Based on the advanced circulation (ADCIRC) model, a storm surge model from the tidal range limit (Datong station) of the Yangtze River to the East China Sea is established to investigate water level distribution along the Yangtze River. Typical hypothetical typhoons with different tracks are constructed, based on typhoon 9711 and typhoon 0012; the influences of typhoon tracks on storm surge level are studied. Distribution of water level under multi-factor conditions along the Yangtze River is analyzed, under the combinations of extreme typhoon storm surges, maximum runoff and high astronomical tides.

Large stepped caisson foundation has been widely used in long-span deepwater bridge in recent years, and local scour caused by the structure has also been concerned. The hooked collar structure has been proposed to reduce the local scour around novel stepped caisson. Laboratory experiments were conducted to investigate the response of local scour of stepped caisson to different hooked collar height. The experimental results show that the local scour depth increases first and then decreases with the rise of hooked collar height under steady flow and uniform sediments. Further analysis indicates that the optimal hooked collar height to minimize the local scour related to the stepped width. The quantitative relationship between dimensionless scour reduction capability and dimensionless hooked collar height is presented in this study, which is able to provide reference for engineering application of relevant structure.

自三峡工程以及上游大型梯级水库的建成运用后,长江河道水流特性发生了一定的变化,本文基于新情势下长江典型河道演变的航道效应与水沙调控进行研究,采用多种手段定量提出了航道条件改善的三峡水库水沙调控关键参数和实施时机,研究表明,通过控制坝前水位消落速度并结合上游流量预报,可达到较好的库尾减淤效果,库尾减淤调度实践证明变动回水区减淤效果明显,有力保障了变动回水区的航道水深条件.研究成果已在长江上游朝天门至涪陵河段长寿水道航道整治工程、长江中游芦家河河段航道维护性疏浚工程等航道治理工程中得到应用,产生了显著的经济与社会效益,也为新情势下其他长江典型碍航浅段的治理提供支撑.

In view of the problems of complex hydrodynamics and changes in riverbed erosion and siltation of Xianxin Road crossing in Nanjing, using fixed-bed and moving-bed river engineering model tests, the construction conditions of the river crossing in the confluence section of the lower reaches of the Baguazhou branch road, as well as the flood control of the project plan and the impact of the river situation are studied and analyzed, which provide technical support for the project construction.

Resuspended sediment is an important carrier of underwater material circulation, and bed shear stress is usually considered to be closely related to sediment resuspension. To analyze the resuspension dynamics in severely eutrophic Lake Chaohu, China, three fixed stations were set up to collect wave, current, and suspended sediment concentrate (SSC) data under windy weather, and two significant sediment resuspension events were recorded. Based on the Gaussian-shaped spectrum characteristics of waves in Lake Chaohu, the wave orbital velocity was estimated by using the wave parameter method. The selection of the general wave spectrum is important for the accurate estimation of wave orbital velocity. The results of the simple linear wave method were very similar to those of the wave parameter method with a Gaussian-shaped spectrum in Lake Chaohu. The total bed shear stress combining waves and currents during the observation period was calculated, and most of it was contributed by wind-driven waves. The bed material of Lake Chaohu has silt-enriched and weak cohesive features, and an examination of critical shear stress showed that the modified Shields curve method was still applicable to Lake Chaohu. When a sediment resuspension event occurred, the vertical gradient of SSC increased significantly, and the peak SSC value depended on the peak value of bed shear stress. As a predictor, bed shear stress only showed a good linear relationship during sediment resuspension events. At other times, the prediction of SSC using bed shear stress may be biased, especially at the time after a significant sediment resuspension event.

