长江中游武汉-湖口段鹅头洲演化动力学分析

Dynamic analysis of braided channel evolution in middle reaches( from Wuhan to Hukou) of Yangtze River

为了探讨长江中游武汉-湖口河段鹅头洲河道的形成及演化规律,运用地球动力学方法进行了河演分析。结果表明,鹅头洲河道弯头上游段微元体所受的弯道离心力与掀斜抬升力和科氏力作用方向相反,相互消减,减弱了河流向左岸的侵蚀作用强度;在弯头下游段,3种力相互叠加,加强了向右岸的侵蚀作用,使鹅头洲河道上游弯道长且宽,下游弯道短,且呈窄的鹅头形状,鹅头顶端始终指向抬升作用一侧。

The formation and evolution of braided channel in middle Yangtze River reach （ from Wuhan to Hukou） was investigated by the analysis method of Geodynamics. The results show that in the upstream of braided channel, the centrifugal force loaded on the microunit at the channel bend are in the opposite direction to tilted lift force and the Coriolis force, which counterbalances constantly and weakens the erosion effect towards the left bank;at the lower reaches, the above 3 forces are added together, which strengthens the erosion effect towards the right bank, forming the braided channel with long and wide bend channel at the upper reach and short bend channel at lower reach. So, the head of the braided channel directs to the side of the lift force.