【作者】 高凯春；

【导师】 李义天；

【作者基本信息】 武汉大学 ， 水力学及河流动力学， 2013， 博士

【摘要】 长江是我国第一大河,贯通东、中、西部的水路交通运输大通道,通航里程与水运量分别占全国内河的53%和80%。长江中游起于宜昌,至于鄱阳湖湖口,长900km,水运条件十分优越,是连接我国东、中、西部地区的重要纽带,是实施西部大开发战略的重要依托,也是长江沿江经济持续、快速发展的重要支撑。保持长江航道畅通和安全直接关系到东西部物质交流和经济交往,对于我国经济、社会发展具有非常重要的促进作用。然而,长江中游浅滩众多,尚未经过大规模系统整治,通航能力差,成为严重制约长江干线航道畅通的“瓶颈”,必须对其开展系统治理。要对长江中游主航道进行经济合理的整治开发,必须以确定合理的设计最低通航水位和航道整治参数为保证。设计水位、航道整治参数与河道变形、枯水流量等因素紧密相关,设计水位设定的高低涉及到船型、船舶航运效益、航道建设和维护投入等问题,航道整治参数的确定涉及到工程成本、效果等问题。2003年以来,随着三峡水库的蓄水运用,长江中游水沙过程受到人为调节,流量调平,清水下泄,河床发生剧烈冲刷,由此引起同流量下枯水位变化以及滩槽格局的改变,设计水位及航道整治参数难以确定,严重影响到长江中游诸多浅滩治理工程的顺利开展,开展三峡水库蓄水后长江中游航道整治参数确定方法的研究是十分必要和紧迫的。本文在系统总结三峡水库蓄水对水沙过程及浅滩河段演变影响的基础上,揭示了决定航道整治参数的影响因素的变化趋势,提出了水库水沙过程调节、河床冲刷双重作用下设计水位的推求方法；考虑枢纽下游河段非恒定输沙、河床单向下切两个主要特点,推导得出了航道整治线宽度计算公式,并对式中系数和指数的拟定进行了分析和讨论；结合长江中游的浅滩特点,得出适用于长江中游的航道整治线宽度计算公式,并提出整治断面的概念；分别将改进后的航道整治参数确定方法应用于三峡水库下游具体河段,首次对就沙量减少、退水加快等情况下整治参数的应用效果及适应性开展了深入分析,为长江中游航道整治参数选取提供了依据。全文主要讨论了以下几个方面的问题：(1)三峡水库蓄水对浅滩河段演变的影响。通过分析三峡水库蓄水后流量、含沙量的变化,揭示了三峡水库蓄水后10月份退水加快,含沙量锐减的特点,同时坝下游河床受到长距离、长时期的冲刷,引起枯水水位下降,冲积河床上航道水深有所提高,抗冲性强的河段可能出现坡陡流急问题,沙质河床洲滩萎缩河宽增大,主流摆动频繁等问题。(2)设计水位确定方法。首先对蓄水前的设计水位确定方法进行总结,提出蓄水后整治流量与同流量下水位均变化情况下的计算方法。针对蓄水后年内出库流量过程被调节、坝下游河床持续冲刷等特点,采用由设计流量推求设计水位的方法确定三峡水库蓄水后15年内的中游各站设计水位,通过对不同方法确定的设计水位进行比较,确定各水文站具体的设计水位取值。最后,在受电站日调节影响明显的近坝段,考虑日调节非恒定流对设计水位的影响,给出了设计水位的修正值。(3)整治线宽度确定问题。系统总结长江中游整治参数的确定方法,并提出优化思路,确定了整治水位的确定方法,此外提出的综合整治线型与整治断面进行航道整治,是按三维条件对河道进行调整和控制,可以综合的考虑洪、枯、中、枯水河道条件的协调,其内容较全面,可以确保河势稳定,体现了对浅滩河道进行全面治理的理念,并开展实体实验研究,对公式的适用性进行了验证。(4)整治参数确定方法应用问题。将改进后的航道整治参数确定方法应用于三峡水库下游明显冲刷段(藕池口水道)和弱冲刷段(牯牛沙水道),就沙量减少、退水加快等情况下整治参数的应用效果及适应性开展了深入分析,证明本文所提航道整治参数确定方法对三峡水库蓄水后的长江中下游浅滩河道具有较好的适用性。更多还原

