黄河口沉积动力对调水调沙的响应

发布时间：2018-05-06 04:35

本文选题：黄河口 + 调水调沙　；参考：《华东师范大学》2014年硕士论文

【摘要】：黄河水利委员会自2002年开始实施黄河调水调沙工程,至今已开展了15次调水调沙实验。调水调沙通过联合调度水库,对黄河来水来沙进行调节和控制,调整自然水沙入海过程,冲刷河槽、从而减轻下游河槽淤积的目的。调水调沙期间入海水沙量约占全年入海水沙量的三分之一,入海水沙量短期内的集聚入海必定会对黄河口及其滨海区沉积动力产生巨大影响。因此,研究调水调沙前后黄河口滨海区沉积物分布特征、水动力特征、泥沙输移和沉积过程以及滨海区岸滩演变规律,对把握新形势下河口近期演变规律和发展趋向具有重要意义。本文基于2000年和2007年黄河口滨海区表层沉积物资料、黄河调水调沙期间及调水调沙后河口区域水文泥沙资料,分析黄河口滨海区表层沉积物沉积特征、悬沙输运对黄河调水调沙的响应过程,并结合黄河调水调沙前后河口滨海区水下地形测深资料分析了该区域水下地形演变特征,探讨河口滨海区水下地形演变特征对黄河调水调沙的响应过程及其机制,研究结果表明：黄河口滨海区表层沉积物类型主要由粘土质粉砂、砂质粉砂组成,总体较细。黄河调水调沙后,河口滨海区表层沉积物类型中粘土质粉砂含量上升5.9%,而砂质粉砂含量下降了12.4%,泥沙呈细化特征；现行河口和老河口外表层沉积物均由粘土质粉砂变为砂质粉砂。黄河口滨海区表层沉积物中值粒径和平均粒径均呈变细特征,分选性变好,偏度值与峰态值均变小。这与黄河调水调沙后入海泥沙的不断补给息息相关,粗颗粒泥沙堆积在现行河口拦门沙附近、老河口附近不断遭受侵蚀致使现行河口和老河口外均出现平均粒径峰值中心,表层沉积物平均粒径的变化直接导致现行河口和老河口外沉积物分选性变好。黄河调水调沙期间,径流携大量泥沙入海改变了黄河口的水动力条件及泥沙输运过程。黄河调水调沙期间,入海主流快速摆动,主流摆动海域涨落潮流得到了明显增强,河口南北两侧海域的流速主要受地形制约。主流向外扩散途中被海水掺混成冲淡水,冲淡水沿海岸呈扇面分布。此外,黄河低流量期间,河口涨、落潮悬沙浓度均小于调水调沙期间。调水调沙期间,主流摆动海域的悬沙浓度远高于南北两侧海域。主流摆动海域的落潮平均悬沙浓度均比涨潮时高3倍左右,表明调水调沙期间,泥沙多随径流悬浮入海。黄河调水调沙期间泥沙通过上层冲淡水向外海扩散,受潮流切变锋影响,入海泥沙快速沉积。落潮切变锋对快速沉积的作用显著,而涨潮切变锋对快速沉积作用较小,但促进了悬沙向莱州湾南部传输,河口海域以淤积为主。一个潮周期内,南侧海域淤积达15.4mm,而北侧海域淤积仅为4.2mm。黄河低流量期间,泥沙未发生快速沉积。黄河改道清8汉道入海以来河口滨海区冲淤演变特征分为3个时期为：黄河改道初期(1997-1999年)、黄河调水调沙适应期(1999-2003年)和黄河调水调沙稳定期(2003年-)。(1)黄河改道初期,河口北侧海域各断面形态未发生明显变化,呈冲刷特征,冲刷厚度在lm左右；现行河口海域各断面呈淤积特征,淤积主要集中在l0m等深线以内,淤积厚度超过3m的区域在现行河口外呈偏南分布；老河口海域各断面呈冲刷特征。(2)黄河调水调沙适应期,现行河口冲淤态势以淤积为主,淤积区域大幅减小,河口北侧海域及老河口水下岸坡普遍冲刷。(3)黄河调水调沙稳定期,入海水沙大幅增加致使河口滨海区整体呈淤积之势,泥沙随落潮流羽状扩散致使淤积区域基本包含了整个黄河口滨海区,仅老河口外出现冲刷区域。
[Abstract]:Since 2002, the the Yellow River Water Conservancy Commission began to implement the the Yellow River water regulation and sediment transfer project, and 15 experiments have been carried out to regulate and control the water and sediment of the reservoir through the joint dispatching of the reservoir. The water and sediment of the Yellow River are adjusted and controlled, the natural water and sand are adjusted to the sea and the river trough is washed, thus reducing the silt of the downstream river trough. The amount of water and sediment accounts for about 1/3 of the amount of water and sand in the sea in the whole year. The accumulation of water and sand into the sea in the short term will have a great influence on the sedimentary dynamics of the Yellow River Estuary and its coastal area. The law is of great significance to grasp the recent evolution and development trend of estuaries in the new situation.
Based on the surface sediment data of the coastal area of the Huanghe River Estuary in 2000 and 2007, the hydrological and sediment data of the estuarine area after the water diversion and sediment transfer in the Yellow River and the water diversion and sediment transfer are analyzed. The sediment characteristics of the surface sediments in the coastal area of the yellow River estuary are analyzed, and the response process of the suspended sediment transport to the water diversion and sediment transfer in the Yellow River is carried out, and the underwater sediment of the estuarine coastal area before and after the water diversion and sediment transfer in the Yellow River is combined. The characteristics of underwater terrain evolution in this area are analyzed by the topographic sounding data, and the response process and mechanism of the Underwater Topography Evolution Characteristics of the estuarine coastal area to the Yellow River water regulation and sediment regulation are discussed.
