洞庭湖响水坎跌水碍航险滩整治方法研究

响水坎跌水严重碍航,是洞庭湖区急待整治的重点滩险,类似滩险在国内外湖区中均极其少见。本文采用遥感地质分析方法与水动力演变分析方法分析洞庭湖草尾河响水坎滩险成因。分析结果表明:地层岩性与沉积厚度的突变、构造单元分布等地质因素是导致响水坎原始河床跌坎形成的内在原因;原始跌坎存在是出现跌水的前提,河湖边界及来水来沙变化是跌水存在的外在条件,水文组合决定了滩险是否碍航。在对跌水滩险形成原因正确认识的基础上,提出了采用超长距离变底坡加局部拓宽疏浚挖槽的航道整治方案,整治工程实施后的实测资料分析表明,整治是成功的。

Investigation on renovation method of Xiangshuikan shoal in Dongting Lake

The formation and evolution principle of water steepfall in the Dongting Lake is very complicated.The reason of formation Xiangshuikan dangerous shoal was studied by methods including remote sensing(RS) image's interpretation analysis,geological change analysis and hydrodynamic motion analysis.Based on the analysis,it can be known that the geology condition is the intrinsic basis for the formation of the river bed falling-step.The sedimentation thickness,mutation of the lithologic character,and the structural unit distribution are the important influencing factors which cause the original bed river falling-step formation.The precondition of water fall is in existence of original bed river falling-step.The external conditions of water fall are the river and the lake boundaries,and the conditions of incoming water and sediment.The combination of hydrological conditions decides whether the shoal obstructs navigation.Based on the formation reason of the Xiangshuikan shoal,the scheme of the channel renovation was put forward.The channel should be dredged in a very long distance with different bottom slope and widened local reach.After the project was completed,the effects of renovation were analyzed and the training work achieves the aims.