在历史演变分析的基础上,重点研究近年来长江北支进口段滩槽时空变化、成因和影响机制.利用数学模型,对进口段规划整治方案效果进行模拟研究.结果表明:受上游来水来沙条件变化、周边整治工程实施等综合影响,长江北支进口段拦门沙经历了舌状沙体→崇头暗沙→崇头沙的发展变化,北支进口入流条件恶化;沙体两侧深槽则呈现"十年河东、十年河西"交替变化的态势,目前主槽位于崇明侧,其走向与南支主流交角已达105°,主流流路极度弯曲.在北支中下段规划整治工程已实施的情况下,进口段的治理已成为北支兴衰的关键;北支进口段规划疏浚工程实施后,进口段流路有所归顺,北支分流比增加0.1％,工程实施有利于河势稳定,可达到治理目的.

Large marginal sandbanks in tidal rivers experience periodic splitting processes. In this paper, the morphodynamic evolution of Jingjiang Beach, a sandbank on the Yangtze tidal river, has been investigated based on measured data. The results show that the duration of the splitting process in the middle and lower sections of Jingjiang Beach is 4–6 years. The periodical evolution occurred both in flood season and dry season, with a slight difference in the initial stage of splitting. This paper focuses on the evolution characteristics related to strong human activities since 2003. Ever since the second stage of the 12.5 m Deepwater Channel Project (DCP), the volumes above the 10 m and 12.5 m isobaths of Jingjiang Beach have been generally decreasing. The elevation data in recent years have demonstrated that the upper section, and nearshore side of the middle section, of Jingjiang Beach have tended to be stable. Moreover, the migration distance for a splitting sand body at the tail of Jingjiang Beach appears to have shortened. With the operation of the Three Gorges Reservoir, the number of days with discharge less than 15,000 m3/s has shown a decreasing trend; thus, the development scale of Jingjiang Beach could decline in the future.

为探究台阶式沉井基础附近局部冲刷的影响,建立三维水动力数学模型,计算分析恒定流下台阶式沉井基础附近水动力特征.基于数值模拟结果设计了8个有效试验工况进行物理模型试验,分别探究了台阶式沉井平台宽度、埋置深度以及挡墙高度对局部冲刷特性的影响并进行讨论.试验结果表明台阶式沉井局部最大冲刷深度随平台截面宽度比增大逐步减小并趋于稳定.台阶式沉井局部最大冲刷深度随平台埋深比增大而逐步减小最终趋于稳定.台阶式沉井平台处设置较低挡墙对减小沉井周围局部冲刷最大深度有小幅的效果.

对近年来靖江边滩周期性切割发生的位置、 切割时的规模和切割体的大小进行梳理分析,并对1966年以来已发生的12次较大规模切割时机和切割流量进行重点研究.结果表明:洪季和枯季均有可能出现切割.洪季落潮切割时上游径流38700～54100 m3/s,平均47000 m3/s;枯季涨潮切割时上游径流11800～23700m3/s,平均17000 m3/s;心滩下移速度1.0～1.8 km/a.为此,可加强易切割流量时地形观测,预估下移心滩进入航槽的时间,提前配置疏浚设备,对航道疏浚维护具有重要的意义.

The bed shear stress under the action of waves is one of the important essential parameters to estimate the incipient motion and transport of offshore sediment, and its bottom friction effect will also have an impact on the offshore hydrodynamic environment. Due to the difficulty in field observation, the understanding of the wave boundary layer and the bed shear stress under the action of waves is mainly based on indoor experimental observation. This paper reviews the relevant theoretical models and experimental measurement research at home and abroad, sorts the advantages and disadvantages of various research methods and measurement techniques, as well as the application conditions, collates a lot of experimental data from 1970s to now, generalizes and analyzes the existing research results, including the impact of wave nonlinearity, wave breaking and other factors on the bed shear stress, summarizes the limitations of the existing research, and puts forward the future research focuses. Super-large water flume is an important facility to break through the bottleneck in the theoretical study of the layer of wave boundary in the future. The development of high-adaptability underwater two-dimensional shear stress sensor is the key to making a breakthrough in the study of bed shear stress under complex dynamic conditions.

