三峡水库运用后, 坝下游水沙过程发生了较大调整, 对下荆江熊家洲至城陵矶弯曲型河段河床冲淤演变造成较大影响, 从而对本河段河势稳定、防洪、航运等可能造成不利的影响, 基于此, 根据最新实测资料分析水沙条件变 化及其对本河段河床调整规律的影响。研究成果显示: 三峡水库运用后, 水流含沙量大幅减小, 且水库调蓄导致熊 家洲至城陵矶河段在枯水期径流量明显增加, 使弯道主流长期偏向于凸岸, 引起凸岸边滩大幅冲刷, 这是近期该河段发生“撇弯切滩”的主要原因之一; 随着三峡上游干支流水库群陆续建成运用, 坝下游河道将会长期遭受清水冲 刷, 河床仍将呈单向冲刷下切的趋势, 弯顶段主流平面摆动仍将较大, 弯道顶冲点也将相应下移, 导致主流贴岸距离 进一步下延, 引起河道岸线的崩退, 未来一段时期内典型弯曲型河道的局部河势变化仍将明显。
After the operation of the Three Gorges Project , the water and sediment process in the downstream of the dam has undergone major adjusted, which has a greater impact on the river bed erosion and deposition of the Xiong jiazhou-Cheng lingji sand-stone-type river section of the Jing jiang River, which may affect the stability , flood control, and navigation of the river in this section. The chang es in water and sediment conditions and their impact on the river bed adjustment procedures were analyzed based on the latest measured data. The research results show that: the runoff of the downstream dam of the Three Gorges reservoir has increased significantly during the dry season, which makes the mainstream of the curve long-term to the convex bank, causing a large erosion of the convex bank, this may be one of the main reasons for the recent occurrence of "squatting and cutting the beach"; with the successive construction and operation of the main and tributary reservoirs in the upperr eaches of the Three Gorges, the rivers downstream of the dam may be subject to long-term cleansing , the typical curved river channel may be in the long-term scouring stage, and the riverbed may have a one-way scouring downward trend, and the main plane of the curved top section may oscillate, Which may be larger, and the top punching point of the curve may also move down correspondingly , and which may cause the distance of the mainstream sticking shore to further defer, causing the collapse of the riverbank line, and the local river potential change is still obvious in the future.
国家重点研发专项( 2016YFC0402303) ;国家自然基金项目( 51679011) ; 湖北省直部门预算项目( 2017221820062004 ) ; 三峡水库科学调度关键技术第二阶段研究项目“新水沙条件下荆南四河及洞庭湖区冲淤演变趋势研究”