented on soil slopes larger than or equal to 10 degrees.
Key words: purple soil; artificial rainfall simulation experiments; runoff volume; erosional sediment yield
Review on the Characteristics and Functions of Riparian Zone
WANG Jia-sheng, KONG Li-na, LIN Mu-song, MIN Feng-yang
(River Department, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: An important transition area of river ecosystem, riparian zone is the most active area with material transportation and energy conversion in the river bank environment. Riparian zone as an important part in the river ecosystem, is a hot topic in the study of river ecology around the world. This paper makes a review on the researches in the definition, scope, characteristics and functions of the riparian zone, and presents the progress and results of theoretical researches in this regard. The paper provides a more extensive theoretical basis for further study.
Key words: riparian zone; transition area; edge effect; ecosystem
Application of Nagios in Earthquake Monitoring Network
Temuqile1, SONG Hua2, LIU Ke1, ZHANG Yi-mei1, LI Yin1
(1. Earthquake Administration of Hubei Province, Wuhan 430071, China; 2.Wuhan Architectural Design Institute, Wuhan 430014, China)
Abstract: With the completion of “the Tenth Five-Year Plan”, Earthquake Administration of Hubei Province has finished the data sharing with China Earthquake Administration and neighboring provinces. Unsatisfied with the effect of applying commercial network management softwares to monitor the whole earthquake network, the authors made in-depth research on the open source monitoring software “Nagios”, and established an earthquake network monitoring system to perform visualized surveillance on network equipments and their services. In this paper, we first describe the structure of the entire monitoring system, and then introduce the implementation of the system and the innovation of alarm function and finally discuss the existing problems.
Key words: earthquake network; network monitoring; Nagios; Nagvis; Cacti
Unstructured Simulation of Thermal and Shallow Circulation Flow Based on DEASM Model
XING Ling-hang1, YAN Ming2, YANG Wen-jun1, HUANG Guo-bing1
(1. Yangtze River Scientific Research Institute, Wuhan 430010, China; 2.School of Environmental Science and Engineering, Hohai University, Nanjing 210098, China)
Abstract: To improve the safety of water intake and alleviate the waste heat pollution from thermal power plants, a new depth-averaged turbulent model (DEASM) based on explicit algebraic Reynolds stress model is developed to describe the whole thermal shallow flow. The algorithm of the turbulent model is based on SIMPLE procedure and discretized on unstructured grid. QUICK scheme is modified to improve the precision of advective flux approximation. The numerical results show that the simulated data by the model are well consistent with the experimental data, including section velocity, circulation streamline and the geometrical centers, flow diversion point and temperature distribution. The present depth-averaged turbulent model provides a detailed and unified pattern for solving the shallow thermal flow in adjacent and distant zones.
Key words: thermal shallow circulation flow; Depth-Averaged Explicit Algebraic Reynolds Stress Model (DEASM); SIMPLE procedure; unstructured grids
Study on the Measurement of Entrained Air Concentration Based on Digital Image Processing
LI Jing, ZHOU Chi, JIANG Bo-le
(Hydraulics Department, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: An image analysis software for entrained air concentration is developed based on object-oriented advanced programming technique VC in association with high speed digital camera. A digital image processing method which automatically recognizes the bubble in water-air two-phase flow is put forward, and an algorithm for calculating the two-dimension and instantaneous air concentration is presented. The study is a multidisciplinary application combining image processing technology with water-air two-phase measurement. The research results will be helpful to understand the mechanism of air entrainment in high speed flow, and will lay a good foundation for studying the application of image processing technology in the measurement of flow field, in particular, high speed water-air two-phase flow field. It’s also of great academic significance and practical value for improving the measurement of air concentration and its precision.
Key words: entrained air concentration; threshold segmentation; iterative method; OTSU’s method (maximum between-class variance method); local dynamic threshold
Causes and Eliminating Measures of Vortices at the Intake of Short Culvert Conveyance System of Shiplock
WU Ying-zhuo1, JIANG Yao-zu1, ZHOU Chi1, JIANG Xiao-min2
(1.Yangtze River Scientific Research Institute, Wuhan 430010, China;2.Changjiang Institute of Survey, Planning, Design and Research, Wuhan 430010, China)
Abstract: Physical model tests were performed to discuss the causes of vortices at the intake of short culvert conveyance system of the shiplock at Xinglong hydro-junction. Effects of the operating mode of the water valve, the submerged water depth at the intake, and the intake shape and solid boundary conditions on the vortex pattern were analyzed. By comparing a series of model tests, measures of properly increasing the submerged water depth at the intake while setting vortex plate at the top of the intake were finally proposed to eliminate the air-inhaling vortices. It provided basis for the optimal design and operation management and could be referential for the design of alike projects.