The surface sediment types in the coastal area of the Yellow River estuary are mainly composed of clay silt and sandy silt. After water diversion and sand regulation in the Yellow River, the content of clay silt in the surface sediments of the estuarine coastal area rises by 5.9%, while the content of sand silt decreases by 12.4%, and the sediment is refined. The current estuarine and the old estuary surface sediments are all from the estuarine. The median grain diameter and average particle size of the surface sediments in the coastal area of the Yellow River estuary are fine, and the separation property is fine and the deviation value and the peak value are all smaller. This is closely related to the continuous recharge of the sediment in the sea after the Yellow River water regulation and sediment regulation, and the coarse sediment is accumulated near the current estuaries, and the old estuary is not near the estuary. The average particle size peak center appears in the current estuaries and the old estuaries. The change of the average particle size of the surface sediments directly leads to the better sediment separation of the current estuaries and the old estuaries.
During the period of water diversion and sediment transfer in the Yellow River, the runoff and sediment transport into the sea changed the hydrodynamic conditions and sediment transport process in the Yellow River Estuary. During the period of water diversion and sediment transfer in the Yellow River, the mainstream of the sea was rapidly swinging, and the flow and flow trend in the mainstream swinging sea area was obviously enhanced. The flow velocity in the sea area between the north and south sides of the estuary was mainly restricted by the topography. In addition, during the low flow of the Yellow River, the estuary rises, and the concentration of the suspended sediment is less than that during water regulation. The concentration of suspended sediment in the main wobble sea area is much higher than that in the north and South waters during the period of water adjustment and sand regulation. During the period of water diversion and sediment transfer in the Ming Dynasty, the sediment was suspended in the sea with runoff. During the period of water diversion and sediment transfer in the Yellow River, the sediment spread through the upper layer of fresh water to the outer sea, affected by the shear front of the tidal current, and the sediment in the sea was deposited rapidly. The effect of the ebb shear front on rapid deposition was remarkable, while the shear front of the tide was smaller, but it promoted the suspended sediment to the southern part of the Laizhou Bay. In the estuarine area, silt is mainly deposited in the estuarine area. In a tidal cycle, the siltation of the southern sea area reaches 15.4mm, while the siltation in the North Sea area is only 4.2mm. the Yellow River low flow period, and the sediment has not been deposited rapidly.
The characteristics of the evolution of the erosion and siltation in the estuarine coastal area of the 8 Han Dynasty in the Yellow River since the reform of the Qing Dynasty are divided into 3 periods: the early period of the diversion of the Yellow River (1997-1999 years), the adjustment period of the adjustment of water and sediment in the Yellow River and the stabilization period of the water diversion and sediment transfer in the Yellow River (2003 -). (1) the morphology of the sections of the northern side of the estuary has not changed obviously, and the characteristics of the erosion are scouring. The thickness of the scour is about LM; the current estuarine cross sections are silt up and the siltation is mainly concentrated in the l0m contour line. The area of the silt is more than 3m in the south of the current estuary; the sections of the old estuary are scoured. (2) the current estuarine adjustment period in the Yellow River, the current estuarine scouring and silting situation is dominated by siltation, and the siltation area is the main area. The northern side of the estuary and the estuary of the estuary are generally washed down. (3) the stable period of water diversion and sediment regulation in the Yellow River, a large increase in water and sediment in the sea, resulting in siltation in the coastal area of the estuary.

【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV148

【参考文献】