【Abstract】 The Yangtze River is the longest river in our country, which is the significant channel through east to west, Navigable mileage is accounted for53%while the water volume is accounted for80%. The middle reaches of the Yangtze River is900km from Yichang to Poyang Lake, Hukou, the water transport condition is extremely advantageous, it is an important link making the East, middle, West of China together, it is the bases of the western development, it is also the important support for the sustainable, rapid development of economic. Keeping Yangtze waterway unimpeded and safe will increase the material exchange and economic exchanges between the East and West, which is benefit for the social and economic development of our country. However, the middle reaches of the Yangtze River have many shoal patch, this problem has not been solved, it is becoming the "bottleneck" for transportation on the yangze river, so we must take action to deal with it.Before manage the Yangtze River comprehensive, we should determine the navigable water level and regulation parameters, Channel regulation parameters. Design water level, waterway regulation parameters are closely related to many factors such as the channel distortion, low water flow. The designing water level impacts the shipping benefits and the cost of Channel construction and Channel maintenance. The determination of waterway regulation parameters influence the engineering cost and effect.Since2003, because of the three gorges reservoir’s impoundment, the water and sediment process in the middle reaches of the Yangze river is determined by artificial regulating, Flow’s leveling, clean water’s washing, riverbed’s changing. so the low water level and beach trough structure changed, then designing water level and the waterway regulation parameters are difficult to determine, which impedes the implementation of the project in the middle reaches in Yangze river. Above, the study of how to determine the waterway regulation parameter in the middle reaches of Yangze river is necessary.This article explains the trends of the rectification parameters in yangze river through considering the changing of water and sediment process and the changing of the terrain by under Three Gorges reservoir. Then find the way to determine the designing water level under the Reservoir regulation and riverbed sedimentation condition. The downstream of the hydro-junction has two characteristics:unsteady sediment transport and unidirectional cutting bed. We has reduced the formulary of calculating the width of channel regulation line, and analysed the parameters in this formulary. To find out the formulary of calculating the width of channel regulation line in middle reach of yangze river, we have made the formulary combined with the feature of middle reach of yangze and put forward the concept of remediation cross-section, using the proved parameter in the downstream of three gorges reservoir. Provides the basis for determining the remediation parameters in the middle reach of yangze by considering the reduction of sand and the acceleration of withdrawal water.This passage focuses on the following aspects:(1) The differences of the river evolution under the three gorges reservoir operating. Because of the three gorges reservoir, the recession of water is expediting and the sands become less on October. The bed below is washing out for long distance and for long time. So low water level is drawdown, channel depth becomes deeper. The strong impact of the river may appears the steep slope and flow anxious problems, the dandy river’s width becomes wider. All above will make the mainstream awe.(2) Method for determining the designing water level. On the basis of summing the method for determining the design water level before impoundment, put forward a better method after impoundment:deducing design water level by the design flow. So we can determine the midstream hydrological station designing water level for15years after the Three Gorges reservoir completion. Determine the designing water level of the hydrological station comparing the different designing water level by different methods. At last, the Power stations also affect water levels, so make same amending is necessary.(3) The determining of regulation line width. We have summarized the method of determining the regulation parameters. And put forwards some optimization ideas, determined the method for the regulation water level, put forward the idea of combining regulation line and rectification section in the Channel regulation. All above is according to the three-dimensional condition to adjust and control the river. We can consider the influence of the flood and the dry water which is overall for a river’s development. To make the river steady and governance the river comprehensive, studies on physical experiment and verify the formula will make it more reasonable.(4) The usage of method for determining regulation parameters. We can put this improved method in the significant erosion period (Lotus pond channel) and Weak erosion period (Guniu Sha channel) on the downstream of The Three Gorges reservoir. Then discuss how adaptable the regulation parameters it is when facing the lesser sand and the accelerated water Withdrawal. To prove the new method for determining regulation parameters mentioned above is better after running Three Gorges Reservoir.更多还原