Key words: shiplock; short culvert conveyance system; vortex at the intake; causes of vortex and eliminating measures
Coupled Seepage Stress in the Connection Aisle of Cross-River-Tunnel Under High Water Pressure
SUN Chuang1, LIN Zeng-hua2, WANG Chen1
(1.School of Civil Engineering and Transportation, Liaoning Technology University, Fuxin 123000, China; 2.School of Resource and Civil Engineering, Liaoning University of Science and Technology, Anshan 1140512, China)
Abstract: To ensure the safety of excavating connection aisle in a cross-river-tunnel, the excavation process is numerically simulated by finite difference software FLAC3D to directly perceive the mechanical features of freezing soil curtain under high water pressure and to investigate the effect of coupled seepage stress on the stability of the curtain. The effect of water level variation on the mechanical features of freezing soil curtain are obtained through numerically analyzing the distribution of displacement field, stress field, and seepage field. It’s found that forces on the curtain are more evenly distributed owing to pore water pressure. The bottom and middle of the curtain, which is more likely subject to stress concentration, should receive more attention. The study provides reference for the simulation of connection aisles and the artificial freezing construction.
Key words: connection aisle; seepage; numerical simulation; freezing soil curtain; coupling
Mechanical Parameters and Slip Boundary of Deposit Slope on Dam Abutment of Hydropower Station
JI Feng, SHI Yu-chuan
(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China)
Abstract: Quantitative calculation of deposit slope stability, which is closely related to the strength parameters and slip boundary, directly determines the cost and planning of the construction. Different from that of the sliding zone, the determination of strength parameter and slip boundary involves great complexity. The deposit slope with neither sliding zone control nor adequate inversion condition is explored. In the study, a deposit slope on the left abutment of a hydropower station in downstream Dadu river is taken as a typical case. Detailed geological data and slip boundary searching by maximum shear stress method show that the potential sliding boundary is formed through the gravel mingled with soft silty clay with unfavorable properties in the middle stratum. The strength parameters are determined comprehensively by engineering analogy, large-scale indoor test and inversion method. Final results reveal that quantitative calculation based on geological data is consistent with the qualitative analysis.
Key words: deposit slope; mechanical parameter; slip boundary
Computation of Block Dynamic Safety Factor Based on Earthquake Time-History Curve
XU Dong-dong1, WU Ai-qing1, LU Bo1, SUN Yu-jie2
(1. Key Laboratory of Geotechnical Mechanics and Engineering of the MWR, Yangtze River Scientific Research Institute, Wuhan 430010, China; 2. Shengli Engineering Consulting Co., Ltd. of Shengli Oil Field, Dongying 257026, China)
Abstract: The block stability based on earthquake time-history curve is studied by computation program. Vector analysis of block theory is adopted for programming. The detailed approach involves the following procedures: input the required information of structural planes and free faces, and subsequently determine the finiteness and mobility of the block according to finiteness theorem and mobility theorem. If the block is movable, find out the sliding mode of the block (single face sliding or double face sliding) under the combined action of dead weight and seismic loads. Finally compute the safety factor under that sliding mode and draw the time-history curve of dynamic safety factor. In addition, a block drawing program is added to obtain information regarding the contact area between each face and the volume of the block required for the computation when the cohesion between the blocks is considered.
Key words: block theory; dynamic safety factor; seismic load; FORTRAN
Experimental Study on Damping Parameters of Marble Under Triaxial Cyclic Loading
REN Hao-nan1,2, XU Jin1,2, NIE Ming1,2, LIU Jian-feng1,2
(1.State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Sichuan610065, China; 2. School of Water Resources and Hydropower, Sichuan University, Sichuan 610065, China)
Abstract: The damping parameters including damping ratio and damping coefficient of marble under triaxial cyclic loading were studied through experiments by MTS815 Flex Test GT rock mechanics testing system sets. For the marble under four grades of confining pressures, cyclic loading and unloading was carried out by three levels of dynamic stress under each confining pressure. The regularity in the changes of damping ratio and damping coefficient of marble under triaxial stress and different stress statuses was found as follows: with the increase of loading times, the plastic deformation of rock under the same stress status increased gradually, and the energy dissipation also increased with the rising ofσmax/σc and confining pressure σ3. Meanwhile, under the same confining pressure, the damping ratio and damping coefficient increased progressively with the increment of dynamic stress amplitude, and accelerated along with the increase of confining pressure. Under the same σmax/σc, the damping ratio and damping coefficient increased progressively with the rising of confining pressure, and accelerated along with the increase ofσmax/σc. Moreover, with the expansion of internal microcrack of the rock and the increase of the quantity and scale of new cracks as well as the irreversible plastic deformation under a cyclic loading of high level stress, the energy dissipation of each cycle increased accordingly.
