【作者】 李琼；

【导师】 周建中； 张勇传；

【作者基本信息】 华中科技大学 ， 水利水电工程， 2012， 博士

【摘要】 洪水灾害是自然灾害中对人类影响和危害较为严重的一种。20世纪以来,以全球气候变暖为主的自然系统的变异以及以城市化为主的现代人类经济社会活动,对自然灾害系统特别是洪水灾害造成了极大的影响。尽管人类已进入信息时代,科学技术有了很大发展,且防洪体系的建设日趋完善,但洪涝灾害仍时有发生,甚至愈演愈烈。人类如何面对全球气候变化下的洪水风险,实现人水和谐发展,是一个关系到人类发展的重大问题,也是一个迫切需要研究和解决的问题。近年来,人类在总结经济发展与洪水灾害相互竞争的历史经验中逐步提出了新的防洪减灾策略,这就是：对洪水灾害进行管理,调整人与水的关系,由原来的“防御洪水”转变为“洪水管理”,实现人与水的协调发展。而在洪水管理中,洪水风险管理是其中一项重要的工作。它是分析、评价、预防和处理洪水灾害的一项复杂的系统工程。天气气候的变化,极端事件频繁的发生、强度的不断加强,这些都对洪水风险管理提出了更高的要求。在我国开展洪灾风险评估和区划研究不仅能够发展和完善我国洪灾风险研究的理论基础,而且可以为我国防洪减灾和风险管理提供理论和技术支持。本文围绕国家“973”重点基础研究发展计划课题“复杂条件下坝堤溃决机理与风险调控理论(2007CB714107)”和国家科技支撑计划课题“三峡及长江上游特大型梯级枢纽群联合调度技术(2008BAB29808)”的研究任务,以大量考察和调研获得的第一手数据资料为基础,建立了一套洪灾风险评估的理论框架和方法,开展了针对小样本情形的洪灾风险评估体系的研究,对促进洪灾风险理论的完善,形成更有效的防洪安全保障体系,达到防洪减灾,促进人与自然的和谐发展,保障社会经济的可持续发展等方面具有一定的科学价值和现实意义。风险分析的传统数学基础是概率论,计算方法是统计方法。本文对这种流行的观点提出了异议,认为由于自然灾害系统具有极端复杂的特点,许多输入输出的关系还无法识别,在现阶段人类认知能力和条件下只能表达为一种模糊性关系。因此,风险分析的数学基础应该是模糊集理论。目前关于自然灾害各环节的研究,已经有了一些较为成熟的方法,现阶段自然灾害风险分析的主要任务是如何把它们有机的结合起来,并对这些研究结果提出改进意见。本文以系统论为科研方法,以模糊数学理论为基本工具,将信息扩散的模糊数学方法引入洪水灾害风险分析领域,在广泛借鉴自然科学、社会科学、环境科学和系统科学等众多分支学科相关理论方法的基础上,针对防洪减灾中的风险评价问题,在理论、模型、方法和应用上进行了较为深入和系统的研究,力求得到稳定并符合实际的风险结果。本文的内容包括以下几个方面：1.本文系统的介绍了洪水灾害风险分析与风险评价的理论、方法、模型与应用的相关理论体系。在总结国内外先进研究成果和深入研究洪水灾害风险形成机制的基础上,以量化研究为途径,以主成分分析、模糊数学方法、层次分析法、神经网络方法、信息扩散技术等分析技术为手段,构建了风险评估的理论框架、指标体系、方法与模型,并对洪水灾害的风险程度进行了评价与等级划分,借助地理信息系统绘制出相应的风险图系。2.论述了自然灾害风险评价的基本理论,其中重点讨论了风险本质、风险分析的基本原理、风险评价的概率统计方法和风险分析的模糊系统方法等,并对其中的主成分分析法进行了改进和完善。根据1998年的10个地区的洪灾损失数据的统计资料,对这10个地区的洪灾损失进行了分析、比较和排序,结果显示,用分组和层次分析法建立的改进主成分分析法,得到的洪灾损失的评估结果与实际情况相符,为科学评估洪灾损失和防洪减灾提供了科学依据。改进主成分分析法可以有效的避免主成分分析法的无序问题,与主成分分析法相比,结果更合理可靠。3.介绍了不完备信息条件下洪水灾害风险评价的理论和模型,详细展示了有关模型的应用研究。在信息分配方法、信息扩散原理和正态信息扩散的理论基础之上提出了改进信息扩散方法。并结合我国国情和历史资料,综合考虑社会、经济、环境与灾害系统的复杂性与多样性,建立了小样本条件下洪水风险综合评价模型与方法体系,综合评价洪水灾害影响程度,对其中的不完备信息进行适当的信息膨胀,可以提高风险评价精度。本文还利用改进的信息扩散方法和可变模糊模型,根据中国某地区1949-2009年洪水的实测资料对洪水灾害风险程度和重现期进行了分析评价和实证研究。本文的研究丰富了洪水风险评价理论的方法和体系,为流域防洪规划提供了科学的决策依据。4.使用计算机仿真技术对有关模型进行可靠性论证。本文主要采用计算机模拟和先进的数值算法,比较了多种方法进行洪水风险评价的优劣性,并对改进信息扩散方法提出了合适高效的数值计算方法,用实例分析说明了该模型的有效性和实用性。5.在洪水风险分析和评价的基础上,利用信息扩散方法提出了小样本条件下洪水风险区域图的绘制方法。这些风险图直观的展示了风险的分布及随灾害程度的增加风险的空间变化趋势,有关研究成果作为国家“973”重点基础研究发展计划项目“复杂条件下坝堤溃决机理与风险调控理论(2007CB714107)”的一部分,已于2011年10月结题验收。理论和实际检验均说明,用信息扩散技术进行的小样本条件下的洪灾风险评价,可以得出相当满意的结论。洪灾风险评估是一个综合多学科、多领域的复杂问题,它包括水文水动力学、气象学、环境学、地理学、灾害学和风险学等等,具有十分丰富的内涵。虽然本文在我国洪水灾害风险分析、评估方法和区划研究上做了一些有意义的的探索,但是相对于本领域基础理论的研究和完善以及现实方案的解决,还有一段相当的距离。总之,洪水灾害风险评估是一项非常复杂的系统工程,在理论研究和工程实践上都需要做进一步更深入、系统的研究和探讨。更多还原

【Abstract】 Floods is a kind of natural disasters which has serious influence and danger to the human beings. Since the20th century, natural variation mainly appears in global-warming-based climate change, urbanization was apparently most pronounced among people’s social life and economic activities. Such appearances have a huge impact on natural disaster especially on flood disasters. Although mankind has entered the age of information, science and technology have been developed rapidly, the construction of flood control system has been improved, but flood disaster still happen from time to time, or even it get worse. Human beings must be able to really realize the sustainable socioeconomic development and the consonance between human being and water. How to face the risk of flooding along with global climate changes, which is an issue counting to sustainable economic development and harmonious society in our country, is also an urgent problem to research and solve.In recent years, the human has put forward the new flood control and disaster alleviation strategy from historical experience of the competition between economic development and the flood disaster, which