长江中游河床下切与节点控制治理初步研究

Preliminary Research on Riverbed Downcutting and Knick-point Control in the Middle Yangtze River

三峡及上游水库蓄水运用后,其下游荆江河段沙质河床下切了3～6m,对两岸的护岸工程、供水工程以及三口分流分沙将带来不利影响.为了抑制荆江河段冲刷、稳定控制枯水位下降,开展节点控制组合工程治理方案的初步研究,提出护底工程组合和护底＋潜坝工程组合的治理方式.经数学模型计算分析,提出的治理方式可减少荆江河段冲刷,控制枯水位不降或少降,同时还可缓解三口分流分沙减少趋势,但对城陵矶至武汉河段的冲刷会带来一定影响,其利弊关系还有待今后深入研究.

Since the impoundment of Three Gorges Project and its upstream cascade reservoirs,the sandy bed of Jingjiang River has been scoured and lowered by 3m-6m,which brought about negative effect on revetment works,water supply projects,as well as the flow-sediment diversion from three diversion channels into Dongting Lake.The aim of this research is to control the scouring in Jingjiang River and to stabilize or control the decrease of low water level by analyzing knick-point control schemes.On the basis of numerical simulation results,it＇s proposed that the riverbed protection or the riverbed protection combined with submerged dikes could reduce erosion in the Jingjiang River,lessen or stop water level lowering,and relief the decrease of flow-sediment diversion from the three diversion channels.However,the proposed regulative projects have certain influence on the morphology of the downstream reach from Chenglingji to Hankou,which should be addressed in the future.