【摘要】 漫堤是天文潮、风暴潮与海浪等物理要素作用于海堤后海水翻越海堤的物理过程。本文利用天文潮-风暴潮-台风浪耦合模式(ADCIRC+SWAN)、基于非结构三角形网格和高分辨率地理数据(海堤位置和高程、岸线和水深等)构建福建沿海精细化漫堤风险等级评估系统。该系统在近岸网格分辨率最高达50m,可精确刻画福建沿海复杂地形。利用模拟的水位与海浪参数,采用波浪爬高公式计算得到各海堤堤前波浪爬高。按照总水位与波浪爬高之和与海堤高程的对比,将漫堤风险分为五个等级。对2013年的超强台风天兔过程进行后报检验。结果显示,该系统计算的漫堤情况与灾后调查的漫堤实况基本一致,结果准确,说明本研究中采用的漫堤风险评估标准和方法是可行的。在此基础上,设计了4种不同的台风强度等级,对福建沿海206条海堤进行了漫堤风险等级评估,探究台风强度对漫堤风险的影响。结果表明:波浪爬高对漫堤风险的影响高于单纯的风暴潮增水;风暴潮增水随台风强度的增强增量较小,对于漫堤的风险影响较小;福建沿海波浪爬高普遍较高,随着台风强度的增强,波浪爬高会显著增加漫堤的风险等级,且应重视台风浪对海堤造成的冲击所导致的溃堤灾害。本研究可为沿海防灾减灾提供科学依据。更多还原

【Abstract】 Overtopping seawall is a physical process of seawater climbing over seawall after physical elements acting on the seawall such as astronomical tide, storm surge, and typhoon waves. In this paper, a fine risk level assessment system of overtopping seawall in Fujian coast, South China, is established, in which astronomical tide, storm surge and typhoon waves are coupled based on unstructured triangular meshes and high-resolution geographic data(location and elevation of seawall, shoreline and water depth) using ADCIRC+SWAN. The system can accurately depicts the complex terrain along Fujian coast in resolution of up to 50 m in the nearshore grid. Using the simulated water level and wave parameters, a formula of wave runup is used to calculate the wave runup in front of each seawall. According to the comparison of the sum of total water level and wave runup and seawall elevation, the risk level of overtopping seawall is divided into five levels. We made a hindcast on the process of super Typhoon Usagi in 2013, the risk level of overtopping seawall is basically the same as that of post-disaster investigation. The results are accurate and shows that the risk assessment criteria and methods for overtopping seawall adopted in this study are feasible. On this basis, four different typhoon intensity scales were designed, 206 seawalls along Fujian coast have been assessed for overtopping seawall risk to investigate the impact of typhoon intensity on the risk of overtopping seawall. The results show that the impact of wave runup on the risk of overtopping seawall is higher than that of pure storm surge. The increase of storm surge is small with the enhance of typhoon intensity, and has small impact on the risk of overtopping seawall. The wave runup is generally high along the coast of Fujian Province, with the enhance of typhoon intensity, the wave runup will significantly increase the risk level of overtopping seawall, and attention should be paid to the disaster of seawall breaking caused by the shock of typhoon waves on the seawall. This study can provide a scientific basis for disaster prevention and mitigation in similar coastal areas.更多还原