长江百里洲段洲滩沉积模拟实验

SIMULATING EXPERIMENT OF SEDIMENTATION ON BAILIZHOU BEACH,YANGZI RIVER

模拟实验表明，长江中游松滋口三角滩以燕尾式和先主流后分流自平衡调整式两种方式加积，洪水期是三角滩生长发育期，具有洪水生根、中水细化、枯水暴露的特点。水流轴线的大水趋中、小水坐弯则是芦家河浅滩形成和演变的主要控制因素，洪水期表现为四岸大边滩、中枯水期表现为大心滩；凤凰滩和江口洲受河湾形态及河道边界条件控制，洪水期凤凰滩以加积为主，江口洲以冲刷为主，前者发展增大，后者削减缩小。

Simulation result shows that the deltaic beach of Songzi River aggrades in the form of swallow tail and self-balance adjustiment in which master stream aggrades first and then branch streams. Flood period is the stage for the beach to develop.The beach roots in flood period, then it gets thinner in medium water level,and is exposed in low-water.River axis tends to the central line in high water level,it flexes in low water level,and this is supposed to be the controlling factor for the formation and evolution of Lujiahe beach.The lujiahe beach turns to be a wide point bar of concave bank in flood periods,and becomes a channel bar in medium and low water periods.Fenghuangtan and Jiangkouzhou Neaches are both dominated by cove pattern and the boundary conditions of the river channel.The Fenghuangtan beach would aggrade in flood periods while Jiangkouzhou would mainly be scoured.It means that the former would grow bigger and the later would decrease and subduce.