潮流环境桥墩冲刷问题已成为目前研究的热点.为深入分析潮流对桥墩局部冲刷影响,文章通过系统梳理河口或近海潮流环境下桥墩局部冲刷文献成果,总结了潮流引起的桥墩局部冲刷特性,明晰潮流引起的桥墩局部冲刷机理与过程,并阐述了潮流桥墩局部冲刷深度、冲刷过程变化及主要影响因素.研究分析认为:潮型及流速的概化差异是造成目前潮流桥墩局部冲刷成果不连续的重要原因,且试验中采用未平衡冲刷试验成果将进一步增加潮流冲刷认识的分歧.同时,文章分析潮流冲刷影响因素发现其与恒定流冲刷特性存在较大差异,且在应用恒定流冲刷成果于潮流冲刷时应谨慎.最后,文章指出潮流桥墩局部冲刷进一步研究方向,为后续相关研究提供了方向与指导.

长江干流江苏段地处长江下游河口地区,全线位于感潮河段,沿程水位既受上游长江径流、外海潮位、台风的影响,也受到工情变化、支流入汇等影响.长江江苏段现行洪潮设计水位是按《长江流域综合利用规划简要报告》(1990年)中确定的无台风影响水位实施.近年来,由于上游水、沙、工情条件变化,开展上游大通径流、风暴潮、区间入汇等对沿程洪潮水位的影响研究十分必要.建立大通至长江口二维水沙数学模型与外海风暴潮模型,研究不同影响因素作用下长江干流江苏段沿程洪潮设计水位变化.研究成果表明:南京河段水位主要受上游径流影响;江阴以下主要受外海潮汐及风暴潮的影响;南京至江阴段则受上游径流、外海潮汐、风暴潮三者的共同作用影响.外海天文大潮、风暴潮"两碰头"和上游大径流、外海天文大潮与风暴潮"三碰头"引起的沿程增水值呈驼峰分布,最大值分别发生在江阴和天生港附近,最大增幅1.65 m.研究结果已为长江江苏段堤防防洪能力提升工程建设提供技术支撑.

Based on summary of the research results of waterway regulation in the lower reaches of the Yangtze River, the design theory and method of waterway regulation in tidal rivers are discussed and expounded. The results show that in a tidal reach, three sections: perennial tidal current, seasonal tidal current and perennial runoff can be divided according to the different runoff and tidal impacts, and there are four types of shoal: single-stage branching type, multi-stage branching type, underwater diara type and submerged bar type according to the characteristics of river type and the beach & channel pattern. The overall principle of the tidal waterway regulation should be established by consideration on many influencing factors and external conditions, and the designed navigable water level of different sections and its connection with the upstream and downstream waterway, as well as the determination method of the regulation parameters (regulation water level and regulation line width) should be sorted out, and the regulation ideas and engineering measures for the characteristics of various shoals are presented, and the concrete component mixed dikes and new type of protection structures are adopted.

天生港水道位于澄通河段,是一条分流比仅占1％ ～2％、涨潮流占优的支汊.为稳定河势、促进地方经济发展,水利部门对天生港水道整治进行了规划.此后随着上游来水来沙条件变化,周边深水航道、桥梁及沿岸港口码头等诸工程的建设,河床地形发生调整,特别是华泰重工等企业位于规划切滩范围内,为适应新的水沙和工程环境,降低规划工程实施的难度,文章通过数模计算和物模试验,对原规划方案进行了深化研究.调整方案减小了天生港水道进口的切滩宽度,增加疏浚范围及深度.研究表明,调整方案实施后的效果与原方案基本一致,对促进地方经济发展有着重要的意义.

With marine bridges extending to the deep sea, wave current force action and scouring on bridge foundations have become the main factors threatening bridge safety. To ensure the design rationality as well as construction and operation safety of bridges, this paper sorts out the major problems faced by marine bridges in terms of wave force action and foundation scour, and proposes that marine bridges should be developed in high-precision prediction method, environmental prediction and pre-warning systems, research on multi-factor coupling effect of environment, scour numerical simulation technology, and wave current force calculation method. Furthermore, countermeasures are proposed from the aspects of macroscopic management, industrial application, and academic technology.