is to manage the flood disaster, to adjust the relationship between human and water, to transform the original" flood defence" to "flood management", and to realize the harmonious development of man and water. And in the flood management, flood risk management is one important work. It’s a complex system engineering involving the analysis, evaluation, prevention and treatment of the flood. With the weather and climate change, extreme events occurring frequently and their intensity being aggravated constantly., people demand for higher performance of the flood management, Carrying out the research of flood risk assessment and division can not only make up for the deficiency of the flood risk research in our country, it can also enrich and develop our flood risk management theory basis and method system.This paper is supported by plan "973"—the National Basic Research Program of China (Project No.2007CB714107)" Dam break mechanism and risk control theory under complicated conditions" and by state technology supporting plan "Flood control technology research in the middle and lower reaches of Yangzi River after the use of the Three Gorges Project (2006BAB05B05)", based on first-hand data through conducting site visits and research, we set up the theory and methodology of flood risk assessment; set up risk assessment system in the situation of small example scale; researches has very important scientific value and realistic meaning on building better security protection system to achieve flood and disaster relief as well as harmonious development of man and nature.Risk analysis is based on the traditional mathematics probability theory, calculation method is statistical method. This paper puts forward the objection and consider that the mathematic basic of the risk analysis is fuzzy set theory because that input output relationship can only be expressed as fuzzy relations owing to the natural disaster complexity. There have been some mature methods on the research of every part of natural disasters. The main task of natural disaster risk analysis is how to connect them organically and put forward the improving suggestions on the results of the research.This research is based on the system theory, using the fuzzy mathematics theory as the basic tools, and it introduces the fuzzy mathematics method of information diffusion method into flood risk analysis field. Natural science, social science for reference, environmental science and scientific system and many other branches of the related theory method are widely used. Aiming at the risk evaluation in the flood control and disaster alleviation, in this paper a thoroughly and systematical study is made center on theory, model, method and application. And we strive to get more stable and actual risk of results. This paper includes the following aspects:1. This paper introduced academic monographs on the theory, method and application of flood risk evaluation and risk evaluation. This paper absorbs the domestic and foreign advanced research result, by means of quantitative research, analysis technology and method as the means such as principle companent analysis, fuzzy mathematics,, AHP method, BP model and information diffusion. After further investigating the the flood disasters and disaster risk formation mechanism, we construct the risk assessment theory frame, index system, method and the model, and we calculate the risk grades and draw the corresponding risk figure by means of GIS. 2. It discusses the basic theories of the natural disasters risk evaluation, and emphasize the risk essence, the