强水沙变化下长江安徽河段护岸失稳及防护研究

Study on instability mechanism and protective measures of bank protection project in Anhui section of Changjiang River under strong water and sediment changes

长江下游安徽河段存在较多的岸线险工段,受近年来沙量锐减及2016年大洪水的影响,岸线及护岸建筑物坡脚冲刷加剧,部分岸线及护岸出现了失稳现象。结合安徽省工程河段水文、地质、地形等资料及河道演变特性,分析了护岸建筑物失稳区域的断面变化特征,研究了护岸工程适应性及失稳破坏机理、防护对策及效果。结果表明:河岸二元土质结构及近岸深槽大幅冲刷是崩岸的主要原因,2016年大洪水加快了崩岸的发生;从防护布置、标准、型式、结构设计等方面制定应急修复、补充完善工程防护对策,实现了2017~2019年成功度汛,总体守护效果较好。研究成果可为探索三峡工程运行后新水沙条件下的崩岸治理方法提供参考依据。

In Anhui section of the lower reaches of the Changjiang River,there are many dangerous sections along the coastline.Affected by the sharp decline of sand transport in recent years and the great flood in 2016,the erosion to the coastline and the slope toe of the revetment building has intensified,and some coastlines and revetments have become unstable.Combined with the hydrology,geology,topography and other data of the engineering river section in Anhui province and the analysis of the river evolution characteristics,we analyzed the variation characteristics of section in instability area of bank revetment buildings,and studied adaptability and instability damage mechanism,protection countermeasures and protection effect of bank protection project.The results showed that the main reasons for bank collapse were the dual soil structure of the river bank and the large scouring of the deep channel near the bank.At same time,the occurrence of bank collapse was accelerated by the flood in 2016.The emergency repair and supplementary engineering protection countermeasures were formulated from the aspects of protection layout,standard,type and structural design,which realized the successful flood control from 2017 to 2019,and the overall protection effect was good.The results can provide a reference for exploring new bank collapse control methods under new water and sediment conditions after the operation of the Three Gorges Project.