梯级土石坝连溃数值模拟

发布时间：2018-08-09 16:08

【摘要】：溃坝具有低概率和高风险的特点,大坝一旦发生溃决事故,将会对下游地区造成极大的破坏,导致巨大的人员伤亡和社会经济损失。土石坝作为当前主要坝型,占各类坝型的95%,而国内发生溃决事故的大坝中,土石坝占到了98%。目前我国已规划13大水电基地共包括310座大中型梯级水库,流域内坝型多为土石坝和面板坝,超高大坝分布集中。考虑到目前我国梯级水库大坝的发展情况,对梯级土石坝连续溃决进行模拟研究具有重要的现实意义。针对梯级水库群,研究土石坝溃决机理,基于上游大坝的溃坝过程以及溃坝洪水对下游水库的影响,建立梯级土石坝连溃数值模型,对于大坝溃决风险分析、库区防洪调度、梯级流域安全防控及水库群工程等级确定具有重要的意义。本文旨在基于单库溃坝模型的研究,耦合洪水演进计算和调洪演算分析,建立梯级水库土石坝连溃数值计算模型,其主要研究内容及研究成果如下:(1)根据土石坝溃坝模型对比分析,确定了土石坝溃坝数学模型。总结分析了现有的溃坝模型的特点,选取了五种溃坝机理模型和一种参数模型:Mike11DB模型、HEC-RAS模型、BREACH模型、DAMBRK模型、DB-IWHR模型以及堰塞坝溃决快速评估模型,通过典型溃坝案例的模拟计算,重点分析比较了各个模型的计算准确性和参数敏感性。对比分析发现,DB-IWHR模型深入研究了溃坝机理,充分考虑了坝体几何参数、材料性质、溃口初始条件等参数的影响,解决了现有溃坝模型不能自主计算溃口发展和所需已知参数过多的问题,对于大坝溃决的预测计算更有实际意义,具有较大的应用价值,因此选取DB-IWHR模型作为土石坝溃决计算模型。(2)建立了溃坝洪水下游演进模型。研究了溃坝洪水一维数值计算方法,基于Preissmann四点隐式差分格式求解圣维南方程组的理论,编制了明渠一维非恒定流计算程序。通过不同算例表明,该程序适用于不同边界条件下的明渠渐变流和急变流。运用非恒定流演进程序计算唐家山溃坝洪水的下游演进过程,与Mike 11软件的计算结果进行对比,证明了溃坝洪水演进模型的准确性和可靠性。以唐家山堰塞坝应急处置为例,应用溃坝洪水演进程序,对遭遇不同重现期洪水的情况,进行下游风险分析。(3)构建了梯级土石坝连溃数学模型。基于四阶龙格-库塔法建立了水库调洪演算模型,计算下游水库水位的变化过程线,判断上游溃坝洪水是否引起下游梯级大坝连溃,根据DB-IWHR模型计算下游溃坝过程,在单库溃坝模型的基础上,耦合洪水演进和调洪演算过程,建立了梯级水库土石坝连溃数学模型。以唐家山-达里梯级水库为例,进行了梯级土石坝连溃模拟计算,研究了下游水库有预警和不同泄流能力等工况下的连溃情况。结果表明,下游梯级水库可以采取增设非常泄洪设施和提前预警全闸泄水等措施,通过调洪容错保证大坝不发生溃坝,避免梯级水库大坝的连续溃决。
[Abstract]:Dam break has the characteristics of low probability and high risk. Once the dam collapses, it will cause great damage to the downstream area, leading to huge casualties and social and economic losses. As the main dam type, earth rock dam accounts for 95% of all types of dam, and the earth rock dam accounts for 98%. in China. The 13 large and medium-sized hydropower bases include 310 large and medium-sized cascade reservoirs. The dam type in the basin is mostly earth rock dam and panel dam, and the super high dam is distributed centrally. Considering the current development of the cascade reservoir dams in China, it is of great significance to simulate the continuous collapse of the cascade earth rock dams. The mechanism, based on the dam break process of the upstream dam and the influence of the dam break flood on the downstream reservoir, the establishment of the cascade dam collapse numerical model is of great significance for the analysis of the risk of dam break, the flood control scheduling in the reservoir area, the safety control of the cascade basins and the determination of the grade of the reservoir group. Coupled flood evolution calculation and flood regulation analysis, the numerical model of cascade reservoir rockfill dam collapse is established. The main research contents and research results are as follows: (1) according to the comparison and analysis of the dam break model of earth rock dam, the mathematical model of earth dam dam break is determined. The characteristics of the existing dam break model are summarized and analyzed, and five kinds of dam break mechanism models are selected. The model and one parameter model: Mike11DB model, HEC-RAS model, BREACH model, DAMBRK model, DB-IWHR model and fast evaluation model of dam break dam. Through the simulation calculation of typical dam break cases, the calculation accuracy and parameter sensitivity of each model are analyzed and compared, and the comparison analysis shows that the DB-IWHR model has deeply studied the dam break machine. According to the influence of the parameters such as the geometric parameters of the dam, the properties of the material and the initial conditions of the ulceration, the problem that the existing dam failure model can not independently calculate the development of the ulceration and the required parameters is too much. It is of more practical significance for the prediction calculation of the dam break, and is of great application value. Therefore, the DB-IWHR model is selected as the earth rock. The calculation model of dam break is established. (2) a downstream evolution model of dam break flood is established. One dimension numerical calculation method for dam break flood is studied. Based on the theory of Preissmann four point implicit difference scheme, a one-dimensional unsteady flow calculation program for open channel is developed. The program is applied to different boundary conditions by different calculation examples. An unsteady flow evolution process is used to calculate the downstream evolution process of the dam break flood in the Tang Jiashan mountain. Compared with the calculation results of the Mike 11 software, the accuracy and reliability of the dam break flood evolution model are proved. In the current flood situation, the downstream risk analysis is carried out. (3) a cascade dam collapse mathematical model is constructed. Based on the four order Runge Kutta method, the reservoir flood calculation model is established to calculate the change process line of the water level of the downstream reservoir, to determine whether the upstream dam break flood causes the cascade cascade dam collapse in the downstream, and the downstream dam break through the DB-IWHR model is calculated. On the basis of single reservoir dam break model, coupled flood evolution and flood diversion and calculation process, a mathematical model of cascade reservoir rockfill dam collapse is established. Taking the Tang Jiashan Dali cascade reservoir as an example, the simulation calculation of cascade rockfill dam collapse is carried out, and the failure of the downstream reservoir with early warning and different discharge capacity is studied. The downstream cascade reservoirs can adopt additional flood discharge facilities and early warning full sluice discharge, so as to ensure that the dam does not break dam through Diao Hongrong error and avoid the continuous collapse of the cascade reservoir.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV122.4

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