basic principle of natural disaster risk analysis, probability and statistics method and fuzzy systematic method in risk assessment, and it improves the principal component analysis method. According to the flood loss data of10area in1998, and the loss of the10area were compared and ranked, in order to compare the severity of the flood disaster in different provinces, The result showa that the assessment has stronger comprehensiveness and can reflect the evaluated problem fully and truly. This paper provide the general procedure and calculation method of systematic analysis and decision, and it can be seen from the model calculation conditions that it is universally applicable for sorting and assessment problems.3. This paper Introduces theory and model on flood risk evaluation under the condition of incomplete information, detailed the application of the proposed model and flood risk evaluation theory under the condition of incomplete information including information matrix framework, information distribution method, information diffusion principle and normal information diffusion, and further more put forward put forward the improved information diffusion method. Based on this method, combining with China’s national conditions and historical material, it establishes the flood risk comprehensive evaluation model and method, synthetically considering the complexity and variety of the social, economic and environmental system. Proper information inflation can improve the precision of risk assessment so as to supply scientific evidence for flood control planning and decision and enrich the flood risk assessment theory system. This paper also uses improved information diffusion method and variable fuzzy set model, and make empirical research on the evaluation and analysis of flood risk degree and return period with the measured data from1949to2009.4. This paper uses the computer simulation technology in the reliability demonstration of the model. By using the computer simulation, both the advantages and disadvantage of several methods are compared, a suitable and efficient numerical calculation method is proposed, and also the validity and practicability of the improved risk assessment method are illustrated.5. Based on GIS technology and information diffusion method, a compiling method of flood risk zoning map are introduced in this paper. The flood risk zoning map illustrates the distribution of disaster risks and the changing spatial trends with the increasing risk degree. AS a part of the research results of the plan "973"—the National Basic Research Program of China (Project No.2007CB714107)" Dam break mechanism and risk control theory under complicated conditions", the relevant research results have been completed and passed the check. The flood risk zoning map completed by our project team is highly descriptive and matches well with the actual situation. Theory and real data tests demonstrate that the information diffusion method presented is satisfactory under the condition of small sample.Flood risk assessment is an interdisciplinary research which include hydrological water dynamics, meteorology, environmental sciences, environmental sciences, geography, risk discipline and catastrophology. Although this work has offered a useful exploration in flood risk assessment and risk zoning, it is just at the beginning of the solution of the problem and the scientific development of the theory. Flood risk assessment is a complicated system engineering, and the further detailed research is still needed in both theory and practice.更多还原