应对极端风暴潮的粤港澳大湾区海堤建设研究

Study on seawall construction in Guangdong-Hong Kong-Macao Greater Bay Area to cope with extreme storm surge

海堤是防御风暴潮侵袭、减轻海洋灾害的重要工程措施。在海平面上升和风暴潮加剧的双重影响下,大湾区海堤防潮能力被动降低,防潮安全备受挑战。通过现场调查梳理了大湾区海堤典型破坏形式,有防浪墙倾覆、迎水坡损毁及背水坡垮塌等,其中案例中背水坡破坏占比近1/2。为应对极端风暴潮灾害,迫切需要对大湾区海堤进行提标加固,但以提高堤顶高程为主的传统提标方式与城市亲水景观需求矛盾突出,基于此提出大湾区海堤建设应由防浪防潮垂向一体式向防浪防潮横向分离式转变,即利用堤身“挡高潮”,利用堤前措施和堤身“消大浪”。相较于传统提标方法,该方法实现了不抬高堤顶高程却提升防潮能力的目标,成果可为粤港澳大湾区海堤建设提供借鉴。

The seawall is an important engineering measure to prevent storm surge and reduce marine disasters.Under the dual impact of sea level rise and storm surge intensification,the storm surge defense capability of the seawall in the Greater Bay Area has been reduced passively,and the storm surge defense safety has been challenged.Through field investigation,the typical failure forms of seawall in the Greater Bay Area were sorted out,including overturning of the breakwater wall,destruction of the upstream slope and collapse of the back slope,among which the failure of the back slope accounted for nearly half of the cases.In order to cope with the extreme storm surge disaster,it is urgent to upgrade and reinforce the Greater Bay Area seawall.However,the traditional way of improving seawall standard,which mainly focuses on raising the embankment top height,is in prominent contradiction with the needs of the urban waterfront landscape.Based on this,it is proposed that the seawall construction in the Greater Bay Area should be transformed from a vertical integration to a horizontal separation from wave and tide,that is,the dike should be used to"block high tide"and the measures in front of the levee and the levee should be used to"dissipate large waves".Compared with the traditional method of raising standards,it achieves the goal of improving the storm surge defense capability without raising the top elevation of the dike.The results can provide reference for the construction of seawall in the Guangdong-Hong Kong-Macao Greater Bay Area.