溃坝洪水演进影响因素分析

Analysis of Influencing Factors of Dam-break Flood Routing

溃坝洪水往往会对下游人民财产安全造成巨大影响.基于二维浅水方程数学模型,采用两步Taylor-Galerkin有限元方法进行离散,分析溃坝洪水在演进过程中对下游河道的影响因素,结果表明:库容面积、水深比、溃口宽度等因素均对溃坝洪水的水位、传播速度及流量产生影响.库容面积越小,洪峰达到的最高水位值越大;水深比越大,水流流速越大;溃口宽度越大,洪水水位越高,洪峰流量越大.该分析规律为水库大坝安全多因素风险分析提供了参考,为防洪减灾、灾害评估和人民财产安全保护提供了依据.

Dam-break floods always affect the potential for loss of life and damages in the downstream flood plain. A numerical method is used to analyze the influencing factors through numerical simulation method, in which the governing equations are discretized by a fractional finite element method using a two-step Taylor- Galerkin scheme. The results show that three factors, i.e. storage area, water depth ratio of upstream to downstream and dam-break width, affect water level, advancing speed and flow of dam-break floods. If the value of water depth ratio gets greater, the floods of downstream advances faster. The smaller the storage area gets, the higher the flood peak water level becomes. The flood water level and the peak flow increase with the dam-break width. The results provide for reference in analyzing multifactor weighting of dam safety evalua- tion, as well as in disaster control and reduction, damage assessment, etc.