马尔代夫维拉纳机场改扩建工程将占用原岛内湖部分水域,对岛内湖水动力产生影响.建立工程区二维潮流数学模型,通过与实测资料对比验证数学模型,在此基础上研究分析工程建设前后岛内湖水动力变化.研究表明,工程区域潮汐为不正规半日潮,潮差较小,正常天气下湖内流速一般<0.05m/s,工程建设对湖内水流流速影响不大.受围填海影响,湖纳潮量减小约13％.工程后湖内的水体交换能力进一步减弱,水环境相对脆弱,因此必须加强环境风险防控,严格控制湖内污染排放,做好突发环境污染事故应急预案.

When the local boundary conditions of the channel are changed causing by the natural or human factors,the flow dynamic will change correspondingly,and it will cause a further adjustment of the riverbed.After the construction of the bridge,hydrodynamic conditions are also changed within a certain range,and the adjustment of local riverbed erosion and deposition will occur, which will bring a certain degree of influence on navigation condition of engineering reach.Taking the construction of the Wuhu Yangtze river bridge in the Shang-He-Hang railway for example,by using the established physical model, the hydrodynamic characteristics at the bridge site was analyzed in this paper,and the influence of bridge construction on the flow dynamic and navigation condition of engineering reach was simulated.Combining with the optimization scheme test, the influence of navigation condition and adaptability analysis of the scheme were also discussed.It provides reference for bridge design.

In this paper, in order to solve the problem of riverbank failure in Yangtze River estuary, the reason of the formation of riverbank failure and mechanism at the estuary of the Yangtze River was first analyzed.Then base on the newly derived formula recently by Chen et al, a two-dimensional riverbank failure numerical code was established, and this code was applied to the Minzhu Shoal and Langshan Shoal in the area of the estuary of the Yangtze River.The results show that the simulation results are in good agreement with the measured data.

For river model tests, the particle image measurement methods for the surface flow field have been applied widely. A new type of distributed measurement system for the surface flow field was developed for large?scale river model tests. Million?pixel high?definition intelligent integrated industrial cameras were used in this system and connected with a computer with wireless network. There is a gigabit POE(Power Over Ethernet) interface in the camera. The image transmission and camera power supply can be completed at the same time by only a cable with a gigabit POE switch. The complexity of wiring can be significantly reduced so that the cameras can be easily added into the system. The system has functions such as visual and automatic acquisition, visual elimination for error vector,data export with a variety of data formats,generation of flow contours and streamlines;A new detection method for the measurement system of the particle image surface flow field is introduced in this study. Water flow can be simulated by the accurate control of the uniform rotation of the platform. The measured data from the flow field measurement system and the accurate data of the rotating platform are compared. The accuracy of the time of the image acquisition control, calibration of image distortion and flow extraction algorithm can be detected. The model test results show that the measurement errors of the measurement system for the surface flow field are less than 5%. The system has been successfully applied in the Yangtze River estuary model tests and other large river models tests.

In order to study the flow force characteristics of a new-type submerged spur dike, a 3D mathematical model is developed by using the fluid calculation software Fluent to study the flow force characteristics of the new-type spur dike with tooth-shaped structures under the conditions of different flow velocities, water depths and dike lengths based on the finite volume method and the free surface capture method. Meanwhile, a physical model with the scale of 1∶ 50 is also designed to make a supplementary verification of the flow force of the new spur dike under the conditions of different dike lengths. The numerical simulation results are in good agreement with the model test results. The distribution laws of the flow velocity and water depth of the spur dike's flow field are obtained, and the flow force response laws of the new-type spur dike with tooth-shaped structures under the conditions of different flow velocities, water depths and dike lengths are analyzed, and the response laws of relative dike lengths and the critical submergence degree to the flow force coefficients via dimensional process are further analyzed. And the sensitivity of relative dike lengths and the critical submergence degree to the flow force coefficients are respectively discussed by means of independent analysis. The research results will provide certain technical supports and scientific guidance for the location of the new-type submerged spur dikes in the 12.5 m deep waterway regulation works in the lower reaches of the Yangtze River from Nanjing.