【作者】 刘蕾；

【导师】 茅志昌；

【作者基本信息】 华东师范大学 ， 港口、海岸及近海工程， 2011， 硕士

【摘要】 上海港自19世纪中期开埠以来一直是我国对内对外交通贸易往来的重要港口,为中国与世界的贸易往来做出了巨大贡献。在上海建设“四个中心”目标的指引下,上海港正加快发展步伐,落实“上海国际航运中心”建设。然而,南港南岸淤积问题对外高桥港区使用造成十分不利的影响,分析南港河势演变,探究南岸淤积原因,对外高桥港口码头群的建设与维护、岸线的充分利用和治理均有重要意义。本文在前人研究的基础上,结合南支、南港地形资料及水文泥沙数据,利用GIS和DEM方法,对50年来的长江口南支、南港沙体变迁、主泓摆动、河槽形态以及冲淤变化进行分析,阐述南支南港河势演变及南岸外高桥港区淤积原因。研究结果表明：1.南支上段白茆沙河段落潮主流的摆动是南支中下段主槽和南北港分流口河势动乱的主要原因。20世纪初至今南支主槽经历了3次主泓摆动,1980年后白茆沙南水道主水道地位稳定,南支中段主泓不再摆动,稳定指向新浏河沙头部。2.南港的演变与南、北港分流口河势的变化密切相关。上世纪60年代起,新崇明水道的发展与衰亡、新宝山水道的发展与壮大、瑞丰沙咀的形成和下延,使南港河槽形态由U型转变为W型。本世纪初,宝山北水道的发展、南港深泓线的北偏,以及瑞丰沙咀下沙体的冲刷消失,使南港河槽形态由W型又转变为U型。3.南港深泓线近50年来发生两次北偏：上世纪70年代,南港河槽淤积,深泓线受迫于河床阻力而北移；上世纪末,宝山北水道发展,水流顶冲区上提引起深泓线北偏。4.自1990年至今,虽然南港北冲南淤现象明显,但总的冲淤量是平衡的。上游南支河道近30年来深泓稳定,确保南北港分流分沙比基本平衡,南港河槽容积不变,通过调整河床形态来适应落潮主流方向的变化。如今,南港上、下口均经过护滩工程改造,南、北岸亦被人工岸线固定,在边界条件固定、流域来沙减少的情况下,南港河床短期内可能不会出现明显的冲淤变化。5.南港南岸外高桥港区淤积的主要原因有三点：首先,进入南港水流汇流点西移引起顶冲点上移,驱使落潮主流北偏,南岸落潮动力减弱,这是南岸淤积的主要动力因素,是南港地形发生变化的先决条件；其次,瑞丰沙咀下沙体的冲刷消失直接导致南港河槽形态由W型变为U型,过水断面的扩大迫使河床通过淤浅河槽来调整自身平衡,这是南岸淤积的直接诱因,是水动力改变的必然结果；第三,南岸水工建筑物阻水作用促使悬沙落淤是近岸水域淤积的重要原因,但其影响不足以改变整个南岸的淤积趋势。更多还原

【Abstract】 Shanghai Port is the most important port for China to develop its foreign trade and traffic since opened in mid-19th century. Now it’s the premier commercial port and make outstanding contributions to China and the World. Under the guide of "Shanghai Four Centers Project", construction of Shanghai International Shipping Center is developing ralidly. But, the siltation in the south bank of the south channel has adverse effects to the Waigaoqiao harbor development. It is of significance for the construction of harbors and utilization of shore lines to study river regime change in south channel and find the reasons of siltation in south bank.On the basis of the former research, combined with the Terrain data and hydrology and sediment data, the author use GIS and DEM to analyse the bed-load transport, the swing of talwegs, channel morphology change and erosion-deposition variation in the south branch and the south channel of the Yangtze River in the past 50 years. The results of the study are listed as follows:1. Swing of the ebb current in the south branch is the main reason leads to the change of river regime in the south channel. The talweg has changed 3 times in the south branch from the early 20th century. Since 1980, the south waterway of Baimaosha became to be the main waterway, the talweg stoped winging and stablely directed to the head of Xinliuhesha.2. The south channel process closely related to the water and sediment discharge ratios in the South-North Channel. In the 1960s, south channel morphology changed from U-shape to W-shape due to the occurrence and decline of Xinchongming waterway, the broadened of Xinbaoshan waterway and the extended downstream of Rifengsha spit. In the beginning of this century, south channel morphology rechanged from W-shape to U-shape because of the developing of Baoshanbei waterway, swinging northward of talweg in south channel and erosion of Ruifengsha spit.3. The talweg swings northward twice in south channel in the past 50 years. In the 1970s, siltation occurred in the south channel, The talweg swinged northward because the bed resistance increase. In the end of last century, Baoshanbei waterway expanded, top spot of ebb current moved upstream caused the talweg swinged northward.4. Since 1990, south channel shows obvious erosion in the south part and deposition in the north part, but the erosion-deposition is unchanged. The talweg in south branch never swinged in recent years and the water and sediment discharge ratios are the same in the South-North Channel. So south channel keep its volume stable by adjusting channel morphology when the ebb current change direction. Now, bank protection projects have been made in the upper and lower extremes of south channel, the south and north bank line are also been artificial modified. The south channel won’t show obvious erosion-deposition variation in the case of fixed boundary and decrease sendiment supply for a short time.5. There are there reasons of the siltation in Waigaoqiao harbor:First, top spot has move upstream because confluence of current flow into south channel move westwords, it made the ebb current swing northwords, and the current power turn down in the south bank. This is the main dynamical factor, which is a prerequisite for the topographical change. Second, the erosion of underpart of Ruifengsha spit led a direct result of the W-shape to U-shape change of channel morphology, thereby the sediment deposition occurred in th south bank for the sake of recovering the largened cross section area of channel. This is the immediate cause of siltation in south bank, and also an inevitable result of hydrodynamicforce change. Third, hydraulic architectures along the south bank block the near-shore current and spur the deposition of sediment. It’s an important reason for near-shore deposition, but it’s influence is not strong enough to affect the whole channel.更多还原