Key words: rock mechanics; triaxial cyclic loading; damping ratio; damping coefficient; hysteretic loop
Calculation and Influencing Factors of Pile-Soil Stress Ratio of PCC Pile Composite Foundation
LU Chang-na1, JIANG Jing-shan2,3
(1.College of Maths & Physics, Nanjing University of Information & Technology, Nanjing 210044, China; 2.Geotechnical Engineering Design Institute, Jiangsu Transportation Research Institute Co., Ltd, Nanjing 211112, China; 3.Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China)
Abstract :The cast-in-situ concrete thin-wall pipe pile (PCC pile) is a kind of rigid pile suitable for reinforcing soft foundation. A new method of calculating the pile-soil stress ratio of PCC pile composite foundation is presented taking the combined action of pile-soil-cushion into account. The relationship of frictional resistance and relative displacement between the pile shaft and the surrounding soil is idealized as perfectly elastoplasticity; meanwhile, settlement of soil between the piles and inside the piles at the same depth is assumed to be equal, and the soil at the pile tip is considered to be in conformity with Winkler ground model. Based on these assumptions, the calculation formulas for pile-soil stress ratio and settlement are derived through analyzing the pile-soil-cushion interaction. The influencing factors of pile-soil stress ratio are discussed according to the obtained formulas, which are beneficial to the optimal design for PCC pile composite foundation.
Key words: PCC pile composite foundation; rigid pile; pile-soil stress ratio; settlement; optimal design; soft foundation improvement
Experimental Study on Test Technology of Tensile Property of Warp Knitted Geogrid
CHEN Ying, CHEN Wen-liang, SUN Cong-yan
(Zhejiang Institute of Hydraulics & Estuary, Hangzhou 310020, China)
Abstract: Current test standards for the tensile properties of geogrid are systematically compared, and problems in tensile test on warp knitted geogrid are summarized. Variations of tensile properties induced by the change of initial fixture distance, tensile rate, and fixture protected by liner or not are investigated through experimental study on the tensile properties of warp knitted geogrid. The results obtained could explain the problems in tensile properties tests.
Key words: material testing; warp knitted geogrid; tensile properties; experimental study
The Influence of Foundation Pit Excavation on the Adjacent Ship Lock
PAN Xuan-he1,2, LIU Xiao-ping2, LIN Ji-da2, CHEN Ya-jiao2
(1.Pearl River Institute of Hydraulic Research, Guangzhou 510635, China; 2.Changsha University of Science & Technology, Changsha 410076, China)
Abstract: The process of excavating the foundation pit of adjacent ship lock supported with row-piles was simulated with finite element method. The authors investigated the displacement of the lock chamber wall and retaining piles, the regularity in the changes of soil pressure behind the chamber wall and subgrade reaction against the excavation depth, as well as the relation between them. The study reveals that the lateral displacement can be reduced to ensure the stability of lock chamber wall by maintaining the soil pressure behind the wall when excavating the foundation pit and meanwhile avoiding an excessive difference of subgrade reactions of the chamber wall between front-toe and back-toe. The study will be helpful for engineering design and construction.
Key words: ship lock; excavation of foundation pit; soil pressure; subgrade reaction
Analysis on the Performance of Double-Row Anti-Slide Frame-Piles
QIAN Tong-hui1,2, CHEN Fang2, CHENG Zhou-bing2, DING Hong-xing2
(1.Three Gorges Research Center for Geohazard of Ministry of Education, China University of Geosciences, Wuhan 430074, China; 2.Faculty of Engineering, China University of Geosciences, Wuhan 430074, China)
Abstract: To study the characteristics of pile-soil interaction and the resistance of frame anti-slide piles, a 3-D finite element model of anti-slide frame-piles was established for Hongshibao landslide control works at Badong County in the Three Gorges Reservoir Area. Impacts on pile-soil interaction exerted by the physical and mechanical parameters of sliding body and sliding bed and the parameters of pile-soil interface were considered during the model establishment. The interaction of pile-beam-soil was investigated through observing the variation characteristics of internal force and displacement of the piles. Simulation results showed that the frame beam coordinated well with the displacement of front and back piles, and the displacement value of frame piles was consistent with that of soil among the piles. A spatial structure of large integral stiffness was thus formed by the piles and the soil among them. The results suggested that anti-slide frame-piles are of large stiffness and stability, and have equivalent support effect to that of multi-arch structure.
