上荆江河段南五洲崩岸整治工程护岸形式选择

Selection of Revetment Works for Bank Collapse Treatment at Nanwuzhou in the Upper Jingjiang Reach

南五洲险段常年抢护但崩岸仍时有发生,采用的水下抛石措施,需大量开山采石而对开采区生态环境产生不可逆转的破坏,同时在工程实施区域需大面积削坡以维持坡面稳定,个别堤段还需退垸堤防、侵占农田、重建相关水工建筑物和农田水利设施等,其经济效益和社会效益都有待综合评估。为此,根据南五洲险段崩岸的主要影响因素及近岸地形变化趋势,针对南五洲险段崩岸整治措施的选择问题进行了详细的分析论述。提出了在不改变河势和对岸滩岸稳定、保持防洪态势和既有航道条件下,利用水下承台堆石护脚、阻滑桩结合长充沙管袋护脚,同时水上护坡工程二级护坡采用三维植被网护坡的新思路。

Although protection have been carried out over the years,bank collapse still occurs frequently at Nanwuzhou river reach.Underwater riprap needs tremendous stone extraction,causing irreversible damage to the ecological environment.Meanwhile,slope cut in large areas is needed in the project region to maintain the slope stability.At some segments,dike retreatment,farmland occupation,hydraulic structure rebuilding,irrigation and drainage facilities rebuilding are required,hence the economic and social benefits need to be comprehensively assessed.In view of this,main influencing factors affecting the bank collapse,and offshore topographic change are analyzed.New measures to solve these problems are proposed as follows： toe protection by rockfill of the underwater bearing platform,toe protection by anti-slide pile with sand filled bag,together with three-dimensional vegetation slope protection as the second level slope protection work above water.Taking these new measures will not change the river regime,the stability of the opposite bank,nor the flood protection situations or the existing navigation channel.