Key words: anti-slide frame-pile; spatial coordinative calculation; pile-soil interaction; finite element
Voronoi Tessellation Method for Stiff Junction Pairs on the Interface Between DDA Blocks
ZHANG Yang1, WU Ai-qing2, LIN Shao-zhong2
(1. College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou 225009, China; 2.Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: In the analysis of applying high order Discontinuous Deformation Analysis (DDA) to continuous structures, some stiff junction pairs are required to be set on the adjacent faces between blocks to connect the discrete blocks into a whole. Nonetheless, it involves great difficulty to rapidly lay out these points for complex structures with multiple structural members. In this paper, the geometric method algorithm to generate Voronoi tessellation is improved on the basis of Voronoi tessellation theory, and the locations of the points are optimized with centroid method. Program is compiled based on the above optimizations and is verified by several examples. The calculation results show that a series of points well distributed in an arbitrary convex polygon can be generated quickly with the suggested method, which thus could be applied in three-dimensional high order DDA analysis easily.
Key words: high order DDA; generation of junction pairs; Voronoi tessellation; geometric method; centroid method
Calculation and Analysis on Flexural Capacity of RC Beam Strengthened with Side-Bonded FRP
CHEN Xu-jun, DAI Mu-xiang, XU Yun
(School of Civil Engineering and Urban Construction, Jiujiang University, Jiujiang 332005, China)
Abstract: The bending failure modes of and design requirements for Reinforced Concrete(RC) member strengthened with side-bonded Fiber Reinforced Polymer(FRP) are investigated through tests on its flexural behavior. With theoretical method of calculating flexural capacity on the positive section based on the assumption of plane section, a practical calculation method for the flexural strength reinforced with side-bonded FRP is put forward. The calculated values, which are well consistent with the test data, are reliable and can be referential for designers. The study also probed into the values of correction coefficient ηf in Design Code for Strengthening Concrete Structure (GB 503672006) when FRP is bonded on the sides of RC beams rather than on the bottom. When hf/h is a fixed value, the correction coefficient ηf is not a definite value as shown in the design above code, but varies with the parameters of the strengthened RC beams.
Key words: Fiber Reinforced Polymer (FRP); Reinforced Concrete(RC) beam; side-bonded; flexural capacity; calculation method
Application of Acoustic Doppler Velocimeter (ADV) in Bridge Pier Model Test
WU Xin-sheng, HAN Xiang-dong, HUANG Wei-dong, LIAO Xiao-yong
(River Department, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: A new type of Acoustic Doppler Velocimeter (ADV) was applied to measure the flow rate accurately in a generalized pier model test tank for the Ma’anshan Yangtze River Bridge which is under construction. The bridge site section and bank slope were generalized through the model test. Focused on changes in water flow observed near the piers as well as on the bed deformation, the test was to obtain the depth and the scope of riverbed erosion around the pier, and thereby providing basis for protective measures and engineering design. It was manifested that ADV could measure the distributions of instantaneous velocity, average velocity and three-dimensional fluctuating velocity as it measured rapidly in wide scope. It is a full-featured flow measuring instrument of high accuracy, and will be more widely used in the study of water movement.
Key words: Acoustic Doppler Velocimeter (ADV); Doppler shift; pulse coherent processing turbulent flow; pier model
Development and Application of Wide Range TSX Settlement Gauge for Dam Foundation
XIONG Guo-wen1, XIONG Meng-jie2, CHENG Jian-yi3
(1.Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing 210029, China; 2.College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China; 3.Water Resources Bureau of Boyang County, Jiangxi Province, Boyang 333100, China)
Abstract:A wide-range TSX settlement gauge for dam foundation with deep overburden has been researched and manufactured to overcome the limitation of conventional water tube settlement gauge. The structure, measuring range, precision, sensor type and calibrated results of this settlement gauge are introduced. Its application field, practices and application effect are also given. It’s shown that the measurement by this gauge is consistent with the rules of dam deformation, and thereby could be used to monitor dam foundation settlement in the long-term with continuous, precise and stable results.
Key words: wide measuring range; dam foundation; settlement gauge; development
Channel Evolution of the Reach from Xiongjiazhou to Chenglingji in Lower Jingjiang River and Regulation Considerations
LU Jin-you, QU Geng, LI Fa-zheng, TANG Feng, ZHU Yong-hui
(Key Laboratory of River Regulation and Flood Control of Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan 430010, China)
Abstract: The characteristics and tendency of channel evolution in the reach from Xiongjiazhou to Chenglingji in lower Jingjiang River is systematically analyzed on the basis of water-sediment and terrain data before and after the operation of the Three Gorges Reservoir (TGR). The results reveal the river regime adjustments as follows: collapse has occurred at the upstream side of Baxing sandbar and Qixing sandbar as well as the river bankline at the unprotected section of the left bank of Guanyin sandbar; evident changes including chute cutoff has been found in the mainstream line of Qigongling bend, and natural cut-off of river channel is likely to happen during big floods. In view of the above analysis, considerations of comprehensively harnessing the channel by stages is proposed to provide scientific basis for the river reach regulation.
Key words: river reach from Xiongjiazhou to Chenglingji; channel evolution; river regime control works; TGR